Business, engineering, Science and Technology

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Benefits of Forming simulation

noreply@blogger.com (Industrial age to information age) — Wed, 25 May 2022 10:48:00 +0000

Benefits of Forming simulation

Forming simulation has been proved most valuable high tech tools introduced in the past decade and is special type of finite element analysis (FEA) that simulates metal deformation along with possible defects may occurs during the process.

One of the biggest uses of the technology in sheet metal industries, where forming of critical shapes is head-ache for the tool designers and tool makers. The simulation package or program so called software uses two types of forming methods :

1. One step simulation

2. Incremental simulation

Benefits of One step forming simulations:

Quick feasibility : One step solver is an easy way to predict the manufacturing feasibility of the geometry in product design stage with FLD plots, thinning and areas of failure. One good book is highly recommended to learn about the method is ''Practical guide to forming simulation'' by Rakesh kumar. Even though there are many books on the topic, shed light only on theory, but nobody tell you how to exactly do that. This book contains the right blend of both theory and practical in very clear and effective manner.

Material size calculation :

This is another advantage, once you finish the setup and solver, with the just series of clicks you can easily calculate the blank in cad format. you can also generate the report to calculate the yield% w.r.t any material size available in the form of proper report. It serves the purpose by auto calculating the best layout w.r.t to the given size of the material.

Robust product design:

Once you learn the one step set up, it will allow you to pass your design in the series of iterations. Product is easy to amend in the design stage rather than the costly ECN in the later stages of life cycle. Weak product design has to be paid in the long run, in terms of money loss, time loss and most important brand image loss. Therefore proper analysis and correction in the design stage would lots of efforts in the later stages and provide competitive edge in the market.

Benefits of Incremental forming simulation:

This setup is specifically for process/die designers for accurate work and arresting possible defects before making physical dies, which saves enormous amount of time in terms of money, which otherwise should have wasted on the costly iterations and time consumed in number of die trials. As a result, product development cycle squeezed. The same book as mentioned above is highly recommended to learn and use the terminologies in details.

Proper process layout:

By learning this set up you can choose the most easy route/process to make the final product, the process designs are easily validated in the design stage. The most value able time and money can be saved, which otherwise should have been wasted in rectifying the dies after each trials.

Boost the confidence:

Once you have learn to set up the virtual process and implemented in 3 or 4 products, your confidence will automatically arise and your process will get refined.

Right input leads to right output:

The above book reading is highly recommended before using the software, even if you have learned it from somewhere. The most tutor will explain you the necessary things and leave the most important inputs, which otherwise can spoil your results.

The inputs such as mechanical properties like n-value, r-value, yield strength, young's modulus, poisson ratio, density, lankford coefficient etc. are utmost important.

The book will facilitate you to understand the terms first before using it, leads you to the more accurate results.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

Raw material standards

noreply@blogger.com (Industrial age to information age) — Fri, 06 May 2022 05:49:00 +0000

HOT ROLLED STEEL PLATES, SHEETS AND STRIPS FOR AUTOMOBILE STRUCTURAL USES
JIS G 3113-1990

HOT ROLLED MEDIUM AND HIGH TENSILE STRUCTURAL STEEL — SPECIFICATION IS 2062 : 2011

HOT-ROLLED STEEL STRIP FOR WELDED TUBES AND PIPES —SPECIFICATION IS 10748 : 2004

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Mechanical Properties of Cast Carbon and Low Alloy Steels

noreply@blogger.com (Industrial age to information age) — Sat, 16 Apr 2022 05:09:00 +0000

Mechanical Properties of Cast Carbon and Low Alloy Steels

For the purpose of this article, carbon steels are considered to be those steels in which carbon is the principal alloying element. Other elements that are present and that, in general, are required to be reported are manganese, silicon, phosphorous and sulfur. In a sense, all of these elements are residuals from the raw materials used in the manufacture of the steel, although the addition of manganese is often made during the steel making process to counter the deleterious effect of sulfur and silicon is added to aid in deoxidation.

The major source of sulfur is the coke used in the blast furnace or cupola. The major sources of phosphorous, manganese and silicon are the iron ore, the limestone used as a flux, and the additions used to deoxidize the steel.

A minimum amount of silicon is needed to provide the necessary fluidity for the casting operation. Other elements, particularly those not easily oxidized, e.g., copper and nickel, will be recovered from the scrap charge. The amounts of these two elements and others, such as chromium, molybdenum and vanadium, may or may not have to be reported by the manufacturer depending upon the specification.

Alloy steels are considered to be those steels to which elements, other than carbon, are added deliberately so as to improve mechanical properties, physical properties and/or corrosion resistance. (Mechanical properties are measured by plastically deforming or breaking the material. Physical properties are those, the measurement of which does not require that the metal be plastically deformed). The American Iron and Steel Institute has defined alloy steels as containing one, or more, of the following elements in quantities as follows:

Manganese	above 1.65%
Silicon	above 0.60%
Copper	above 0.60%
Aluminum	up to 3.99%
Chromium	up to 3.99%

and cobalt, columbium, molybdenum, nickel, titanium, tungsten, vanadium, zirconium, and any other element added to obtain a desired alloying effect.

The effectiveness of any alloying element is greatest when it is completely soluble in the steel. If a particular element forms, or tends to form, a compound with iron or another element present in the steel, the effectiveness of both elements is decreased. For example, if chromium is added to a carbon steel to increase hardenability, the austenitizing heat treatment must be at a temperature high enough to dissolve the chromium carbides, otherwise the presence of chromium carbides diminishes the effect of both chromium and carbon on increasing hardenability.

MECHANICAL PROPERTIES

For all alloy systems, the mechanical properties are controlled by the chemical composition and the microstructure of the alloy. With respect to the carbon and alloy steels, the influence of microstructure is so great as to overshadow that of chemical composition and, for cast steels, the only practical method for changing the microstructure is by heat treatment. With few exceptions, the mechanical properties of the cast carbon and low alloy steels are controlled by heat treatment. Among the exceptions are the effect of carbon on increasing hardness, the effect of nickel on increasing toughness, and the effect of combinations of chromium, molybdenum, vanadium, and tungsten on increasing elevated temperature strength.

Hardenability

The major reason for using alloying elements in steels, wrought as well as cast, is to make the role of heat treatment on increasing strength effective over a wide range of metal thicknesses. This effectiveness is termed hardenability, i.e., a steel with low hardenability can only be strengthened by heat treatment in thin sections whereas a steel with high hardenability can be strengthened in thick sections.

Hardenability is the retarding of the austenite formation during cooling and is increased by all of the alloying elements, except cobalt. Hardenability, or austenite retention, should not be confused with austenite formation, which is the expansion of the austenite field at high temperature. Only a few elements increase the austenite field; these are carbon, cobalt, copper, manganese, nickel and nitrogen.

A large number of elements, particularly those that have a tendency to form carbides, delay the softening of steel that occurs during the tempering operation. The carbide forming tendency need not be strong. For example, silicon, not a particularly strong carbide former, will delay the softening during tempering, but its effect is not as strong as that of chromium; likewise, the effect of chromium is not as strong as that of vanadium, etc. In addition to retarding softening, some carbide forming elements will, during tempering, cause an increase in hardness due to the precipitation of the alloy carbides (precipitation hardening).

The role of the alloying elements on increasing hardenability and retarding softening during tempering was the subject of an extensive, international research effort during the first half of the 20th Century. Another result is the ability to estimate the hardenability of a given steel from calculations based upon the chemical composition of the steel. Multiplying factors for each element as published by the American Iron and Steel Institute are shown in Fig. 1.

Although these values were developed for wrought steels, they probably can be used for cast steels with some minor corrections. This figure does not illustrate the effect of carbon, which is quite large, nor the effect of boron, which is high for low carbon steels and is negative for high carbon steels (about 0.9% C) because it forms carbides.

In addition to alloying elements, the grain size of the austenite before quenching affects hardenability. A steel having a fine austenitic grain size has lower hardenability than a steel having a coarse austenitic grain size.

Although a steel having a coarse austenitic grain size has higher hardenability, a fine grain steel has better toughness, less distortion on heat treatment, lower tendency to develop quench cracks, and, probably, lower internal stresses. Of these characteristics, the improved toughness is the most important and, for structural applications, the steel should be of the fine-austenitic-grain type. A word of caution: The term aluminum-killed fine-grain steel often is misinterpreted. The term describes the grain size of the austenite at the heat treating temperature before quenching, not the grain size of the ferrite, tempered martensite, or martensite at room temperature. Methods for determining and measuring the austenitic grain size are described in ASTM Specification E112.

When heat treating aluminum-killed (aluminum deoxidized) steels, caution must be taken to avoid the use of austenitizing temperatures above about 1800F (982C), otherwise the aluminum nitrides will dissolve and a very coarse austenite grain size will result.

Hardness and Strength

All elements dissolved in steel increase its hardness and strength; however, as compared with the increase obtained by heat treatment, this effect is small. An exception is carbon, the effect of which is large, although not as large as the effect of heat treatment. Referring to the ASTM specification, A732/A732M, the effect of carbon on increasing the strength of annealed carbon steels is:

Type of Steel	Average Carbon Content	Minimum Tensile Strength.
Type of Steel	Average Carbon Content	ksi	MPa
IC 1020	0.20%	60	414
IC 1030	0.30%	65	448
IC 1040	0.40%	75	517
IC 1050	0.50%	90	621

The carbon effect on the strength of quenched and tempered martensite in low alloy steel is more dramatic:

Type of Steel	Average Carbon Content	Minimum Tensile Strength.
Type of Steel	Average Carbon Content	ksi	MPa
IC 4130	0.30%	150	1030
IC 4330	0.30%	150	1030
IC 18630	0.30%	150	1030
IC 4140	0.40%	180	1241
IC 4340	0.40%	180	1241

With respect to elements other than carbon, IC 4130 has about 1.2% total alloying elements; IC 4330 has about 3.0% total alloying elements; and IC 8630 has about 1.3 % total alloying elements, yet all have the same minimum tensile strength. This negligible effect of alloying elements on strength further emphasizes the previous statement that the most important role of the alloying elements in steel is their effect on hardenability.

Because of the close relationship between hardness and tensile strength of alloy steels, there could be a tendency to use carbon, an inexpensive element, to achieve a high strength steel. This tendency has some validity but entails some penalties. For example, at a given strength level, the toughness (resistance to brittle fracture) of a steel decreases with increasing carbon.

Consequently, a preferred plan is to select a steel having a combination of the lowest possible carbon content and the required amount of alloying elements to achieve, in a tempered martensite microstructure, the desired strength. Of course, the alloy content selected must be that required to achieve the hardenability needed for the section size (thickness) being considered.

Toughness

Toughness, the ability of a steel to resist brittle, rapid fracture, is an essential property for structural components subject to high loading rates. All of the test methods used to measure toughness involve the use of a sample containing a sharp notch or a crack. The reason for employing such samples is that for every service failure caused by brittle fracture, the source of the fracture has been found to be a discontinuity in the metal, and every engineering structure will contain some sort of one or more discontinuities (notches). Consequently, the test procedures used for toughness evaluations are aimed at determining the resistance of the metal to the rapid propagation of a discontinuity.

For structural carbon and low alloy cast steels, the following specifications either contain a toughness requirement or provide for a toughness test in the supplementary requirement:

A148/A148M
A352/A352M
A487/A487M
A703/A703M
A757/A757M
A781/A781M

For those specifications not mentioned, namely A216, A217, A389, and A487, the toughness (impact test) requirement of A703 may be used based upon agreement between the producer and the user.

Fatigue Strength (Endurance Limit)

For cast steels, the fatigue strength, or endurance limit, as determined by tests on smooth bars is generally in the range of 40-50% of the tensile strength. In non percentage terms, this relationship is expressed as 0.40 to 0.50 and is termed the endurance ratio. As illustrated by Table 1 the endurance ratio is largely independent of the tensile strength, chemical composition and heat treatment of the steel. Under conditions of rough surfaces, i.e., as cast, machined (not polished), notches, and cracks, both the endurance limit and the endurance ratio decreases. Fatigue strength values are affected by the mass effect in a manner similar to tensile strength. (See Alloy and Heat Treatment Influence on Section Size Effects.)

Section Size, Mass Effects-Mass effects are common to steels, whether rolled, forged or cast, because the cooling rate during the heat treating operation varies with section size, and because the microstructure components, grain size, and nonmetallic inclusions increase in size from surface to center.

The section size, or mass effect, is of particular importance to steel castings because the mechanical properties are typically assessed from test bars machined from standardized coupons which have fixed dimensions and are cast separately from or attached to the castings. To remove test bars from the casting is impractical because removal of material for testing would destroy the usefulness of the component or require costly weld repairs to replace the material for testing purposes.

It cannot be routinely expected that test specimens removed from a casting will exhibit the same properties as test specimens machined from the standard test coupon designs for which minimum properties are established in specifications. The mass effect discussed above, i.e., the differences in cooling rate between that of test coupons and of the part being produced, is the fundamental reason for this situation. Several specifications provide for the mass effect by permitting the testing of coupons which are larger than the basic keel block.

Temper Embrittlement

When many alloy steels are heated in or slowly cooled through the range 800- 1100F (427- 593C), a significant loss in ductility and toughness occurs. This loss in toughness is believed to be caused by a grain boundary precipitation of iron compounds rich in phosphorous, arsenic, antimony, and tin; manganese and silicon enhance the action of these elements, and molybdenum retards the effect. Obviously, the use of melting practices to achieve low phosphorous (the practice to lower phosphorous also will lower arsenic, antimony and tin) is desirable, and such practices have been developed via ladle treatments. However, such practices are expensive, and for most applications the use of molybdenum and/or avoiding heating-in or slow cooling through the critical range 800- 1100F (475- 593C) is sufficient. When these practices are impractical, the use of the special melting-refining should be considered.

Hydrogen Effects

Hydrogen is an undesirable element in steel; none of the effects of hydrogen are good. Amongst the sources of hydrogen in steel, the most important are the raw materials used in the melting and refining process and traces of moisture in the molds used for casting. Care should be taken to dry all steelmaking and refining additions as well as molds.

When present in amounts as low as 3 parts per million, hydrogen in steel significantly reduces toughness and ductility. The hydrogen can be removed by heating the steel at about 400F (204C). However, the removal from heavy sections, e.g., above 8-in. (203.2mm), requires a very long heating time at 400F (204C), and because resistance to crack propagation decreases as the section size increases, hydrogen removal from heavy castings intended for severe structural applications is essential.

Fortunately, the attainment of the low amounts (less than 3 ppm) of hydrogen in steel can be achieved by the use of ladle vacuum treatments. Of course, the benefit of achieving a low hydrogen content must be sufficient to justify the high cost of the vacuum treatment.

Also, hydrogen can enter solid steel as a result of a corrosion reaction at the surface of the steel. When this occurs in steels having a hardness above 23 HRC, cracking may occur and the susceptibility of a steel to cracking increases rapidly as the hardness increases above 23 HRC. For this reason, the petroleum industry has imposed a maximum hardness restriction of Rc 23 on steels intended for service where corrosion will generate hydrogen absorption in the steel. One example is in sour crude wells.

Another form of hydrogen cracking of steel occurs when the steel is exposed to hydrogen at high pressure and high temperature. The steel does not need to have high values of hardness or strength. The physical mechanism at work, is that hydrogen, at the high pressure and temperature, diffuses into the steel and reacts with the carbides to form methane gases, the pressure of which becomes high enough to rupture the steel. The solution to the problem is to add alloying elements that form stable carbides which will not react with the hydrogen. The elements most commonly used are chromium, molybdenum, and, occasionally, vanadium.

Corrosion Resistance

The cast carbon and low alloy steels are not considered to be corrosion resistant materials. As is true for the wrought steels, minor additions of nickel, chromium, phosphorous, copper and silicon will increase resistance of cast steels to atmospheric corrosion to the extent that for some applications no protection such as paint is required. At elevated temperatures increasing amounts of chromium increase resistance to oxidation and, as already stated, low alloy steels for elevated temperature service contain chromium. Additions of aluminum and/or silicon are at least as effective as those of chromium; however, the amount of either of these elements required to impart the necessary oxidation resistance may cause a serious loss in ductility and toughness.

The role of the alloying elements in cast steel may be summarized as follows:

All elements, except cobalt, increase hardenability.
All carbide forming elements retard softening during tempering.
Nickel improves toughness.
Chromium improves oxidation resistance.
Molybdenum retards temper embrittlement and increases elevated temperature strength.
Vanadium and tungsten improve elevated temperature strength.
Manganese plus sulfur improve machinability.
Sulfur causes hot cracks.
Carbon increases strength but decreases toughness.
Phosphorous, arsenic, antimony, and tin accelerate temper embrittlement.

Summary

Structural carbon and low alloy cast steels enjoy a wide application for load bearing applications. The optimum utilization of these steels can be obtained best from a thorough understanding of the specifications covering these steels, and the metallurgical characteristics of the steel.

Both the manufacturer and the user have an obligation to cooperate in the preparation of specifications that reflect and combine both the needs of the users and the capabilities of the manufacturers. This obligation requires a sound understanding of the metallurgical characteristics of the steel, and a continuous communication between the two groups on the pertinent problems encountered in manufacture, fabrication and service performance.

REFERENCES

Steel Castings Handbook, published by the Steel Founders' Society of America, and ASM International.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

HYDRAULIC PRESS - BRIEF TERMINOLOGY

noreply@blogger.com (Industrial age to information age) — Sat, 16 Apr 2022 04:52:00 +0000

Hydraulic Press

The hydraulic press continues to be the press of choice for today's modern manufacturers. The advantages of the hydraulic press versus mechanical presses is being realized and utilized by more and more manufacturers. Today's modern hydraulic presses provide; Performance, Reliability, and Unlimited Capability in almost any application. Stamping, Punching, Blanking, Drawing, Bending etc. All standard press designs and circuits can be configured to match even the most non-standard press requirements.

Hydraulic Press Benefits

1. Full Tonnage Throughout The Stroke - The hydraulic press has the ability to deliver full pressing force anywhere in the range of stroke, unlike mechanical presses which can only develop full force at close to bottom of stroke. This significantly adds to the inherent flexibility of hydraulic presses.

2. Dedicated or Multi-Functional - The hydraulic presses can be designed to any level of sophistication. Whether the need be a simple dedicated cell press or a fully integrated multi-purpose system, hydraulics are cost effective and easily modified for the task at hand. Their flexibility is further enhanced by additional stroke capability for simplifying die changes and reducing set-up time. Multiple dies with varying shut heights can be run efficiently in a single press.

3. Lower Up Front Costs / Fast ROI - In regard to presses, hydraulic presses are the most simple in basic design and often utilize standardized, proven hydraulic components that are readily available. The basic components to mechanical presses, such as crankshafts, clutch and brake systems, etc..., are expensive and often custom built components which serve to add machine cost. hydraulic presses are often much less expensive up-front and in long term operation.

4. No Design Limitations - The principles of hydraulic force allow for creative engineering. Presses can be designed for traditional down-acting, up-acting, side-acting and multi-action operation. Power systems can be placed above, below or remote from the press and force actuators. Large bed presses can be designed for low tonnage applications and small bed presses can be designed for high tonnage requirements.

5. Over-Pressure Protection - The incorporation of hydraulic relief valves into hydraulic circuits provide built-in overload protection. A press' force cannot exceed the pressure that it is allowed to build, thereby limiting the maximum pressure attainable controls maximum force.

6. Unlimited Control Options - The hydraulic press can be controlled in a variety of ways ranging from basic relays to more sophisticated PLC or PC control systems. Operator interfaces can be added to press systems to facilitate ease of job set by storing individual job parameters for each die. Presses can be controlled for precise pressure and position; including pressure holding, speed control and dynamic adjustments to realtime operating variances. Ram force and speed can be controlled in any direction with various levels of precision.

7. Condensed Footprint - Hydraulics allow for generation of high pressure over small surface area. This ability reduces the overall structure required for support of the force actuators. When compared to mechanical presses, hydraulic presses consume almost 50% less space for the same tonnage capability. This size advantage results in lower manufacturing costs and a faster return on investment by requiring less long term overhead expense.

Hydraulic Press Industrial Terminology

Stroke
The amount of possible ram travel. Stroke is the total distance that the ram can travel, from full extension to full retraction.

Shut Height
The distance between the bed bolster and the ram bolster when the ram is fully extended. This is also commonly known as the Closed Height. As standard, this dimension is usually within "0.25" due to assembly processes. For precision shut height requirements, consult the factory.

Daylight
The distance between the bed bolster and the ram bolster when the ram is fully retracted. This is also commonly known as the Open Height.

Bolster
The removable plate that serves as the working surface for the bed and ram. The plate is typically bolted to the bed and ram substructures. The bolsters can be machined with a variety of work holding features such as; T-Slots, Drilled and Tapped Holes, Lift Rails for Quick Die Change, etc...

Stroke Control
The ram travel of the press may be controlled in a variety of ways. Most hydraulic presses are standard with Adjustable Retract Limit Switches to limit the retract distance of the ram (also know as the Up Limit Position). This can shorten cycle times by only utilizing the required stroke for part loading and unloading. Other adjustable limits may include: Slow Down Limit for deceleration from Fast Speed to Slow Speed; Bottom Stop Position and/or Bottom Stop Pressure, etc...

Bottom Stop
By Pressure:
- The press may be designed to 'return on pressure'. This method utilizes a pressure sensing device which is adjustable and is set to determine the desired maximum pressure to be achieved by the ram. Once this pressure is achieved, the ram typically completes the cycle by returning to the home position or Up Limit position.
By Position:
- The press may be designed to 'return on position'. This method utilizes either a position sensing device or a limit or proximity switch that can be set to signal that the desired ram extension has been achieved.

Bed Height
Bed Height is the distance from the bottom of the hydraulic press structure to the working height or top of the bed bolster.

Dwell
Hydraulic presses are capable of maintaining force on the work for extended periods of time. This is typically accomplished by using pressure lock valves or variable volume pumps that are remotely controlled for precise and long periods of pressure holding.

Bed Cushion
A bed cushion is a commonly required for draw tooling and is a system that applies resistance when pushed upon. This resistance can be dynamic or statically controlled throughout the stroke. Bed cushions have a "pusher pin plate" that is located just beneath the bed bolster. The bed bolster is provided with multiple through holes where "pusher pins" are inserted. These pins are used by the tooling to generate resistive force as the hydraulic press ram pushes down. The cushion can also be configured for multiple control zones for on-the-fly dynamic control.

Remote Power Skid
Some press applications may require that the hydraulics be located remotely from the press itself. Other applications may preclude the power system from being able to be installed at the top around the crown structure of the press. In these cases, the power system and even the controls may be designed into a separate unit capable of being placed adjacent to the press or away from the press.

Heated Platens
These are plates that have heating capabilities. They can be heated using electric rods, steam, oil, water or other medium. These system usually require thermal breaks between the heated plates and the hydraulic press structure. Heating controls can be separate or fully integrated into the press control system.

Hydraulic Press Speeds

What Ram Speeds Do You Need?
Hydraulic presses are normally offered with multiple ram speeds, such as; Fast Approach, Pressing and Fast Retract. Typically, these speeds are expressed in Inches Per Minute. The Fast Approach Speed is designed to lower the ram quickly during the portion of the stroke that does not require any force. The pressing speed is commonly referred to as the working portion of the stroke where force is required and is usually slower. After the working or pressing portion of the stroke is completed, the ram retracts at a Fast Retract Speed which affords little force. This Retract Force is commonly referred to as the "Stripping Force".

Many customers with mechanical press experience refer to press speed in cycles per minute. Hydraulic presses can be designed to provide a certain amount cycles per minute once the cycle profile has been determined. The cycle profile consist of an accurate description of the physical aspects of the cycle. These aspects are:

1. Distance of ram travel under no load (Fast Approach)
2. Distance of actual working stroke (Pressing)
3. Distance of Fast Retract (usually the combination of the previous two distances)
4. Any Dwell Time at the bottom of the stroke or while under pressure

Once these parameters have been established, the appropriate ram speeds can be developed in conjunction with the right power system to provide the necessary cycles per minute.

Variable ram speeds are also available through the use of flow controls and variable volume pump systems. These and many other cycle profile characteristics can be provided.

ANATOMY OF HYDRAULIC PRESS

Bed: The press bed is the flat, stationary, machined surface that supports the lower bolster or dies.

Bed Cushion: Commonly required for deep draw applications, a bed cushion is used to apply resistance force when pushed upon. This resistance force ensures the material is drawn smoothly, without wrinkling or tearing. Bed cushion force can be dynamically controlled throughout the stroke, allowing the resistance force to change based on the position of the bed cushion.

Bed Height: The bed height on a press machine is the distance from the bottom of the press structure to the working height or the top of the bed bolster. If a press requires a pit, the working bed height could be defined as the distance from the floor to the top of the bed bolster.

Bolster: The bolster is the removable plate that serves as the working surface of a press. The plate is typically bolted to the bed and ram weldments. Tooling is attached to the bolster, which can feature a variety of work-holding features such as T-slots, drilled and tapped holes, lift rails to accommodate quick die change systems, and more.

Bushing: Found on 2-post and 4-post hydraulic presses, the bushing is a fixed or removable cylindrical metal lining used to guide the ram and reduce friction. Graphite-impregnated bronze bushings that do not require external lubrication are the longest-lasting type of bushing.

Crown: The crown on a press is the upper structural weldment containing cylinders that drive the motion of the ram.

Cycle: A hydraulic press cycle is the complete movement of the ram, from the initial start position back to the same start position, that may include feeding and removal of the material or workpiece(s).

Cylinder: The cylinder is the main actuator of a press. This mechanical actuator converts pressure into linear movement, creating force.

Daylight: Also commonly known as the open height of a press, daylight is the distance between the bed bolster and the ram bolster when the ram is fully retracted.

Deflection: Deflection is the amount of deviation from a straight line that occurs when force is applied to the structure of a press. In c-frame press designs, this is often referred to as yawning, and expresses the amount a frame flexes under a load.

Dwell: Dwell is the amount of time required for a press to maintain pressure during a cycle. This is typically accomplished by using pressure lock valves or variable volume pumps that are remotely controlled during long periods of precise pressure holding. Hydraulic presses often use pneumatic dwell systems, powered by a pneumatic pump integrated into the hydraulic circuit, to reduce noise output and energy consumption.

Finite Element Analysis (FEA): Finite Element Analysis is computerized method for predicting how a press’s structure will react to real-world forces such as vibration, heat, fluid flow, etc. Performed during the press engineering phase, FEA works by breaking down a real object into finite elements and using mathematical equations to predict the behavior of each element.

Gibs: Gibs are adjustable metal bolts on gib-guided (or “straight-sided”) presses that guide the reciprocating motion of the ram to ensure squareness and parallelism. Gibs are usually provided with replaceable liners and are adjustable front-to-back as well as left-to-right to enable the setting of proper clearance and to compensate for wear.

Heated Platens: Heated platens are steel plates to which the press’s tooling is attached that are heated using water (steam), oil, or electricity. These systems usually require thermal breaks (insulation) between the platens and the press structure. Heating controls can be separate or fully integrated into the press control system.

Human-Machine Interface (HMI): A Human Machine Interface (HMI) is a programmable touch screen computer that initiates the press cycle, monitors press health, and logs critical data and cycle parameters. On a hydraulic press, the HMI also acts as a check-engine light for the hydraulic system, notifying operators of oil particulate count, viscosity, temperature, and leaks.

Hydraulic Power Unit (HPU): The Hydraulic Power Unit (HPU) on a hydraulic press is a system comprising the tank, motor, hoses, pumps, and chillers that work in unison to create pressure. It is the mechanism that applies pressure to drive motors, cylinders, and other parts of a hydraulic system. HPUs are typically either skid-mounted or crown-mounted on the press, depending on the footprint requirements.

Motor: The motor on a hydraulic press is the electric machine that transforms hydraulic energy (fluid power) into rotary energy.

Platen: Platens are the steel plates, sometimes heated, that are attached to a moving or stationary press member.

PSI: PSI is an abbreviation for Pounds per Square Inch, a unit for measuring pressure in a hydraulic press.

Pump: A pump is the device that converts mechanical force and motion into hydraulic fluid power on a hydraulic press.

Ram (or Slide): The ram (or slide) is the middle weldment on a press that slides within the frame to create pressure on the tool or die. The ram can move vertically or horizontally depending on the press configuration. Some multi-action hydraulic presses even have multiple rams for complex forming processes.

Ram Knockout: A ram knockout is an ejection device required by many press operations that strips the formed part from the punch or die.

Ram Speed: Ram speed on a hydraulic press is the total time it takes for the ram to move from the open to the closed position, measured in IPM (inches per minute). Speed is also commonly measured at the three distinct stages of the stroke:

Fast Approach Speed lowers the ram quickly during the portion of the stroke that does not require any force.

Pressing Speed, commonly referred to as the “working portion” of the stroke, is when force is required and speed is slower.

Stripping/Retract Speed is after the Pressing portion of the stroke is completed, when the ram retracts at a Fast Retract speed which affords little force.

Return on Pressure: Return on pressure is a programmable hydraulic press cycle parameter that uses an adjustable pressure sensing device (transducer) to determine the desired maximum pressure to be achieved by the ram. Once this pressure is achieved, the ram completes the cycle by returning to the “Home” (or “Up Limit”) position.

Return on Position: Return on position is a programmable cycle parameter on a hydraulic press that uses a position sensing device (transducer) to determine the desired position to be achieved by the ram. Once this position is achieved, the ram completes the cycle by returning to the “Home” (or “Up Limit”) position.

Shut Height: Shut height is the distance between the bed bolster and the ram bolster when the ram is fully extended. This is commonly known as the “Closed Height.”

Stroke: Stroke is the total distance the ram can travel, from full extension to full retraction.

Stroke Control: Most hydraulic presses feature Adjustable Retract Limit Switches to restrict the retract distance of the ram (also known as the “Up Limit” Position). Using only the required stroke for part loading and unloading can shorten cycle times. Other programmable limits may include: Slow Down Limit for deceleration from Fast Speed to Slow Speed; Bottom Stop Position and/or Bottom Stop Pressure.

T-Slot: A t-slot is a notch machined into the platens of a press to hold the die in place. This work-holding feature also facilitates quick die changes.

Throat Clearance: On c-frame (gap-frame) presses, the throat clearance is the distance from the vertical centerline of the bed to the back of the press behind the bed. This measure is required to determine the diameter of parts and tools that can be positioned within the press.

Tie Rod: Tie rods on a 2-post or 4-post press are long rods with threads and nuts on both ends that hold the frame members together. These rods are stretched to place the frame members under compressive load.

Tonnage: Tonnage is the maximum amount of force a press machine can exert, typically called out in U.S. tons.

Transducer: A transducer is a device that measures the linear position or pressure of the ram or cylinder rod.

Weldment: Weldments are structural components formed by welding together steel plates. Most hydraulic presses have three main weldments: crown, bed, and ram.

References

Beckwood hydraulic press company

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HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

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A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

noreply@blogger.com (Industrial age to information age) — Sat, 16 Apr 2022 04:27:00 +0000

GLOSSARY OF CAR TERMINOLOGY

Anti-lock Braking System (ABS)

Braking systems which sense wheel rotation and automatically "pump" the brakes for the driver in emergency braking conditions. The pumping and the prevention of wheel lockup allow the driver to retain steering capabilities during the braking emergency. Any Fool purchasing a vehicle with such a system would be well advised to insist on the dealership demonstrating the proper use and maintenance of it. Most of these systems work when the driver applies heavy, constant braking pressure, and do not work properly if the driver "pumps" the brakes as he may have been previously taught.

Air-conditioning/AC

Introduced during the 1970's in USA, as standard on many cars since 1990, globally. Causes quick cooling of cabin by way of chilled air flow.

Air Brakes

Usually found on heavy-duty trucks, using compressed air to operate.

Air Injection

A method for reducing exhaust emissions. The injection of fresh air into the engine exhaust ports, combined with the high heat present in the exhaust manifold, causes the burning up of leftover fuel vapors.

Aerodynamic

The wind resistance of a vehicle's design elements. Aerodynamic vehicles claim to offer increased performance and reduced wind noise while moving. See Coefficient of Drag.

Alloy Wheels

Any non-steel road wheel. Mostly aluminum, but technically a mixture of two or more metals.

Alternative Fuels

May be alcohol-based, such as ethanol or methanol; compressed natural gas; or combinations of gasoline and alcohol.

All-Season Tyres

Tyres designed to provide good traction in winter snow and slush without wearing too quickly on dry roads.

Anti-Roll Bar

A suspension component. A steel rod or tube that connects the left and right suspension members to resist roll or swaying of the vehicle. Improves handling.

A-pillar

Vertical roof support between the windshield and front edge of the front side window.

Aspect Ratio

The ratio between the width and sidewall (or height) of the tyre. Tyres with lower aspect ratios, usually found on sports models, provide superior handling but a harsher ride.

Auto Mall

Several Dealership operations located on one site.

Automatic Locking Retractor

Standard on 1995 and later models, this device is built into the shoulder belt retractor and keeps the belt cinched tightly, which is essential for properly securing a child-safety seat.

Automatic Transmission

A system that varies the power and torque to a drive-train without the use of a foot-operated clutch.

Alternator

A device that converts mechanical energy into electrical energy for the purpose of charging the car battery.

ATF

Automatic Transmission Fluid. A liquid used within an automatic transmission to transfer the movement of the torque converter to the driveshaft.

ATC

Automatically controls a vehicle's heating and cooling systems, maintaining a temperature preset by the occupant.

B-pillar

Vertical metal roof support between front and rear side windows on the side of the vehicle.

Back Pressure

The pressure produced by restrictions in an exhaust system. Back pressure affects the rate at which exhaust gases are extracted from the cylinders.

Ball Joint

A dynamic joint of ball-and-socket configuration used in the steering and suspension systems.

Base-Coat

A coat of paint acting as the base for other layers to be applied.

Beltline

A horizontal line, usually imaginary but sometimes indicated by a feature in the body design, just below the window openings on a car or truck body.

Bench Seats

Full-length seat that runs along the rear width of the car cabin so that more than two passengers can sit there.

Benzene

An air pollutant produced via the combustion engine an the fossil fuels it burns.

Booster Seat

This child-safety seat is designed for children who are too large for a baby seat, but not big enough to sit safely in the vehicle's seats.

Body Style

The type of exterior shell or shape to a vehicle (sedan, coupe, hatchback, etc.).

Booster Seat

This child-safety seat is designed for children who are too large for a baby seat, but not big enough to sit safely in the vehicle's seats.

Bore

Diameter of an individual engine cylinder. Relates to that of the piston stoke length, both being given in millimeters, eg- 77.0/85.5mm

Blowby

Gases created during combustion that leak past the piston rings and are removed from the crankcase via the PCV system.

Brake Booster

Device or system that helps reduce the force the driver must exert against the brake pedal. May be hydraulic or electric.

Brake Caliper

A hydraulic (liquid-pressured) piston assembly that holds disc-brake pads.

Brake Pad

Used in a disc system, it is a replaceable piece of backing plate and additional friction lining. The Disc, a thick, round metal plate located behind each wheel, against which a set of brake pads are applied by a caliper during braking.

Brake Pull

Occurs when the vehicle pulls suddenly to the left or right as the brake pedal is depressed. It indicates the brakes may be out of adjustment.

Brake Rotor

Shiny metal disk that brake pads squeeze to stop the vehicle; hence the name disc brakes.

Brake Shoe

A curved, replaceable piece of friction material used on drum brakes. The wheel cylinder pushes the brake shoes against the brake drum.

Bucket Seats

Individual driver or passenger seats, that enclose a person by means of depth curvature an side lips. Usually found in customized an sporting cars.

Bumper

a length of metal with spring or rubber backing that sits rear-most on a car, and fronts the radiator.

Box car

a small car made from light wood an metal, with no mechanical content other than a steering mechanism plus 2 axles.

Boxer Engine

The cylinders are opposite (180 degrees apart) from each other. Also called flat engines, these are relatively flat compared to In-line or V en

C-pillar

The vertical metal roof support between the side edge of the rear windshield (also called the backlight) and the rear edge of the rear window.

Cabin

The interior people-space within a car. For a truck its called a Cab. The 'Greenhouse' is a term used in automotive circles to describe all of the windows enclosing the passenger compartment.

Cabriolet

A two-door small open car with a hand- retractable roof, being either a rag (cloth) top or hard top. Seating 4 usually, it appeared first in the 1920's but faded-out a decade later, an returning to fashion by the 1960's.

Cam

An irregularly shaped disc or projection whose rotation creates a rocking motion in an adjacent part.

Camber

Inward or outward tilt of the wheels tires. This adjustment affects how the vehicle holds the road and handles cornering.

Camshaft

A metal shaft supporting the cams that cause the open/close operation of the intake and exhaust valves. The camshaft turns at 1/2 the speed of the crankshaft and is connected to it either via gears, a timing chain or a timing belt.

Carbon Brakes

Introduced by the Brabham Team in 1978, these offer improved performance and superior durability to the steel brakes they superseded. Carbon disc brakes operate at their best when heated to extremely high temperatures, up to 1000° centigrade. Therefore, they are not suitable for road going cars as there performance when cold is very poor.

Carbon Fibre

This is an ultra-light, but extremely strong material that has been used to manufacturer vehicle parts for road an racing cars. It was introduced to the World of Formula 1 racing in the 1970's in the form of large but light wings. McLaren were the first team to use it to produce the whole monocoque of a Formula 1 car in 1981.

Carburetor

Device that mixes air with fuel, delivering the mixture into the engine's combustion chambers. Only found on older vehicles. By the mid-1980s, new emissions standards led to the use of fuel-injection systems, which do not require frequent adjustment.

CATS

Computer Aided Traction System, in which a machine automatically adjusts the road holding ability of a car while it covers slippery or uneven ground. A standard high-tech add-on for expensive sports-cars an luxury saloons, introduced in the 1990's.

Catalytic Converter

A component of the exhaust system that creates a heat- producing chemical reaction to convert potentially harmful combustion byproducts into carbon dioxide and water.

Capitalized Cost

In a lease transaction, the price at which a financial institution buys a vehicle from a dealer. Equivalent to the cash purchase price if the consumer were buying the vehicle outright, it includes taxes and any other additional charges. Also called Capital Cost.

Captive Finance Company

A car insurance institution owned by a car manufacturer. Examples include Chrysler Credit, Ford Motor Credit and General-Motors-AutoCredit.

Center-Locking Differential

On all-wheel drive vehicles, a third differential in addition to those for the front and rear axles. This third differential allows the front and rear wheels to turn at different speeds as needed for cornering on dry pavement. On slippery surfaces, it locks all four wheels together, either automatically or manually depending on the system, for greater traction.

C^dA

Aerodynamic efficiency (Cd) multiplied by frontal area (A). This will tell you how much effort is required to push the car through the air at a given speed.

CD changer

a jukebox style enclosure containing 5 to 50 audio CDs, each being accessible via a built-in CD player, all remotely controlled from the car-hi-fi panel on the dashboard.

Central Locking System

On a vehicle with power door locks, the system locks or unlocks all doors at one time.

CHMSL

Center High-Mounted Stop Light - required brake light mounted higher than the taillights, at the top center or bottom center of the rear windshield, as for racing purposes by regulation.

Check valve

A safety valve which allows fuel, air or a vacuum to flow in only one direction.

Chicane

A sequence of tight corners. Often inserted on straights to slow cars into the following corner. A number of race tracks have been modified to reduce speeds.

Chassis

This is the part of the car in which the driver sits and to which the engine and suspension are attached. In modern Formula 1 cars the chassis is a monocoque design manufactured from carbon fibre.

Christmas Tree

The pole of lights that starts a drag race, named for its red and green lights. Most drag races use the pro or heads up start which has three lights in between the first (red) and last (green) stage.

Choptop

The result of the process of lowering the top of a car, usually as part of a customized design.

Clearcoat

The transparent top coat of paint on many newer vehicles; designed to create a long-lasting, lustrous appearance.

Climate-Control System

The non-technical term for the heating, ventilation and air-conditioning system (HVAC). Most current vehicles have all three - heating, defrost, and AC.

Clutch

This drivetrain component is found between the engine and the transmission. It acts as a coupling device which is used to engage and disengage the transmission from the engine when shifting gears. It is necessary to do this joining and detaching because the engine is turning at a relatively high rate (thousands of revolutions per minute), and attempting to alter a gear ratio at this point could send various bits of transmission shrapnel careening about the occupant compartment.

Clutch Disk

Presses against the transmission flywheel to transfer power from the engine to the transmission.

Club seat

The rear seat in a coupe.

Coefficient of Drag (Cd)

A measure of the aerodynamic resistance of the vehicle body. The smaller the number, the more wind-cheating the body design and the greater likelihood that passengers won't have to endure wind noises.

CO₂ emissions

Carbon dioxide pollution expelled from the exhaust pipe, that since the 1990's must be at low enough levels to make the car meet world toxicity regulations. Figure given in grams per kilometer.

Coil

A transformer used in the ignition system for stepping up the voltage of the electric current conducted through the spark plugs. This high level of "electrical pressure" is what causes the current to jump the gap at the tip of each spark plug and create the actual spark that ignites the fuel inside the cylinder.

Coil Spring

A heavy-duty, spiraled metal component of the suspension system which forms a dynamic connection between the body of an automobile and its chassis.

Collision Coverage

Optional insurance that pays for damage to your car caused by collision with another car or object.

Compression

The stage prior to combustion during which the piston in a cylinder pushes down on the fuel vapor within to pressurize it.

Compression Ratio

The ratio of the volume within an engine cylinder when the piston is at the bottom of its stroke, compared to the volume in the cylinder when the piston is at the top of its stroke. The higher the ratio, the more compression during combustion and the more powerful the engine. Eg- 8:3:1

Comprehensive Coverage

Optional insurance that pays for damage to your car caused by things other than collision. For example, if your car is stolen or vandalized.

Combustion Chamber

Top section of the engine cylinder, where the air-fuel mixture is ignited by a spark plug. The explosion of the combustion pushes the piston down into the cylinder, producing the force that the transmission delivers to the drive wheels.

Constant-Velocity Joint (CV Joint)

On front-wheel drive and all-wheel drive vehicles, a coupling that allows the front axle to turn at a constant speed at various angles when the vehicle turns. The CV joint is a shaft that transmits engine power from the transmission to the wheel.

Continental kit

A spare tyre mounted on the bumper at the rear of the car, usually requiring a bumper extension.

Convertible

A medium-large sized car seating upto 5 people an having possibly 4 doors. Largely occurring in America, as with a top that can be either lowered or removed. Originally, many popular American cars were of this design, but soon the protection of the closed in sedan gained dominance. Convertibles have always had a niche except for a brief period in the '70's and '80's when the disappeared due to safety concerns.

Corporate Average Fuel Economy (CAFE)

The government tracks the average fuel economy of all the vehicles produced in a single model-year by each individual manufacturer. CAFE is that rating.

Coupe

Generally, a two-door car with close-coupled passenger compartment.

Coupe de Ville

A coupe with an enclosed, rear passenger section and an open driver's section.

Crankcase

The area inside the engine block where the crankshaft, piston rods and other moving parts operate and receive continuous lubrication.

Crankshaft

The main shaft of an engine through which the power produced during combustion is transferred to the transmission (and ultimately the wheels) as torque. Its rotation results from the reciprocating motion of the pistons.

Crash-Test

Crash protection research programs run by government backed authorities. Cars are crashed head-on into a rigid barrier at 35 mph, and instrumented dummies measure crash forces endured by properly restrained occupants. Each tested vehicle is assigned a score indicating the likelihood of moderate, severe or fatal injury.

Cruise Control

A device that, when set by the driver, will hold the car at the chosen speed.

Cruiser skirts

Optional accessory similar in function to fender skirts but are normally longer, fit on the outside of the body of the car, and are most often used in customization work.

Crumple Zone

Portions of a vehicle's structure designed to buckle and fold in an impact, absorbing crash force rather than transmitting it to vehicle occupants.

Cylinder

One of a group of chambers in the engine within which the process of combustion takes place. The most common engine configurations utilize either four (4), six (6) or eight (8) cylinders.

Cylinder Block

The main part of the engine to which other parts are attached.

Cylinder Head

At the top of the engine block is the cylinder head which contains intake and exhaust valves. Air and fuel enter the cylinder head through the intake valves and spent leftovers are released after combustion through the exhaust valves

Damper

A device which reduces vibration.

Daytime Running Lights (DRL)

These lights come on whenever the vehicle is turned on; they make the vehicle more visible to other drivers. Mandatory in Canada and standard equipment on many vehicles sold in the United States.

Dashboard

This may refer to the unit found between the front driver and passenger seat that contains the automatic transmission shifter, cupholders and a storage compartment. But it can also refer to the section of the instrument panel that includes the controls for the sound system and climate-control system, particularly if the panel flows down the center of the vehicle and includes the automatic-transmission shifter. Called a Console in USA.

Dealer Invoice Price

Also called dealer cost. The amount the dealer pays for a car or truck. Deducted from this price may be a dealer incentive, which is a set discount offered for a limited period of time, or a dealer holdback, which is a percentage of the vehicle's wholesale price.

Depreciation

The decrease in a vehicle's market value over time. The amount of yearly depreciation is affected by vehicle condition; resale-marketplace supply and demand; and make and model reputation. Convertibles, high-performance cars, trucks and vans tend to depreciate less than other vehicles.

Decked

the process of removing the body trim or contour lines from the hood or trunk of a car, usually as part of a customized design.

Diesel

An internal combustion engine in which the air-fuel mixture is ignited by compression in the cylinder rather than by a spark. Diesel engines use diesel fuel rather than gasoline and tend to be more fuel-efficient and require less maintenance than gasoline engines, but it is more complicated to get them to run cleanly. Also used as a slang term: after turning off the ignition, the engine continues to run for a short period.

Differential

A mechanical gearbox or fluid coupling that allows wheels to rotate at different speeds. Usually located on an axle, it allows the outside wheels to turn faster than the inside wheels during cornering. Four-wheel-drive and all-wheel drive vehicles have two differentials, one for the rear axle and one for the front. all-wheel drive vehicles also may have a third or center differential on the drive shaft that runs between the front and rear axles.

Diffuser

A rear outlet for expelling engine noise.

Ding

A small dent or scrape in the body of the vehicle.

Disc Brakes

Shiny metal discs, called brake rotors, are attached to the wheel hub, rotating with the wheel. When the brake pedal is depressed, the brake calipers squeeze the discs to slow the vehicle. See Brake Caliper and Brake Rotor. Diameter given in millimeters.

Displacement

The volume displaced by an engine's cylinders. Formerly measured in cubic inches, it is now more commonly expressed in liters.

Distributor

Part of the ignition (electrical) system. Delivers electricity from the ignition coil to the distributor cap and the spark plug wires in the correct firing order. (The firing order is that sequence in which each cylinder begins its power stroke.) The spark plugs ignite the fuel and air mixture in each cylinder thousands of times a minute, producing the explosion that pushes the piston down in the cylinder to power the vehicle.

Dogleg

Popular name applied to the angle created at the door opening by the wrap-around windshields found on many mid to late '50's models.

Downforce

The air pressure applied to the surface of a car at high speed, by means of aerodynamic body details, thus improving its traction, as airflow tries to lift the car.

Downpipe

The pipe that joins the entire exhaust system to the exhaust manifold.

Double Wishbone Suspension

A type of independent suspension in which the upper and lower support pieces, or members, look somewhat like a wishbone.

Dragster

A straight-line racing car where the engine is half exposed an the rear wheels are larger than the front wheels. Exotic booster fuels are usually added like nitro-gas.

Drafting

A phenomena where two cars running nose to tail together can move faster than an individual vehicle.

Drive Axle

Connects the transaxle to the front wheels on a front-wheel drive vehicle.

Drive Range (EV)

The distance an electric vehicle can drive without re-charging its batteries.

Drum Brakes

A braking system that uses a metal drum. Brake shoes press against the drum to slow or stop the car.

Drivetrain

Vehicle components which act together to move the vehicle forward or backward. On a rear-drive vehicle, it is the combination of the engine, transmission, differential and drive shaft. On a front-drive vehicle, it consists of the engine, transaxle and drive axles.

Driveshaft

A long metal cylinder located between the transmission and the rear axle, in front-engine rear-wheel drive vehicles. The shaft is connected to the components on each end with a universal joint, which allows for movement up and down without bending the shaft

EBD

Electronic Brake Distribution is a component used with ABS an usually a brake assist mechanism, for small powerful cars, like the new Mini of 1998.

Electronic Mufflers

In an electronic muffler system, sensors and microphones in the exhaust system sense the pattern of exhaust pressure waves. This information is sent to an on-board computer that controls loudspeakers in the muffler. The computer operates the loudspeakers to generate sound waves that oppose and cancel the original exhaust sound waves produced by the engine.

Electronic Stabilization Program

(ESP) increases vehicle control in situations near the vehicle's limits. It reduces the risk of skidding and helps to keep the vehicle on course. ESP recognizes the course desired and the car's reactions. Through brake application at individual wheels, it generates one-sided forces which help the car to move in the desired direction. The ESP program uses other driving aids and is permanently engaged.

Electronic Control Module (ECM)

Electronic Control Module. The master computer responsible for interpreting electrical signals sent by engine sensors and for activating automated engine components and processes accordingly in order to produce optimum performance.

Electronic Ignition

A system which uses an electronic unit as opposed to an older mechanical style distributor with points (contacts) to control the timing and firing of spark plugs.

Electronic Valve Timing (EVT)

System in which a computer controls the timing of the opening and closing of cylinder valves.

Engine

The basic job of an engine is to take fuel and convert its energy to some usable mechanical form (burn gasoline to spin a shaft and, ultimately, the wheels). Usually made from alloy & block. Its Cubic Capacity number [cc] represents the interior fuel space within it. The higher cc# the greater power it generates. Most vehicles today are fitted with what is known as a 4-cycle internal combustion engine. The four cycles are: Intake, Compression, Power, Exhaust.

Engine Displacement

The total of the volume used for combustion inside the cylinders of an engine. Measured in liters on newer models, or in cubic inches on older models.

Engine layout

The position it sits within the chassis, the cylinder amount, their arrangement, the CC total, plus any extra add-ons.

Engine management system

Computerized control of the ignition an fuel systems, making driving more economical, quieter, and power-effective. It can be made by the company using it, or be bought from another car manufacturer, or from a specialist electronics maker.

Engine noise pollution

An environmental concern measured in SPL decibels, at various speeds, an when the engine is idling. Leaded emissions relate to 'toxic pollution'.

Engine cooler

An air intake with behind it a large inducting fan, drawing air through a water cooled piping arrangement, thus preventing engine overheating, where the event is highly expected.

Environmental Protection Agency (EPA)

The federal agency that regulates air quality and sets automotive fuel-economy and emissions standards.

Equity

The value left in a used vehicle after subtracting the outstanding loan balance from its market value. For example, if £4,000 is still owed on a car worth £8,000 on the open market, then it has an equity of £4,000.

Escrow

A process in which a neutral third party takes care of the transfer of ownership of the vehicle.

Evaporative Emissions

Evaporated fuel from the carburetor or fuel system which mixes with the surrounding outside air.

Evaporator Core

Part of the climate-control system that contains a liquid refrigerant which turns to gas to absorb heat from the air.

Excess Mileage

Any mileage over the amount agreed upon within a car hire lease contract. Generally incurs a per-mileage charge at the end of the lease. Experts recommend a yearly mileage limit, or Mileage Cap, that exceeds normal driving needs.

Extra urban

A government fuel consumption rating in mpg for when driving along motorways.

Exhaust Manifold

A cast set of pipes or passages through which exhaust gases exit the engine cylinders on their way into the exhaust system.

Exhaust Valves

Devices that open passageways from the cylinders for exhaust gases to exit but which also close them during compression and combustion to maintain cylinder pressure.

Exhaust Gas Recirculation (EGR)

Part of the emissions system, it recirculates exhaust gases into the intake manifold, cooling the combustion chamber.

Factory standard

The basic design and options that make up the packaging of an entry-level vehicle.

Fan Belt

Transmits power from a crankshaft-driven pulley to an engine fan and other accessories.

Feed-through

The accepted an safest method by which a driver turns a steering wheel.

Fender

A body panel that lies below either side of the bonet, between the front bumper and front-most door edge, encompassing the wheel space in-between, [2 off].

Fifth Wheel

Provides a flexible connection between car an that which it tows, like a caravan.

FIA

Federation Internationale De L'Automobile

Final Drive Ratio

The reduction ratio of the transmission gear set furthest from the engine. In other words, the ratio of the number of rotations of the drive shaft for one rotation of a wheel. In general, a low final drive ratio results in better fuel efficiency, and higher final drive ratio results in better performance.

Firewall

The metal panel that separates the engine compartment from the passenger compartment. It also often includes sound and heat insulation.

Forced Induction

When a gas is blown into the engine to increase speed, by a turbo or supercharger.

Formula Racing

The most popular, sophisticated, and expensive of all the forms of auto racing is Formula 1 [F1]. It tends to be dominated by European drivers, who race through non-ovular circuits around the globe. The parallels to Indy Car racing have lead to the defections of drivers like Nigel Mansell, who sought the greater spoils of victory in the US, even though the technical expertise an racing challenge are lower their. Formula 2, 3, an 4 are lesser versions of F1, in terms of finance, spectacle, an Skillman-ship. Since 1970, F2 cars have tended to succeed in the Le Mans 24hr race. Of the 3 cars from left of the picture below, they represent F1, F2, & F3. Next is a rally car, then a vintage racer, and right-most is a touring-car racer.

Four-Wheel Drive (4WD)

A transfer case distributes power to both axles in order to drive all four wheels. Sometimes called All-Wheel-Drive in USA.

Four-Wheel Steering

Vehicle on which all four wheels turn when the driver turns the steering wheel. The rear wheels turn at a smaller angle than the front wheels. This system appeared on a few sports models in the 1980s but was never very popular in North America.

Fog lights

Two special headlights designed for cutting through foggy conditions along the road ahead.

Firing Order

The sequence in which spark plugs fire and combustion takes place in the engine cylinders.

Flywheel

A large disc bolted to the rear end of the crankshaft. The flywheel is encircled by a ring gear whose teeth are designed to mesh with the pinion gear in the starter during the process of starting the engine.

Frame-off restoration

A restoration method in which the car is completely disassembled with all parts cleaned or replaced as necessary, including the engine and all other mechanical components) so the restored car meets the exact factory specifications of the time as closely as possible.

Front Wheel Drive

The front wheels are the ones that are being powered by the engine/transmission, and the rear wheels just follow along. Generally speaking, these cars are more fuel-efficient than their rear-wheel drive counterparts, and they operate more easily in snow, but they are more expensive to build and maintain.

Fuel

A combustible, vaporous mixture of air and gasoline which is ignited within an engine to produce power. "Fuel" is a term often used in reference to the gasoline itself.

Fuel Cell

The name for a volumous fuel tank used in formula racing cars, that sits behind the driver an is reinforced with Kevlar.

Fuel Injection System

Injects fuel into the engine's cylinders with electronic control to time and meter the fuel flow.

Fuel System

These systems are vast and countless, but today's basic systems divide into two fundamental groups: carburetor systems and fuel Injection systems. Carburetor systems work by allowing the vacuum created by the engine in the intake stroke to pull fuel and air into the engine. Fuel Injection systems are more common these days. Sensors and computer controls monitor various engine speeds, air flows and throttle positions, and then tell the system what to do. A fuel pump is used to transfer the gasoline from the fuel tank to the injector (which is kind of like a spray nozzle).

Fuel Injector

Taking the place of carburetors in the 1980s, the fuel injector is an electrically controlled valve that delivers a precise amount of pressurized fuel into each combustion chamber.

GAP Insurance

Stands for Guaranteed Auto Protection insurance. Extra insurance for lease customers to cover the difference in the actual value of the vehicle and whatever is owed on the lease. Important if the car is stolen or totaled early in the lease term. It also covers the difference in value between what may be paid by an insurance carrier and what is still owed to the leasing company, including future lease payments.

Gas-Charged Shocks

Also called gas-filled shocks. They are shock absorbers filled with a low-pressure gas to smooth the vehicle's ride during up-and-down movement.

Gasket

A thin, expanding material used to seal the gaps and imperfections between hard, adjoining surfaces.

Gear Ratio

The ratio of teeth counts between meshing gears.

Gearbox

A metallic enclosure containing several cogs, each one affecting the effort in which the car moves. Each cog/gear has a different mph ratio per 1000rpm. Overall control maybe manual via the gear stick, automatic, or semi via a hand paddle.

Go-Cart

A small lightly powered single seat sporting car, driven by juveniles for leisure, or more seriously as a precursor to professional sport driving, as like F1 champion Ayrton Senna did while training before turning Pro.

Grand Prix

A type of car race popular in Europe. Also, a French term meaning great prize.

Gray Market Vehicle

Any car that is imported, but not through authorized retailers. May have insufficient emissions standards.

Gridlock

A traffic situation where most vehicles cannot move in any direction.

Grille

An opening in the front of the vehicle that allows air to reach the radiator.

Gross Vehicle Weight Rating

The kerb weight of the vehicle plus the maximum load it is designed to carry.

Ground Clearance

The distance between the ground and the lowest point of the vehicle chassis (usually the axle). A vehicle can drive over any object shorter than its minimum ground clearance.

Gross Vehicle Weight Rating

The actual weight of the vehicle plus the maximum load it is designed to carry

Hardtop

A car designed to resemble a convertible in looks and feel but without a removable top. Hardtops do not have the fixed post between the side windows.

Halogen bulb

A special headlight form whose brightness power is greater than standard bulbs, though they cost more an last shorter.

Hairpin

A tight looping curve on a race track.

Handling

The ease of vehicle steering and maneuverability around turns, up hills, etc.

Hatchback

A passenger car with a full-height rear door that includes a rear window. Usually has a rear folding seat. Called a 'Compact' by leasing companies in USA.

Head Room

The distance from the top of an occupant's head to the headliner.

Headliner

The interior covering of the roof. Headliners often contain consoles with slots for garage-door openers and other devices, as well as dome lights and wiring for electrical and electronic components attached to the headliner. The covering usually includes a sound-absorbing material.

Hip Room

The allotted room between a passenger's hips and any other part of the vehicle.

Horsepower (hp, bhp)

Abbreviated as hp, as in 200-hp engine, or bhp (brake horsepower or net horsepower) to designate power produced by an engine. In general, the higher the horsepower, the higher the vehicle's top speed. One horsepower is the power needed to lift a 550-pound weight one foot in one second.

Hot Rod

A normal vehicle that has been altered to improve speed and overall appearance or look. When racing acts as a variation of a dragster by hiding the usual front engine chassis under a lightweight body that looks like a street car.

Holdback

Manufacturer refund to a dealer after a vehicle is sold. Usually a percentage of the recommended retail price.

Hood ornament

A chromeplated metal figurine that sits atop the radiator or at the middle-front of the bonnet.

Hydraulic

An integral car component operated by means of liquid under pressure, as used in the braking system. Word derived from Grecian origin.

I-Beam Suspension

A suspension beam under the car that supports the body in the shape of a capital I.

Idle Speed

The speed of the engine at minimum throttle and the engine in neutral.

Ignition System

The system responsible for generating and distributing the electrical spark needed to ignite fuel in the cylinders and for altering the frequency (timing) of that spark in relation to changes in engine speed.

Inboard Air Jack

A device added to some racing cars which raises their chassis after making a pitstop, so quicker action can be taken on their maintenance. It is powered by a compressed air canister.

Injectors

Devices which receive fuel at low pressure and shoot it into the engine cylinders at predetermined intervals under higher pressure.

Intake Manifold

A cast set of pipes or passages through which fuel or air is directed into the cylinders.

Intake Valves

Devices that open passageways for fuel vapor to enter the cylinders but which also close them to maintain cylinder pressure during compression and combustion.

Independent Suspension

A suspension design that lets each wheel move up and down independently of the others. A vehicle can have two-wheel or four-wheel independent suspension; sportier models have four-wheel independent suspension. See also Multi-Link Suspension, Live Axle.

Installation

the engine location maybe front, rear, or mid. If its mid or further back the car is rear-wheel drive. Its orientation maybe traverse or longitudinal.

IHRA

International Hot Rod Association

IMSA

International Motor Sports Association, founded by John Bishop in 1969. Sanctions, organizes, markets and officiates professional auto racing events.

In-Line Engine

Cylinders are arranged side by side in a row and in a single bank. Most four-cylinder and some six-cylinder engines are in-line engines. In V-6, V-8 or V-12 engines, the cylinders are divided into two banks, each of which is angled away from the other in a 'V' pattern.

Imobiliser

An electronic safety feature that prevents a car from being illegally driven away.

Indy 500

The big race held in Indianapolis every year on Memorial Day weekend.

Inflatable Tubular Restraint

This tube of woven material is stiffer and stays inflated longer than a traditional airbag cushion. The tube protects the occupant's head and torso in a side impact, in part by keeping them away from the point of intrusion. The uninflated tube is tucked into the edge of the roof headliner. The tube is attached at the base of the A-pillar in front of the occupant, and at the roofline behind the occupant. When it inflates, the tube angles across the window to keep the occupants head from hitting the window glass or metal side pillar. Because of the longer time the tubular restraint stays inflated, it is expected to also offer protection in a rollover.

Intercooler

Device that cools air as it leaves a turbocharger or supercharger before the air is blown into the engine air intake. Cooling makes the air denser and richer in oxygen, which lets the engine produce more power.

Interior Payload

The amount of space or material that can be carried inside the vehicle.

J-gate

A metal plate with a J shaped whole, in which the gear-stick must slip between during gear changes.

Jackknife

The point at which the cab of an articulated lorry is overtaken by the trailer its pulling while still attached.

Journal

The surface of a bearing against which a moving shaft turns.

Jump start

To transfer electrical power from one car battery to another to enable the cars ignition system to startup, using jump leads.

Keyless Entry

A system for locking and unlocking doors of a vehicle with a central locking system without using the key. Usually, the user controls the locks by pressing a button on a remote key-fob transmitter. Some vehicles have electronic combination locks on the doors near the handle.

Kilometers Per Hour (KPH)

Multiply by 0.621 to convert to miles per hour.

Kit Car

A vehicle that is designed for assembly by the private hobbyist.

Landau top

A roof style characterized by a (usually small) rear section being covered by vinyl fabric or otherwise set apart.

Lap-and-Shoulder Belt

A safety belt that secures the driver and/or passenger in the seat with a continuous web of material which fits across the lap and crosses the upper body. It keeps the occupant from jerking forward in the event of a crash. Also called three-way belt, three-point belt, or three-point safety harness.

Land yacht

A large luxury car, especially the huge, chrome laden, finned monsters of the late '50's.

Leaf Spring

Suspension spring made up of several thin, curved, hardened-steel or composite-material plates attached at the ends to the vehicle underbody. The curved shape of the plates allows them to flex and absorb bumps.

Lean or Rich Fuel Mixture

The fuel mixture is lean when it has too much air, and rich when it has too much fuel. These terms can also be used to refer to adjustments the electronic control module makes to the fuel mixture in response to various driving conditions, particularly on engines with variable-valve technology.

Leg Room

With the front seat adjusted all the way back, the distance from the accelerator pedal's heel point to the back of the front seat cushion.

Lien

A legally documented claim against a vehicle by another party to which the vehicle has been offered as security for repayment of a loan or other debt. A lien against the title may make it impossible to sell the vehicle and transfer the title until the lien is cleared.

Lift Gate

The rear opening on a hatchback. Called a tailgate in Europe, or hatch door.

Liftover

The distance a person must lift an object off the ground to put it in a trunk, boot, or cargo bay.

Limited-Slip Differential

A device that helps prevent the drive wheels from skidding or losing traction by diverting power from the slipping wheel to the opposite wheel on the same axle.

Litre

Engine-displacement measurement, as in a 2.0-litre engine. The metric equivalent to the imperial measuring standard, which is largely favoured by American car makers. A Gallon is this other liquid volume standard, an contains 3.78541 litres.

Live Axle

A solid axle allowing movement of the wheel on one end to affect the opposite wheel. Found on older rear-drive cars and tucks. Also called a rigid axle.

Leased car agreement

A contract between leasor and lessee for a specified time period and at a specified payment. The title to the car remains in the name of the leasor as owner of the asset.

Loan to Value Ratio (LTV)

Obtained by divided price or value into loan amount. A vehicle with a £10,000 price and an £8,000 loan would have a loan-to-value ratio of 80 percent.

Lock-to-lock

The amount of turns the steering wheel must rotated for the wheels to be turned from rightmost to leftmost. Eg - for the Mini Cooper its 2.5.

Lowrider

Generally, a car on which the chassis has been lowered; however, other customizations are often present. Some American cars have a hydraulic mechanism that does this action during driving.

M+S Rating

A tyre rating which indicates a tyre designed to perform well in mud and snow.

MacPherson Strut

A MacPherson strut is a unit that includes a damper or shock absorber cartridge inside a large, long metal spring. MacPherson struts are used over the front wheels of most front-drive cars. Replacement of MacPherson strut cartridges requires a spring compressor.

Manifold Absolute Pressure Sensor (MAP sensor)

Detects engine load by measuring air pressure or vacuum in the intake manifold.

Manual Transmission

A transmission that varies the power and torque through a foot pedal controlled clutch and a floor-mounted or steering-shaft-mounted gear selection lever.

Mass Airflow Sensor

Device that measures the flow of air entering the throttle housing.

Master Cylinder

The primary component for pressurizing fluid in a hydraulic system. Used in the braking system, it supports a reservoir for holding brake fluid and is activated each time the driver depresses the brake pedal.

Max power

Two figure totals given in brake-horse-power by engine revs per minute. [bhp x rpm].

Max torque

The weight of force per foot, given in pounds, and the rpm level, eg 100 lb ft at 1000 rpm.

Metallic paint

A glittery sheen within the paintwork by customer request at an additional cost.

Minivan

A quite large car of saloon capacity but resembling a small van with windows.

Miles Per Gallon / MPG

Fuel economy measurement. Generally, a vehicle maker may offer mpg ratings for city driving, highway driving, and combined driving, so their is no definitive single measure overall.

Muffler

A chamber in the engine exhaust system used to suppress exhaust noise and smooth exhaust pulsations. Also referred to as a "silencer". Motorbike an moped owners sometimes remove these to beef-up their sound.

MPV

A multi-person vehicle, pioneered by Renault, like a windowed van with several seats. Similar to a mini-bus but with modcons an for private use.

Multi-Link Suspension

Independent suspension controlled with several link arms that restrict undesired motion of the suspension for a smoother ride and more precise handling.

Multi-Port Fuel Injection

An electronic fuel-injection method that uses individual injectors to spray fuel directly into each intake port, bypassing the intake manifold. Also called multi-point fuel injection.

Muscle car

A term used beginning in the mid-'50's to refer to cars which had very high horsepower and is still in use today. Occasionally called a 'pony car' in USA. The Aston-Martin Vanquish is a perfect example.

NASCAR

National Association of Stock Car Auto Racing; the governing body which sets the rules and regulations for stock car racing.

Nitro-methane

A mixture of nitric acid and methane which is used to fuel Top Fuel Dragsters and Hotrods; is also called nitro or top fuel.

Nose

A small frontal body section of a car which extends beyond the bonnet line, typically slanting downwards. The narrower version used on Formula cars is called a shark-nose. 'Nosed' refers to the process of raising a small peak in the center of the bonnet of a car, usually as part of a customized design.

Octane

The hydrocarbon substance in gasoline that reduces engine knock or pinging, which is a noise caused by premature ignition of fuel in the cylinder combustion chamber. The higher the octane number, the less chance of premature ignition. High octane, which has a rating above 91, is useful only when recommended by the manufacturer.

Odometer

Indicates the number of miles a vehicle has been driven, an is also called a Mileometer. It is illegal to tamper with the odometer reading. This illegal practice of rolling a vehicle's odometer back to indicate that it traveled fewer miles than it actually has, is done by 2nd-hand sellers. Odometer Rollover occurs when the vehicle's mileage exceeds the mechanical limits of the odometer - usually 99,999 miles. This must be certified by the seller, under law binding Mileage Acts.

Offroader

A wheeled road vehicle whose design allows it to move across rugged terrain with greater ease than standard vehicles.

Overhead Cam (OHC)

The camshaft is on top of the cylinder head on overhead-cam engines. Single overhead-cam (SOHC) engines have a single cam above the cylinder head. Dual overhead-cam (DOHC) engines have two cams above the cylinder head.

(OHV) engine

An overhead-cam engine with overhead-valves, which means the intake and exhaust valves sit atop the cylinder head.

Oversteer

Occurs when the rear tyres lose adhesion under cornering. In motor sports, this is also called loose. Oversteer can lead to a spin if the driver doesn't reduce acceleration. See also Understeer.

Overdrive

A transmission gear with a ratio below 1:1, which improves fuel economy by reducing engine revolutions per minute at highway speeds. On a five-speed manual transmission, the fourth and fifth gears are overdrive. On a four-speed automatic transmission, the fourth gear is overdrive. When an overdrive gear set is engaged, the output shaft turns at a higher rate than the input shaft, reducing engine revolutions at cruising or highway speeds.

Oxygen Sensor

An emissions related device which senses the presence of oxygen in the exhaust. The voltage it puts out is interpreted by the main computer (ECM) along with other sensor input to determine automatic adjustment of the air/fuel mixture.

Optional Equipment

Machines or features that can be added to a particular model which are not part of the standard package. These usually involve additional cost and can be ordered individually or as part of a package. A CD changer/jukebox is an example.

Pace Car

Seen at racing meets, the pace car leads race cars into their pole positions at the beginning of races, or after a yellow flag or restart has been called.

Parts car

A car that is suitable only for gleaning parts. Such cars are often, wrecked, incomplete and do not run. Such a car would normally have a condition number of #6.

Passive Restraint

A device or structure that automatically helps restrain vehicle occupants in an impact. This includes airbags, belt pretensioners, padded knee bolsters, and shoulder belts that are motorized, or attached to the door.

Package Shelf

The ledge between the rear seat and the backlight (or rear windshield). The name is misleading because it's a bad idea to put anything on the package shelf. However, it often contains the sound system's rear speakers and, on some vehicles, the CHMSL or center brake light. Sometimes also called the package tray. On European cars the package tray often contains a first-aid kit; on higher-end models it may contain storage compartments.

Phaeton

A four-door open car (convertible). Most true phaetons had vanished by the late '30's, but as late as the '60's, a few models that roughly qualify for the term were briefly re-introduced by Lincoln. VW brought back the term in 2002 for their luxury saloon model.

Pick-up

The type of light-duty truck with an open cargo bed behind a closed cab.

Pinion

A type of gear that has small teeth that mesh with other, larger gears.

Pinion Gear

The smaller of two meshing gears. A pinion gear is used in a starter motor to engage the flywheel ring gear and also rides along the surface of the steering rack (hence "rack and pinion" steering).

Pitstop

This is the garage area at F1 races, where major mechanical work is done on the cars. The pitlane runs its length. At Indy racing [in USA] its called the 'gasoline alley'.

Piston

A solid, cylindrically shaped part that alternately compresses fuel vapor within a cylinder (the compression stroke) and is thrust downward (the power stroke) by the force of the explosion that results when the vapor is ignited. Rocker arms connect the pistons to the crankshaft.

Piston Rings

Metal rings seated in grooves on the outside of a piston that are used to ensure a proper seal between the piston and the cylinder wall. Typically, three (3) rings are used: two (2) ensure proper compression is produced and one (1) prevents oil from leaking into the cylinder.

Poke

The degree of acceleration after exiting a sharp turn, as in 'pokey'.

Pole position

The leading spot amongst an array of cars on the starting grid of a race.

Positive Crankcase Ventilation Valve

An emission device that routes oil pan vapors to the intake manifold to be burned during combustion. Also known as the PCV valve.

Power Steering

A steering system that uses a separate motor or engine power to reduce the effort necessary to turn the front wheels.

Power Steering Fluid

Many power steering systems use hydraulic power. These systems use a power steering pump driven by a belt from the crankshaft. The pump moves fluid under pressure through hoses to the steering gear. The pressure is used in the steering gear to reduce steering effort. A reservoir for fluid is attached to the rear of the pump.

Power-to-Weight Ratio

The maximum power output of the vehicle per unit mass. The higher the ratio, the more powerful the vehicle. In comparing several vehicles, this can be a better measurement than engine horsepower or torque because it considers the weight variable. In other words, a car that seems to have a powerful engine but is also heavy may have less get-up-and-go than a vehicle that has a similar or less powerful engine but also weighs less. Lotus are the best exponents of this. Given in a BHP per tonne value.

Powertrain

The combination of engine and transmission.

Pretensioner

A device that rapidly yanks in shoulder-belt slack when a crash sensor detects an impact. Some pretensioners are activated by a small explosive charge in the belt retractor; some contain their own inertial sensors. So far, pretensioners are still found on more expensive models, particularly those by European manufacturers. By pulling in belt slack within milliseconds of an impact, pretensioners help reduce chest and head injury by restricting occupant motion and preventing the occupant from hitting the belt.

Projector-Beam Headlights

A headlight that uses a spherical reflector to tightly control the light beam. The bulb or light source directs the light inward, toward the reflector at the back of the headlight assembly, which then projects it forward from the vehicle. These lights are more powerful, accurate and expensive than standard sealed-beam and halogen headlights, and are generally found on sport and luxury models.

PRO

Professional Racers Organization

Pro Start

A method of starting a drag race that differs from most starts in that it only has one amber light between the initial staging and the final lights on the track-owners car.

Pro street

A customized automobile designed for very high-performance and racing.

Project car

An essentially complete, usually running car, that is capable of being restored. A project car usually has a condition number of #4 or #5.

Pro Rallies

Road rallies which are very competitive and are run at high speeds on roads closed to the public. Often sponsored by the SCCA.

Pressure Plate

Holds the clutch disc against the flywheel.

PSI

Acronym for pounds per square inch. A pressure measurement used in tyre inflation and turbocharger boost.

Pushrod

A metal rod that transmits the motion of the camshaft to the valve actuators to open and close the valves. Used on engines with overhead valves but without overhead camshafts.

Quarter Panel

Sheet of metal panel that covers the front and rear quarters of the vehicle.

Quality control

A department within a company that ensures its products meet the required standard, such as checking if a car has adequate weather-proofing.

Quickest Lap

Counted officially by race organisers, this determines each cars position on the 'starting grid'. It is achieved by each competitor driving their cars their fastest around 1 circuit of the race-course, over 1 session.

R-134a

The environmentally safe refrigerant now used in air-conditioning systems. It requires a slightly bulkier condenser unit than the older R-12 type. Vehicles equipped with R-12 systems can be converted to use R-134a. Since Freon is now banned, expensive and hard to obtain, the conversion may be a good idea when an R-12-based system needs recharging, particularly if technicians detect a leak.

Roadster

An open car having a single seat for two or three passengers, with originally a rumble seat in the rear, an usually a folding roof.

Rack and Pinion Steering

The steering wheel is connected to a pinion gear that meshes with a toothed bar, also called a rack or linear gear. As the pinion turns, the rack moves side to side, moving the steering linkage and causing the front wheels to turn left or right. The ends of the rack are linked to the steering wheel with tie rods.

RACMSA

The RAC Motor Sports Association is recognized by the FIA as the governing body of motor sport in Great Britain.

Radiator

The copper or aluminum device in front of the engine through which hot engine coolant is circulated and cooled. The liquid is then recirculates back through the engine block to cool it.

Rag Top/Soft-top

A convertible with a soft top, usually made from canvas or a polymer.

Rally

Competing teams, consisting of a driver and a navigator, are given route instructions, which they must follow exactly. Each team follows the course independently, trying to rack up points based on how well they meet a pre-determined schedule.

Rear axel assembly

The drive shaft turns (spins) a set of gears within the rear axle assembly known as the differential, or rear differential. The differential changes the direction of power from the driveshaft out to the rear wheels via the rear axle.

Rear-Wheel Drive (RWD)

The drivetrain in which power is applied through the rear wheels only.

Recall

A manufacturer calls in vehicles to repair defects, usually safety-related. Recalls may be voluntary, requested by the government, or mandated by NHTSA.

Recirculating Ball

A steering mechanism in which the steering shaft turns a worm gear causing a toothed metal block to move back and forth, turning the front wheels. Ball bearings reduce friction between the worm gear and the metal block.

Redline

The point on the engine tachometer that indicates the maximum RPM the engine can safely withstand.

Release Fork

Disengages the clutch disc from the flywheel by pressing on the pressure plate release springs.

Retractable

A car having a mechanically retractable hardtop such as the late '50's Ford Skyliner.

Restrictor

An electronic safety device preventing high-speeds above 160mph from being reached.

Revolutions Per Minute (RPM)

Describes at which speed the engine crankshaft is turning.

Rev counter

Usually sits near the Speedometer. Shows the driver the rpm level while pressing the accelerator, thus indicating how much fuel maybe unnecessarily be being burned.

Rim

The outer edge of a bare wheel. A hub-cap sometimes sits within this.

Rocker Panel

The body panel that runs beneath a vehicle's doors.

Road test

A neutral road vehicle examination done by transport depts., publishers, an consumer associations. It covers - design, engineering, performance, braking, handling, ride, comfort, safety, equipment, specifications, economy, market & finance.

Rotor

The rotating part of a machine or mechanism. The brake disc itself is referred to as a "rotor," as is the center of a distributor or starter motor.

Rollcage

A protective steel cage to prevent driver injury during a rollover.

Rollover

The type of vehicle impact in which the car or truck rolls over on its side, onto its roof, or turns over completely. The biggest cause of injury in a rollover is ejection of the occupant or any part of the occupant. Rollover is a greater risk in any sport-utility vehicle - because of its high center of gravity - than in a minivan, pickup truck or passenger car. Rollover can occur immediately upon impact or in the seconds after an impact, which makes it more difficult to protect occupants with traditional airbags. Inflatable tubular restraints and similar designs that stay inflated longer than traditional airbags will be more effective in rollover situations.

Running Yellow

This indicates that something may be wrong on the race track, but the cars are allowed to stay, running at a reduced speed. A quick check by the officials usually resolves the issue and the green light comes back on.

Rumble seat

Fold-up seat in the rear of a car.

Running board

A strip running between the fenders and below the doors of early autos used both as a step up into the car and to wipe the mud from one's feet.

Rush hour

A time period between 8am>10am, where traffic peaks more so than at any time during the day, but excluding weekends

Sat-nav

An LCD showing the vehicle position within the local area, as pinpointed by a GPS satellite.

Scrub radius

The distance from the point where the steering axis intersects the ground to the longitudinal line that runs through the center of the tyre's contact patch. Also called "steering offset."

Sedan

A fixed-roof car with at least four doors or any fixed-roof two-door car with at least 33 cubic feet of rear interior volume. Called a Limousine outside America. Daimler only make this car type.

Sedanette

A two-door sedan having a slanted back with the rear window and trunk along one unbroken curve. This name for the early streamlined design is most often used for Buick and Cadillac models, but similar designs of other makes are known by various names.

Sensor Algorithm

An algorithm is a mathematical formula or series of formulas used by an on-board computer or processor to make decision. In an airbag system, a crash-sensor algorithm determines whether the change in velocity indicates an impact of great enough force to require airbag deployment, based on pre-programmed parameters. If the change in velocity is great enough, the processor sends a signal to the device that inflates the airbag.

Sequential Fuel Injection

Similar to multi-port fuel injection, but the injectors spray fuel into the individual intake ports exactly at the beginning of each cylinder's intake cycle. The precise fuel control provides better engine performance.

Semi-trailing-arm suspension

An independent rear-suspension system in which each wheel hub is located only by a large, roughly triangular arm that pivots at two points. Viewed from the top, the line formed by the two pivots is somewhere between parallel and perpendicular to the car's longitudinal axis.

Shift Interlock

On a vehicle with automatic transmission, a safety device that prevents the driver from shifting out of park unless the brake pedal is depressed.

Shift gate

The mechanism in a transmission linkage that controls the motion of the gearshift lever. The shift gate is usually an internal mechanism; however, in some transmissions: including Ferrari five-speeds and Mercedes-Benz automatics: the shift gate is an exposed guide around the shift lever.

Shock absorber

A device that converts motion into heat, usually by forcing oil through small internal passages in a tubular housing. Used primarily to dampen suspension oscillations, shock absorbers respond to motion; their effects, therefore, are most obvious in transient maneuvers.

Short Block

The lower portion of an engine below the cylinder head.

Side Airbag

An inflatable cushion that fills the space between the door and the occupant to prevent head, torso and pelvis injuries when a vehicle is hit from the side. Side airbags may be stored in the door-trim panel or the outboard side of the seat; they may protect the hip and torso only or also protect the head. A new design, called an inflatable tubular restraint, is stored in the edge of the roof headliner and attached at the base of the A-pillar at the front end and above the doors along the roofline at the other. The device inflates into a somewhat stiff tube that prevents the occupant's head from hitting the side pillar or the window.

Side-Impact

safety regulations require that vehicles absorb a certain amount of force when hit from the side. To meet side-impact standards, automakers have stiffened side-impact beams, which resist intrusion into the passenger compartment, and added safety devices such as side airbags and extra padding, which are designed to push the occupant toward the interior of the vehicle and away from the point of intrusion.

Side mount

A spare tyre mounted on the side of a car, normally on the fender just above and behind the front wheel.

Single Overhead Cam (SOHC)

An engine with a single overhead cam generally has one intake and one exhaust valve per cylinder; the single cam opens and closes both valves. See also Overhead Cam and Dual Overhead Cam.

Skidpad

A large area of smooth, flat pavement used for various handling tests. Road holding is measured by defining a large-diameter circle (Car and Driver uses 300 feet) on the skidpad and measuring the fastest speed at which the car can negotiate the circle without sliding off.

Slicks

A type racing tyre characteristically very wide with no tread.

Slalom

Several soft turns in a row at a race-track, like at Brands Hatch in the UK.

Society of Automotive Engineers

The professional association of transportation-industry engineers. The SAE sets most auto-industry standard for the testing, measuring, and designing of automobiles and their components.

Solenoid

The electromagnetic device positioned above the starter which thrusts the pinion gear against the engine flywheel when starting ("turning over") the engine.

Space frame

A particular kind of tube frame that consists exclusively of relatively short, small-diameter tubes. The tubes are welded together in a configuration that loads them primarily in tension and compression.

Specific output

The amount of BHP produced from 1 litre of fuel.

Spark Plug

Converts voltage into an arc that passes between its electrodes; the arc ignites the fuel-air mixture in the combustion chamber. The mixture explodes, creating power by pushing down the piston.

Speedo

An instrument dial above the steering wheel which informs the driver of the current speed, in MPH and/or KPH.

Sport Utility Vehicle (SUV)

Refers to a style of truck which has a square passenger cabin and hatchback, and may be equipped with two- or four-wheel drive.

Sports Car

A body type designation. Generally a small, powerful car seating only two people.

Sprint Car

Two types of sprint cars exist, the first is the open-wheel cars that feature a upright roll cage. The second is a similar car that has a large wing mounted to the top for stability.

Spoiler

An aerodynamic device that changes the direction of airflow in order to reduce lift or aerodynamic drag and/or improve engine cooling..

Spyder

A very fast sports car with a removable roof and a top speed above 170mph.

Smart Airbag

There are many designs, but each contains similar elements including a system of sensors and mathematical algorithms to detect the presence or absence of an occupant in the seat; to determine the size, weight and nature of any occupant (including whether it is a rear-facing infant and determine whether the occupant is an adult, a dog, a bag of groceries or a rear-facing infant seat); and to determine whether the occupant is too close to the airbag door for safe deployment. A smart system will use that information to decide whether to inflate the airbag in an impact. Later generations of smart airbags will adjust the rate of inflation based on force of impact and size of the occupant.

Slip angle

The angular difference between the direction in which a tyre is rolling and the plane of its wheel. Slip angle is caused by deflections in the tyre's sidewall and tread during cornering. A linear relationship between slip angles and cornering forces indicates an easily controllable tyre.

Slushbox

A slang for an automatic transmission.

Squat

The opposite of dive, squat is the dipping of a car's rear end that occurs during hard acceleration. Squat is caused by a load transfer from the front to the rear suspension.

Straight-line tracking

The ability of a car to resist road irregularities and run in a straight line without steering corrections.

Stator

As opposed to the moving rotor, the stationary portion of a device. In an alternator, for example, the stator includes an intricate copper winding that picks up the current induced by the rotation of the rotor within a magnetic field.

Starter

An electric motor used to initiate movement of internal engine parts so that combustion can begin. Activating the starter causes the solenoid to thrust the pinion gear in the starter against the engine flywheel ring gear and begin turning it.

Street rod

A customized, usually modernized, most often classic, automobile designed for show and/or pleasure driving.

Starting Grid

The first section or portion of a race track.

Station Wagon

A two- or four-door passenger car with a cargo area that extends all the way to the rear bumper. A model variant derived from an extension of a popular saloon model. In Europe is termed an estate version.

Steering axis

The line that intersects the upper and lower steering pivots on a steered wheel. On a car with a strut suspension, the steering axis is defined by the line through the strut mount on top and the ball joint on the bottom.

Steering feel

The general relationship between forces at the steering wheel and handling. Ideally, the steering effort should increase smoothly as the wheel is rotated away from center. In addition, the steering effort should build as the cornering forces at the steered wheels increase. Finally, the friction built into the steering mechanism should be small in comparison with the handling-related steering forces.

Steering gain

The relationship between yaw and the steering wheel's position and effort. All three should be proportional and should build up smoothly.

Steering Ratio

The ratio of the different steering gears. Usually a lower gear means a faster response.

Steering Rack

The device by which the movement of the steering wheel is transferred to the front wheels of an automobile.

Steering Rods

The metal rods on each end of the steering rack that connect it to the front wheels via ball joints (tie rod ends).

Strut

A single, self contained pivoting suspension unit that integrates a coil spring with a shock absorber. Struts are used on front wheel drive automobiles. A suspension element in which a reinforced shock absorber is used as one of the wheel's locating members, typically by solidly bolting the wheel hub to the bottom end of the strut.

Stock Car Racing

Started by NASCAR's founder, Bill France, in the 1940s. Initially meant track cars equipped with showroom parts. Today, few cars use stock parts. Most are built from custom parts, made especially for these race cars, that look like those in showrooms.

Stroke

The up-and-down distance the piston travels within the cylinder. On a traditional internal combustion engine, the piston makes four strokes during the combustion cycle, only one of which is a power stroke. On the power stroke, the piston is near the top of the cylinder, and it has compressed the air and fuel mixture. The spark plug ignites the mixture, and the force of the explosion pushes the piston down into the cylinder, producing the force that turns the crankshaft. The piston returns to the top of the cylinder to expel the exhaust gases on the second, or exhaust, stroke. It slides down to the bottom of the cylinder during the intake stroke, when the valves open to let in air and fuel. The piston rises to the top of the cylinder on the compression stroke to begin the cycle anew. This process repeats hundreds or thousands of times a minute, resulting in the number of crankshaft revolutions per minute at which the crankshaft is rotating. Length measured in millimeters.

Subcompact

The car size class one step up from the mini-car, like the Rover 45 an Austin Maestro.

Suicide doors

Car doors that open from the front rather than the rear, by being hinged beneath the windscreen or rear window. Although most often thought of as applying to rear doors of four-door cars, several early models had suicide-style front doors. Some of the last suicide doors to appear on an American car were on the '1960's Lincolns. In 2002 Mazda introduced a car called the RX8 which brought back this obscure idea.

Supercharger

Serves the same function as a turbocharger but avoids lag time because it runs off an engine-driven pump. Both turbochargers and superchargers are used to produce more power without increasing engine displacement, but neither are particularly fuel efficient and both can require costly maintenance as vehicles age. A standard piece of equipment of Hotrods and Top Fuel dragsters, this provides more power by blowing a combination of more air and vaporized fuel into the car's engine.

Suspension

Springs, dampers, shock absorbers, hydraulics, wishbones, roll bars, struts, and links used to suspend the frame, body and engine above the wheels.

Sump

The space in the engine block under the crankshaft into which the oil drains from its various applications.

Switch-gear

The variety an quality of function controls the driver can utilize while driving.

Synthetic oil

Engine lubricant not derived from raw petroleum. It has superior engine-protection properties but costs as much as five times more than petroleum oil.

T-top; Targa top

A hand removable plastic roof, as with TVR's Tuscan model, leaving a T shaped roof opening.

Tachometer

The instrument gauge that shows engine speed, or revolutions per minute. On a vehicle with manual transmission, the driver can use the tachometer to tell when to upshift or downshift. Also called tach.

Tappet

A pivoting actuator that opens and closes cylinder intake and exhaust valves.

Taxometer

A machine which counts the travel-time of a taxi journey.

Throttle-Body Fuel Injection

A form of electronic fuel injection in which the injectors are centrally located in a throttle-body housing that contains a valve to regulate air flow through the intake manifold. Less efficient and precise than multi-port or sequential fuel injection.

Timing Belt

On overhead cam equipped engines, an external belt used to synchronize the operation of intake/exhaust valves with the compression/ignition process occurring in the cylinder head and engine block below.

Timing Valve

A valve in a fuel injection pump which times the delivery of fuel.

Tie Rod End

A type of ball joint which transfers the movements of the steering wheel to the wheels.

Toe-in

A wheel-alignment term that indicates the leading edges of a pair of wheels angle slightly toward each other. Front-drive cars are often aligned with slight toe-in to compensate for the effects of torque steer, or the tendency of the front wheels to pull to the side under hard acceleration.

Toe-out

A wheel-alignment term that indicates the leading edges of a pair of wheels angle slightly away from each other.

Top-Fuel Dragsters

The fastest of drag racing vehicles, these have a characteristically long body and use top fuel which accounts for the tremendous speeds these vehicles can attain.

Torque

A measure of twisting force, given in foot-pounds (abbreviated as lb.-ft.) or Newton-meters (N-m). In the case of an automobile, it is the twisting or rotational force the engine exerts on the crankshaft. Vehicle specifications often include the maximum torque an engine produces at a specific number of revolutions. An engine that produces 200 lb.-ft. of torque at 3,000 revolutions per minute, or 200 lb.-ft.@ 3,000 rpm, accelerates better at low speeds than an engine that provides 200 lb.-ft.@5,000 rpm.

Torque Converter

An enclosed device connected to the crankshaft that uses a turbine-based system and a thin fluid (ATF) to propel the movement of the automatic transmission mainshaft. As opposed to an automobile equipped with a manual transmission and clutch that must be engaged/disengaged, this "fluid" connection between the engine and the wheels is what enables a car to come to a full stop with its automatic transmission still in gear.

Torque Steer

The tendency of the front wheels on a front-drive vehicle to pull to the side under hard acceleration.

Torque-to-weight

The amount of torque derived power effort, in pounds per foot, over the tonnage of the vehicle.

Torsion Bar

A simple, rugged type of suspension spring that twists as it is compressed or stretched.

Torsional Stiffness

A vehicle body's resistance to twisting motions.

Towing Capacity

The amount of weight a vehicle can tow behind it, eg a trailer carrying a speed-boat.

Track

Vehicle width, measured from the center of one tyre's contact patch to the center of the opposite tyre's contact patch. 2 - a racing surface at race-course, like at Silverstone in the UK.

Traction Control

A system for limiting wheel slip under acceleration, thus maintaining each wheel's contact with the road surface. Traction-control systems generally use the anti-lock braking system to stop wheel spin and reduce power from one or more engine cylinders when an electronic sensor detects wheel spin.

Traction

The amount of friction between the tyre and the ground.

Trade-in Value

The amount a dealership credits you for the used vehicle you provide as partial payment for another vehicle. The amount credited is often about 5 percent below the vehicle's wholesale market value.

Transfer Case

On four-wheel drive vehicles, a gearbox that allows power to be delivered to front and rear wheels.

Transaxle

A transmission and differential housed together in the same enclosure. This setup is most commonly found in today's front-wheel-drive-dominated car (not truck) market. The transmission and differential are married together because no drive shaft is required in front-wheel drive (front engine) vehicles.

Transmission

The transmission is used to take the high-speed, low-torque power of the engine and convert it to a lower-speed, higher-torque output, which ultimately turns the drive wheels. Transmissions come in a wide variety of choices, but they basically divide into three categories: Manual, Automatic, and Manumatic. Lower gears allow fast acceleration, higher gears provide better gas mileage. Manual transmission uses a system of gears to create the high torque output required from the engine's high speed input. A clutch is used to disengage the transmission from the engine when shifting gears. Automatic transmissions do the shifting for the driver. No clutch is required. The shifting is accomplished by a hydraulic oil system. Manumatic transmissions are a hybrid of manual and automatic transmissions. In most cases they require no manually operated clutch, but they allow for the driver to shift gears manually when desired.

Tread-Wear Index

A tyre rating consisting of a number followed by two letters, such as 300AB. The number indicates the useful life of the tyre, the first letter (A, B, or C, A for best, C for worst) indicates its traction in wet conditions, and the second letter (A, B, or C, A for best, C for worst) its resistance to heat buildup.

Tri-Link Suspension

A fully independent rear suspension featuring a single fiberglass or composite leaf spring.

Trim Decor

the embellishments added to the cars interior that give it identity an character, such as leather, wood, fabric, chrome etc.

Trim Level

The level of options or features added to a model (as like with a GT version). An optional extra as selected by the customer, like an airbag, doesn't instigate a new trim level. Only the car maker selects the attributes to a car to make it a special variant of the basic version, which is the 'factory standard' version, an is the cheapest within the range.

True MPH

The actual velocity a body moves at as opposed to the reading given by internal instrumentation. Used by speed cameras an police with timing guns in speed-traps.

Tune-up

A regularly scheduled maintenance to check normal operation of the vehicle.

Turbine

An integral piece of the turbocharger, this small fan drives the compressor. A rotor with vanes or blades which is driven by the movement of fluid or gases across its surface. The turbine wheel in a turbocharger spins as a result of exhaust gases. In a torque converter, a turbine is used to propel ATF within the unit.

Turbo Lag

The time it takes the turbocharger to kick in after the driver accelerates; the lag results because a turbocharger compressor is spun by exhaust gases in the exhaust manifold.

Turbocharger

Device that compresses and forces extra air into the intake manifold to produce extra power. Both turbochargers and superchargers are used to produce more power without increasing engine displacement, but neither are particularly fuel efficient and both can require costly maintenance as vehicles age. By forcing fuel through the engine, this system allows the car to gather more speed. Usually they're made by specialist component makers like Roots, X-Trac, Bosch, etc.

Turning circle

The minimum distance a car needs to turn around in one step. A low figure is a prerequisite for a proper Taxi deign, an in the venues of big cities is a regulation.

Twist-Beam Axle

A semi-independent rear axle often used on front-drive vehicles. The horizontal beam, which connects the two rear wheels, can twist to reduce the effect of one wheel's motion on the other. Less expensive and more compact than fully independent suspension.

Understeer

Occurs when the front wheels have lost adhesion or the driver is turning the steering wheel too sharply for the vehicle's speed. In understeer, the front wheels do not follow the steering wheel angle, and the car refuses to turn and pushes ahead. In motor sports, this is called push. The driver can regain traction by reducing speed. Also may be called plow.

Unidirectional tyre

Tire whose tread pattern is designed to get optimum traction only when the tyre is mounted to roll in one direction.

Unitized construction

A type of body construction that doesn't require a separate frame to provide structural strength or support for the car's mechanical components. A unitized body can employ monocoque construction, or it can utilize strong structural elements as an integral part of its construction. Before 1980 cars were built almost exclusively from frames. In other words, underneath everything was a basic rectangular steel assembly. Everything else on the car attached to the frame in one way or another. Today, nearly every car and many trucks are built on the "unibody" concept, for reasons of weight and cost. Unibody construction uses the body assembly itself to create the infrastructure of the vehicle and is constructed in most cases by spot welding together hundreds of smaller metal assemblies. On a modern assembly line you may see automated spot welders sparking away on hunks of sheet metal, eventually forming a car body.

Universal joint

A joint that transmits rotary motion between two shafts that aren't in a straight line. Depending on its design, a universal joint can accommodate a large angular variation between its inputs and outputs. The simplest kind of universal joint, called a "Hooke joint," causes the output shaft to speed up and slow down twice for every revolution of the input shaft. This speed fluctuation increases with the angular difference between the shafts.

Uninsured Motorist Coverage

Insurance which pays for costs resulting from a hit-and-run or an accident with an uninsured motorist.

V6

A vehicle with six cylinders. The cylinders are divided into two banks, each of which is angled away from the other at the top, forming a 'V'. Typically, this angle is 60 degrees on V-6 engines.

V8

A vehicle with eight cylinders. The cylinders are divided into two banks, each of which is angled away from the other at the top, forming a 'V'. Typically, this angle is 90 degrees on V-8 engines

V12

A vehicle with a dozen cylinders. The cylinders are divided into two banks, each of which is facing each other at the top, an slightly forms a 'V' shape. Typically this angle is 30 degrees on most V-12 engines. Occasionally two V6 engines can be combined to act as a V12.

Valve Train

The valves and camshaft(s) within an engine, and any parts attached to the valves, such as rockers and pushrods, to move them up and down.

Valves

Many overhead-cam engines, particularly multi-valve models, are described by the total number of intake and exhaust valves in the cylinder head. A 24-valve V-6 engine would have four valves per cylinder: two intake and two exhaust valves. A 16-valve V-8 engine has only the standard single exhaust and single intake valve for each of its eight cylinders.

Valve gear

The valve number per cylinder and the cam number plus its position.

Valve float

A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valvetrain components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valvetrain.

Valve lifter

Also called a "valve follower": the cylindrically shaped component that presses against the lobe of a camshaft and moves up and down as the cam lobe rotates. Most valve lifters have an oil-lubricated hardened face that slides on the cam lobe. So-called "roller lifters," however, have a small roller in contact with the cam lobe: thereby reducing the friction between the cam lobe and the lifter.

Valvetrain

The collection of parts that make the valves operate. The valvetrain includes the camshaft(s) and all related drive components, the various parts that convert the camshaft's rotary motion into reciprocating motion at the valves, and the valves and their associated parts.

Viscous coupling

A particular kind of fluid coupling in which the input and output shafts mate with thin, alternately spaced discs in a cylindrical chamber. The chamber is filled with a viscous fluid that tends to cling to the discs, thereby resisting speed differences between the two shafts. Viscous couplings are used to limit the speed difference between the two outputs of a differential, or between the two axles of a car.

Van

A box-shaped truck with a forward cab and a cargo area to the back bumper.

Variable-Assist Steering

A power-steering system that varies the amount of assistance it provides according to driving conditions. It provides maximum assistance at low speeds for maneuvers such as turning into a parking space or turning a corner after leaving a stop light. It provides minimum assistance at cruising or highway speeds to provide greater vehicle stability.

Vehicle Identification Number (VIN)

A seventeen-digit identification number, unique to each vehicle, which includes codes for the manufacturer, year, model, body, and engine specifications.

Vented Disc Brakes

A brake disc that has cooling passages between the friction surfaces.

V-Type Engine

In a V-6, V-8 or V-12 engine, the cylinders are divided into two banks, each of which is angled away from the other at the top, forming a 'V'. Typically, this angle is 60 degrees on V-6 engines and 90 degrees on V-8 engines. From the rear are identified by having twin exhaust pipes, an by ear have a deep rumble engine sound.

Waste gate

A valve used to limit the boost developed in a turbocharger. A waste gate operates by allowing some of the engine's exhaust flow to bypass the turbocharger's turbine section under certain conditions.

Water Pump

The pump that circulates coolant through the engine block, cylinder head and radiator. It is driven by the engine crankshaft.

Weight distribution

Measured in Kg, representing the balance, control an stability, with the centre of gravity acting as the fulcrum.

Wheel Size

Determined by the diameter and width of the wheel on which the tyre is mounted. A 15-inch wheel has a diameter of 15 inches. A 15 X 7 wheel has a 15-inch diameter and a 7-inch width.

Wheelbase

The distance between the center of the front wheels to the center of rear wheels.

Wheelstand

A mainstay in drag races, this refers to when the front end of car lifts up during a race. It is also known as a wheelie.

Wheel hop

An undesirable suspension characteristic in which a wheel (or several) moves up and down so violently that it actually leaves the ground. Wheel hop can be caused by many problems, including excessive unsprung weight, insufficient shock damping, or poor torsional axle control.

Wheelspin

When a wheel continues turning after its lost traction during a sharp turn, or looses surface contact while over uneven ground.

Wheel well/arch

The area of space between a wheel and the fender that shrouds it. The arch follows the profile of the wheel size.

Wing

2 body panels that exist either rear side, beneath the trunk cover, partly enclosing the rear-wheel-space.

Winston Cup

The high-point of NASCAR racing, a race that spans the entire season as drivers accumulate points at each of 31 events. The driver that accumulates the most points, not the most wins, becomes the eventual Winston Cup winner.

Woody

Refers to a vehicle which has part of its side body-panels covered or replaced with decorative wood.

X series

The name given to the famous chassis designs used by Jaguar since the 1960s, such as the XJ, XK an X-type.

X-ray detection

This is used by law enforcement agencies when searching for illegal materials concealed within the door panels an bodywork of cars, such as Semtex an heroin.

Yaw

The rotation about a vertical axis that passes through the car's center of gravity.

Yugo

The only car company named after a country that no longer exists, ie Yugoslavia.

Zero-offset steering

A steering system whose geometry has a scrub radius of zero. This configuration minimizes the steering effects produced during acceleration (with front drive) or braking on varying traction surfaces.

Z-axis

The plain of movement a road vehicle cant access.

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Surface coatings to increase the tool wear life

noreply@blogger.com (Industrial age to information age) — Fri, 01 Apr 2022 05:19:00 +0000

Surface coatings to increase the tool wear life

Producing intricate shapes quickly with excellent precision and good surface quality at a low cost is one of the advantages of die casting. But, maintaining this advantage is difficult. A die casting die can cost more than the machine that operates the die. Die casting is hard on dies and die components and pulling the dies and pins for repair and/or to polish them is costly.

To help maintain the advantages of die casting and production up time, die life needs to be extended by reducing repairs. A tool treatment process called thermal diffusion (TD) can help die casters reduce maintenance and repairs and extend core and core pin life.

The TD process prolongs die life by decreasing the damage caused by thermal and mechanical cyclic loadings and the reaction with active cast materials that severely damage dies and die components. It reduces the soldering, corrosion, erosion, wash-out, wear and heat checking from the loadings and reactions with other materials. It also provides excellent peel and adhesion strength. Die life is significantly extended and repairs and polishing are reduced.

The process also helps protect aluminum die casting dies which are especially vulnerable to die casting problems.

One of the reasons it works effectively in die cast operations is found in the process itself. During the treatment process, the substrate surface of the core and core pins is modified, creating a metallurgically bonded non-porous vanadium carbide (VC) layer.

The VC layer is infused into and onto the dies and die components (Fig. 1 & 2). This VC layer is .0001- to .0006-inch thick and has a hardness of 3200 Vickers at room temperature.

Even under the high working temperatures used in die casting, the VC layer retains its hardness level. And, once the die is cooled to room temperature, the original hardness of VC is restored to previous levels.

For example, at 800° Centigrade, the hardness of the VC layer drops to approximately 900 Vickers, which is still above the hardness of other treated surfaces. As the VC layer cools to room temperature, it returns to near its original hardness of 3200 Vickers. Its ability to maintain its hardness under high temperature applications allows it to perform well in casting operations.

The process also is effective in die cast operations because the hardness of the VC layer is higher than abrasives such as aluminum oxide, which is found in hone stones and sandpaper used for polishing cores and pins. This allows any aluminum that mechanically sticks to a pin to be easily removed without significant damage or dimensional change to the pin. Polishing time and the resultant wear on the pin are greatly reduced.

What is TD?

Developed in Japan in 1969 at the Toyota Central Research and Development Laboratories, Inc. by Dr. Tohru Arai, the TD process is a high-temperature tool treatment. During the process a nonporous metallurgically bonded vanadium carbide (VC) layer is diffused into and onto tooling substrate. The VC layer is .0001- to .0006-inch thick and has a hardness of 3,200 to 3,800 on the Vickers hardness scale. The VC layer retains its hardness under high temperature working conditions like die casting.

Because the VC layer is diffused into and onto the tool substrate, it significantly reduces wear, soldering and corrosion and provides superior peel strength and adhesion strength. It extends the life and performance of core pins, dies, punches and tooling by 5 to 50 times and more.

The process is effective with air-hardening cold and hot working die steels such as A2, D2 and H13, high speed steels and cemented carbides. The steels should have a .2 percent or greater carbon content.

In Japan, the treatment process has been shown to be especially effective with conventional hot working die steels such as H13, a tool steel typically used to make die cores and core pins (see Fig. 3). Damages caused by die casting were significantly reduced. The results from European die casters tooling treatment have been detailed in several European publications as well as Die Casting Engineer.²

By using treated tooling, the Japanese also realized other benefits. They reduced interruptions in the production process, helping to eliminate the reconditioning of the casting condition. This reduced cast scrap and energy usage.

The surface quality and dimensional accuracy of cast products were also improved. Using the treatment process meant less sticking of cast materials on pins. The improved surface quality and dimensional stability of the cored surfaces also allowed thread tools to last longer.

Benefits from Using TD

Improves pin life 10 times or more by reducing corrosion and erosion damage which can cause pin breakage
during cast ejection.
Reduces polishing work which can damage pin surface.
Increases casting shots several to ten times or more in comparison to polishing to remove stuck aluminum.
Drastically reduces cleaning operations to remove pickup.

Decreases die repair work and soldering since it reduces the tendency of aluminum to mechanically attach to die surface. When soldering occurs, adhesion can easily be removed by polishing with a scotch-brite pad or emery paper without taking die sets out of production.

Production Evaluation of Coatings and Surface Treatments for Die Casting Dies

Interaction between the die surface and cast metal leads to both mechanical and chemical degradation of the surface. The mechanical degradation is caused by the high speed impingement by the melt particles of the die surface near gates. This type of die wear is called washout. The chemical affinity of the cast metal atoms for the die surface leads to the formation of intermetallic layers at the interface. This phenomenon is called soldering. Production experience has shown that oxide layers and other protective layers on the die surface successfully retard the onset of soldering and washout of these surfaces. There are many surface engineering techniques and a wide range of coatings available in the market which are potential candidates for soldering and washout prevention. The quest is to identify suitable candidates to combat the harsh die casting conditions. As part of this quest, production evaluation campaigns are being held at die casting companies with varying matrix of die wear problems. These production campaigns will help pinpoint the best surface engineering technique and composition for maximum die life increases in a predetermined production campaign. The first production campaign was held at Pace Industries in Monroe City, Mo. In this campaign, the use of coatings (chromium carbide, chromium nitride and vanadium carbide) significantly reduced the soldering tendency and the soldering-related downtime was totally eliminated for the production run of 180,000 shots. The results of this campaign were reported in an earlier paper published in the 1997 NADCA Transactions. This paper contains details of the second campaign that was run at Premier Tool in September-December 1998.

Premier Tool & Die Cast Corporation in Bemen Springs, MI, was selected as the ß-test site for the production evaluation campaign presented in this paper. The objective of the production evaluation campaign at Premier was to evaluate promising coating compositions and application techniques for their efficacy in preventing the occurrence of soldering on the core pins in the two 16 cavity dies for suspension mounts. This campaign was designed to involve both surface treatments and surface coatings.

Production Evaluation/Process Conditions

Premier offered a challenging testing environment in its high volume 16 cavity die. The die was used to produce automobile suspension mounts. The problems associated with the 16 cavity die were not solely soldering-related. There were issues regarding cooling, gating and load bearing capacity of the ejector pins too. Parts were sticking to the ejector half. The cores were snapping at the head. Soldering on the cores was severe especially near the parting line. The cores were removed 1-2 times every shift for polishing. 1-4 cores broke per run. The die had to be removed every 5,000 shots for die maintenance.

Premier addressed some of the above problems by incorporating design changes. The dimensions of the core were modified to eliminate the breaking of the head. Heating and cooling lines were provided within each core to reduce the occurrence of potential hot spots that would promote soldering. The dimensions and position of the ejector pins were modified to facilitate ejection.

Coating/surface treatment selection criteria

Premier, in its 16 cavity die, offered many potential sites for severe soldering and washout problems. The cores on the cover half of Die 2 did not possess a cooling line and were highly prone to soldering. The geometry of the core pins was complicated with non-uniform dimensions that made efficient heat transfer tough. Hence an effective coating or surface treatment candidate, for combating the conditions at Premier, needed to possess the following properties:

Sound adhesion to the substrate
Sufficient hardness and toughness
Low chemical affinity for and low solubility in molten aluminum
Superior oxidation resistance
Good thermal and impact shock resistance
High thermal conductivity to dissipate heat from the interface quickly
Compatible Coefficient of thermal expansion with the
substrate

A potential surface engineering technique should be able to deposit the coating uniformly in spite of the complexity of the geometry. This surface engineering technique could either be a coating deposition process or surface treatment process.

If material with desired properties is added to the surface, then the process is called a Coating Deposition Process
If the chemistry and/or micro-structure of the substrate of the base material is altered, then the process is called a Surface Treatment Process

Physical Vapor Deposition (PVD) coating

Physical Vapor Deposition (low deposition temperature) and Thermo-reactive diffusion process (high temperature deposition process) were identified as potential coating techniques. Nitriding and Carburizing were identified as potential surface treatment techniques. A duplex treatment was also included in the design to compare the performance of a surface textured PVD coating and a smooth PVD coating. The micro texturing of the substrate was provided by shot micro-peening. Three coatings, CrNx, CrxCy and BxC, were the selected physical vapor deposition (PVD) coatings and VC was the selected thermo-reactive diffusion (TRD) coating. CrNx (PVD) on shot peened substrate was the selected duplex treatment. Ferritic Nitro carburizing and ion nitriding were the selected surface treatments. Table 1 includes relevant information about these selected candidates.

Physical Vapor Deposition (PVD) processes deposit coatings on a substrate atomistically, i.e. atom by atom. The material to be deposited is transported in the form of vapor, either through a plasma or vacuum, to the substrate on which the vapor condenses. The source for the vapor could either be thermal or non-thermal. These processes can deposit both single elements and compounds as coatings. The thickness of the coatings can vary from a couple of nanometers to a few millimeters. All PVD processes are line of sight processes. Usually, PVD coatings possess columnar structure which is not as good as equiaxed structure in combating liquid metal corrosion. The columnar grains provide a pathway for the molten alloy to diffuse through. Physical Vapor Deposition is classified into three types: evaporation, sputter deposition and ion plating. The production campaign had candidate coatings applied by either evaporation process or by sputter deposition.

Arc Evaporation: Vacuum evaporation takes places at gas pressure ranges of 10^-5 Torr to 10^-9 Torr. The coating material is in an electrically neutral state and is expelled from the surface of the source at thermal energies typically from 0.1 to 0.3 eV The substrate is preheated to elevated temperatures (200 to 1600°C) for dense and equiaxed grain morphology.

CrNx: This coating was provided by Multi-Arc Inc which utilized the arc evaporation process to deposit the coating. In this process, a vapor plasma is generated by striking an arc between the solid cathode (target) and the arc source. The arc melts a small area (10 micrometers) of the cathode surface generating metal droplets (Cr), ions and large volume of free electrons. This vapor is highly ionized (up to 80%) and arrives at the substrate with high energies (50 eV). The substrate temperatures are in the range 200 to 550°C. Nitrogen gas is inducted in the vacuum chamber to create nitrides. Process times are of the order of 4 hours for a coating thickness of 6 microns.

Sputter Deposition: In this process, the substrate is deposited with particles vaporized from a surface, which is called the sputtering target. It is a non-thermal vaporization process where the coating material is dislodged from the surface of the target by momentum transfer from energetic particles which bombard the surface. The substrate is positioned in front of the target so as to intercept the flux of sputtered atoms. Sputter deposition can be performed in a vacuum or low pressure gas (<5 mTorr). Sputter deposition can also be deposited at higher gas pressures (5-30 mTorr).

CrxCy: This coating was provided by Balzers Tool Coating Inc., which applied it by the e-beam sputtering process. In the e-beam evaporation process, the surface of the workpiece is bombarded with noble gas ions in order to remove contaminants and to sputter off some substrate material. These substrate atoms then condense with the coating element (Cr) which is then evaporated in the second stage. Reactive gas (carbon) is then introduced into the chamber, which combines with the chromium ions on the surface of the workpiece to form hard CrxCy coatings.
BxC: This coating was provided by Diamond Black Inc. It was applied by magnetron sputtering process, which is performed at low temperature (250°F). The coating was vacuum sputtered to a thickness of 0.00008" or 2 microns at 250°F.

Thermo-Reactive Diffusion Process

In the TRD process, the carbon and the nitrogen in the steel substrate diffuse into a deposited layer with carbide-forming or nitride-forming elements such as vanadium, niobium, tantalum, chromium, molybdenum or tungsten. The diffused carbon or nitrogen reacts with the carbide and nitride forming elements in the deposited coating so as to form a dense and metallurgically bonded carbide or nitride coating at the substrate surface. The possibility of distortion is present with this high temperature process. Dimensional changes due to the high phase transformations in the heat treatment of the base steel and the formation of the carbide layer are a good possibility. The coatings formed have a fine and nonporous composition. Though the diffusion layer is thin, it is very dense and shares a sound metallurgical bond with the substrate.

VC: This coating was supplied by Arvin TD using the TRD process. The high temperature salt bath TRD process was performed in a molten borax bath at 850 to 1050°C (1560 to 1920°F). Immersion time ranges from 0.5 to 10 hours to obtain an optimum carbide layer thickness of 7 -10µm.

Duplex Treatment

Metalife+ CrNx; The duplex coating was formed by first shot peening (micro-shot) the substrate and then coating it with CrNx (Arc Evaporation PVD). The CrNx coating was applied by the arc evaporation technique by Multi-Arc. The shot peening treatment was supplied by Badger Metal. Badger Metal Technologies applied a patented micro-peening treatment (Metalife) on the core pins and the DME pins. The treatments for die casting are categorized by "T" processes (T10, T21, T41, T61 and the newer T71). The surface of the pin is impacted with special media, a temporary plastic flow of the metal (with penetration depths of 0.010 to 0.015 in. on 44 to 48 HRC surface) results in generation of compressive residual stresses inside the peened surface layer.

Surface Treatments

Ferritic Nitrocarburizing: Ferritic Nitrocarburizing processes are thermochemical processes, which involve the simultaneous diffusion of both nitrogen and carbon to the surface of ferrous materials at temperatures completely in the ferriric phase field. The primary objective of such treatment is to improve the anti-scuffing characteristics of ferrous engineering components by producing a "compound layer" on the surface, which has good tribological properties. A single phase epsilon carbonitride compound layer is produced supported by nitrogen rich subsurface diffusion zone. Dynamic Metal Treating Inc. uses fluid bed (salt bath) ferriric-nitrocarburizing at (600°F to 1000°F) and steam blueing. The ferriric carburizing process takes between 4 to 12 hours. Steam blueing is achieved by sealing in a tempering furnace at 350°C to 370°C and introducing steam. This process creates a blue black surface finish due to the formation of a tight blue oxide layer. A surface hardness higher than 70 HRc is achieved. The growth in dimensions, due to the process are, of the order of 0.0001 to 0.0002" per side. Typical compound zone depths of 0.0005 to 0.001" and case depths of 0.005" are achieved. Dynablue 10B was used in the tests.
Ion Nitriding: Ion nitriding is an extension of the conventional nitriding process using the plasma-discharge physics. In vacuum, high-voltage electrical energy is used to form plasma through which nitrogen ions are accelerated to impinge on the work piece. This ion bombardment not only cleans the work piece surface but also heats up the surface and provides active nitrogen for nitriding. Two different companies supplied the ion nitriding treatments for the campaign at Premier.

a) Ultralow: Ultralow process, applied by Advanced Heat Treat, is basically ion nitriding process with treating conditions optimized to reduce the white gamma prime compound zone on nitride surface. The nitriding parameters were adjusted to yield an average surface hardness of 90 to 94 HR15N on the core pins for Premier Tool and Die Cast and 90 to 91 on the DMG pins. The case depths are maintained from 0.006 to 0.008 in.

b) Ion Wear: lon Wear treatment was provided by Sun Steel. This process involves a combination of ion nitriding at 400 to 565°C and steam treating (oxidation). This diffusion treatment creates a multi-layer composed of complex oxy-carbo-nitrides up to 0.0004" (10 micrometer) and case depths up to 0.025" (0.6 mm). For the Premier test the treatments had a surface hardness of 800-850 HV1, a compound layer of 0.0002 in (5 microns) thick and case depth of 0.005 to 0.0009 in (75 to 125 microns)

Diffusion Carbide Coating for Distortion Control

Carbide coating by TRD (Thermo-Reactive Deposition and Diffusion) can ensure very high adhesion strength of the carbide layers onto substrates due to the nature of the carbide formation mechanism. Carbide coatings made by this method have very good resistance to erosion and corrosion against molten cast metals.

Therefore, carbide coating by TRD has large potential to prevent failures of mold components used in die casting and other casting methods and to provide tremendous benefits to the die casting industry. In fact, many field test results recently obtained are accelerating the wide application of the process in the American die casting industry as in Japan, where the process has been successfully used since the mid-1970s.

TRD coating is usually carried out at temperatures similar to hardening temperatures for steels; for example, 1877°F (1025°C) for H-13. Steel substrates are quench-hardened during cooling from the coating temperatures and followed by tempering. Therefore, distortion may occur. Overcoming distortion was the key point for successful application of the process. Working surfaces of the molds must meet required dimensional specifications on completion of the coating operation since the coated molds are put into use without a finishing process. Carbide layers formed in the TRD process are too thin to be polished off for dimension control.

Distortion in application of high temperature coating processes such as TRD and CVD is often overstated by recalling the distortion in ordinary hardening of steels. People often expect the degree of distortion to be similar to that in ordinary hardening of die molds based on past experience. This thinking is not correct. Ordinary hardening is done in most cases on the premise that the articles are to be ground to the finish size with grinding allowance large enough to get the finish size. This premise lessens the incentive to heat treaters to minimize distortion. Equipment and procedures are well organized and extra care is usually taken in the coating application to minimize distortion. Furthermore, ordinary hardening is applied to annealed steels while TRD coating, in most cases, is applied to already hardened steels. This brings about a good effect on dimensional change due to a smaller difference in microstructure change before and after TRD processing. Thus, the coating has been successfully applied to very close tolerance tools with tolerances of some µm in diameter. Following is an explanation of causes and countermeasures for distortion and some examples of results obtained on die casting molds.

Criteria of distortion

Dimension (size) change: Symmetric change and shape of tools remains unchanged ("a change of size without a change of shape"). This includes size difference between the edges and in the center of the faces.

Deformation: Non-symmetric and shape is changed ("a change of shape and size").

Most tools change shapes to barrel or spool, more or less, depending on the shape and size of molds, and the coating condition. This is usually symmetric and stays in the category of dimension change.

Deformation becomes evident by curvature of long axes of slender tools and non-symmetric-shaped tools. Another typical one is out-of-roundness of ring-shaped tools.

Dimension of molds after TRD coating

Dimensions of molds will be changed by the following two reasons:

Buildup of carbide on substrate
Dimensional change of substrate material before and after the coating operation.

The dimension of tools after the coating, therefore, can be shown in relation to the initial dimension:

Da = Db + 2 Tc + D
Da ; Dimension after coating
Db ; Dimension before coating
Tc ; Thickness of coatings
D ; Dimension change of substrate

Carbide layer thickness, Tc, is usually selected from 0.0002 to 0.0005 in. (5 to 12 µm) in die casting application regardless of shape, size and kind of mold components to be coated. Tc can usually be small enough to not be a concern. D can be much larger than Tc in the case of large cores, large core pins, etc., depending on various factors and should be a more serious concern than Tc. Under-sizing or over-sizing to the targeted final dimension can compensate for the possible dimensional changes. Therefore, scattering of Db, Tc, and D should be of more serious concern rather than their individual values.

Causes of the dimension change and related factors

Tc is controlled mainly by TRD bath temperature, immersion time in the bath, and bath control and has a very minor effect. Scattering of chemical composition and microstructure of substrate steels can change the thickness of carbide layers through scatter of carbon content in the matrix phase (austenite) at the coating temperatures. However, this problem is not serious in H-type steels widely used in die casting since they contain relatively small carbon and alloying elements. Therefore, scattering of Tc can usually be out of consideration in die casting applications.

D and its scattering can be affected by a number of factors related to the shape and size, substrate materials, heat treating condition, and coating condition. Volumetric change of the substrate by change of microstructures of the substrates is the primary reason for D. That is to say, from pearlite to martensite and retained austenite, (in the case TRD on the un-hardened molds), change in amount of austenite (in the case of TRD on hardened substrates), and tempering of martensite. However, D is not isotropic.

The size and shape of molds highly affects the difference in temperature between the surface and core during hearing or cooling which produces thermal stress and transformation stress. The barrel- and spool- shaped changes are determined not only by the values of these stresses but also the sequence in time by which the transformation stress is added to the thermal stress. Temperature differences and stresses will also be induced by change of thickness within a mold. Larger size, higher temperature, and larger rate of heating and cooling will make D more considerable.

The banded structure in forged and rolled steels, which is large amounts of carbide particles in a line parallel to the rolling direction, make the expansion and construction heterogeneous. This carbide alignment usually leads to larger size movement in length than in diameter, thickness and width. The banded structure is determined not by the size of steel stocks but by steel making processing, including ingot size, forging ratio, and rolling direction etc.

Size change of tools can occur even at room temperature by transformation of "retained austenite" (high temperature phase of steel) to "martensite" (the phase caused by quench-hardening of steel). Except for tools that need very strict dimensional tolerance, this change of size is usually negligible.

In some cases, some factors are very serious and others are small and negligible.

Causes of deformation and related factors

Distortion is formed by the following reasons:

Non-uniform heating and cooling during high temperature coating and heat treatment
Non-uniform micro-structure in substrate material

Residual stress produced during tool making, such as machining and grinding.

Creep by gravity during high temperature coating and heat treatment.

Most heating and quenching equipment is not likely to make uniform heating and cooling within tools. The complicated shape accelerates this tendency. Not enough spacing between molds, or molds and basket components also results in differences of the heating and cooling rate. The heterogeneous microstructure in forged and rolled steels gives rise to different transformation temperatures and the time lag in transformation within a mold leading to deformation. Improper machining conditions bring about residual stress in molds, and relieving of the stress at high temperature can cause deformation, if heating rate is high. Steels have very small yielding stress at high temperature. The loading of self-gravity easily results in deformation such as warpage of long slender cools loaded in the baskets in such a way that the end of tools arc placed on the basket bottom, or disk shaped tools placed on a plate with bend, for example.

How to get TRD coated molds with minimum distortion

Following are some countermeasures to ensure minimized distortion:

Select good type of substrate materials
Select premium quality materials
Cut out molds from steel stocks in consideration of rolling direction
Machine and grind under proper condition to minimize residual stress
Make molds with tight dimensional control
Apply under- or over-sizing on targeted size
Harden molds under precisely controlled conditions
Apply TRD coating under precisely controlled conditions
Control movement and deformation by selection of proper tempering conditions
Apply deformation correction after TRD coating
Design mold with consideration of finish grinding on non-working surface to ensure extremely tight tolerance.

As mentioned before, the H-type steels are basically good materials. It is, however, highly recommendable to use steel stock produced by the same steel maker since there is some scattering in quality, difference in smelting method, forging ratio, and scattering of chemical composition etc., between steel makers and even between steel stock made by the same steel maker.

Bending

Bending of pins was measured on two long pins. A pin 7 in. (180mm) long with 0.4 in. (10 mm) shank diameter and long tapered portion bent about 0.003 in. (0.08 mm). Another pin 7 in. (180 mm) long with 0.6 in. (15mm) shank diameter and short taped working area bent 0.0016 to 0.0024 in. (0.04 to 0.06 mm). These bending were successfully corrected by pressing.

Out-of-Roundness

Deterioration of out-of-roundness was evaluated in several examples. Out-of-roundness of the un-hardened round core specimens increased only 0.00015 - 0.00047 in. (4 - 12 µm) in both ID and OD. Those of hardened round core specimens showed only small increases: 0.00004 - 0.0004 in. (1-10), and 0.00008 - 0.00075 in. (2 - 19 µm).

Range of Diameter and Length

The relation between the range (maximum — minimum) of diameter and length were investigated, in the core pins before coating and those after the coating. The size range can increase by max. 0.00067 in. (17 µm) in diameter and max, 0.0018 in (40 µm) in length. Making the molds with minimized scattering of dimension should be the first step to satisfy the tight dimensional tolerance.

Application to die casting molds

As for TRD application, benefits similar to those obtained in Japan were reported in the USA two years ago. The application in American die casting is now being accelerated and a large number of pins and cores have been put into production reporting satisfactory results. Application on various types of pins including squeeze pins ranging in size from very small pins such as 0.157 in. (4 mm) in shank diameter to large pins as 1.57 in. (40 mm) in shank diameter and 19.7 in. (500 mm) long. Some types of core inserts with very complicated shapes, and sprue cores with 6 in. (150 mm) in diameter have been successfully used. Substrate steels are usually H-13 and other H type steels. Modified high speed steels are rarely used.

Conclusive Summary

It seems to be commonly believed that high temperature coating processes cannot be applied to dimensionally tight products. This is not necessarily true. Punch makers in Japan have been making standard type punches for metal stamping with 0.00008 to 0.00012 in. (2 to 3 µm) tolerance in diameter and less than 0.0002 in. (5 µm) in bend for more than twenty years. The results of Example 1 and others suggest that die casting pins with similar tolerances can be made without difficulty by well-considered procedures. It cannot be expected to industrially realize similar tight tolerances for some large cores, especially with complicated shapes. However, the examples of actual applications shown in the previous paragraphs suggest that even relatively large cores can be successfully TRD coated, satisfying the required tolerance.

Unfortunately, a number of factors relate to distortion problems, most of which are out of the die caster's specialty. It should be emphasized that to easily control all these factors, the die caster should keep in close contact with steel makers, heat treaters, tool makers and especially with the coaters if he wants to apply the high temperature coating process to tight tolerances molds. The extra effort will be worthwhile and shown through cost savings.

Cleaning and coating procedure:

1) Cleaning Procedure:

a) Incoming Inspection of the Tools.

b) De-greasing using Alkaline Solutions.

c) Removal of In-organic contaminants using Aluminum Oxide powder and Aluminum Oxide Slurry.

d) Rinsing the tools with Water.

e) Drying tools using Dry Air.

After drying the tools are loaded in the appropriate fixture and taken up for the next step of coating.

2) Coating Procedure:

a) Loading the tools with the fixture inside the coating chamber.

b) Creating vacuum to a level of 10^-5 Torr.

c) In-situ plasma cleaning of the tools and heating them using radiant heating to 200°C.

d) Creation of Ti ions by striking arc on the surface of the source.

e) Bombardment of Ti ions and introduction of N₂ gas.

f) This forms TiN and gets adhered to the Tools.

3) The tools removed from the coating chamber and are allowed to cool in atmosphere.

4) Post- coating inspection of the tools is carried out prior to dispatch.

References

1. Ford, Eric, Special Coatings Improve Die and Mold Performance, DIE CASTING ENGINEER, Sept./Oct. 1990, p. 36.
2. Arai, T., "Research and Applications of Carbide and Nitride Coatings onto Aluminum Die Casting Molds in Japan," NADCA Transactions, T95-102, p. 327.

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A to Z Terminology of surface treatment and heat treatment

noreply@blogger.com (Industrial age to information age) — Thu, 31 Mar 2022 04:43:00 +0000

A to Z Terminology of surface treatment and heat treatment

Abradable coatings

Coatings which are designed to rub down against the action of a mating surface to form a tight gas or air seal.

Abrasion Resistance - Degree of resistance of a material to abrasion or wear.

Abrasive – A substance used for grinding, honing, lapping, superfinishing, polishing, pressure blasting or barrel finishing. It includes natural materials such as garnet, emery corundum and diamond and electric-furnace products like aluminum oxide, silicon carbide and boron carbide.

Abrasive blasting – A pressurized stream of hard metal or oxide grit material used to clean and / or roughen surfaces prior to coating.

Abrasive wear – Wear caused by hard, sharp particles.

Accm, Ac1, Ac3, and Ac4 – Defined under transformation temperature.

Acetylene C2H2 - Unsaturated aliphatic hydrocarbon gas. Used as a fuel gas in combustion thermal spray processes, welding and cutting. Acetylene has the highest flame temperature and requires the smallest amount of oxygen to form a neutral flame.

Acicular Ferrite – A highly sub-structured conequiaxed ferrite that forms upon continuous cooling by a mixed diffusion and shear mode of transformation that begins at a temperature slightly higher than the temperature transformation range for upper bainite. It is distinguished from bainite in that it has a limited amount of carbon available; thus, there is only a small amount of carbide present.

Acoustic emission – Acoustic emissions are sound or ultrasound pulses generated during crack initiation or propagation in materials and coatings as a result of being subjected to stress. Acoustic emissions can be detected by transducers.

Adhesion - The ability of a coating to remain on the surface without spalling, flaking or cracking. Adhesion is probably the single most important property of a coating.

Adhesion scratch test - Currently the most commonly used method of assessing coating adhesion. Used in the analysis of organic and inorganic soft and hard coatings. Examples are thin and multiplayer PVD, CVD, PECVD, TD, photoresist, paints, lacquers, and many other types of films, covering optical, micro-electronic, protective, decorative and other applications. Substrates can be hard or soft, including metals, alloys, semiconductors, glass, refractive and organic materials. Scratch testing consists of introducing stresses at the interface between coating and substrate. This is achieved by pressing a diamond stylus on the sample surface with a normal load FN. As the sample is displaced at constant speed, the resulting stresses at the interface cause flaking or chipping of the coating. The minimum load at which a specific failure event is recorded is call the Critical Load (Lc). See Critical Load.

Adhesive Wear - Wear caused by sliding surfaces, where surface asperities interact and adhere.

Aecm, Ae1, Ae3, and Ae4 – Defined under transformation temperature.

Aerated bath nitriding – A type of liquid nitriding in which air is pumped through the molten bath creating agitation and increased chemical activity.

Age hardening – Hardening by aging, usually after rapid cooling or cold working. See also aging.

Age softening – Spontaneous decrease of strength and hardness that takes place at room temperature in certain strain hardened alloys, especially those of aluminum.

Agglomerate - Several particles adhering together.

Agglomerated powder - A mechanically mixed combination of fine particles of different materials held together with an organic binder and formed into power particles.

Aging – A change in the properties of certain metals and alloys that occurs at ambient or moderately elevated temperatures after hot working or a heat treatment (quench aging in ferrous alloys, natural or artificial aging in ferrous and nonferrous alloys) or after cold working operation (strain aging). The change in properties is often, but not always, due to a chemical composition of the metal or alloy. See also age hardening, artificial aging, interrupted aging, natural aging, overaging, precipitation hardening, precipitation heat treatment, progressive aging, quench aging, step aging.

Air Cap - A component of thermal spray guns used for shaping the air flow for atomizing the wire or rod feedstock.

Air classification - The separation of powder into particle size fractions by means of an air stream of controlled velocity.

Air-hardening steel – steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. The terms should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 in. (50 mm) or more in diameter. Same as self-hardening steel.

Alkyd resin - A type of polyester resin used in paints and other surface coating. The original alkyd resins were made by copolimerizing phathalic anhydride with glycerol, to give a brittle cross. Linked polymer.

Allotropy – A near synonym for polymorphism. Allotropy is generally restricted to describing polymorphic behavior in elements, terminal phases, and alloys whose behavior closely parallels that of the predominant constituent element.

Alloy – A substance having metallic properties and being composed of two or more chemical elements of which at least one is a metal.

Alloying element – An element which is added to a metal (which remains within the metal) to effect changes in properties.

Alloy steel - Steel containing specified quantities of alloying elements (other than carbon and the commonly accepted amounts of manganese, copper, silicon, sulfur, and phosphorus) within the limits recognized for construction alloy steels, added to effect changes in mechanical or physical properties.

Alpha ferrite – See ferrite.

Alpha iron - The body-centered cubic form of pure iron, stable below 910°C (1670°F).

Alumina - Aluminum Oxide compound used in both abrasive blasting as an abrasive and in thermal spraying as a consumable feedstock (powder and rod) for the production of coatings. Alumina is a hard wear resistance ceramic and can be alloyed with various amounts of titania (titanium dioxide) to improve certain properties.

Aluminizing (gas) -- High temperature (approx 900°C) pack or gaseous diffusion of aluminum into the surface of a component to enhance high temperature corrosion and oxidation resistance.

Aluminizing (hot dip) - A liquid aluminum submersion technique at temperatures above 600°C depositing layer of aluminum (usually on steel sheet) for enhance corrosion protection

Aluminizing (thermal spray method) - Thermal sprayed coatings of aluminum usually on substrates of steel or nickel chromium alloys which are subsequently heat treated to aluminize the surface.

Aluminum (Al) – Used to deoxidize steel and control grain size. Grain size control is affected by forming a fine dispersion with nitrogen and oxygen which restricts austenite grain growth. Aluminum is also an extremely effective nitride former in nitriding steels.

Aluminum Ion Plating - The deposition of aluminum by a vacuum evaporative process. Provides galvanic corrosion resistance. Normally given a passivation treatment.

Amorphous - Non-crystalline, or devoid of regular structure.

Anion - A negatively charged ion.

Annealing – A generic term denoting a treatment, consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. The purpose of such changes may be, but is not confined to: improvement of machinability, facilitation of cold work, improvement of mechanical or electrical properties, and/or increase in stability of dimensions. When the term is used without qualification, full annealing is implied. When applied only for the relief of stress, the process is properly called stress relieving or stress-relief annealing.
In ferrous alloys, annealing usually is done above the upper critical temperature, but the time-temperature cycles vary widely in both maximum temperature attained and in cooling rate employed, depending on composition, material condition, and results desired. When applicable, the following commercial process names should be used: black annealing, blue annealing, box annealing, bright annealing, cycle annealing, flame annealing, full annealing, graphitizing, intercritical annealing, isothermal annealing, malleablizing, order hardening, process annealing, quench annealing, spheroidizing, subcritical annealing.
In nonferrous alloys, annealing cycles are designed to: (a) remove part or all of the effects of cold working (recrystallization may or may not be involved); (b) cause substantially complete coalescence of precipitates from solid solution in relatively coarse form; or (c) both, depending on composition and material condition. Specific process names in commercial use are final annealing, full annealing, intermediate annealing, partial annealing, recrystallization annealing, stress-relief annealing, anneal to temper.

Annealing carbon - Fine, apparently amorphous carbon particles formed in white case iron and certain steels during prolonged annealing. Also called temper carbon.

Annealing twin - A twin formed in a crystal during recrystallization.

Anneal to temper - A final partial anneal that softens a cold worked nonferrous alloy to a specified level of hardness or tensile strength.

Anode – The positive electrode in a plasma spray torch (gun). Generally made from copper but can be lined with tungsten to increase life. See also cathode.

Anodic coating -A coating that becomes the anode in an electrochemical cell with the substrate (cathode). The only metals in common use for thermal spraying which are anodic to iron and steel are zinc and aluminum.

Anodizing - The production of an oxide layer on aluminum alloys. The process is electrolytic, a typical electrolyte being sulfuric acid. Treatment at room temperature produces thin, decorative layers with some corrosion protection. Treatment at 0°C produces hard, thicker layers (up to 100µ) with wear resistance. They can be post sealed to give improved corrosion resistance.

Antireflection coating (AR coating) - A coating whose reflection is zero, used for lenses. They are usually fabricated by the technique of interference oscillations with a He-Ne laser.

Apparent density - The weight of a unit volume of powder or coating

Apparent hardness – The value obtained by testing a coating or sintered material with standard indentation hardness equipment. See macro hardness. Since the reading reflects a composite of pores and solid material, (which may be particles relatively poorly bonded together) it is usually lower than that of an equivalent solid wrought or cast material. Not to be confused with particle hardness. See micro hardness.

Arcm, Ar1, Ar3, Ar4, Ar’, Ar” – Defined under transformation temperature.

Arc Blow (Plasma) - Arc blow is the deflection of an electric arc under the influence of the magnetic field associated to the flow of electrons (electric charge), which results in arc instability. Arc blow can be reduced and minimized in plasma welding by an appropriate design of shape and sizes of the electrodes (namely cathode tip and anodic nozzle plenum).

Arc Wire Spraying - A thermal spray process in which two electrically conducting wires are brought together to form an electric arc. The consequent molten metal is then projected by an air stream towards the work piece to form a coating.

Argon (Ar) - Monatomic noble gas, atomic number 18, one of the most inert elements. Commonly used as a plasma gas for plasma spraying and providing inert environments for many processes.

Artificial aging – Aging above room temperature. See aging. Compare with natural aging.

Athermal transformation – A reaction that proceeds without benefit of thermal fluctuations; that is, thermal activation is not required. In contrast, a reaction that occurs at constant temperature is an isothermal transformation; thermal activation is necessary in this case and the reaction proceeds as a function of time.

As cast - Referring to metal which has not received finishing (beyond gate removal or sandblasting) or treatment of any kind including heat treatment after casting. Similarly, as drawn, as forged and as rolled.

Atomization - The dispersion of a molten material into particles by a rapidly moving gas or liquid stream or by mechanical dispersion.

Atomic force microscopy (AFM) – An extremely accurate and versatile technique for measuring structures or surface forces. A very fine sensor tip mounted to the end of a small deflecting spring, known as a cantilever, is brought into contact with the sample surface to be investigated. The sensor tip is moved across the surface in numerous line scans. Due to the surface roughness (topography), the tip and the cantilever move up and down. This movement can be measured with high resolution and the resulting data allows imaging of the surface structure. Also called scanning probe microscopy.

Atomized powder - A powder produced by the dispersion of a molten material into particles by a rapidly moving gas or liquid stream or by mechanical dispersion.

Atmosphere - The gaseous environment in which the metal being treated is heated for processing. Atmospheres are used to protect from chemical change or to alter the surface chemistry of steel through the addition or removal of carbon, nitrogen, hydrogen, and oxygen and to add certain metallic elements as chromium, silicon, sulfur, etc.

Auger Electron Spectroscopy (AES) - An electron beam technique applied for near-surface elements identification. well used in thin film science.

Ausforming – Thermo mechanical treatment of steel in the metastable austenitic condition below the recrystallization temperature followed by quenching to obtain martensite and/or bainite.

Austempering – A heat treatment for ferrous alloys in which a part is quenched from the austenitizing temperature at a rate fast enough to avoid formation of ferrite or pearlite and then held at a temperature just above Ms until transformation to bainite is complete. Although designated as bainite in both austempered steel and austempered ductile iron (ADI), austempered steel consists of two phase mixtures containing ferrite and carbide, while austempered ductile iron consists of two phase mixtures containing ferrite and austenite.

Austenite – A solid solution of one or more elements in face-centered cubic iron. Unless otherwise designated (such as nickel austenite), the solute is generally assumed to be carbon.

Austenite Steel - Any steel containing sufficient alloy to produce a stable austenitic (gamma iron) crystalline structure at ambient temperatures.
Austenitic grain size – The size by the grains of steel when heated to the austenitic region; may be revealed by appropriate etching of cross sections after cooling to room temperature.

Austenitizing – Forming austenite by heating a ferrous alloy into the transformation range (partial austenitizing) or above the transformation range (complete austenitizing). When used without qualification, the term implies complete austenitizing.

Autoclaving - The production of a stable, protective oxide on steel parts by treatment in a pressurized, high temperature steam containing atmosphere.

Bainite – A metastable aggregate consisting of dispersed carbide in ferrite resulting from the transformation of austenite at temperatures below the pearlite range but above Ms. Its appearance is in the form of relatively coarse ferrite laths between which carbides are precipitated as platelets if formed in the upper part of the bainite transformation range; acicular, resembling tempered martensite, if formed in the lower part.

Bainitic hardening – Quench-hardening treatment resulting principally in the formation of bainite.

Banded structure - A layering effect that is sometimes developed during the hot rolling of steel.

Bark - An older term used to describe the decarburized skin that develops on steel bars heated in a non-protective atmosphere.

Base coats for electroplating - Materials that are difficult to electroplate because of rapid oxide formation can have an adherent base coat applied by PVD processes and then the coating built-up by electrodeposition. Examples are plating on titanium, uranium, and zirconium where a base coat of a material like nickel or copper is applied by a PVD process before the electroplated coating is built up.

Batch furnace – A furnace used to heat treat a single load at a time. Batch-type furnaces are necessary for large parts such as heavy forgings and are preferred for complex alloy grades requiring long cycles. See car furnace, horizontal batch furnace.

Belt furnace – A continuous-type furnace which uses a mesh-type or cast-link belt to carry parts through the furnace.

Beta annealing – Producing a beta phase by heating certain titanium alloys in the temperature range of which this phase forms followed by cooling at an appropriate rate to prevent its decomposition.

Billet - A solid semi finished round or square that has been hot worked usually smaller than a bloom. Also a general term for wrought starting stock for forgings or extrusions.

Binder - A cementing medium used in producing composite or agglomerate powders.

Black annealing – Box annealing or pot annealing ferrous alloy sheet, strip, or wire to impart a black color to the oxidized surface. See box annealing.

Black oxide – A black finish on a metal produced by immersing it in hot oxidizing salts or salt solutions.

Blackadizing - A pressurized stream of some materials (Glass, plastic, metal, ahs, etc) applied on a surface to clean and/or roughen. It can be, depending on the media, abrasive or non-abrasive.

Blank annealing – Simulating the carburizing operation without introducing carbon. This is usually accomplished by using an inert material in place of the carburizing agent, or by applying a suitable protective coating to the ferrous alloy.

Blank Carburizing - Simulating the caruburizing operation without introducing carbon. This is usually accomplished by using an inert material in place of the carburizing agent, or by applying a suitable protective coating to the ferrous alloy.

Blank nitriding – Simulating the nitriding operation without introducing nitrogen. This is usually accomplished by using an inert material in place of the nitriding agent or by applying a suitable protective coating to the ferrous alloy.

Blasting - A pressurized stream of particulates (ceramic, plastic, metal, etc.) applied on a surface to clean, peen or abrade.

Blended Powder - A powder consisting of two or more different powder materials thoroughly mixed.

Bloom - A semi-finished hot rolled rectangular product. The width of the bloom is no more than twice the thickness and the cross-sectional area is usually not less that 36 square inches.

Blue annealing – Heating hot-rolled ferrous steel in an open furnace to a temperature within the transformation range and then cooling in air, in order to soften the metal. The formation of a bluish oxide on the surface is incidental.

Blue brittleness – Brittleness exhibited by some steels after being heated to some temperature within the range of about 205 to 370°C (400 to 700°F), particularly if the steel is worked at the elevated temperature. Killed steels are virtually free of this kind of brittleness.

Bluing – Subjecting the scale-free surface of a ferrous alloy to the action of air, steam, or other agents at a suitable temperature, thus forming a thin blue film of oxide and improving the appearance and resistance to corrosion. Note: This term is ordinarily applied to sheet, strip, or finished parts. It is used also to denote the heating of springs after fabrication to improve their properties.

Bond - This represents the state of adhesion between the coating and the substrate. Its strength will depend on the details of the thermal spraying process and the materials used. Bonding mechanisms may be mechanical, physical or metallurgical or a combination of these.

Bond coat - A coating applied as an intermediary between the main or top coating and the substrate in order to improve the bond strength.

Bond strength - The strength of the adhesion between the coating and the substrate. A number of test methods are in use to measure the bond strength of coatings.

Boriding – Thermo chemical treatment involving the enrichment of the surface layer of an object with borides. This surface-hardening process is performed below the Ac1 temperature.

Boron (B) - is usually added between .0005-.003% to significantly increase the hardenability, especially for low carbon alloys. It does not affect the strength of ferrite, therefore not sacrificing ductility, formability or machinability in the annealed state.

Boronizing - The diffusion of boron into the surface of a component (usually steel) by a high temperature (approx. 900°C) gas or pack process. Produces hard phases within the surface (Typically 100µm deep).

Boundary condition - The loads, displacements, temperatures, densities etc. at the periphery of the domain or mesh in a numerical simulation.

Box annealing – Annealing a metal or alloy in a sealed container under conditions that minimize oxidation. In box annealing a ferrous alloy, the charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly; this process is also called close annealing or pat annealing. See black annealing.

Breaks – Creases or ridges usually in “untempered” or in aged material where the yield point has been exceeded. Depending on the origin of the break, it may be termed a cross break, a coil break, an edge break, or a sticker break.

Bright annealing – Annealing in a protective medium to prevent discoloration of the bright surface. Compare with blank nitriding.

Brinell hardness test – A test for determining the hardness of a material for forcing a hard steel or carbide ball of specified diameter into it under a specified load. The result is expressed as the Brinell hardness number, which is the value obtained by dividing the applied load in kilograms by the surface area of the resulting impression in square millimeters.

Brine quenching – A quench in which brine (salt water-chlorides, carbonates, and cyanides) is the quenching medium. The salt addition improves the efficiency of water at the vapor phase or hot stage of the quenching process.

Brittle fracture – Separation of a solid accompanied by little or no macroscopic plastic deformation. Typically, brittle fracture occurs by rapid crack propagation with less expenditure of energy than for ductile fracture.

Brittle tempering range - Some hardened steels show an increase in brittleness when tempered in the range of about 450°F to 700°F even though some tempering causes some softening.

Burning – (1) Permanently damaging a metal or alloy by heating to cause either incipient melting or intergranular oxidation. See overheating, grain-boundary liquidation. (2) In grinding, getting the work hot enough to cause discoloration or to change the microstructure by tempering or hardening.

Cadmium ion plating - The deposition of cadmium by a vacuum process to provide galvanic corrosion protection.

Cadmium plating - The electrolytic deposition of cadmium to provide galvanic corrosion protection. Restricted by environmental considerations.

Calcium (Ca) - is used in certain steels to control the shape, size and distribution of oxide and/or sulfide inclusions. Benefits may include improved ductility, impact strength and machinability.

Calorizing – Imparting resistance to oxidation to an iron or steel surface by heating in aluminum powder at 800 to 1000°C (1470 to 1830°F).

Capped steel - A type of steel similar to rimmed steel, usually cast in a bottle top ingot, in which the application of a mechanical or chemical cap renders the rimming action incomplete by causing the top metal to solidify.

Carbon (C) - is the most important alloying element which is essential for the formation of cementite, pearlite, spheriodite, bainite, and iron-carbon martensite. Compared to steels with similar microstructures, strength, hardness, hardenability, and ductile-to-brittle transition temperature are increased with increasing carbon content up to approximately .60%. Toughness and ductility of pearlitic steels are decreased with increasing carbon content.

Carbonitriding – A case hardening process in which a suitable ferrous material is heated (about 900°C by pack, gas, salt bath or plasma process) above the lower transformation temperature in a gaseous atmosphere of such composition as to cause simultaneous absorption of carbon and nitrogen by the surface and, by diffusion, create a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the workplace. Compare to carburizing.

Carbonization – Conversion of an organic substance into elemental carbon. (Should not be confused with carburization.)

Carbon potential – A measure of the stability of an environment containing active carbon to alter or maintain, under prescribed conditions, the carbon level of the steel. Note: In any particular environment, the carbon level attained will depend on such factors as temperature, time, and steel composition.

Carbon restoration – Replacing the carbon lost in the surface layer from previous processing by carburizing this layer to substantially the original carbon level. Sometimes called recarburizing.

Carbon steel – Steel having no specified minimum quantity for any alloying element (other than the commonly accepted amounts of manganese, silicon, and copper) and containing only an incidental amount of any element other than carbon, silicon, manganese, copper, sulfur, and phosphorus.

Carburizing – Absorption and diffusion of carbon into solid ferrous alloys by heating (about 900°C by pack, gas, salt bath or plasma process), to a temperature usually above Ac3, in contact with a suitable carbonaceous material. A form of case hardening that produces a carbon gradient extending inward from the surface, enabling the surface layer to be hardened either by quenching directly from the carburizing temperatures or by cooling to room temperature, then reaustenitizing and quenching.

Carburizing flame – A gas flame that will introduce carbon into some heated metals, as during a gas welding operation. A carburizing flame is a reducing flame, but a reducing flame is not necessarily a carburizing flame.

Car furnace – A batch-type furnace using a car on rails to enter and leave the furnace area. Car furnaces are used for lower stress relieving ranges.

Carrier gas – Usually nitrogen or argon gas that carries powder into the thermal spray process.

Case – That portion of a ferrous alloy, extending inward from the surface, whose composition has been altered so that it can be case hardened. Typically considered to be the portion of the alloy (a) whose composition has been measurably altered from the original composition, (b) that appears dark on an etched cross section, or (c) that has hardness, after hardening, equal to or greater than a specified value. Contrast with core.

Case-Depth – The hardened depth on carburized or nitrided parts, often defined as the depth to which the hardness exceeds 500 Hv.

Case hardening – A generic term covering several processes applicable to steel that change the chemical composition of the surface layer by absorption of carbon, nitrogen, or a mixture of the two and, by diffusion, create a concentration gradient. The processes commonly used are carburizing and quench hardening; cyaniding; nitriding; and carbonitriding. The use of the applicable specific process name is preferred.

Casting – (1) An object at or near finished shape obtained by solidification of a substance in a mold. (2) Pouring molten metal into a mold to produce an object of desired shape.

Cathode – The negative electrode in a plasma torch (gun). Generally made from thoriated tungsten (thorium is added to reduce the metal work function aiding electron release). See also anode.

Cathodic coating – Coatings which become the cathode in an electrochemical cell with the substrate (anode). This type of coating protects the substrate from corrosion only by being a complete barrier. If the coating allows the environment to reach the substrate, accelerated corrosion of the substrate will occur.

Cathodic protection – A technique to reduce the corrosion rate of a metal by making it the cathode of an electrochemical cell. Thermal spray zinc and aluminum coatings provide this protection to steel substrates, the coating being the anode and the steel being the cathode.

Cation - A positively charged ion.

Caustic quenching – Quenching with aqueous solutions of 5 to 10% sodium hydroxide (NaOH).

Cavitation – The formation and rapid collapse within a liquid of cavities or bubbles that contain vapor or gas or both.

Cavitation erosion – A form of erosion causing material to be removed by the action of vapor bubbles in a very turbulent liquid.

CCT diagram – See continuous cooling transformation diagram.

Cermet powders – A composite powder of metal and ceramic constituents produced by methods such as agglomeration, sintering and spray drying. Examples include WC-Co, TiC-Ni.

Cementation – The introduction of one or more elements into the outer portion of a metal object by means of diffusion at high temperature.

Cementite – A compound of iron and carbon, known chemically as iron carbide and having the approximate chemical formula Fe3C. It is characterized by an orthorhombic crystal structure. When it occurs as a phase in steel, the chemical composition will be altered by the presence of manganese and other carbide-forming elements.

CFD – An acronym for Computational Fluid Dynamics

Checks – Numerous, very fine cracks in a coating or at the surface of a metal part. Checks may appear during processing or during service and are most often associated with thermal treatment or thermal cycling. Also called check marks, checking, heat checks.

Chemical conversion coating – A protective or decorative nonmetallic coating produced by chemical reaction of a metal with a chosen environment. (It is often used to prepare the surface prior to the application of an organic coating.)

Chemical Vapor Deposition (CVD) – The deposition of a coating by means of a chemical reaction in gases in a chamber producing components which deposit on and adhere to the substrate.

Chromating – Chromate conversion is a process which completely degreases and removes all traces of the oxide film, replacing it by immersion with a chromate coating which can then be painted. It is used as a post-treatment for cadmium, zinc and aluminum coatings

Chromic acid anodizing – A gray/brown anodic coating (1-2 micron) produced on Aluminum Alloys in Chromic acid at room temperature. It will act as an effective undercoat for paint.

Chromizing – High temperature (approx 900°C) pack or gaseous diffusion of chromium into the surface of a component to enhance high temperature corrosion and oxidation resistance.

Chromium (Cr) – is used in low alloy steels to increase 1) resistance to corrosion and oxidation, 2) high temperature strength, 3) hardenability, and 4) abrasion resistance in high carbon alloys. Straight chromium steels are susceptible to temper embrittlement and can be brittle.

Chromium Nitride – Metallic colored ceramic, often applied as a thin coating by PVD. Very hard (3500Hv). Used on cutting tools and other surfaces needing wear resistance.

Cladding - The application of a thick (generally above 1mm) coating which melts or diffuses into the substrate. Processes include weld cladding and plasma transferred arc (PTA).

Close annealing – Same as box annealing.

Coalescence – Growth of grains at the expense of the remainder by absorption or the growth of a phase or particle at the expense of the remainder by absorption or reprecipitation.

Coating - The application of a thin (generally less than 1mm) layer of material onto the surface of a substrate.

Coating thickness – Optical inspection of the depression reveals the projected surfaces of the abraded coating and substrate sections. By measuring the parameters X and Y, the thickness of the coating can be calculated by a simple geometrical equation.

Coating wear – Wear can be determined by using a slurry composed of water and SiC particles falling continuously onto the ball at the contact region. The slurry wears the substrate in a controlled manner and thus assures highly reproducible results. By comparing the geometry of the crater for different periods of wear time, the wear rate of the coating and the substrate can be determined precisely.

Coatings, corrosion protective - Protection from an aggressive chemical environment can be accomplished in several ways. The surface can be coated with an inert material or with a material that forms a protective surface after reacting with the environment or with a material that will be sacrificially removed to protect the underlying material. Tantalum, platinum, and carbon are inert in many chemical environments. For example, carbon coatings are used on metals that are implanted in the human body to provide compatibility. In the aerospace industry parts are aluminum coated by the PVD process of ion vapor deposition (IVD) so as to prevent galvanic corrosion of dissimilar materials in contact. Chromium, aluminum, silicon, and the MCrAlY (where M is Ni, Co, Fe) alloys will react with oxygen to form a coherent protective oxide layer on the surface. If the metal ions (Fe, Cu) diffuse more rapidly than the oxygen through the oxide, a thick oxide will form on the surface. If the oxygen diffuses more rapidly through the oxide than the metal ions (Al, Si, Ti, Zr—the "valve" metals), oxidation will occur at the interface and a thin oxide will be formed. The MCrAlY alloy coatings are used as protective coatings on aircraft engine turbine blades. Cadmium, aluminum, and Al:Zn alloys are used as galvanic sacrificial coatings on steel. Vacuum cadmium ("vac cad") plating has the advantage over electroplated cadmium in that there is no possibility of hydrogen embrittlement of high-strength steel when vacuum deposition processing is used.

Coatings, decorative and decorative/wear - Metallization for strictly decorative purposes is a large market. Applications vary from coating polymer webs—which are then converted to decorative uses such as balloons and labels—to metallization of three-dimensional articles, such as sports trophies, zinc die cast and molded polymer decorative fixtures, and cosmetic containers. Often these coatings consist of a reflective aluminum coating that is deposited on a smooth base coat, then over coated with a dyed lacquer to give the coating the desired color and texture and also corrosion and wear resistance. In some applications, in addition to the decorative aspects of the coating, the coating is required to withstand wear. For example, titanium nitride (TiN) is gold colored, and titanium carbonitride (TiCxNy) can vary in color from gold to purple to black depending on the composition. Zirconium nitride (ZrN) has the color of brass and is much more wear and scratch resistant than brass. Decorative/wear coatings are used on door hardware, plumbing fixtures, fashion items, marine hardware, and other such applications.

Coatings, hard and wear-resistant - Hard coatings are often called metallurgical coatings and are a type of tribological coating. The hard coatings are used to increase the cutting efficiency and operational life of cutting tools and to maintain the dimensional tolerances of components used in applications where wear can occur, such as injection molds. In addition, the coatings can act as a diffusion barrier where high temperatures are generated by motion between surfaces or corrosion protection in aggressive environments. There are various classes of hard coating materials. They include: ionically bonded metal oxides (Al2O3, ZrO2, and TiO2), covalently bonded materials (SiC, boron carbon [B4C], diamond, diamond-like-carbon [DLC], TiC, AlN, CrC, mixed carbide, vanadium carbide, nitride and carbonitride compound alloys, and cubic boron nitride), and some metal alloys (cobalt chromium aluminum yttrium [CoCrAlY], NiAl, NiCrBSi). In some cases the coatings may be layered to combine properties. Hard coatings also are used to minimize fatigue-wear, such as is found in ball bearings. Wear-resistant coatings also may be applied to surfaces where there is a light or periodic load. For example, hard coatings are deposited on plastics to improve scratch resistance. Applications are on molded plastic lenses and plastic airplane canopies. In some cases wear coatings, such as SiO2 or Al2O3, may be applied to already hard surfaces, such as glass, to increase the scratch resistance.

Coatings, packaging - Barrier coatings are used on flexible polymer films and paper for food packaging to reduce the water vapor transmission rate (WVTR) and the oxygen transmission rate (OTR) through the paper or polymer film. The most common barrier coating material is aluminum, which is deposited on rolls of polymer film (web), then supplied to "converters" who fabricate the packaging. In some cases the metal coatings are deposited on a surface and then "transferred" to the packaging film. Transparent barrier coatings are desirable in many instances. Layers of SiO2-x, by reactive evaporation and PECVD and composite coatings of SiO2:30% Al2O3 by E-beam co-evaporation are used to form transparent barrier layers. The composite coating material is more dense and flexible than the SiO2 or Al2O3 deposited material alone. Aluminum films are used on polymer helium-filled balloons to reduce the loss of helium

Coatings, reflector - Metal films are widely used for reflector surfaces. Silver is often used when corrosion is not a problem, such as for back-surface mirrors. Aluminum can be used either as a front-surface or back-surface reflector. Often, aluminized front-surface reflectors, such as headlight reflectors, are over coated with a protective polymer film (top coat). Chromium is used on front-surface reflectors when corrosion is a problem even though its reflectivity in the visible (60%) is less than that of aluminum (> 90%). Reflector films are used in numerous commonly encountered applications, such as on compact discs for video and music storage, lamp reflectors, and visual mirrors such as the rear-view mirrors for cars. In some cases multilayer films, similar to multilayer optical films, are used to selectively reflect certain wavelengths and not others. Examples are "cold mirrors" that reflect the visible radiation but not the infrared wavelengths and "heat mirrors" that reflect the infrared but not the visible. Heat mirrors are used to raise the internal temperature of halogen lamps. Cold mirrors are used to reduce the heat of stage lighting on actors.

Coatings, solid film lubricants/low friction - NASA pioneered the use of vacuum-deposited thin film solid lubricants. The lubricants are of two types: the low-shear metal lubricants—such as silver and lead—and the laminar-shearing compound materials—such as molybdenum disulfide (MoS2). The low-shear metal lubricants are used in high-torque applications such as the rotating anodes in X-ray tubes. Low-shear compound materials are used in mechanical-bearing applications in vacuum and where lubricant "creep" can be a problem. Because only a very thin film is needed for lubrication, the application of the lubricant film does not result in significant changes of dimensions. Low friction coatings of metal-containing carbon (Me-C) are used to reduce wear in mechanical contact applications.

Coatings, thermal control - The composition of the thermal control coatings on windows differs with the end result desired. If the object is to keep solar radiation from entering through the window, a multilayer film of glass-TiO2-Cr-TiO2 may be used (solar control coating). If the object is to keep heat in the room, a thin film of silver can be used to reflect 85% to 95% of the low-temperature infrared radiation back into the room (low-E coating). One such "double-E coating" is glass-ZnO-Ag-(Ti)-ZnO-Ag-(Ti)-ZnO-TiO2. The ZnO provides an antireflective coating. Other types of thermal control coatings are used to absorb solar radiation (solar absorbers), selectively adsorb solar radiation and not emit infrared radiation (selective solar absorbers), or to have a high emissivity to enhance cooling by radiation. Thermal barrier coatings are used to reduce the thermal transport from a hot environment to the substrate. Zirconium oxide (ZrO2) stabilized with calcium oxide (CaO), MgO, or Y2O3 is used as a thermal barrier coating on aircraft engine turbine blades.

Coarsening – An increase in the grain size, usually, but not necessarily, by grain growth.

Coherent precipitate – A crystalline precipitate that forms from solid solution with an orientation that maintains continuity between the crystal lattice of the precipitate and the lattice of the matrix, usually accompanied by some strain in both lattices. Because the lattices fit at the interface between precipitate and matrix, there is no discernible phase boundary.

Cold die quenching – A quench utilizing cold, flat, or shaped dies to extract heat from a part. Cold die quenching is slow, expensive, and is limited to smaller parts with large surface areas.

Cold dry die quenching – Same as cold die quenching.

Cold treatment – Treatment carried out after quenching to transform retained austenite into martensite, involving cooling and holding at a temperature below ambient.

Cold welding - Cohesion between two surfaces of a metal, generally under the influence of externally applied pressure at room temperature.

Cold working - Plastic deformation of a metal at a temperature low enough so that re-crystallization does not occur during cooling.

Columnar structure – A coarse structure of parallel elongated grains formed by unidirectional growth, most often observed in castings, but sometimes in structures resulting from diffusional growth accompanied by a solid-state transformation.

Combined carbon – The part of the total carbon in steel or cast iron that is present as other than free carbon.

Composite - Mixture of two or more materials. Nearly all have a reinforcing material (wood, glass, etc), called filler, and a natural or artificial resin, called matrix to achieve specific characteristics and required properties.

Composite Coating - Mixture of two or more materials. Many thermal spray coatings could be considered as composites.

Composite Powder - A powder in which each particle consists of two or more distinct materials joined together. (Not the same as a powder blend.)

Compound layer - A non-etching layer of iron nitrides formed at the surface of ferrous materials during nitriding or nitrocarburizing. Normally removed by grinding prior to component installation

Computational Fluid Dynamics (CFD) - A method of simulating a flow field on a computer, by replacing the governing nonlinear partial differential equations (Navier-Stokes Equations) with numbers, and advancing these numbers in space/time to obtain a final numerical description of the flow.

Conditioning heat treatment – A preliminary heat treatment used to prepare a material for desired reaction to a subsequent heat treatment. For the term to be meaningful, the exact heat treatment must be specified.

Congruent transformation – An isothermal or isobaric phase change in which both of the phases concerned have the same composition throughout the process.

Constitution diagram – See phase diagram.

Constricted arc (Plasma) - Column of plasma arc obtained by a constricted nozzle (usually in Copper and water cooled) connected to positive polarity (anode), while the negative polarity is connected to the cathodic electrode (usually tungsten added with thorium oxides).

Continuous Casting - Operation in which a cast shape is continuously drawn through the bottom of the mold as it solidifies. The length is not determined by mold dimensions.

Continuous cooling transformation (CCT) diagram – Set of curves drawn using logarithmic time and linear temperature as coordinates, which define for each cooling curve the beginning and end of the transformation of the initial phase.

Continuous precipitation – Precipitation from a supersaturated solid solution in which the precipitate particles grow by long-range diffusion without recrystallization of the matrix. Continuous precipitates grow from nuclei distributed more or less uniformly throughout the matrix. They usually are randomly oriented, but may form a Widmanstätten structure. Also called general precipitation. Compare with discontinuous precipitation, localized precipitation.

Continuous-type furnace – A furnace used for heat treating materials that progress continuously through the furnace, entering one door and being discharged from another. See belt furnace, direct-fired tunnel-type furnace, rotary retort furnace, shaker-hearth furnace.

Controlled cooling – Cooling from an elevated temperature in a predetermined manner, to avoid hardening, cracking, or internal damage, or to produce desired microstructure or mechanical properties.

Convergence - A description of the decrease in the relative error between successive iterations in a numerical solution. When a certain predefined limited has been reached, the solution is considered to have converged, and therefore the solution is stable and correct.

Cooling curve – A curve showing the relation between time and temperature during the cooling of a material.

Cooling stresses – Residual stresses resulting from non-uniform distribution of temperature during cooling.

Copper (Cu) - is detrimental to hot workability and subsequent surface quality. It is used in certain steels to improve resistance to atmospheric corrosion. For foundry applications, copper is meant to include all alloys containing 98% or more copper. Used for conductivity castings. Melting point 1083°C (1981.4°F).

Copper plating - The electrolytic deposition of copper to provide either a corrosion barrier (often as an undercoat for hard chrome plate) or for reclamation of worn parts.

Core – In a ferrous alloy prepared for case hardening, that portion of the alloy that is not part of the case. Typically considered to be the portion that (a) appears light on an etched cross section, (b) has an essentially unaltered chemical composition, or (c) has a hardness, after hardening, less than a specified value.

Corrosion – (1) Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents. (2) Chemical attack of furnace linings by gases, slags, ashes or other fluxes occurring in various melting practices.

Corrosion fatigue - The process in which a metal fractures prematurely under conditions of simultaneous corrosion and repeated cyclic loading at lower stress levels or fewer cycles than would be required in the absence of the corrosive environment.

Corrosion Index - A number expressing the maximum depth in microns or mils to which corrosion would penetrate in one year on the basis of a linear extrapolation of the penetration occurring during the lifetime of a given test or service.

Corrosion potential - The potential of a corroding surface in an electrolyte relative to a reference electrode measured under open circuit conditions.

Corrosive wear - Wear in which chemical or electrochemical reaction with the environment is significant.

Cr-Ni coatings - Anticorrosion coatings resistant to high temperatures.

Cracking - Breaks or splits in the coating's surface

Cracking Strip - A fin of metal molded on the surface of a casting to prevent cracking.

Crevice corrosion - Localized corrosion of a metal surface at, or immediately adjacent to, an area that is shielded from the full exposure to the environment because of close proximity between the metal and the surface of another material.

Critical cooling rate – The rate of continuous cooling required to prevent undesirable transformation. For steel, it is the minimum rate at which austenite must be continuously cooled to suppress transformations above Ms temperature.

Critical diameter (D) – Diameter of the bar that can be fully hardened with 50% martensite at its center.

Critical Load (Lc) – The Critical Load value translates the complex intrinsic properties of a specific coating system into very reproducible figures of great practical significance. Scratch testers provide cross-referenced data on Lc by simultaneously recording three different effects: tangential force variations, acoustic emission fluctuations, and microscopic deformations.

Critical point – (1) The temperature or pressure at which a change in crystal structure, phase, or physical properties occurs. Same as transformation temperature. (2) In an equilibrium diagram, that specific value of composition, temperature, and pressure, or combination thereof, at which the phases of a heterogeneous system are in equilibrium.

Critical range - The temperature range between an upper and lower critical point for a given material.

Critical strain – The strain just sufficient to cause recrystallization; because the strain is small, usually only a few percent, recrystallization takes place from only a few nuclei, which produces a recrystallized structure consisting of very large grains.

Critical temperature – (1) Synonymous with critical point if the pressure is constant. (2) The temperature above which the vapor phase cannot be condensed to liquid by an increase in pressure.

Critical temperature ranges – Synonymous with transformation ranges, which is the preferred term.

Crushed powder - Powder formed from a solid which is then crushed to the appropriate size for spraying.

Cryogenic treatment – See cold treatment.

Curie temperature – The temperature of magnetic transformation below which a metal or alloy is ferromagnetic and above which is paramagnetic.

CVD - See Chemical Vapor Deposition

Cyaniding – A case-hardening process in which a ferrous material is heated above the lower transformation range in a molten salt containing cyanide to cause simultaneous absorption of carbon and nitrogen at the surface and, by diffusion, create a concentration gradient. Quench hardening completes the process.

Cycle annealing – An annealing process employing a predetermined and closely controlled time-temperature cycle to produce specific properties or microstructures.

Dead soft – A temper of nonferrous alloys and some ferrous alloys corresponding to the condition of minimum hardness and tensile strength produced by full annealing.

Degreasing - The removal of grease and oil from a surface. Degreasing by immersion in liquid organic solvents or by solvent vapors condensing on the parts to be cleaned.

Decalescence – A phenomenon, associated with the transformation of alpha iron to gamma iron on the heating (superheating) of iron and steel, revealed by the darkening of the metal surface owing to the sudden decrease in temperature caused by the fast absorption of the latent heat of transformation. Contrast with recalescence.

Decarburization – Loss of carbon from the surface layer of a carbon-containing alloy due to reaction with one or more chemical substances in a medium that contacts the surface.

Degreasing - The removal of grease and oil from a surface. Degreasing by immersion in liquid organic solvents or by solvent vapors condensing on the parts to be cleaned.

Degrees of freedom – The number of independent variables (such as temperature, pressure, or concentration within the phases present) that may be altered at will without causing a phase change in an alloy system at equilibrium; or the number of such variables that must be fixed arbitrarily to define the system completely.

Delta ferrite – See ferrite.

Density - The mass per unit volume of a substance, usually expressed in grams per cubic centimeter or in pounds per cubic foot.

Deposit corrosion - Localized corrosion under or around a deposit or collection of material on a metal surface. See also crevice corrosion.

Detonation Gun - A thermal spraying process in which the coating material is heated and accelerated to the work piece by shock waves from a series of detonations or explosions from gas mixtures. Also known as D-Gun (Praxair).

Dew point – The temperature and pressure at which a gas begins to condense to a liquid.

Dew point analyzer – An atmosphere monitoring device that measures the partial pressure of water vapor in an atmosphere.

DI (Ideal Diameter) - The diameter of a round steel bar that will harden at the center to a given percent of martensite when subjected to an ideal quench (i.e., Grossman quench severity H=infinity)

Diamond Like Carbon - A thin film coating applied by a PVD or CVD process. It possesses some of the hardness of diamond, but with the low friction properties of graphite (Friction Coefficient = about 0.1). Used on cutting and forming tools, on medical implants and for low friction surfaces.

Die - A metal block used in forming materials by casting, molding, stamping, threading, or extruding.

Die Assembly - The parts of a die stamp or press that hold the die and locate it for the punches.

Die Casting - A rapid, water-cooled permanent mold casting process limited to nonferrous metals. There are three types: the plunger-type operated hydraulically, mechanically or by compressed air with or without a gooseneck; the direct-air injection which forces metal from a goose-neck into the die, and the Cold-Chamber Machine. All force the metal into the die with a pressure greater than that of gravity flow.

Die Coating - A material, e.g. silicone, stearate, oil, or wax for lubricating a die pattern or core box to facilitate easy removal of a casting, mold or core.

Differential heating – Heating that intentionally produces a temperature gradient within an object such that, after cooling, a desired stress distribution or variation in properties is present within the object.

Diffusion – (1) Spreading of a constituent in a gas, liquid, or solid, tending to make the composition of all parts uniform. (2) The spontaneous movement of atoms or molecules to new sites within a material.

Diffusion coefficient – A factor of proportionality representing the amount of substance diffusing across a unit area through a unit concentration gradient in unit time.

Dilatometer – An instrument for measuring the linear expansion or contraction in a metal resulting from changes in such factors such as temperature and allotropy.

Dip Coat - In solid and shell mold investment casting, a fine ceramic coating applied as a slurry to the pattern to produce maximum surface smoothness, followed by a cheaper conventional investment.

Direct Chill (DC) Casting - A continuous method of making ingots or billets or extrusion by pouring the metal into a short mold. Some times called semi-continuous casting.

Direct-fired tunnel-type furnace – A continuous-type furnace where the work is conveyed through a tunnel-type heating zone, and the parts are hung on hooks or fixtures to minimize distortion.

Direct quenching – (1) Quenching carburized parts directly from the carburizing operation. (2) Also used for quenching pearlitic malleable parts directly from the malleablizing operation.

Dirty Casting - A casting containing an excessive amount of nonmetallic inclusions in the body of the metal.

Discontinuous precipitation – Precipitation from a supersaturated solid solution in which the precipitate particles grow by short-range diffusion, accompanied by recrystallization of the matrix in the region of precipitation. Discontinuous precipitates grow into the matrix from nuclei near grain boundaries, forming cells of alternate lamellae of precipitate and depleted (and recrystallized) matrix. Often referred to as cellular or nodular precipitation. Compare with continuous precipitation, localized precipitation.

Dissociation – As applied to heterogeneous equilibria, the transformation of one phase into two or more new phases of different composition. Compare with order-disorder transformation.

Disturbed Metal - The cold worked metal formed on a polished surface during the processes of grinding and polishing.

Double aging – Employment of two different aging treatments to control the type of precipitate formed from a supersaturated matrix in order to obtain the desired properties. The first aging treatment, sometimes referred to as intermediate or stabilizing, is usually carried out at higher temperature than the second.

Double tempering – A treatment in which a quench-hardened ferrous metal is subjected to two complete tempering cycles, usually at substantially the same temperature, for the purpose of ensuring completion of the tempering reaction and promoting stability of the resulting microstructure.

Drawing – A misnomer for tempering.

Dry cyaniding – (obsolete) Same as carbonitriding.

Dry Sand Casting - The process in which the sand molds are dried at above 100°C (212°F) before using.

Ductile cast iron – A cast iron that has been treated while molten with an element such as magnesium or cerium to induce the formation of free graphite as nodules or spherulites, which imparts a measurable degree of ductility to the cast metal. Also known as nodular cast iron, spherulitic graphite cast iron, and SG iron.

Ductile fracture – Fracture characterized by tearing of metal accompanied by appreciable gross plastic deformation and expenditure of considerable energy. Contrast with brittle fracture.

Ductility – The ability of a material to deform plastically without fracturing, measured by elongation or reduction of area in a tensile test, by height of cupping in an Erichsen test, or by other means.

Dust - Small solid particles created by the breaking up of larger particles.

475°C (885°F) embrittlement – Embrittlement of stainless steels upon extended exposure to temperatures between 400 and 510°C (750 and 950°F). This type of embrittlement is caused by fine, chromium-rich precipitates that segregate at grain boundaries; time at temperature directly influences the amount of segregation. Grain-boundary segregation of the chromium-rich precipitates increases strength and hardness, decreases ductility and toughness, and changes corrosion resistance. This type of embrittlement can be reversed by heating above the precipitation range.

Elastic limit – The maximum stress that a material is capable of sustaining without any permanent strain (deformation) remaining upon complete release of the stress.

Elastic modulus (also called Young's modulus) - A parameter which measures the stiffness of a material.

Elasticity - The property of certain materials that enables them to return to their original dimensions after an applied stress.

Electrical Insulators - Electrically insulating films are used to electrically isolate conducting components in semiconductor devices, and as a dielectric within capacitors. Common insulator film materials are silicon dioxide (SiO2), aluminum trioxide (Al2O3), tantalum pentoxide (Ta2O5), silicon nitride (Si3N4), and aluminum nitride (AlN). Interposing a thin oxide film between a metal film and a semiconductor allows the formation of the technologically important metal-oxide-semiconductor (MOS) device. Thick coatings of SiO2, with its low coefficient of thermal expansion, can be rf sputter deposited. Insulating layers of SiO2, silicon nitride (Si2N3), and glass are deposited by PECVD for encapsulation and insulation layers in semiconductor processing.

Electrically active films - Doped silicon films are used in semiconductor devices, and these films often are deposited by a very sophisticated PVD evaporation technique called molecular beam epitaxy (MBE) or a CVD technique of vapor phase epitaxy (VPE). Amorphous silicon for solar cells is deposited by PECVD on webs and rigid substrates. Electochromic films, which change optical transmission on the application of a voltage, depend on the diffusion of a mobile species in the film under an electrical field. Films of a material such as selenium can become electrically charged when exposed to light. Such films are used to hold the toner in photocopying machines.

Electrically Conductive Films - Metal films are the most common electrical conductor films. Metal films may be used as "blanket" metallizations or can be formed into discrete conductor lines ("stripes") by masking the substrate during deposition or by subsequent photolithographic etching processes. Conductor lines are used in hybrid microcircuit technology and in the manufacture of semiconductor devices. Often, the electrical conductors are multilayer films (stacks) where each layer has a function. For example, the conductor film stack might have the composition: glass-Ti-Pd-Cu-Au. The titanium (Ti) is the "glue" layer, the palladium (Pd) provides corrosion resistance, the copper (Cu) is an electrical conductor, and the gold (Au) provides corrosion protection. Deposited metal conductors in "vias" are used in establishing electrical contacts between different layers in semiconductor device manufacturing. Blanket metallization is used to provide electromagnetic interference (EMI) and radio frequency interference (RFI) shielding on structures such as the plastic cases for cellular phones, electrodes for rigid and flexible capacitor electrodes, and surfaces for radar "chaff." Metal nitride, carbide, and silicide films generally are electrically conductive (Si3N4 and AlN are important exceptions). In some applications, films of these refractory materials are used to provide diffusion barriers between materials. For example, in semiconductor metallization, aluminum or gold electrode material will diffuse into the silicon during high-temperature processing. An electrically conductive titanium nitride film deposited on the silicon surface before the metal electrode is deposited will prevent the diffusion. Generating stable, electrically conductive, nonrectifying, metal semiconductor contacts of metals or metal-silicide compounds is an important aspect of semiconductor device fabrication. Metal nitrides such as tantalum nitride (TaN) are used as thin film resistor materials. Nontransparent electrically conductive oxides such as chromium trioxide (Cr2O3), lead oxide (PbO), and ruthenium oxygen (RuO) are used as electrodes in high-temperature oxidizing atmospheres. Superconductors are materials that have close to zero electrical resistivity below some critical temperature (Tc). Low- Tc (less than [<] 10 Kelvin [K]) superconductors are often metals. A typical high- Tc (greater than [>] 50 K) superconductor material is a mixture of oxides (yttrium-bismuth-copper [Y-Bi-Cu] oxides, YBCO). High- Tc superconductor thin films are often deposited by laser ablation in vacuum.

Electrochemical cell - An electrochemical system consisting of an anode and a cathode in metallic contact and immersed in an electrolyte. (The anode and cathode may be different metals or dissimilar areas on the same metal surface.

Electroless Nickel - The autocatalytic deposition of nickel/phosphorous and nickel/boron have many useful corrosion and tribo/corrosion applications. Unlike the electrolytic processes, they produce a deposit with completely uniform coverage. In the case of Ni P, deposits around 25 to 50 microns thick with a hardness of about 500Hv is obtained, but thermal ageing at temperatures around 400°C can develop hardness values in excess of 1000Hv.

Electrolyte - A conducting medium in which the flow of current is accompanied by movement of matter. A substance that is capable of forming a conducting liquid medium when dissolved or melted.

Electrolysis - Production of chemical changes of the electrolyte by the passage of current through an electrochemical cell.

Electromotive Force Series (EMF Series) - A list of elements arranged according to their standard electrode potentials, with "noble" metals such as gold being positive and "active" metals such as zinc being negative.

Electron-beam heat treating – A selective surface hardening process that rapidly heats a surface by direct bombardment with an accelerated stream of electrons.

Electroplating - The application of a layer of metal onto a substrate in a conducting solution of metal slats.

Elongation – In tensile testing, the increase in the gage length, measured after fracture of the specimen within the gage length, usually expressed as a percentage of the original gage length.

Embrittlement – The severe loss of ductility or toughness or both of a material, usually a metal or alloy. Many forms of embrittlement can lead to brittle fracture. Many forms can occur during thermal treatment or elevated-temperature service (thermally induced embrittlement). Some of these forms of embrittlement, which affect steels, include blue brittleness, 475°C (885°F) embrittlement, quench-age embrittlement, sigma-phase embrittlement, strain-age embrittlement, temper embrittlement, tempered martensite embrittlement, and thermal embrittlement. In addition, steels and other metals and alloys can be embrittled by environmental conditions (environmentally assisted embrittlement). The forms of environmental embrittlement include acid embrittlement, caustic embrittlement, corrosion embrittlement, creep-rupture embrittlement, hydrogen embrittlement, liquid metal embrittlement, neutron embrittlement, solder embrittlement, solid metal embrittlement, and stress-corrosion cracking.

Enantiotropy – The relation of crystal forms of the same substance in which one form is stable above a certain temperature and the other form stable below that temperature. Ferrite and austenite are enantiotropic in ferrous alloys, for example.

End-quench hardenability test – A laboratory procedure for determining the hardenability of a steel or other ferrous alloy; widely referred to as the Jominy test. Hardenability is determined by heating a standard specimen in a fixture so that a stream of cold water impinges on one end, and, after cooling to room temperature is completed, measuring the hardness near the surface of the specimen at regularly spaced intervals along its length. The data is normally plotted as hardness versus distance from the quenched end.

Energy Dispersive X-ray (SEM-EDX) - An electron beam microprobe for X-ray-fluorescence analysis. Commonly associated with electronic microscopy, it permits measuring the elementary composition of materials.

Entrainment - The sucking in of fluid from outside the shroud or nozzle of a plasma spray gun. To conserve momentum, the total momentum of the entrained flow must balance the total momentum of the expelled fluid.

Epitaxy - A film is called epitaxial when its crystallographic order is being significantly influenced by that of the substrate as a result of some degree of matching between the two along the interface.

Equilibrium diagram – A graphical representation of the temperature, pressure, and composition limits of phase fields in an alloy system as they exist under conditions of complete equilibrium. In metal systems, pressure is usually considered constant.

Erosion - Removal of material from a surface caused by the flow of particles within a liquid or gas.

Erosion-corrosion - Associated action involving corrosion and erosion in the presence of a corrosive substance.

Etch - A roughened surface produced by chemical, electrochemical or mechanical means. To dissolve unevenly a part of the surface of a material to highlight microstructure in metallography.

Eutectic – (1) An isothermal reversible reaction in which a liquid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the number of components in the system. (2) An alloy having the composition indicated by the eutectic point on an equilibrium diagram. (3) An alloy structure of intermixed solid constituents formed by a eutectic reaction.

Eutectic carbide – Carbide formed during freezing as one of the mutually insoluble phases participating in the eutectic reaction of ferrous alloys.

Eutectic melting – Melting of localized microscopic areas whose composition corresponds to that of the eutectic in the system.

Eutectoid – (1) An isothermal reversible reaction in which a solid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the number of components in the system. (2) An alloy having the composition indicated by the eutectoid point on an equilibrium diagram. (3) An alloy structure of intermixed solid constituents formed by a eutectoid reaction.

Exfoliation - Corrosion that proceeds laterally from the sites of initiation along planes parallel to the surface, generally at grain boundaries or coating interfaces, forming corrosion products that force metal or coating away from the body of the material, giving rise to a layered appearance.

Exothermic reaction of material - Certain materials undergo chemical reactions when heated in an arc or plasma and produce extra heating. This can be useful in improving adhesion of the coating to the substrate. There is also a potential explosive or fire hazard when handling powders which are exothermic.

Explosive cladding –Coatings applied by explosive gas mixture. Also called cladding.

Extensometer – An instrument for measuring changes in length caused by application or removal of a force. Commonly used in tension testing of metal specimens.

Extra hard – A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength and hardness about one-third of the way from full hard to extra spring hard.

Extra spring – A temper of nonferrous alloys and some ferrous alloys corresponding approximately to a cold-worked state above full hard beyond which further cold work will not measurably increase the strength and hardness.

Fatigue - A cumulative effect causing a metal to fail after repeated applications of stress none of which exceeds the ultimate tensile strength. The fatigue strength (or fatigue limits) is the stress that will cause failure after specified number cycles.

Fatigue Crack or Failure - A fracture starting from a nucleus where there is an abnormal concentration of cyclic stress. The fracture surface is smooth and frequently shows concentric (sea shell) markings with a nucleus as a center.

Fatigue Limit (Endurance Limit) - Maximum stress that a material will endure without failure for an infinite number of load cycles.

Fatigue Strength - Maximum stress that a material will endure without failure for a specified number of load cycles.

Fatigue wear - Wear of a solid surface caused by fracture arising from material fatigue.

Feeding - The process of supplying molten metal to compensate for volume shrinkage while the casting is solidifying.

Ferrite – A solid solution of one or more elements in body-centered cubic iron. Unless otherwise designated (for instance, as chromium ferrite), the solute is generally assumed to be carbon. On some equilibrium diagrams, there are two ferrite regions separated by an austenite area. The lower area is alpha ferrite; the upper, delta ferrite. If there is no designation, alpha ferrite is assumed.

Ferritizing anneal – A treatment given as-cast gray or ductile (nodular) iron to produce an essentially ferritic matrix. For the term to be meaningful, the final microstructure desired or the time-temperature cycle used must be specified.

Filler - A solid inert material added to a synthetic resin or rubber, either to change its physical properties or simply to dilute it for economy.

Final annealing – An imprecise term used to denote the last anneal given to a nonferrous alloy prior to shipment.

Fines - The portion of a powder composed of particles which are smaller than the specified size

Finish annealing – A subcritical annealing treatment applied to cold-worked low- or medium-carbon steel. Finish annealing, which is a compromise treatment, lowers residual stresses, thereby minimizing the risk of distortion in machining while retaining most of the benefits to machinability contributed by cold working. Compare with final annealing.

Finishing temperature – The temperature at which hot working is completed.

Finite difference - A numerical method of solving the Navier-Stokes equations, where the domain is divided up into small areas/volumes, with nodes (or grid points) placed at each corner. The fluid is then considered to exist only at these nodes. The difference between the nodes describes the property gradients in the fluid.

Finite element - A numerical method of solving the Navier-Stokes equations, where the domain is divided up into small areas/volumes. A shape function is then placed over the volume, it should be representative of the shape of the variation over the volume.

Finite volume - A numerical method of solving the Navier-Stokes equations, where the domain is divided up into small areas/volumes, and the flow properties are considered to be constant across the volume.

Fixturing – The placing of parts to be heat treated in a constraining or semi constraining apparatus to avoid heat-related distortions. See racking.

Flame annealing – Annealing in which the heat is applied directly by a flame.

Flame hardening – A process for hardening the surfaces of hardenable ferrous alloys in which an intense flame is used to heat the surface layers above the upper transformation temperature, whereupon the work piece is immediately quenched.

Flame spraying - A thermal spraying process in which the particles are heated and accelerated in a flame produced from the combustion of oxygen and fuel.

Flame straightening – Correcting distortion in metal structures by localized heating with a gas flame.

Fluidized-bed heating – Heating carried out in a medium of solid particles suspended in a flow of gas.

Fog quenching – A quench utilizing blasts of compressed air against relatively small parts such as a gear.

Forced-air quench – A quench utilizing blasts of compressed air against relatively small parts such as a gear.

Free carbon – The part of the total carbon in steel or cast iron that is present in elemental form as graphite or temper carbon. Contrast with combined carbon.

Free ferrite – Ferrite that is formed directly from the decomposition of hypoeutectoid austenite during cooling, without the simultaneous formation of cementite. Also called proeutectoid ferrite.

Freestanding structures - Freestanding structures can be made by depositing a coating on a surface (mandrel), then separating the coating from the mandrel surface or dissolving the mandrel. The technique is useful for fabricating very thin structures, complex surfaces, or foils or sheets of materials that are hard to deform by rolling. Examples are beryllium windows used for X-ray transmission, boron thin-wall cones for high-frequency audio speakers, and Ti-V-Al metal alloy foils. A relatively new application is the production of microelectromechanical systems (MEMS) devices where very small structures are fabricated using deposition and etching processes.

Freezing range – That temperature range between liquidus and solidus temperatures in which molten and solid constituents exist.

Fretting - Surface damage caused by very small relative movement between two surfaces usually under heavy load.

Fretting corrosion - A form of fretting wear in which corrosion plays a significant role.

Fretting wear - Wear arising as a result of fretting.

Friction - The reaction force resulting from surface interaction and adhesion during sliding. The friction Coefficient is defined as the friction force divided by the load.

Frictional Wear - The displacement and/or detachment of metallic particles from a surface as a consequence of being in contact with another moving component.

Full annealing – An imprecise term that denotes an annealing cycle to produce minimum strength and hardness. For the term to be meaningful, the composition and starting condition of the material and the time-temperature cycle used must be stated.

Full hard – A temper of nonferrous alloys and some ferrous alloys corresponding approximately to a cold-worked state beyond which the material can no longer be formed by bending. In specifications, a full hard temper is commonly defined in terms of minimum hardness or minimum tensile strength (or, alternatively, a range of hardness or strength) corresponding to a specific percentage of cold reduction following a full anneal. For aluminum, a full hard temper is equivalent to a reduction of 75% from dead soft; for austenitic stainless steels, a reduction of about 50 to 55%.

Fused and crushed powder - Powder formed from a fused solid mass which is then crushed to the appropriate size for spraying.

Fused coatings - A process in which the coating material is deposited by thermal spraying and then fused by post heat treatment. This can be done by flame, induction heating, furnace or by laser.

Galling - Damage to the surfaces of materials sliding in contact with each other, usually caused by the localized welding together of high spots. Common for materials like stainless steel, aluminum alloys and titanium.

Galvanic corrosion - Accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte.

Galvanic Series - A list of metals and alloys arranged according to their relative corrosion potentials in a given environment.

Galvanized - The process of coating steel with zinc for corrosion resistance.

Galvanizing - A hot dip process for deposition of zinc for galvanic corrosion protection of steel.

Gamma iron – The face-centered cubic form of pure iron, stable from 910 to 1400°C (1670 to 2550°F).

Gas carburizing - See Carburizing.

Gas cyaniding – A misnomer for carbonitriding.

Gas flow rate - The flow rate of gas (e.g. liters per minute) through the spraying torch.

Gas nitriding – Also called nitriding.

Gas nitrocarburizing – Also called nitrocarburizing.

Gold plating - The electrolytic deposition of gold for decorative or electrical applications.

Grain-boundary liquidation – An advanced stage of overheating in which material in the region of austenitic grain boundaries melts. Also termed burning.

Grain coarsening – A heat treatment that produces excessively large austenitic grains.

Grain growth – An increase in the average size of the grains in polycrystalline metal, usually as a result of heating at elevated temperature.

Grain refiner – A material added to a molten metal to induce a finer-than-normal grain size in the final structure.

Grain size – For metals, a measure of the areas or volumes of grains in a polycrystalline material, usually expressed as an average when the individual sizes are fairly uniform. In metals containing two or more phases, the grain size refers to that of the matrix unless otherwise specified. Grain sizes are reported in terms of number of grains per unit area or volume, average diameter, or as a grain-size number derived from area measurement.

Granular powder - Particles having approximately equidimensional nonspherical shapes.

Graphite - A black lamella solid with low friction, anti wear properties. The low friction is not sustained in vacuum. In air it can be used up to 400 °C.

Graphitic carbon – Free carbon in steel or cast iron. See graphitization.

Graphitization – Formation of graphite in iron or steel. Where graphite is formed during solidification, the phenomenon is called primary graphitization; where formed later by heat treatment, secondary graphitization.

Graphitizing – Annealing a ferrous alloy in such a way that some or all of the carbon is precipitated as graphite.

Grinding - The removal of material by the use of fixed abrasives like grinding wheels or emery paper.

Grit blasting - A pressurized stream of hard metal or oxide grit material used to clean and/or roughen surfaces prior to coating.

Grossmann chart – A chart describing the ability of a quenching medium to extract heat from a hot steel work piece in comparison to still water.

Guinier-Preston (G-P) zone – A small precipitation domain in a supersaturated metallic solid solution. A G-P zone has no well-defined crystalline structure of its own and contains an abnormally high concentration of solute atoms. The formation of G-P zones constitutes the first stage of precipitation and is usually accompanied by a change in properties of the solid solution in which they occur.

Hafnium Nitride (HN) - Gold colored ceramic, typically applied as a thin coating. Very hard (3500Hv). Used on cutting tools and forming tools and other surfaces needing wear resistance.

Half hard – A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength about midway between that of dead soft and full hard tempers.

Hardenability – The relative ability of a ferrous alloy to form martensite when quenched from a temperature above the upper critical temperature. Hardenability is commonly measured as the distance below a quenched surface where the metal exhibits a specific hardness (50 HRC, for example) or a specific percentage of martensite in the microstructure.

Hardening – Increasing the hardness by suitable treatment, usually involving heating and cooling. When applicable, the following more specific terms should be used: age hardening, flame hardening, induction hardening, laser hardening, precipitation hardening, and quench hardening.

Hard chrome plating - The electrolytic deposition of chromium to form a very hard (1000Hv), tough coating with good wear resistance. The structure is micro-cracked.

Hardfacing - The application of a cladding or coating of material designed to resist wear.

Hardness – Resistance of metal to plastic deformation, usually by indentation. However, the term may also refer to stiffness or temper, or to resistance to scratching, abrasion, or cutting. Indentation hardness may be measured by various hardness tests, such as Brinell, Rockwell, and Vickers.

Hardness profile – Hardness as a function of distance from a fixed reference point (usually from the surface).

Hard temper – Same as full hard temper.

HCD - See Hollow Cathode Discharge

Heat Resistant Coating - Any coating which during normal use must withstand temperatures of at least 204°C (400°F).

Heat tinting – Coloration of a metal surface through oxidation by heating to reveal details of the microstructure.

Heat-treatable alloy – An alloy that can be hardened by heat treatment.

Heat-treating film – A thin coating or film, usually an oxide, formed on the surface of metals during heat treatment.

Heat treatment – A combination of heating and cooling operations and applied to a metal or alloy to produce desired properties and microstructures. Heating for the sole purpose of hot working is excluded from the meaning of this definition.

Helium (He) - Monatomic noble gas, Most inert element, atomic number 2. Used as a plasma gas in plasma spraying.

High-Alloy Steel - Ferrous alloy with more than 12 weight percent of noncarbon additions.

High Pressure Mold - A strong high-density mold, made by air, hydraulic, or other squeeze process.

High Strength Low Alloy Steel (HSLA) - Steel with relatively high strength and impact properties. The carbon level is low and the alloying additions are significantly less than 5 weight percent.

High Velocity Oxy-fuel Spraying (HVOF) - A Thermal spray process. The spray powder particles are injected into a jet formed by the combustion of oxy-fuel, heated and accelerated to the work piece.

HIPPING - The high temperature/high pressure consolidation of a powder metallurgy component or thermally sprayed coating. Density is greatly increased and metallurgical changes provide enhanced corrosion and wear properties.

Holding – The portion of the thermal cycle during which the temperature of the object is maintained constant.

Holding temperature – The constant temperature at which the object is maintained.

Holding time – Time for which the temperature of the object is maintained constant.

Hollow Cathode Discharge - A technique to deposit high quality TiN, CrN, TiCN, and TiCrN thin films on cutting tools, machine parts, molds, etc
Homogeneous carburizing – Use of a carburizing process to convert a low-carbon ferrous alloy to one of uniform and higher carbon content throughout the section.

Homogenizing – Holding at high temperature to eliminate or decrease chemical segregation by diffusion.

Horizontal batch furnace – A versatile batch-type furnace that can give light or deep case depths, and because the parts are not exposed to air, horizontal batch furnaces can give surfaces almost entirely free of oxides.

Hot dip coating - A metallic coating obtained by dipping the substrate metal into a molten metal.

Hot quenching – An imprecise term used to cover a variety of quenching procedures in which a quenching medium is maintained at a prescribed temperature above 70°C (160°F).

Hot-wire analyzer – An electrical atmosphere analysis device that is based on the fact that the electrical resistivity of steel is a linear function of carbon content over a range from 0.05% C to saturation. The device measures the carbon potential of furnace atmospheres (typically). This term is not to be confused with hot-wire test, which measures heat extraction rates.

HVOF - See High Velocity Oxy-fuel spraying.

Hydrogen (H2) - Diatomic gas, atomic number 1, The lightest element, very reactive and powerful reducing agent. Used as a secondary plasma gas in the plasma spraying process and as a fuel gas in combustion thermal spray processes (CWS, CPS and HVOF)

Hydrogen embrittlement - Hydrogen induced cracking or severe loss of ductility caused by the presence of hydrogen in the metal. Hydrogen absorption may occur during electroplating, pickling etc. ( The use of hydrogen as a secondary gas in plasma spraying does not appear to effect substrates and the majority of coatings, one exception being titanium coatings.)

Hydrophilic - Tending to absorb water.

Hydrophobic - Tending to repel water or lacking affinity for water

Hydroxyapatite - Hydroxyapatite is a biocompatible ceramic. It may be deposited by plasma spray onto orthopedic implants in order to increase the bone-implant contact. It may also be sprayed over a porous titanium coating where it is used to promote bone ingrowth.

Hypereutectic alloy – In an alloy system exhibiting a eutectic, any alloy whose composition has an excess of alloying element compared with eutectic composition, and whose equilibrium microstructure contains some eutectic structure.

Hypereutectoid alloy – In an alloy system exhibiting a eutectoid, any alloy whose composition has an excess of alloying element compared with the eutectoid composition, and whose equilibrium microstructure contains some eutectoid structure.

Hypereutectoid Steel - A steel containing more than the eutectoid percentage of carbon (0.83 wt. %).

Hypoeutectic alloy – In an alloy system exhibiting a eutectic, any alloy whose composition has an excess of based metal compared with the eutectic composition, and whose equilibrium microstructure contains some eutectic structure.

Hypereutectoid alloy – In an alloy system exhibiting a eutectoid, any alloy whose composition has an excess of base metal compared with the eutectoid composition, and whose equilibrium microstructure contains some eutectoid structure.

Ideal critical diameter (DI) – Under an ideal quench condition, the bar diameter that has 50% martensite at the center of the bar when the surface is cooled at an infinitely rapid rate (that is, when H = , where H is the quench severity factor).

Immersed-electrodes furnace – A furnace used for liquid carburizing of parts by heating molten salt baths with the use of electrodes immersed in the liquid. See submerged-electrode furnace.

Impact test - A test to determine the behavior of materials when subjected to high rates of loading, usually in bending, tension or torsion. The quantity measured is the energy absorbed in breaking the specimen by a single blow, as in the Charpy or Izod tests.

Impurity - An element unintentionally allowed in a metal or alloy. Some impurities have little effect on properties; others will grossly damage the alloy.

Inclusions - Particles of impurities (usually oxides, sulphides, silicates and such) which separate from the liquid steel and are mechanically held during solidification. In some grades of steel, inclusions are made intentionally high to aid machinability.

Indentation method for hardness and modulus measurements – An indenter tip with a known geometry is driven into a specific site of the material to be tested by applying an increasing normal load. When reaching a preset maximum value, the normal load is reduced until partial or complete relaxation. This procedure is performed repetitively; at each stage of the experiment the position of the indenter relative to the sample surface is precisely monitored. For each loading/unloading cycle, the applied load value is plotted with respect to the corresponding position of the indenter. The resulting load/displacement curves provide data specific to the mechanical nature of the material under examination. Established models are used to calculate quantitative hardness and modulus values from such data.

Indium-tin oxide (ITO) - Transparent semiconducting material used as an electrode on flat-panel displays and other electro-optical devices.

Impingement - A process resulting in a continuing succession of impacts between (liquid or solid) particles and a solid surface.

Impingement corrosion - a form of erosion-corrosion generally associated with the impingement of a high velocity, flowing liquid containing air bubbles against a solid surface.

Induction hardening – A surface-hardening process in which only the surface layer of a suitable ferrous work piece is heated above 900°C by electromagnetic induction to above the upper critical temperature and immediately quenched.

Induction heating - The heating of a electrically conductive material by an induction coil producing alternating magnetic fields which induce alternating electric currents to flow in the material and cause heating by resistance. Used in many heating process (induction fusing, induction plasma, induction hardening etc..)

Induction tempering – Tempering of steel using low-frequency electrical induction heating.

Infrared analyzer – An atmosphere-monitoring device that measures a gas (usually carbon monoxide, carbon dioxide, and methane) presence based on specific wavelength absorption of infrared energy.

Ingot - A casting of a simple shape which can be used for hot working or remelting.

Injection Molding - The injection of molten metal or other material under pressure into molds.

Insert - A part usually formed from metal, which is placed in a mold and may become an integral part of the casting.

Intense quenching – Quenching in which the quenching medium is cooling the part at a rate at least two and a half times faster than still water. See Grossmann chart.

Interconnected porosity - A network of pores in and extending to the surface of a coating.

Intercritical annealing – Any annealing treatment that involves heating to, and holding at, a temperature between the upper and lower critical temperatures to obtain partial austentization, followed by either slow cooling or holding at a temperature below the lower critical temperature.

Intergranular – Between crystals or grains. Also called intercrystalline. Contrast with transgranular.

Intergranular corrosion - Preferential corrosion at or adjacent to the grain boundaries of a metal or alloy.

Intergranular cracking – Cracking or fracturing that occurs between the grains or crystals in a polycrystalline aggregate. Also called intercrystalline cracking. Contrast with transgranular cracking.

Intergranular fracture – Brittle fracture of a metal in which the fracture is between the grains, or crystals, that form the metal. Also called intercrystalline fracture. Contrast with transgranular fracture.

Intermediate annealing – Annealing wrought metals at one or more stages during manufacture and before final treatment.

Internal Friction - Ability of a metal to transform vibratory energy into heat; generally refers to low stress levels of vibration; damping has a broader connotation since it may refer to stresses approaching or exceeding yield strength.

Internal oxidation - The formation of isolated particles of corrosion products beneath the surface of the metal or coating. (This occurs as a result of preferential oxidation of certain alloy constituents by inward diffusion of oxygen, nitrogen, sulfur, etc.

Internal Shrinkage - A void or network of voids within a casting caused by inadequate feeding of that section during solidification.

Internal Stresses - Generally stresses which occur during the cooling of a part.

Interrupted aging– Aging at two or more temperatures, by steps, and cooling to room temperature after each step. See aging, and compare with progressive aging and step aging.

Interrupted quenching – A quenching procedure in which the work piece is removed from the first quench at a temperature substantially higher than that of the quenchant and is then subjected to a second quenching system having a different cooling rate than the first.

Interval test – Method used to test heat extraction rates of various quenchants. This test measures the increase in temperature of a quenchant when a standard bar of metal is quenched for five seconds. Faster quenchants will exhibit greater temperature increases.

Ion carburizing – A method of surface hardening in which carbon ions are diffused into a work piece in a vacuum through the use of high-voltage electrical energy. Synonymous with plasma carburizing or glow-discharge carburizing.

Ion nitriding – A method of surface hardening in which nitrogen ions are diffused into a work piece in a vacuum through the sue of high-voltage electrical energy. Synonymous with plasma nitriding or glow-discharge nitriding.

Ion plating - A process in which positive ions produced in a glow discharge are attracted to the substrate which is connected as the cathode. The ions are typically made by evaporation.

Ion scattering spectroscopy - Surface sensitive technique where the depth of analysis can be limited to the outermost atomic layer. In ISS a low-energy monoenergetic beam of ions is focused onto a solid surface and the energy of the scattered ions is measured at a fixed angle. A primary beam of an inert gas (He+, Ne+, Ar+) is usually employed, and since the collision with the atoms on the surface can be considered as elastic, the energy loss identifies the element on the surface.

Ion-Implantation - A process in which a beam of positive ions is projected towards and into the surface. It is carried out in partial vacuum and the ions diffuse into the surface layer of the substrate. Typically this is carried out with nitrogen giving a nitrided effect.

Irregular powder - Particles lacking symmetry.

Isothermal annealing – Austenitizing a ferrous alloy and then cooling to and holding at a temperature at which austenite transforms to a relatively soft ferrite carbide aggregate.

Isothermal transformation – A change in phase that takes place at a constant temperature. The time required for transformation to be completed, and in some instances the time delay before transformation begins, depends on the amount of supercooling below (or superheating above) the equilibrium temperature for the same transformation.

Isothermal transformation (IT) diagram – Set of curves drawn using logarithmic time and linear temperature as coordinates, which define for each level of temperature the beginning and end of the transformation of the initial phase under isothermal conditions.

Jobbing Foundry - A foundry engaged in the manufacture of numerous types of castings.

Jominy test – See end-quench hardenability test.

Kerosene - Liquid fuel used in some HVOF thermal spray processes.

Killed steel - Steel treated with a strong deoxidizer to reduce oxygen to a level where no reaction occurs between carbon and oxygen during solidification.

Kish – Free graphite that forms in molten hypereutectic cast iron as it cools. In castings, the Kish may segregate toward the cope surface, where it lodges at or immediately beneath the casting surface

Ladle - Metal receptacle frequently lined with refractories used for transporting and pouring molten metal. Types include hand bull, crane, bottom-pour, holding, teapot, shank, lip-pour.

Laminar flow - The flow regime which exists when Reynolds Number is below 2000. The path lines of the particles are smooth and regular, and there is little interchange of fluid mass between adjacent layers.

Lapping - Rubbing two surfaces together, with or without abrasives, for the purpose obtaining extreme dimensional accuracy or superior surface finish.

Lap - A surface imperfection which appears as a seam. It is caused by the folding over of hot metal, fins, or sharp corners and then rolling or forging them into the surface but not welding them. Laps on tubes can form from seams on piercing mill billets.

Laser Ablation - A deposition technique which uses a pulsed UV laser beam for vaporizing solid source materials. Much of the material ablates as macroparticles rather than vaporizing as atoms or molecules. A key advantage is that it can achieve congruent evaporation of complex materials, such as mixed oxides.

Laser alloying - The application of a powder to a surface followed by fusing and alloying into the surface via the heat from an impinging laser.

Laser glazing - The melting and quenching of a surface to form a fine grained structure or 'glaze'.

Laser hardening – A surface-hardening process which uses a laser to quickly heat a surface above 900°C. Heat conduction into the interior of the part will quickly cool the surface, leaving a shallow martensitic layer.

Latent heat – Thermal energy absorbed or released when a substance undergoes a phase change.

Lead (Pb) - improves machinability. It does not dissolve in steel but stays as globules. Environmental concerns are resulting in a decreased usage of lead in the steel industry.

Ledeburite – The eutectic of the iron-carbon system, the constituents being austenite and cementite. The austenite decomposes into ferrite and cementite on cooling below the Ar1.

Leidenfrost phenomenon – Slow cooling rates associated with a hot vapor blanket that surrounds a part being quenched in a liquid medium such as water. The gaseous vapor envelope acts as an insulator, thus slowing the cooling rate.

Liquation temperature – The lowest temperature at which partial melting can occur in an alloy that exhibits the greatest possible degree of saturation.

Liquid carburizing – Surface hardening of steel by immersion into a molten bath consisting of cyanides and other salts.

Liquid impingement erosion - Progressive loss of material from a solid surface due to continue exposure to impacts by liquid drops or jets.

Liquid nitriding – A method of surface hardening in which molten nitrogen-bearing, fused salt baths containing both cyanides and cyanates are exposed to parts at subcritical temperatures.

Liquid nitrocarburizing – A nitrocarburizing process (where both carbon and nitrogen are absorbed into the surface) utilizing molten liquid salt baths below the lower critical temperature.

Liquid spray quench – Same as spray quenching.

Localized corrosion - Corrosion at discrete sites, for example, pitting, crevice corrosion, and stress corrosion cracking.

Localized precipitation – Precipitation from a supersaturated solid solution similar to continuous precipitation, except that the precipitate particles form at preferred locations, such as along slip planes, grain boundaries, or incoherent twin boundaries.

Low Activation Interior Coating - Any Coating used on the interior of ships to minimize the activation of pigments on painted surfaces within a radiation environment.

LPPS - See Vacuum or Low Pressure Plasma Spraying.

Lubricant - Any substance interposed between two surfaces for the purpose of reducing the friction or wear between them.

Macrohardness - The hardness of a coating as measured on a macroscopic scale, which shows the coatings bulk properties.
Magnetic Storage Media - Magnetic materials are classified as "hard" or "soft" depending on how hard it is to magnetize, demagnetize, or "switch" the magnetic field. Soft magnetic materials, such as the Permalloys (iron [Fe]:40 to 80% Ni) and Y2Fe5O12 (garnet) are used in memory storage devices where the data are changed often. Hard magnetic materials such as Fe3O4, Co:Ni:tungsten [W], Co:rhenium [Re], gadolinium [Gd]:Co, and Gd:terbium [Tb]:Fe are used in more permanent recording media such as audio tapes. Various techniques are used to define the magnetic domains that act as the storage sites.

Magnetic test – Method used to test heat extraction rates of various quenchants. The test works by utilizing the change in magnetic properties of metals at their Curie point – the temperature above which metals lose their magnetism.

Magnetron sputtering - In this PVD process, the sputtering action is enhanced by intense magnetic fields. Also called sputtering.

Malleable cast iron – A cast iron made by prolonged annealing of white cast iron in which decarburization or graphitization, or both, take place to eliminate some or all of the cementite. The graphite is in the form of temper carbon. If decarburization is the predominant reaction, the product will exhibit a light fracture surface, hence, “whiteheart malleable”; otherwise, the fracture surface will be dark, hence, “blackheart malleable.” Ferritic malleable has predominantly ferritic matrix; pearlitic malleable may contain pearlitic, spherodite, or tempered martensite depending on heat treatment and desired hardness.

Malleablizing – Annealing white cast iron in such a way that some or all of the combined carbon is transformed to graphite or, in some instances, part of the carbon is removed completely.

Manganese (Mn) - is important because it deoxidizes the melt and facilitates hot working of the steel by reducing the susceptibility to hot shortness. It combines with sulfur to form MnS stringers which increases machinability. Manganese contributes to the effectiveness of normalizing for strengthening, to the formation of fine pearlite, and lowers the Ms temperature, therefore increasing the probability of retained austenite.

Maraging – A precipitation-hardening treatment applied to a special group of iron-base alloys to precipitate one or more intermetallic compounds in a matrix of essentially carbon-free martensite.

Marine Coating - Any coating, except unsaturated polyester resin (fiberglass) coatings, containing volatile organic materials and applied by any means to ships, boats, and their appurtenances, and to buoys and oil drilling rigs intended for the marine environment.

Marquenching – See martempering.

Martempering – (1) A hardening procedure in which an austenitized ferrous work piece is quenched into an appropriate medium whose temperature is maintained substantially at the Ms of the work piece, held in the medium until its temperature is uniform throughout – but not long enough to permit bainite to form – and then cooled in air. The treatment is frequently followed by tempering. (2) When the process is applied to carburized material, the controlling Ms temperature is that of the case. This variation of the process is frequently called marquenching.

Martensite – A generic term for microstructures formed by diffusionless phase transformation in which the parent and product phases have a specific crystallographic relationship. Martensite is characterized by an acicular pattern in the microstructure in both ferrous and nonferrous alloys. In alloys where the solute atoms occupy interstitial positions in the marensite lattice (such as carbon in iron), the structure is hard and highly strained; but where the solute atoms occupy substitutional positions (such as nickel in iron), the martensite is soft and ductile. The amount of high-temperature phase that transforms to martensite on cooling depends to a large extent on the lowest temperature attained, there being a rather distinct beginning temperature (Ms) and a temperature at which the transformation is essentially complete (Mf).

Martensite range – The temperature interval between Ms and Mf.

Martensitic Stainless Steels - A corrosion-resistant ferrous alloy with a predominant martensitic phase.

Martensitic transformation – A reaction that takes place in some metals on cooling, with the formation of an acicular structure called martensite.

Mass Effect - The effect that the mass of a component has on the properties of the material from which the part is made. In castings such effects may arise due to the effect of mass on the solidification and on the rate of temperature change heat treatment.

Matrix - The continuous phase of a material or coating in which separate particles of another constituent are embedded. (Like tungsten carbide particles in a cobalt matrix)

McQuaid-Ehn test – A test to reveal grain size after heating into the austenitic temperature range. Eight standard McQuaid-Ehn grain sizes rate the structure, No. 8 being finest, No. 1 coarsest.

MCrAlY - MCrAlY's (where M = Ni, Co or Fe) are a group of high temperature, corrosion resistant alloys used to combat sulfidation and oxidation.

Mechanical bonding - Usually represented by mechanical interlocking of the deposited particles with the rough heights on the substrate surface produced during grit blasting.

Mechanical properties – The properties of material that reveals its elastic and inelastic behavior when force is applied, thereby indicating its suitability for mechanical applications: for example, modulus of elasticity, tensile strength, elongation, hardness, and fatigue limit. Compare with physical properties.

Mechanical testing – Determination of mechanical properties.

Mesh - The area made up of elements and nodes (or grid points) in a numerical simulation.

Metal – An opaque lustrous elemental chemical substance that is a good conductor of heat and electricity and, when polished, a good reflector of light. Most elemental metals are malleable and ductile and are, in general, denser than the other elemental substances.

Metallic Coating - Coating which contains more than 5 grams of metal particles per liter of coating, as applied.

Metallurgical bonding - Produced by chemical bonding between areas of the coating and substrate in intimate contact or even by diffusional interaction between the coating and substrate. Metallurgical bonding can be enhanced by post diffusion heat treatments.

Metallographic Structure - The nature, distribution, and amounts of the metallographic constituents in a metal.

Metallurgy – The science and technology of metals and alloys. Process metallurgy is concerned with the extraction of metals from their ores and with refining of metals; physical metallurgy, with the physical and mechanical properties of metals as affected by composition, processing, and environmental conditions; and mechanical metallurgy, with the response of metals to applied forces.

Mf Temperature – For any alloy system, the temperature at which martensite formation on cooling is essentially finished. See transformation temperature for the definition applicable to ferrous alloys.

Micrograph - A micrograph is produced when a section of the coating is taken, polished to show the particulate layers and then photographed through a microscope.

Microhardness – The hardness of a material as determined by forcing an indenter such as a Vickers or Knoop indenter into the surface of a material under very light load; usually, the indentations are so small that they must be measured with a microscope. Capable of determining hardness of different microconstituents within a structure, or a measuring steep hardness gradients such as those encountered in case hardening.

Microinch - One millionth of an inch, 0.000001".

Micrometer (µm) - One millionth of a meter, 0.001mm.

Microscopic stresses – Residual stresses that vary from tension to compression in a distance (presumably approximating the grain size) that is small compared with the gage length in ordinary strain measurements. They are not detectable by dissection methods, but can sometimes be measured from the line shift or line broadening in an x-ray diffraction pattern.

Microsegregation – Segregation within a grain, crystal, or small particle.

Microstructure - The structure of a metal as revealed at high magnification, usually at 100x and higher.

Microtrack - A device for measuring powder particle size distributions.

Mil - One thousandth of an inch, 0.001"

Mill scale – The heavy oxide layer formed during hot fabrication or heat treatment of metals.

Minus sieve - The portion of a powder sample which passes through a standard sieve of specified number e.g. -140 mesh +325 mesh. See Plus sieve.

Modulus Of Elasticity (E) - In tension it is the ratio of stress to the corresponding strain within the limit of elasticity (Yield Point) of a material. For carbon and low alloy steels any composition and treatment, the value is approximately 200 GPa or 30,000,000 psi.

Modulus of Resilience (ur) - The amount of strain energy per unit volume required to stress a material from zero to the yield stress limit. The modulus of resilience is proportional to the area under the elastic portion of the stress-strain diagram. Units are Pa or psi.

Modulus of Rigidity - In a torsion test the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range.

Modulus of Rupture - Used in both bending and torsion testing. In bending, the modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar section modulus.

Modulus of Toughness (ut) - Amount of work per unit volume of a material required to carry that material to failure under static loading. Equal to the area under the entire stress-strain curve. Units are Pa or psi.

Mold Coating (Mold Facing, Dressing) – (1) Coating to prevent surface defects on permanent mold castings and die castings. (2) Coating on sand molds to prevent metal penetration and improve metal finish.

Molybdenum (Mo) - increases hardenability of steels and helps maintain a specified hardenability. It increases high temperature tensile and creep strengths. Molybdenum hardened steels require higher tempering temperatures for softening purposes. A metal used widely in alloying of other metals. It is used as hardening element for steel, and for diecasting dies. Melting point 2620°C (4748°F), atomic number 42.

Molybdenum Disulphide (MoS2) - A black, lamella structured solid with low sliding friction. Often applied as a powder filler to lubricants or dispersed in a polymer coating.

Monotropism – The ability of a solid to exist in two or more forms (crystal structures), but in which one form is the stable modification at all temperatures and pressures. Ferrite and martensite are a monotropic pair below Ac1 in steels, for example. May also be spelled monotrophism.

Ms temperature – For any alloy system, the temperature at which martensite starts to form on cooling. See transformation temperature for the definition applicable to ferrous alloys.

Multiport nozzle (Plasma) - Constricted nozzle with two or more internal bores, in order to achieve a better control of the shape and stability of plasma arc.

Natural aging – Spontaneous aging of a supersaturated solid solution at room temperature. See aging, and compare with artificial aging.

Navier-Stokes Equations - Probably the most pivotal equations in all of theoretical fluid dynamics, these equations relate all the flow field variables together into nonlinear partial differential equations. The NS equations are basically a reformulation of Newtons 2nd Law of a Motion, F=ma.

NCA - See notched coating adhesion.

Neutral flame – A gas flame in which there is no excess of either fuel or oxygen in the inner flame. Oxygen from ambient air is used to complete the combustion of CO2 and H2 produced in the inner flame.

Neutralization number – An ASTM number given to quenching oils that reflects the oil’s tendency toward oxidation and sludging. See saponification number.

Nickel (Ni) - is used in low alloy steels to reduce the sensitivity of the steel to variations in heat treatment and distortion and cracking on quenching. It also improves low temperature toughness and hardenability melting point 1455°C (2651°F). Nickel is also a base metal for many casting alloys resistant to corrosion and high temperature oxidation.

Nickel plating - The electrolytic deposition of nickel to form a corrosion barrier or to reclaim a worn part. Can also include hard ceramic particles to from a wear resistant composite coating.

Ni-Hard - Hard white cast iron containing 4% Ni and 2% Cr.
Niobium (Nb) (Columbium - Cb) - lowers transition temperature and raises the strength of low carbon steel. Niobium increases strength at elevated temperatures, results in finer grain size and forms stable carbides, lowering the hardenability of the steel.

Nitrogen (N) - increases the strength, hardness and machinability of steel, but it decreases the ductility and toughness. In aluminum killed steels, nitrogen combines with the aluminum to provide grain size control, thereby improving both toughness and strength. Nitrogen can reduce the effect of boron on the hardenability of steels.

Nitriding – Introducing nitrogen into the surface layer of a solid ferrous alloy by holding at a suitable temperature (below Ac1 for ferritic steels) in contact with a nitrogenous appropriate composition. Quenching is not required to produce a hard case. See aerated bath nitriding, bright nitriding, and liquid nitriding.

Nitrocarburizing – Any of several processes in which both nitrogen and carbon are absorbed into the surface layers of a ferrous material at temperatures below the lower critical temperature and, by diffusion, create a concentration gradient. Nitrocarburizing is done mainly to provide an antiscuffing surface layer and to improve fatigue resistance. Compare with carbonitriding.

Nitrogen (N2) - Diatomic gas. Used as a primary and secondary gas in plasma spraying. Inert to most materials, with some exceptions like titanium.

Noble metal - A metal that does not readily tend to furnish ions, and therefore does not dissolve readily, or easily enter into such reactions as oxidation, etc. The opposite of base metal.

Node - Used in a numerical simulation to attach the adjacent elements.

Nodular powder - Irregular particles having Knotted, rounded, or similar shapes.

Nonferrous - A negative term, refers to alloy in which the predominate metal or solvent is not iron.

Non transferred arc (Plasma) - The plasma arc which transfers heat energy to plasmagenic gas (Argon, Helium, Hydrogen, Nitrogen) in order to promote the plasma state according to the Saha's law. This arc strikes between the tungsten electrode (cathode) and the constricting nozzle (anode). The term Pilot Arc is also used in Plasma Transferred Arc process (P.T.A. welding).

Normal Steel - Steel in which the pearlite is completely laminated.

Normalizing – Heating a ferrous alloy to a suitable temperature above the transformation range and then cooling in air to a temperature substantially below the transformation range.

Notched Coating Adhesion (NCA) - A recent characterization technique (test) used to analyze adhesive bond durability.

Nuclear Reaction Analysis (NRA) - An ion beam technique which allows light mass elements profiling into materials. Analysis depth up to one micrometer.

Nucleation – The initiation of a phase transformation at discrete sites, the new phase growing on nuclei. See nucleus.

Nucleus – The first structurally stable particle capable of initiating recrystallization of a phase or the growth of a new phase, and possessing an interface with the parent matrix. The term is also applied to a foreign particle that initiates such action.

Oil hardening – Quench-hardening treatment involving cooling in oil.

Oil quenching – Hardening of carbon steel in an oil bath. Oils are categorized as conventional, fast, martempering, or hot quenching.

OMCVD - See Organic Metal Chemical Vapor Deposition.

Optical Films - Optical films, usually multilayer films ("stacks"), are films that affect the optical transmission or reflection of a surface. They are generally alternating layers of materials having high (germanium [Ge], Si, TiO2, zirconium dioxide [ZrO2], SiO, cerium dioxide [CeO2]) and low (magnesium fluoride [MgF2], SiO2) indices of refraction. A major application is the antireflection (AR) coatings on lenses. Optical film stacks can be used as optical filters. Neutral density or gray filters reduce the light intensity equally for all wavelengths; broadband filters affect the transmission of radiation over a wide wavelength range, while narrow or monochromatic filters affect transmission over a very narrow wavelength region. An example of a broadband filter is an "edge filter" that "cuts off" the ultraviolet (UV) emitted by a mercury vapor lamp. Examples of narrow-band filters are the color filters used in photography and in projectors. Some film stacks are a special type of optical film that has a color that is related to the angle-of-observation (OVIDs). These films allow holographic-like imaging. These OVID films are used as security devices to prevent counterfeiting. These films are an outgrowth of the interference-colored films used for decorative films and, when pulverized, as pigments.

Optical pyrometer – An instrument for measuring the temperature of heated material by comparing the intensity of light emitted with a known intensity of an incandescent lamp filament.

Order-disorder transformation – A phase change among two solid solutions having the same crystal structure, but in which the atoms of one phase (disordered) are randomly distributed; in the other, the different kinds of atoms occur in a regular sequence upon the crystal lattice, which is in an ordered arrangement. Compare with dissociation.

Order hardening – A low-temperature annealing treatment that permits short-range ordering of solute atoms within a matrix, which greatly impedes dislocation motion.

Orange Peel - A finish resembling the dimpled appearance of an orange peel.

Organic Metal Chemical Vapor Deposition (OMCVD) - This process uses metal organic reactants having a low cracking temperature. It allows deposition of metallic carbides such as CrC with a moderated process temperature (~400°C).

Orsat analyzer – An atmosphere analysis device in which gases are absorbed selectively (volumetric basis) by passing them through a series of preselected solvents.

Overaging – Aging under conditions of time and temperature greater than those required to obtain maximum change in a certain property, so that the property is altered in the direction of the initial value. See aging.

Overheating – Heating a metal or alloy to such a high temperature that its properties are impaired. When the original properties cannot be restored by further heat treating, by mechanical working, or by a combination of working and heat treating, the overheating is known as burning.

Oxidation – (1) A reaction in which there is an increase in valence resulting from a loss of electrons. (2) A corrosion reaction in which the corroded metal forms an oxide; usually applied to reaction with a gas containing elemental oxygen, such as air.

Oxidized surface (on steel) – Surface having a thin, tightly adhering, oxidized skin (from straw to blue in color), extending in from the edge of a coil or sheet. Sometimes called annealing border.

Oxidizing - The production of a stable oxide layer on a steel component by heating in a controlled atmosphere. Provides corrosion protection and reduced friction.

Oxidizing agent – A compound that causes oxidation, thereby itself becoming reduced.

Oxidizing flame – A gas flame produced with excess oxygen in the inner flame.

Oxygen (O2 ) - Gas used to support combustion of fuel gases in combustion thermal spray processes. Achieves much higher flame temperatures than using air.

Oxygen probe – An atmosphere-monitoring device that electronically measures the difference between the partial pressure of oxygen in a furnace or furnace supply atmosphere and the external air.

Pack carburizing – A method of surface hardening of steel in which the parts are packed in a steel box with carburizing compound and heated to elevated temperatures.

Pack nitriding – A method of surface hardening of steel in which parts are packed in a steel box with the nitriding compound and heated to elevated temperatures.

PACVD - See Plasma Assisted Chemical Vapor Deposition

Paint - A coating including resin, a solvent, additives, pigments and, in some products, a diluent. Paints are generally opaque, and commonly represent the portion of the industry known as "architectural coatings."

Painting - The application of organic based layers (acrylics, etc) for corrosion protection and decorative purposes.

Partial annealing – An imprecise term used to denote a treatment given cold-worked material to reduce the strength to a controlled level or to effect stress relief. To be meaningful, the type of material, the degree of cold work, and the time-temperature schedule must be stated.

Particle - The metal powder which is introduced into a plasma spray gun. One of two phases after the fluid that are modeled in a two-phase flow plasma spray gun simulation.

Particle chemistry - The elements contained within the particles of a spray powder.

Particle size - The controlling lineal dimension of an individual particle as determined by analysis with sieves or other suitable means.

Particle size distribution - The percentage by weight, or by number, of each fraction into which a powder sample has been classified with respect to sieve number or microns.

Particles Induced Gamma-ray Emission (PIGE) - An ion beam technique particularly well suited for the determination of light mass element concentrations into materials. Analysis depth up to a few micrometers.

Particles Induced X-ray Emission (PIXE) - An ion beam technique used in surface science for stoichiometry analysis and trace elements quantification. Ideal for coating impurities analysis.

Passivation - The process in metal corrosion by which metals become passive.

Passivating - The post treatment (usually by chromating) of nickel, cadmium or zinc coatings to reduce their corrosion rates.

Passivator - A type of inhibitor which appreciably changes the potential of a metal to a more noble (positive) value.

Passive - The state of a metal surface characterized by low corrosion rates in a potential region that is strongly oxidizing for the metal.

Patenting – In wiremaking, a heat treatment applied to medium carbon or high-carbon steel before the drawing of wire or between drafts. This process consists of heating to a temperature above the transformation range and then cooling to a temperature below Ae1 in air or in a bath of molten lead or salt.

Pearlite – A metastable lamellar aggregate of ferrite and cementite resulting from the transformation of austenite at temperatures above the bainite range.

Peeling - The detachment or partial detachment of a coating.

Peening - A stream of sharp material particles which break superficial fiber, reducing internal stress fields.

Penetration, Metal - Condition where molten metal has penetrated into the sand, resulting in a mixture of metal and sand adhering to the casting.

Perfluro Alkyle Ether (PFA) - Relatively hard long chain polymer with inert, orientated structure. Applied by spraying and then melt flowing at temperatures above 250°C. Combines non-stick with wear resistance.

Perfuoroether (FEP) - A soft long chain polymer with an inert, orientated structure. Applied by spraying and then melt flowing at 400°C. Excellent non-stick properties.

Permanent Mold - A metal mold of two or more parts; not an ingot mold. It is used repeatedly for the production of many casting of the same form.

Permeability - A property measured as a rate of passage of a liquid or gas through a coating.

Phase diagram – A graphical representation of the temperature and composition limits of phase fields in an alloy system as they actually exist under the specific conditions of heating or cooling (synonymous with constitution diagram). A phase diagram may be an equilibrium diagram, an approximation to an equilibrium diagram, or a representation of metastable conditions or phases. Compare with equilibrium diagram.

Phosphating - A conversion process for steel surfaces to enhance corrosion protection. It is often zinc based.

Phosphorus (P) - is generally restricted to below 0.04 weight percent to minimize its detrimental effect on ductility and toughness. Certain steels may contain higher levels to enhance machinability, strength and/or atmospheric corrosion resistance.

Photothermal NDE - An NDE technique for spayed coatings. A repeated pulse of heat, from a laser source, flows through the coating and substrate. The thermal signature is detected and related to the input signal thereby indicating coating thickness.

Physical properties – Properties of a metal or alloy that are relatively insensitive to structure and can be measured without the application of force; for example, density, electrical conductivity, coefficient of thermal expansion, magnetic permeability, and lattice parameter. Does not include chemical reactivity. Compare with mechanical properties.

Physical Vapor Deposition - A term covering all the vapor deposition processes including Ion plating, It does not include CVD as this is chemical not physical.

Pickling - An operation by which surface oxide (scale) is removed by chemical action. Sulfuric acid is typically used for carbon and low-alloy steels. After the acid bath, the steel is rinsed in water.

Pin-on-disk tribometer – A measuring device used to determine wear characteristics of material samples. A flat or sphere shaped contact (“pin”) is loaded onto the test sample (“disk”) with a precisely known force. The pin is mounted on a stiff lever, designed as a frictionless force transducer. As the disk is rotated, resulting frictional forces acting between the pin and the disk are measured by very small deflections of the lever. Wear coefficients for both the pin and disk material are calculated from the volume of the material lost during a specific friction run. This simple method facilitates the determination and study of friction and wear behavior of almost every solid-state material combination, with varying time, contact pressure, velocity, temperature, humidity, lubricants, etc.

Pipe - A cavity formed by shrinkage of the metal during solidification, usually occurring in a riser having feeder metal for the casting.

Pirani gage – An instrument used to measure the pressure inside a vacuum chamber. The gage measures electrical resistance in a wire filament which will change in temperature depending on atmospheric pressure.

Pitot gage – An instrument that measures the stagnation pressure of a flowing fluid, consisting of an open tube pointing into the fluid and connected to a pressure indicating device.

Plasma - Plasma is a gas (usually Argon, Helium, Nitrogen, Hydrogen) that has been heated to a sufficiently high temperature to become partially ionized and therefore electrically conductive. The term was introduced by Irving LANGMUIR in 1930.

Plasma Assisted Chemical Vapor Deposition - This process enables to reduce the high process temperature of CVD (commonly 800-1000°C) to the 150-250°C range. It allows for a larger panel of basic materials.

Plasma carburizing – Same as ion carburizing.

Plasma jet - A jet of highly ionized gas usually produced from a plasma torch. An electric arc is struck between a cathode and anode and is then blown through a nozzle to form the jet.

Plasma nitriding – Same as ion nitriding.

Plasma Spraying - A thermal spraying process in which the heat source is a plasma jet.

Plasma transferred arc – Also called transferred arc.

Plasma-Based Ultra-fine Particle Synthesis - A liquid precursor is atomized and injected into the plasma flame; the plasma synthesized particles are collected either as a deposit on a substrate or as a powder on an electrostatic precipitator.

Plenum (Plasma) - Space or chamber confined by the inner wall of the constricting nozzle and the cathodic electrode. The shape and size of this annular chamber play the highest role in Plasma Arc torches (welding, spraying).

Plastic deformation – The permanent (inelastic) distortion of metals under applied stresses that strain the material beyond its elastic limit.

Plus sieve - The portion of a powder sample retained on a sieve of specified number. See minus sieve.

Pitting-tribology - A form of wear characterized by the presence of surface cavities the formation of which is attributed to processes such as fatigue, local adhesion, or cavitation.

Pitting--corrosion - corrosion of a metal surface, confined to a point or small area, that takes the form of cavities

Plasma Transferred Arc (PTA) - Similar to the plasma spray process in that powder is sprayed through a plasma, but instead of being heated via a neutral plasma (carrying no electric current) the arc is transferred to the substrate (made to be the anode). This is a hot process and produces coatings similar to fused or weld hardfacing coatings.

Plowing - The formation of grooves by plastic deformation of the softer of two surfaces in relative motion.

Polishing - The smoothing of a material surface by means of the action of abrasive particles attached usually to a fabric cloth. The final mechanical step in metallographic preparation.

Polyester - A condensation polymer formed by the interaction of polyhydric alcohols and polybasic acids. They are used in the manufacture of glass-fiber products. See Alkyd resin.

Polymer - A substance having large molecules consisting of repeated units. There are a number of natural polymers, such as polysaccharides synthetic polymer are extensively used in plastics.

Polymer films - There is increasing interest in depositing organic and inorganic polymer films in vacuum. These films can be formed by condensation of a monomer followed by E-beam or UV curing to polymerize the monomer or by plasma polymerization of the monomer. The monomer precursor can yield a carbon, silicon, or boron-based polymer material often containing hydrogen, chlorine, or fluorine. Fluorine-containing films are used to form hydrophobic surfaces

Polymorphism – The property of a chemical substance crystallizing into two or more forms having different structures, such as diamond and graphite.

Polytetrafluorethylene (PTFE) - A long chain polymer with orientated structure providing low friction. Applied as a coating (by spraying or dipping and curing) or as powder additions to other coatings (for instance electroless nickel).

Porosity - The presence of pores or voids in a coating whether connected or not. Porosity is not the same as pull-out.

Postheating – Heating weldments immediately after welding, for tempering, for stress relieving, or for providing a controlled rate of cooling to prevent formation of a hard or brittle surface.

Pot annealing – Same as box annealing.

Pouring - Transfer of molten metal from furnace to ladle, ladle to ladle, or ladle into molds.

Powder coating - Polymeric coatings applied for corrosion protection on low friction. Applied dry with electrostatic attraction to the part

Powder gas flow rate - The flow rate of the gas propelling the powder into the plasma jet in plasma spraying.

Powder injection angle - The angle from which the powder is injected into the plasma jet in plasma spraying.

Pre-alloyed powder - A powder composed of two or more elements which are alloyed in the powder manufacturing process and in which the particles are of the same nominal composition throughout.

Precipitation hardening – Hardening caused by the precipitation of a constituent from a supersaturated solid solution. See also age hardening and aging.

Precipitation heat treatment – Artificial aging in which a constituent precipitates from a supersaturated solid solution.

Preheating – Heating before some further thermal or mechanical treatment. For tool steel, heating to an intermediate temperature, immediately before final austenitizing. For some nonferrous alloys, heating to a high temperature for a long time, to homogenize the structure before working. In welding and related processes, heating to an intermediate temperature for a short time immediately before welding, brazing, soldering, cutting, or thermal spraying.

Press quenching – A quench in which hot dies are pressed and aligned with a part before the quenching process begins. Then the part is placed in contact with a quenching medium in a controlled manner. This process avoids part distortion.

Pretreatment Coating - A coating which contains no more than 12 percents solids by weight, and at least 1/2-percent acid by weight, is used to provide surface etching, and is applied directly to metal surfaces to provide corrosion resistance, adhesion, and ease of stripping.

Process annealing – An imprecise term denoting various treatments used to improve workability. For the term to be meaningful, the condition of the material and the time-temperature cycle used must be stated.

Profile Tolerances - A system of locating and tolerancing developed to control the orientation of rough parts in machine fixtures. From locating points on the casting a "perfect profile" is established for all surfaces and features. A tolerance envelope surrounding that profile defines the limitations of an acceptable part.

Progressive aging – Aging by increasing the temperature in steps or continuously during the aging cycle. See aging and compare with interrupted aging and step aging.

Propane (C3H8) - Aliphatic hydrocarbon gas used as a fuel gas in thermal spray processes.

Propylene (C3H6) - Hydrocarbon gas used as a fuel gas in thermal spray processes. Higher flame temperature than hydrogen and propane.

Properties - Fluid or particle properties as used in a CFD simulation. Fluid properties would be: density, viscosity, volume of expansion; Particle properties would be: density, specific heat of evaporation.

Pseudocarburizing – See blank carburizing.

Pseudonitriding – See blank nitriding.

PSP - See Plasma-Based Ultra-fine Particle Synthesis

PTA welding - See Plasma Transferred Arc Welding

Pull-out - Pull-out occurs when particles are plucked from the coating during machining or grinding. Also occurs during metallographic preparation. It is sometimes confused with porosity.

Pusher furnace – A type of continuous furnace in which parts to be heated are periodically charged into the furnace in containers, which are pushed along the hearth against a line of previously charged containers thus advancing the containers toward the discharge end of the furnace, where they are removed.

PVD - See Physical Vapor Deposition

Pyrometer – A device for measuring temperatures above the range of liquid thermometers

Quality Control - All aspects of the control of the spraying process including the surface preparation, spraying, control of thickness deposited and the oxide and porosity levels, surface finish and NDE checks as specified.

Quarter hard – A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength about midway between that of dead soft and half hard tempers.

Quench-age embrittlement – of low-carbon steels resulting from precipitation of solute carbons at existing dislocations and from precipitation hardening of the steel caused by differences in ferrite at different temperatures. Quench-age embrittlement usually is caused by rapid cooling of the steel from temperatures slightly below embrittlement Ac1 (the temperature at which austenite begins to form) and can be minimized by quenching from lower temperatures.

Quench aging – Aging induced by rapid cooling after solution heat treatment.

Quench annealing – Annealing an austenitic ferrous alloy by solution heat treatment followed by rapid quenching.

Quench Crack - A crack resulting from thermal stress induced during rapid cooling or quenching, or from stresses induced by delayed transformations some time after the article has been fully quenched.

Quench cracking – Fracture of a metal during quenching from elevated temperature. Most frequently observed in hardened carbon steel, alloy steel, or tool steel parts of high hardness and low toughness. Cracks often emanate from fillets, holes, corners, or other stress raisers and result from high stresses due to the volume changes accompanying transformation to martensite.

Quench hardening – (1) Hardening suitable alpha-beta alloys (most often certain copper to titanium alloys) by solution treating and quenching to develop a martensitic-like structure. (2) In ferrous alloys, hardening by austenitizing and then cooling at a rate such that a substantial amount of austenite transforms to martensite.

Quenching – Rapid cooling. When applicable, the following more specific terms should be used: brine quenching, caustic quenching, cold die quenching, forced-air quenching, intense quenching, oil quenching, press quenching, spray quenching, direct quenching, fog quenching, hot quenching, interrupted quenching, and water quenching.

Racking – A term used to describe the placing of parts to be heat treated on a rack or tray. This is done to keep parts in a proper position to avoid heat-related distortions and to keep parts separated. See fixturing.

Recalescence – A phenomenon, associated with the transformation of gamma iron to alpha iron on cooling (supercooling) of iron or steel, revealed by the brightening (reglowing) of the metal surface owing to the sudden increase in temperature caused by the fast liberation of the latent heat of transformation. Contrast with decalescence.

Recarburize – (1) To increase the carbon content of molten cast iron or steel by adding carbonaceous material, high-carbon pig iron, or a high-carbon alloy. (2) To carburize a metal part to return surface carbon lost in processing; also known as carbon restoration.

Recovery – Reduction or removal of work-hardening effects, without motion of large-angle grain boundaries.

Recrystallization – (1) The formation of a new, strain-free grain structure from that existing in cold-worked metal, usually accomplished by heating. (2) The change from one crystal structure to another, as occurs on heating or cooling through a critical temperature.

Recrystallization annealing – Annealing cold-worked metal to produce a new grain structure without phase change.

Recrystallization temperature – The approximate minimum temperature at which complete recrystallization of a cold-worked metal occurs within a specified time.

Recuperator – Equipment for transferring heat from gaseous products of combustion to incoming air or fuel. The incoming material passes through pipes surrounded by a chamber through which the outgoing gases pass.

Reducing Agent - A substance that causes reduction, thereby itself becoming oxidized.

Reducing flame – A gas flame produced with excess fuel in the inner flame.

Reduction - A reaction in which electrons are added to the reactant. More specifically, the addition of hydrogen or the abstraction of oxygen.

Reduction of area – (1) Commonly, the difference, expressed as a percentage of original area, between the original cross-sectional area of a tensile test specimen and the minimum cross-sectional area measured after complete separation. (2) The difference, expressed as a percentage of original area, between original cross-sectional area and that after straining of the specimen.

Refractory – (1) A material of very high melting point with properties that make it suitable for such uses as furnace linings and kiln construction. (2) The quality of resisting heat.

Regenerator – Same as recuperator except the gaseous products of combustion heat brick checkerwork in a chamber connected to the exhaust side of the furnace while the incoming air and fuel are being heated by the brick checkerwork in a second chamber, connected to the entrance side. At intervals, the gas flow is reversed so that incoming air and fuel contact hot checkerwork while that in the second chamber is being reheated by exhaust gases.

Residual stress – An internal stress not depending on external forces resulting from such factors as cold working, phase changes, or temperature gradients.

Resin - A synthetic or naturally occurring polymer.

Retort – A vessel used for distillation of volatile materials, as in separation of some metals and in destructive distillation of coal.

Reverberatory furnace – A furnace with a shallow hearth, usually nonregenerative, having a roof that deflects the flame and radiates heat toward the hearth or the surface of the charge.

RFI Shielding - Thermal spray coatings of electrically conductive metals such as zinc, aluminum and copper are used on non-conducting composite casing materials to shield sensitive electronic devices from radio frequency electromagnetic interference.

Rhodium plating - The electrodeposition of rhodium for oxidation resistance combined with surface hardness.

Rimmed steel - A low carbon steel having enough iron oxide to give a continuous evolution of carbon monoxide during solidification giving a rim of material virtually free of voids.

Rockwell hardness test – An indentation hardness test based on the depth of penetration of a specified penetrator into the specimen under certain arbitrarily fixed conditions.

Rotary retort furnace – A continuous-type furnace in which the work advances by means of an internal spiral, which gives good control of the retention time within the heated chamber.

Runout - A casting defect caused by incomplete filling of the mold due to molten metal draining or leaking out of some part of the mold cavity during pouring; escape of molten metal from a furnace, mold or melting crucible.

Rutherford Backscattering Spectrometry (RBS) - A relevant ion beam technique for surface composition analysis (analyzed depth: up to 1 micrometer). It is widely used in thin film science.

Salt bath carburizing - See Carburizing.

Salt bath heat treatment – Heat treatment carried out in a bath of molten salt.

Salt bath nitriding - See Nitriding.

Salt bath nitrocarburizing - See Nitrocarburizing.

Salt spray test - Accelerated testing of corrosion properties of metallic coatings

Sand - In metalcasting, a loose, granular material high in SiO2, resulting from the disintegration of rock. The name sand refers to the size of grain and not to mineral composition. Diameter of the individual grains can vary from approximately 6 to 270 mesh. Most foundry sands are made up principally of the mineral quartz (silica). Reason for this is that sand is plentiful, refractory, and cheap; miscellaneous sands include zircon, olivine, chromite, CaCO3, black sand (lava grains), titanium minerals and others.

Sand Casting - Metal castings produced in a green sand, dried sand or core sand mold.

Sand Control - Procedure whereby various properties of foundry sand, such as fineness, permeability, green strength, moisture content, etc., are adjusted to obtain castings free from blows, scabs, veins, and similar defects.

Sand Porosity - Volume of the pore spaces or folds in sand. Not synonymous with permeability.

Saponification number – A number given to quenching oils that reflects the oils amount of compounding with fatty materials, which thereby helps evaluate the condition of these oils in service. See neutralization number.

Scab - An expansion discontinuity defect on the surface of a casting which appears as a rough, slightly raised surface blemish, crusted over by a thin porous layer of metal under which is a honeycomb or cavity that usually contains a layer of sand.

Scaling (Scale) - Surface oxidation, partially adherent layers of corrosion products, left on metals by heating or casting in air or in other oxidizing atmospheres.

Scanning probe microscopy (SPM) – An extremely accurate and versatile technique for measuring structures or surface forces. A very fine sensor tip mounted to the end of a small deflecting spring, known as a cantilever, is brought into contact with the sample surface to be investigated. The sensor tip is moved across the surface in numerous line scans. Due to the surface roughness (topography), the tip and the cantilever move up and down. This movement can be measured with high resolution and the resulting data allows imaging of the surface structure. Also called atomic force microscopy.

Scanning Tunneling Microscopy - Technique to directly observe individual atoms on surfaces. In STM a solid specimen in air, liquid or vacuum is scanned by a sharp tip located very close to the surface. A quantum -mechanical tunneling current flows between atoms on the surface and those on the tip. The magnitude of the current depends upon the separation between the surface and tip atoms, so that it is possible to obtain surface topography with atomic resolution.

Scarfing - Cutting off surface projections such as gates and risers from casting by means of gas torch.

Scoring - A severe form of wear characterized by the formation of extensive grooves and scratches in the direction of sliding.

Scrap Metal - Metal to be remelted; includes scrapped machinery fabricated items such as rail or structural steel and rejected castings.

Scratching - The mechanical removal or displacement, or both, of material from a surface by the action of abrasive particles or protuberances sliding across the surfaces.

Screen Analysis - Distribution of particle size sand expressed in terms of the percentage of weight retained on each of a series of standard screens decreasing in mesh size and the percentage passed by the screen of finest mesh.

Sealant, Sealer - A preparation of resin or wax type materials for sealing the porosity in coatings.

Sealing - A process which, by absorption of a sealer into thermal spray coatings, seals porosity and increases resistance to corrosion of the underlying substrate material.

Seam - A defect on the surface of a metal which appears as a crack. Experience indicates that most seams are created during the cooling or reheating of cast structures.

Secondary hardness - The higher hardness developed by certain alloy steels when they are cooled from a tempering operation. This should always be followed by a second tempering operation.

Selective heating – Intentionally heating only certain portions of a work piece.

Selective quenching – Quenching only certain portions of an object.

Self-bonding coatings - A name given to thermal spray coatings that are capable of bonding to clean smooth surfaces. Bond and "one-step" coatings are normally in this group. These are particularly important where grit blasting or surface roughening processes must be omitted.

Self-hardening steel – See preferred term, air-hardening steel.

Semi-killed steel - Incompletely deoxidized steel which contains enough dissolved oxygen to react with the carbon to form carbon monoxide to offset solidification shrinkage.

Sensitization – In austenitic stainless steels, the precipitation of chromium carbides, usually at grain boundaries, on exposure to temperatures of about 540 to 845°C (1000 to 1550°F), leaving the grain boundaries depleted of chromium and therefore susceptible to preferential attack by a corroding (oxidizing) medium.

Severity of quench – Ability of quenching medium to extract heat from a hot steel work piece; expressed in terms of H value.

Shaker-hearth furnace – A continuous-type furnace that uses a reciprocating shaker motion to move the parts along the hearth.

Shear - A type of deformation in which parallel planes in the metal crystals slide so as to retain their parallel relation.

Shear Modulus (G) - In a torsion test, the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range. Units are Pa or psi.

Shear Strain - Elastic displacement produced by pure shear loading.

Shear Strength - Maximum shear stress a material is capable of withstanding without failure.

Shell hardening – A surface-hardening process in which a suitable steel work piece, when heated through and quench hardened, develops a martensitic layer or shell that closely follows the contour of the piece and surrounds a core of essentially pearlitic transformation product. This result is accomplished by a proper balance among section size, steel hardenability, and severity of quench.

Shell Molding - A process for forming a mold from resin-bonded sand mixtures brought in contact with pre-heated (150-250°C / 300-500°F) metal patterns, resulting in a firm shell with a cavity corresponding to the outline of the pattern.

Shift - A casting defect caused by mismatch of cope and drag or of cores and mold.

Shim – A thin piece of material placed between two surfaces to obtain a proper fit, adjustment, or alignment. The piece can also be analyzed to measure furnace carbon potential (that is, because while in the furnace it will quickly carburize to a level equal to the furnace carbon potential).

Shot peening - The bombardment of a component surface with steel or ceramic shot. Produces a residual compressive stress in the surface and improves fatigue and stress corrosion performance.

Shrinkage - A decrease in dimensions of a coating during processing.

Shrinkage stress - The residual stress in a coating caused by shrinkage during processing.

Shroud - A gaseous and/or mechanical or physical barrier placed around the spraying process designed to reduce the ingress of air into the system and so reduce oxidation of the particles being sprayed.

Sieve Analysis - Distribution of particle size sand expressed in terms of the percentage of weight retained on each of a series of standard screens decreasing in mesh size and the percentage passed by the screen of finest mesh.

Sieve classification - That portion of a powder sample which passes through a standard sieve of specified number and is retained by some finer sieve of specified number.

Sigma phase – A hard, brittle, nonmagnetic intermediate phase with a tetragonal crystal structure, containing 30 atoms per unit cell occurring in many binary and ternary alloys of the transition elements. The composition of this phase in the various systems is not the same, and the phase usually exhibits a wide range in homogeneity. Alloying with a third transition element usually enlarges the field of homogeneity and extends it deep into the ternary section.

Sigma-phased embrittlement – Embrittlement of iron-chromium alloys (most notably austenitic stainless steels) caused by precipitation at grain boundaries of the hard, brittle intermetallic sigma phase during long periods of exposure to temperatures between approximately 565 and 980°C (1050 and 1800°F). Sigma-phase embrittlement results in severe loss in toughness and ductility and can make the embrittled material structure susceptible to intergranular corrosion. See also sensitization.

Signal-to-noise ratio – Ratio of the average response to the root-mean-square variation about the average response. Ratio of variances associated with the two parts of the performance measurement.

Silica Sand - Sand with a minimum silica content of 95% used for forming casting molds.

Silicon (Si) - is one of the principal deoxidizers with the amount used dependent on the deoxidization practice. It slightly increases the strength of ferrite without a serious loss of ductility. In larger quantities, it aids the resistance to scaling up to 500°F in air and decreases magnetic hysteresis loss.

Siliconizing – Diffusing silicon into solid metal, usually steel, at elevated temperature.

Silver plating - The electrodeposition of silver for electrical, decorative or anti-fretting properties.

Simulation - A procedure which describes, numerically, a given flow regime. The solution of the numerical method should replicate the real life flow characteristics.

Single Port Nozzle (Plasma) - Constricted nozzle with only one internal bore, concentric with the longitudinal axis of the tungsten electrode. The shape and design accuracy of this single orifice is decisive for arc stability in plasma welding.

Sintering – The bonding of adjacent surfaces in a mass of particles by molecular or atomic attraction on heating at high temperatures below the melting temperature of any constituent in the material. Sintering strengthens a powder mass and normally produces densification and, in powdered metals, recrystallization.

Size analysis - Analysis of the size of the particles being deposited by spraying processes.

Size distribution - The distribution of sizes within a size analysis. The distribution may be normal or skewed in some way due to the powder manufacturing process.

Skewed Tolerances - Tolerances which are non-symmetrically distributed about the design parameter.

Skim Core (Skimmer) - A flat core or tile placed in a mold to skim a flowing stream of metal. Commonly used in pouring basins, it holds back slag and dirt while clean metal passes underneath to the downsprue.

Skim Gate - A gating arrangement which changes the direction of flow of molten metal and prevents the passage of slag and other undesirable materials into the mold cavity.

Skimming - Removing or hold back dirt or slag from the surface of the molten metal before or during pouring.

Skin - A thin surface layer different chemically or structurally from the main mass of a metal object.

Skin-Drying - Drying the surface of the mold by direct application of heat.

Slack quenching – The incomplete hardening of steel due to quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel, resulting in the formation of one or more transformation products in addition to martensite.

Slag Inclusion - Nonmetallic solids entrapped in solid metal.

Slag Trap - An enlargement, dam, or extrusion in the gating or runners system in a mold for the purpose of preventing molten slag particles from entering the mold cavity.

Slicking (Sleeking) - Smoothing the surface of molds.

Slot furnace – A common batch furnace where stock is charged and removed through a slot or opening.

Slurry - A term loosely applied to any clay-like dispersion. It may be use to wash ladles or other refractory linings to impart a smooth surface; as a bonding addition to molding sand; as a thin loam over specially made molds or as a mixture to fine joints or cracks of a core, etc.

Smelting - A metallurgical thermal process in which a metal is separated in fused form from nonmetallic materials or other undesired metals with which it is associated.

Snap temper – A precautionary interim stress-relieving treatment applied to high-hardenability steels immediately after quenching to prevent cracking because of delay in tempering them at the prescribed higher temperature.

Soaking – Prolonged holding at a selected temperature to effect homogenization of structure or composition.

Soft temper – Same as dead soft temper.

Solution heat treatment – Heating an alloy to a suitable temperature, holding at that temperature long enough to cause one or more constituents to enter into solid solution, and then cooling rapidly enough to hold these constituents in solution.

Sorbite – (obsolete) A fine mixture of ferrite and cementite produced either by regulating the rate of cooling of steel or by tempering steel after hardening. The first type is very fine pearlite difficult to resolve under the microscope; the second type is tempered martensite.

Spalling – A chipping or flaking of a surface due to any kind of improper heat treatment or material dissociation.

Specific Gravity - A numerical value representing the weight of a given substance as compared with the weight of an equal volume of water at 3.9°C (39°F), for which the specific gravity is taken as 1,000 kg/m3.

Specific Heat - Equivalent to thermal capacity, or the quantity of heat required to produce a unit change in the temperature of a unit mass.

Specific Volume - Volume of one gram of a substance at a specific temperature, usually 20°C (68°F).

Spinodal hardening – See aging.

Spheroidite – An aggregate of iron or alloy carbides of essentially spherical shape dispersed throughout a matrix of ferrite.

Spheroidizing – Heating and cooling to produce a spheroidal or globular form of carbide in steel. Spheroidizing methods frequently used are:

1. Prolonged holding at a temperature just below Ae1

2. Heating and cooling alternately between temperatures that are just above and just below Ae1

3. Heating to a temperature above Ae1 or Ae3 and then cooling very slowly in the furnace or holding at a temperature just below Ae1

4. Cooling at a suitable rate from the minimum temperature at which all carbide is dissolved, to prevent the reformation of a carbide network, and then reheating in accordance with method 1 or 2 above. (Applicable to hypereutectoid steel containing a carbide network.)

Spinodal structure – A fine homogeneous mixture of two phases that form by the growth of composition waves in a solid solution during suitable heat treatment. The phases of a spinodal structure differ in composition from each other and from the parent phase but have the same crystal structure as the parent phase.

Spray chamber - A chamber in which the spraying process is carried out. It may merely be an acoustic chamber for plasma spraying or a vacuum chamber for vacuum plasma spraying.

Spray dried powder - Powder formed by the spray drying process.

Spray-fused coatings - A process in which the coating material is deposited by flame spraying and then fused into the substrate by the addition of further heat. This can be applied by flame induction heating or by laser.

Spray quenching – A quenching process using spray nozzles to spray water or other liquids on a part. The quench rate is controlled by the velocity and volume of liquid per unit of time of impingement.

Spring temper – A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength and hardness about two-thirds of the way from full hard to extra spring temper.

Sputtering - This is a glow discharge process whereby bombardment of a cathode releases atoms from the surface which then deposit onto a nearby target surface to form a coating.

Stabilizing treatment – (1) Before finishing to final dimensions, repeatedly heating a ferrous or nonferrous part to or slightly above its normal operating temperature and then cooling to room temperature to ensure dimensional stability in service. (2) Transforming retained austenite in quenched hardenable steels, usually by cold treatment. (3) Heating a solution-treated stabilized grade of austenitic stainless steel to 870 to 900°C (1600 to 1650°F) to precipitate all carbon as TiC, NbC, or TaC so that sensitization is avoided on subsequent exposure to elevated temperature.

Stainless Steel - A wide range of steels containing chromium or chromium and nickel, exhibiting high resistance to corrosion.

Standard Deviation - A statistical quantity used to describe the variation of a measurable attribute about some average value.

Statistical process control – The application of statistical techniques for measuring and analyzing the variation in processes.

Statistical quality control – The application of statistical techniques for measuring and improving the quality of processes and products (includes statistical process control, diagnostic tools, sampling plans, and other statistical techniques).

Stead’s brittleness – A condition of brittleness that causes transcrystalline fracture in the coarse grain structure that results from prolonged annealing of thin sheets of low-carbon steel previously rolled at a temperature below about 705°C (1300°F). The fracture usually occurs at about 45° to the direction of rolling.

Steam tempering - The production of a stable oxide on steel parts by treatment in steam at about 300°C. Improves corrosion performance and reduces friction.

Steel - An alloy of iron and carbon that may contain other elements and in which the carbon content does not exceed about 1.7%; it must be malleable at some temperature while in the as-cast state.

Step aging – Aging at two or more temperature, by steps, without cooling to room temperature after each step. See aging, and compare with interrupted aging and progressive aging.

Sticker - A lump on the surface of a casting caused by a portion of the mold face sticking to the pattern. Also, a forming tool used in molding.

Strain - A measure of the extent to which a body is deformed when it is subjected to a stress.

Strain-age embrittlement – A loss in ductility accompanied by an increase in hardness and strength that occurs when low-carbon steel (especially rimmed or capped steel) is aged following plastic deformation. The degree of embrittlement is a function of aging time and temperature, occurring in a matter of minutes at about 200°C (400°F) but requiring a few hours to a year at room temperature.

Strain aging – Aging following plastic deformation.

Strand casting - Operation in which a cast shape is continuously drawn through the bottom of the mold as it solidifies. The length is not determined by mold dimensions.

Streamlines - A streamline is a line of fluid particles, the velocity of each particle is tangential to the line, the particle can not cross the streamline.

Stress - The force per unit area on body that tends to cause it to deform. It is a measure of the internal forces in a body between particles of the material of which it consists as they resist separation, compression, or sliding.

Stress-Corrosion Cracking - Spontaneous failure of metals by cracking under combined conditions of corrosion and stress, either residual or applied.

Stress equalizing – A low-temperature heat treatment used to balance stresses in cold-worked material without an appreciable decrease in the mechanical strength produced by cold working.

Stress relieve temper - A thermal treatment to restore elastic properties and to minimize distortion on subsequent machining or hardening operations. This treatment is usually applied to material that has been heat treated (quenched and tempered). Normal practice would be to heat to a temperature 100°F lower than the tempering temperatures used to establish mechanical properties and hardness. Ordinarily, no straightening is performed after the stress relieve temper.

Stress, Relieving - A heat treatment to reduce residual stresses followed by sufficiently slow cooling to minimize development of new residual stresses.

Stress, Residual - Those stresses setup up in a metal as a result of nonuniform plastic deformation or the unequal cooling of a casting.

Strike-Off - Operation of removing excess sand from top or core box or flask.

Stripping - Removing the pattern from the mold or core box from core.

Structurals - Steel product group that includes I-beams, H-beams, wide-flange beams and sheet piling. These products are used in the construction of multi-story buildings, industrial buildings, bridge trusses, vertical highway supports, and riverbank reinforcement.

Structure (Cast Structure) - The size and disposition of the constituents of a metal as cast.

Subcritical annealing – A process anneal performed on ferrous alloys at a temperature below Ac1.

Submerged-electrode furnace – A furnace used for liquid carburizing of parts by heating molten salt baths with the use of electrodes submerged in the ceramic lining. See immersed-electrode furnace.

Substrate - The parent or base material to which the coating is applied.

Sulfidation - The reaction of a metal or alloy with a sulfur containing species to produce a sulfur compound that forms on or beneath the surface of the metal or alloy.

Sulfur (S) - A nonmetallic element, melting point 444°C (831.2°F) occurring as an undesirable tramp (trace) element in most ferrous alloys. Detrimental to transverse strength and impact resistance. It affects longitudinal properties to a lesser degree. Existing primarily in the form of manganese sulfide stringers, sulfur is typically added to improve machinability.

Supercooling – Cooling below the temperature at which an equilibrium phase transformation takes place, without actually obtaining the transformation.

Superheating – Heating above the temperature at which an equilibrium phase transformation should occur without actually obtaining the transformation.

Surface Coating Operations - All operations involving the application of protective, decorative, adhesive or strengthening coating or impregnation to one or more surfaces, or into the interstices of any object or material, by means of spraying, spreading, flowing, brushing, roll coating, pouring, cementing or similar means; and any subsequent draining or drying operations, excluding open-tank operations.

Surface Hardening - Conferring a superficial hardness to a steel while maintaining a relatively soft core.

Surfacing - Depositing a filer metal on a metal surface by any method to obtain certain desired properties or dimensions.

Surface Texture - The roughness, waviness, lay or other characteristics of the surface of a part.

Surfacing - The application of a coating or cladding to a surface to impart a change in its surface behavior.

Stress-Corrosion Cracking - Spontaneous failure of metals by cracking under combined conditions of corrosion and stress, either residual or applied.

Surface energy - Surface energy exists because the molecules of a condensed phase are attracted to each other, which is what causes the condensation. The force required for the removal of molecular contact from above a surface, i.e. for the bond-breaking, is the surface energy.

Surface Finish (or Surface Texture) - A measure of the roughness of a surface by expressing the average deviation of the peaks and valleys from the mean line (denoted Ra).

Surface hardening – A generic term covering several processes applicable to a suitable ferrous alloy that produces, by quench hardening only, a surface layer that is harder or more wear resistant than the core. There is no significant alteration of the chemical composition of the surface layer. The processes commonly used are carbonitriding, carburizing, induction hardening, flame hardening, nitriding, and nitrocarburizing. Use of the applicable specific process name is preferred.

Surface parameter Ra - Arithmetical mean roughness: is the arithmetical average value of all departures of the surface profile from the mean line throughout the sampling length.

Surface parameter Rmax - It is the largest single peak-to-valley height within five adjoining sampling lengths 'le'.

Surface parameter Rt - Maximum roughness depth: is the distance between the highest and the lowest points of the surface profile within the evaluation length Lm.

Surface parameter Rz - Mean peak-to-valley height: is the average of the single peak-to-valley of five adjoining sampling lengths 'le'.

Surface preparation - Cleaning and roughening the surface to be sprayed, usually by grit or bead blasting. This is to increase the adhesion of the coating to the substrate.

Surface topography - The geometrical detail of a surface, relating particularly to microscopic variations in height.

Surface Treatment - General term denoting a treatment involving a modification of the surface: superficial heat treatment, diffusion treatment, conversion coating (consisting of a compound of the surface metal by chemical or electrochemical treatment).

Surfacing - The application of a coating or cladding to a surface to impart a change in its surface behavior.

Swell - A casting defect consisting of an increase in metal section due to the displacement of sand by metal pressure.

Synthetic Molding Sand - Any sand compounded from selected individual materials which, when mixed together, produce a mixture of the proper physical and mechanical properties from which to make foundry molds.

System Sand - Foundry sand used in making molds and which eventually becomes the bulk of the sand used in the mechanical system or mechanized unit.

Tellurium (Te) - is added to steel to modify sulfide type inclusion size, morphology and distribution. The resulting sulfide type inclusions are finer and remain ellipsoidal in shape following hot working, thereby improving transverse properties.

Temper – (1) In heat treatment, reheating hardened steel or hardened cast iron to some temperature below the eutectoid temperature for the purpose of decreasing hardness and increasing toughness. The process also is sometimes applied to normalized steel. (2) In tool steels, temper is sometimes used, but inadvisably, to denote carbon content. (3) In nonferrous alloys and in some ferrous alloys (steels that cannot be hardened by heat treatment), the hardness and strength produced by mechanical or thermal treatment, or both, and characterized by a certain structure, mechanical properties, or reduction in area during cold working.

Temper carbon – Same as annealing carbon.

Temper color – A thin, tightly adhering oxide skin that forms when steel is tempered at a low temperature, or for a short time, in air or a mildly oxidizing atmosphere. The color, which ranges from straw to blue depending on the thickness of the oxide skin, varies with both tempering time and temperature.

Tempered martensite embrittlement – Embrittlement of ultrahigh-strength steels caused by tempering in the temperature range of 205 to 400°C (400 to 750°F); also called 350°C or 500°F embrittlement. Tempered martensite embrittlement is thought to result from the combined effects of cementite precipitation on prior-austenite grain boundaries or interlath boundaries and the segregation of impurities at prior-austenite grain boundaries.

Temper embrittlement – Embrittlement of alloy steels caused by holding within or cooling slowly through a temperature range just below the transformation range. Embrittlement is the result of the segregation at grain boundaries of impurities such as arsenic, antimony, phosphorus, and tin; it is usually manifested as an upward shift in ductile-to-brittle transition by retempering above the critical temperature range, then cooling rapidly.

Temper Stressing - Quenching in water from the tempering temperature to improve fatigue strength.

Tempering - A treatment consisting of heating uniformly to some predetermined temperature under the critical range, holding at that temperature a designated period of time and cooling in air or liquid. This treatment is used to produce one or more of the following end results: A) to soften material for subsequent machining or cold working, B) to improve ductility and relieve stresses resulting from prior treatment or cold working, and C) to produce the desired mechanical properties or structure in the second step of a double treatment.

Temperature - Degree of warmth or coldness in relation to an arbitrary zero measured on one or more of accepted scales, as Centigrade, Fahrenheit, etc.

Tensile Strength - The maximum stress in uniaxial tension testing which a material will withstand prior to fracture. The ultimate tensile strength is calculated from the maximum load applied during the test divided by the original cross-sectional area. Compare with yield strength.

Tensile stress - Axial forces per unit area applied to a body that tend to extend it.

Thermal analysis – A method for determining transformations in a metal by noting the temperatures at which thermal arrests occur. These arrests are manifested by changes in slope of the plotted of mechanically traced heating and cooling curves. When such data are secured under nearly equilibrium conditions of heating and cooling, the method is commonly used for determining certain critical temperatures required for the construction of equilibrium diagrams.

Thermal barrier coating - A coating produced to present an insulating barrier to a heat source and to protect the substrate.

Thermal conductivity - The property of matter by which heat energy is transmitted through particles in contact. For engineering purposes, the amount of heat conducted through refractories is usually given in Btu per hour for one square foot of area, for a temperature difference of one degree Fahrenheit, and for a thickness of one inch, Btu/hr·ft·F/in.

Thermal Diffusion (TD) - A salt bath treatment at about 900°C for high carbon tool steels. Produces a very hard layer of vanadium carbide, typically .0002-.0003” thick. Also called Thermo-Reactive Diffusion (TRD).

Thermal electromotive force – The electromotive force generated in a circuit containing two dissimilar metals when one junction is at a temperature different from that of the other. See also thermocouple.

Thermal fatigue – Fracture resulting from the presence of temperature gradients that vary with time in such a manner as to produce cyclic stresses in a structure. Failure resulting from rapid cycles of alternate heating and cooling.

Thermal shock – Stress developed by rapid and uneven heating of a material.

Thermal spraying - A process in which coating material is heated and accelerated from a spray torch towards the work piece. The deposited material forms a coating on the surface.

Thermal stresses – Stresses in metal resulting from nonuniform temperature distribution. Usually occurs during the cooling of a part.

Thermochemically formed coatings - A painted, dipped or sprayed chromium oxide based coating consolidated by repeated deposition and curing cycles (about 500°C).

Thermochemical treatment – Heat treatment carried out in a medium suitably chosen to produce a change in the chemical composition of the object by exchange with the medium.

Thermocouple – A device for measuring temperatures, consisting of lengths of two dissimilar metals or alloys that are electrically joined at one end and connected to a voltage-measuring instrument at the other end. When one junction is hotter than the other, a thermal electromotive force is produced that is roughly proportional to the difference in temperature between the hot and cold junctions.

Thermography - An NDE technique in which the coating is flash heated and then viewed with an infra red camera. "Hot spots" indicate areas of poor bonding or greater coating thickness.

Thermomechanical working – A general term covering a variety of processes combining controlled thermal and deformation treatments to obtain specific properties. Same as thermal-mechanical treatment.

Three-quarters hard – A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength and hardness about midway between those of half hard and full hard tempers.

Time quenching – A term used to describe a quench in which the cooling rate of the part being quenched must be changed abruptly at some time during the cooling cycle.

Time-temperature-transformation (TTT) diagram – See isothermal transformation (IT) diagram.

Titanium (Ti) - is added to boron steels because it combines with oxygen and nitrogen, thus increasing the effectiveness of boron. Titanium, as titanium nitride, also provides grain size control at elevated temperatures in microalloy steels. In excess, titanium is detrimental to machinability and internal cleanness.

Titanium nitride (TiN) - Gold colored ceramic, typically applied as a thin coating by either PVD or CVD. Very hard (3500Hv). Used on cutting tools and forming tools and other surfaces requiring wear resistance

Tolerance - The permissible deviation of a dimension from the nominal or desired value. Minimum clearance between mating parts.

Tool Steel - Any high-carbon or alloy steel used to make a cutting tool for machining and forming metals and for metal-casting dies.

Total carbon – The sum of the free and combined carbon (including carbon in solution) in a ferrous alloy.

Total indicator reading – See preferred term total indicator variation.

Total indicator variation – The difference between the maximum and minimum indicator readings during a checking cycle.

Toughness – The ability of a metal to absorb energy and deform plastically before fracturing.

Trajectory - The path a particle takes when it’s injected into a stream of moving gas (or fluid). It is used in CFD to predict the path of the metal powder used in the plasma spray gun analysis.

Transcrystalline – See transgranular.

Transferred arc - In a plasma torch the plasma jet is emitted from the torch and the current flows from the internal cathode to the internal anode represented by the nozzle of the torch. When the jet is carried to another anode with it being electrically favorable to do so the current will then transfer to the second anode, usually the work piece and the arc is said to be transferred.

Transferred Arc (Plasma) - The plasma arc which transfers heat energy to the work piece (base material). This arc strikes between the tungsten electrode (cathode) and the base material (anode). The term Main Arc is also used in Plasma Transferred Arc process (P.T.A. welding).

Transformation hardening – Heat treatment comprising austenitization followed by cooling under conditions such that the austenite transforms more or less completely into martensite and possibly into bainite.

Transformation-induced plasticity – A phenomenon, occurring chiefly in certain highly alloyed steels that have been heat treated to produce metastable austenite or metastable austenite plus martensite, whereby, on subsequent deformation, part of the austenite undergoes strain-induced transformation to martensite. Steels capable of transforming in this manner, commonly referred to as TRIP steels, are highly plastic after heat treatment, but exhibit a very high rate of strain hardening and thus have high tensile and yield strengths after plastic deformation at temperatures between about 20 and 500°C (70 and 930°F). Cooling to -195°C (-320°F) may or may not be required to complete the transformation to martensite. Tempering usually is done following transformation.

Transformation ranges – Those ranges of temperature within which a phase forms during heating and transforms during cooling. The two ranges are distinct, sometimes overlapping but never coinciding. The limiting temperatures of the ranges depend on the composition of the alloy and on the rate of change of temperature, particularly during cooling. See transformation temperature.

Transformation temperature – The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range. The following symbols are used for iron and steels.

Accm – In hypereutectoid steel, the temperature at which the solution of cementite in austenite is completed during heating.

Ac1 – The temperature at which austenite begins to form during heating.

Ac3 – The temperature at which transformation of ferrite to austenite is completed during heating

Ac4 – The temperature at which austenite transforms to delta ferrite during heating.

A3cm, Ae1, Ae3, Ae4 – The temperature of phase changes at equilibrium.

Arcm – In hypereutectoid steel, the temperature at which precipitation of cementite starts during cooling.

Ar1 – The temperature at which transformation of austenite to ferrite or to ferrite plus cementite is completed during cooling.

Ar3 – The temperature at which austenite begins to transform to ferrite during cooling.

Ar4 – The temperature at which delta ferrite transforms to austenite during cooling.

Ar’ – The temperature at which transformation of austenite to pearlite starts during cooling.

Mf – The temperature at which transformation of austenite to martensite finishes during cooling.

Ms (or Ar”) – The temperature at which transformation of austenite to martensite starts during cooling.

Note: All these changes except the formation of martensite occur at lower temperatures during cooling than during heating, and depend on the rate of change of temperature.

Transgranular – Through or across crystals or grains. Also called intracrystalline or transcrystalline.

Transgranular cracking – Cracking or fracturing that occurs through or across a crystal or grain. Also called transcrystalline cracking. Contrast with intergranular cracking.

Transgranular fracture – Fracture through or across the crystals or grains of a metal. Also called transcrystalline fracture or intracrystalline fracture. Contrast with intergranular fracture.

Transition temperature – (1) An arbitrarily defined temperature that lies within the temperature range in which metal fracture characteristics (as usually determined by tests of notched specimens) change rapidly, such as from primarily fibrous (shear) to primarily crystalline (cleavage) fracture. Commonly used definitions are “transition temperature for 50% cleavage fracture,” “10 ft • lbf transition temperature,” and “transition temperature for half maximum energy.” (2) Sometimes used to denote an arbitrarily defined temperature within a range in which the ductility changes rapidly with temperature.

Transmission Electron Microscopy (TEM) - Applied to thin and thick film analysis, it permits observation of smaller features such as microcolumnar voids and patterns of dislocations in the bulk.

Transparent Electrical Conductors - Transparent conductive oxide (TCO) films, such as indium trioxide (In2O3), tin dioxide (SnO2), zinc oxide (ZnO) and an alloy of indium oxide and tin oxide (ITO), have numerous applications such as heaters on windows for defrosting, antistatic coatings on display screens, electrodes on flat panel displays and electrochromic devices, and electrodes on both flexible (resistive screen) and rigid (capacitive screen) touch screens. Electrical resistivity for the TCO films can vary from greater than 1,000 ohms per "square" to less than 10 ohms per square with good optical transmission.

Trap - This condition applies to a wall entity during a CFD analysis of a particulate two-phase flow. A particle touches the wall entity, its momentum and energy are assumed to be completely lost to the wall entity, while the mass is assumed lost to the fluid.

TRD (Thermo-Reactive Diffusion) - A salt bath treatment at about 900°C for high carbon tool steels. Produces a very hard layer of vanadium carbide, typically .0002-.0003” thick. Also called Thermal Diffusion (TD).

TRIP steel – A commercial steel product exhibiting transformation-induced plasticity.

Troostite – (obsolete) A previously unresolved rapidly etching fine aggregate of carbide and ferrite produced either by tempering martensite at low temperature or by quenching a steel at a rate slower than the critical cooling rate. Preferred terminology for the first product is tempered martensite; for the latter, fine pearlite.

Tungsten carbide - Metallic colored ceramic, often applied as a coating by thermal spraying. With a Co or Ni binder. Used for high load applications requiring extreme wear resistance.

Tungsten disulphide - Dry lubricant coating - applied at ambient temperature. Coating is 0.5 micron thick works at temperatures -273deg k to 650deg C. For use at high vacuum, cryogenic or high temperatures. Extends bearing life. Prevents galling, fretting & seizing. Can be applied to miniature ball races in assembled condition. Developed by NASA for use in deep space. Used in plastics industry as permanent release coating.

Turbulent flow - Technical terminology for the type of flow which occurs when the Reynolds Number exceeds 2000. In contrast to laminar flow, turbulent flow can be described as an irregular and random-looking motion.

Two-phase - Particular type of analysis where two of the three phases (gas, liquid and solid) are modeled together. The numerical equations are modified to produce an interaction between the two phases.

Ultrasonic - An NDE technique which relies on an ultrasonic beam passing through a coating and substrate and providing a signal from the back wall which is then detected. The height of this backwall echo depends on the discontinuity in impedance from the sprayed coating to the substrate. Bonding flaws can be easily seen by the weakening of the back wall echo.

Undercooling – Same as supercooling.

Upgrading - In castings, the removal and repair of discontinuities to raise the quality level of the casting beyond that which can be economically achieved by good foundry practice.

Vacuum annealing – Annealing carried out at subatmospheric pressure.

Vacuum carburizing – A high-temperature gas carburizing process using furnace pressures between 7 and 55kPa during the carburizing portion of the cycle.

Vacuum Casting - A casting in which metal is melted and poured under very low atmospheric pressure; a form of permanent mold casting where the mold is inserted into liquid metal, vacuum is applied, and metal drawn up into the cavity.

Vacuum furnace – A furnace using low atmospheric pressures instead of a protective gas atmosphere like most heat-treating furnaces. Vacuum furnaces are categorized as hot wall or cold wall, depending on the location of the heating and insulating components.

Vacuum or Low Pressure Plasma Spraying - Plasma spraying carried out in a chamber which has been evacuated to a low partial pressure of oxygen. It is then usually partially backfilled with argon to avoid the possibility of forming a glow discharge.

Vacuum Coating - Vacuum coatings processes use a vacuum (sub-atmospheric pressure) environment and an atomic or molecular condensable vapor source to deposit thin films and coatings. The vacuum environment is used not only to reduce gas particle density but also to limit gaseous contamination, establish partial pressures of inert and reactive gases, and control gas flow. The gaseous environment may be in the form of a partially ionized plasma. The vapor source may be from a solid or liquid surface (physical vapor deposition—PVD), or from a chemical vapor precursor (chemical vapor deposition—CVD). The term "vacuum deposition" is often used instead of PVD, particularly in the older literature. Vacuum is an environment where the gas pressure is less than the ambient. A plasma is a gaseous environment in which there are enough ions and electrons for there to be appreciable electrical conductivity. Vacuum coating is the deposition of a film or a coating in a vacuum (or low-pressure plasma) environment. Generally the term is applied to processes that deposit atoms (or molecules) one at a time such as physical vapor deposition (PVD) or low-pressure chemical vapor deposition (LP-CVD) processes or plasma-enhanced CVD (PECVD). In PVD processes, the material being deposited comes from the vaporization of a solid or liquid surface. In CVD processes, the material being deposited comes from a chemical vapor precursor species that is decomposed by reduction or thermal decomposition—mostly on a hot surface. In some cases the material being deposited reacts with the gaseous environment or a codeposited species to form a film of a compound material such as an oxide, a nitride, carbide, or a carbonitride. In CVD processing, the use of a plasma to fragment the chemical vapor precursor in the vapor phase allows the decomposition or reduction processes to proceed at lower temperatures than with thermal activation alone. PECVD can be performed at pressures as low as those used in PVD processing (low-pressure PECVD, LP-PECVD), where the precursor vapor is decomposed mainly in the plasma. In some cases a hybrid deposition process of PVD and LP-PECVD is used to deposit alloys, composites, or compounds. An example is metal carbonitrides where the carbon comes from a chemical vapor precursor such as acetylene; the nitrogen comes from a gas; and the metal from evaporation, sputtering, or arc vaporization of a solid or liquid surface.

Vacuum nitrocarburizing – A subatmospheric nitrocarburizing process using a basic atmosphere of 50% ammonia / 50% methane, containing controlled oxygen additions of up to 2%.

Vanadium (V) - inhibits grain growth during heat treating while improving strength and toughness of hardened and tempered steels. Additions up to .05% increase hardenability whereas larger amounts tend to reduce hardenability because of carbide formation. Vanadium is also utilized in ferrite/pearlite microalloy steels to increase hardness through carbonitride precipitation strengthening of the matrix.

Vector plot - A way of displaying results from a CFD analysis, where the velocity of each particle is visualized with an arrow. Since the arrow represents "velocity" it has a direction and magnitude (the length of the arrow indicates the relative magnitude)

Veins - A discontinuity on the surface of a casting appearing as a raised, narrow, linear ridge that forms upon cracking of the sand mold or core due to expansion of the sand during filling of the mold with molten metal.

Vickers hardness test – A microindentation hardness test employing a 136° diamond pyramid indenter (Vickers) and variable loads, enabling the use of one hardness scale for all ranges of hardness – from very soft lead to tungsten carbide. Also known as diamond pyramid hardness test.

Walking-beam furnace – A continuous-type furnace consisting of two sets of rails, one stationary and the other movable. Only the work being processed has to be heated because trays or fixtures are not needed.

Warpage - Deformation other than contraction that develops in a casting between solidification and room temperature; also, distortion occurring during annealing, stress relieving, and high-temperature service.

Wash - A casting defect resulting from erosion of sand by metal flowing over the mold or corded surfaces. They appear as rough spots and excess metal on the casting surface. Also called cuts.

Washburn Core - A thin core which constricts the riser at the point of attachment to the casting. The thin core heats quickly and promotes feeding of the casting. Riser removal cost is minimized.

Water quenching – A quench in which water is the quenching medium. The major disadvantage of water quenching is its poor efficiency at the beginning or hot stage of the quenching process.

Wear - Loss of material from a surface by means of relative motion between it and another body. Third bodies i.e. grit

Welding - A process used to join metals by the application of heat. Fusion welding, which includes gas, arc, and resistance welding, requires that the parent metals be melted.

Welding, Autogenous - Method of uniting two pieces of metal by melting their edges together without solder or any added welding metal, as by the thermite process that employs a medium of finely divided aluminum powder and oxide or iron by which a temperature of some 2982.2°C (5400°F) is obtained.

Welding Electrode - A metal or alloy in rod or wire forms used in electric arc welding to maintain the arc and at the same time supply molten metal or alloy at the point where the weld is to be
accomplished.

Welding Flash - Skin exposed too long to the ultraviolet rays of welding or melting arcs will burn as in a sunburn. Though temporary blindness can result, it is not permanent, as is popularly believed.

Welding Process - The joining of materials by the application of heat or friction.

Welding Stress - That stress resulting from localized heating and cooling of metal during welding.

White layer – Compound layer that forms as a result of the nitriding process.

Wire spraying - A thermal spray process whereby the supply for the coating material is fed into the gun in the form of a continuous wire.

Work hardness - Hardness developed in metal resulting from cold working.

X-Ray Diffraction (XRD) - A surface science technique for crystalline structure analysis of materials. Widely used both in the research and industrial area. analyzed depth up to 10 micrometers.

X-ray Photoelectron Spectroscopy (XPS) - An electron beam technique applied for near-surface elements identification and chemical state analysis. Widely used in thin film science. Analysis depth: a few Angstroms.

Yield point - The first stress in a material, usually less than the maximum attainable stress, at which an increase in strain occurs without an increase in stress. If there is a decrease in stress after yielding, a distinction may be made between upper and lower yield points.

Yield strength – The stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals. Compare with tensile strength.

Zinc (Zn) - Thermal spray coatings of zinc or zinc alloys (e.g. Zn/Al, Zn/Sn) provides galvanic corrosion protection.

Zinc Plating - The electro deposition of zinc or zinc alloys (e.g. Zn/Ni, Zn/Sn) to provide galvanic corrosion protection

Electric vehicle (EV) – Future of Transport

noreply@blogger.com (Industrial age to information age) — Sat, 15 Jan 2022 11:13:00 +0000

Electric vehicle (EV) – Future of Transport

Working principle of EV

All-electric vehicles (EVs), also referred to as battery electric vehicles, have an electric motor instead of an internal combustion engine. The vehicle uses a large traction battery pack to power the electric motor and must be plugged in to a wall outlet or charging equipment, also called electric vehicle supply equipment (EVSE). Because it runs on electricity, the vehicle emits no exhaust from a tailpipe and does not contain the typical liquid fuel components, such as a fuel pump, fuel line, or fuel tank.

Reasons to adopt EV

Back in 2019, the research company BloombergNEF made a grand prediction that by 2040, India would be one of the 4th largest passenger electric vehicle markets, with electric vehicle sales at 2.6 million. In its report, it further forecast that India would join Germany in numbers. China would stand at 14.6 million and the United States at 9.7 million. Moreover, EV sales in India may beat France, Japan, the UK, and Korea. The report foretells this result while simply analyzing the sales of electric four-wheeler.

High fuel prices

On a cost per distance basis, a fully electric car could cost you a quarter or fewer of what a conventional petrol or diesel car might. These savings quickly add up, you could save on each journey when driving an EV.

Low operating cost

Over a five-year period, which is well within the 8-year battery warranty period on the EV, most owners can be expected to cover 75,000 km or 15,000 km a year. Running the Nexon EV over this period should cost Rs 72,750 against the Rs 4.59 lakh needed for the petrol Nexon.

Low maintenance

Though electric vehicles may still cost more to purchase than their conventionally powered counterparts, they’re generally cheaper to keep running via affordable home charging. Electric vehicles also save their owners cash on an ongoing basis via lower long-term maintenance costs.

That’s because EVs eliminate over two-dozen mechanical components that would normally require periodic service. An EV owner avoids having to pay for things like tune-ups, oil changes, cooling system flushes, transmission servicing, and replacing the air filter, spark plugs and drive belts. Sources suggest electric vehicle owners spend roughly a third of what conventionally powered auto owners do for regular service.

Still, an EV is not maintenance free. All automakers insist owners follow a series of periodic checks and services in order to keep the vehicle’s warranty in effect. If you don’t follow the recommended schedule, your car may not be covered if it requires repairs.

Aside from tire rotation, replacing the cabin air filter and wiper blades, and topping off the washer fluid, much of this comes down to various mechanical inspections. Automakers advise, and appropriately so, that aside from simple tasks like checking the air pressure in the tires, topping off the windshield washer fluid, and perhaps changing the wiper blades, these procedures should be performed by a trained technician at the dealer’s service department.

Except for the initial investment, once you convert to an EV, overall costs are much lower than if you were to continue driving on petrol or diesel. An electric four-wheeler has few parts, is less complex, so the cost of maintenance is low.

Reduced noise pollution

Far more than other factors, you can enjoy a smooth, almost noise-free ride as you navigate your way through chockablock traffic. Apart from a slight whirring sound, an EV is a hummer with just the sounds of gravel, wind, road noise, and nothing else.

Zero emissions

With zero emissions on the road. EVs will assist decrease of CO2 and toxic greenhouse fumes.

Govt. subsidies

Under fame scheme-The incentives will be offered by the Government for electric buses, three-wheelers and four-wheelers to be used for commercial purposes.

New electrical vehicles available in the market

Electric two wheelers

The Indian Electric Vehicle Market was valued at USD 5 billion in 2020. The same is expected to reach USD 47 billion by 2026, registering a CAGR of above 44% during the forecast period (2021–2026). And with the boom of the Indian EV Industry, Electric Two-Wheeler Companies are also expected to grow at a fast pace in the upcoming years.

The entrance of Ola has already boosted the revolution in the 2-Wheeler EV segment and has increased the competition. Other auto companies are also expected to increase their 2-wheeler EV production to reduce the cost and get more EV bikes on Indian roads. In this article, we'll look into the top 2-wheeler Electric Companies in India.

Hero Electric is the largest player in the Electric two Wheeler (E2W) market in India, another big Auto manufacturers in this list is Bajaj Auto.

Electric four wheelers

There is a list of 14 popular electric cars available in India in the price range of Rs. 4.50 Lakh - Rs. 2.10 Crore. The most popular electric cars include BMW iX (Rs. 1.16 Crore), MG ZS EV (Rs. 21.49 Lakh) and Hyundai Kona Electric (Rs. 23.79 Lakh). The top car manufacturers that produce electric cars are BMW, MG, Hyundai, Audi, Jaguar.

However TATA motor have launched a competitive edge by firstly launching its Nexon, Tigor and Tiago EV variants.

Retrofitted EV kits for old cars

The cost of getting retrofitting kits starts around 5 lakhs, if you want a range of around 80 kms on a single charge and the same can go up to ₹7 lakhs for a drivable range of up to 150 kms.

The company will remove all the IC engine-related components and will retrofit the car with an all-electric drivetrain. The engine is replaced by an electric motor. Unlike the new electric vehicles, there is a need for some modifications to be done in the car in order to make it driveable. You can reach a top speed of nearly 80 kmph in such electric-retrofitted cars. The batteries in these cars can be charged in 5-6 hours and it will take around one hour with a fast charger.

Parts of a Retrofitted EV kit

Battery pack

In an electric drive vehicle, the auxiliary battery provides electricity to power vehicle accessories.

Smart BMS, IP67 grade water and dust protection, Robust LFP Cells (Performance), Low Insulation packaging, Active and Passive Balancing, Active Temperature Control, Modular Battery System.

Charge port

The charge port allows the vehicle to connect to an external power supply in order to charge the traction battery pack.

DC/DC converter

This device converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.

Electric traction motor

Using power from the traction battery pack, this motor drives the vehicle's wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.

Onboard charger

Takes the incoming AC electricity supplied via the charge port and converts it to DC power for charging the traction battery. It also communicates with the charging equipment and monitors battery characteristics such as voltage, current, temperature, and state of charge while charging the pack.

Power train

The transmission transfers mechanical power from the electric traction motor to drive the wheels.This unit manages the flow of electrical energy delivered by the traction battery, controlling the speed of the electric traction motor and the torque it produces.

3 phase AC Induction & IPM motors (efficient, performance), High thermal endurance and structural safety (Safety), Compact e-axle design, High Endurance Magnet, Double Bearing Aluminium based axle.

Thermal system (cooling)

This system maintains a proper operating temperature range of the engine, electric motor, power electronics, and other components.

Electronics

Efficient PCB Design and high-performance microcontroller selection, IP67 design with multiple failure protection control, Thermal management of complete systems, Advanced Software Controls.

Connectivity

GPS, Geofencing, Remote Immobilization, Predictive Maintenance, Driver Diagnostics, Cell health and performance, motor health and performance, power electronics health and performance.

Customization by App

Gives you the summary of functions of your vehicle and allow you some customization.

ARAI approved companies in India

E-trio

E-Trio is a Hyderabad based EV company with a vision to be the widest range of EVs. We aim to be an affordable and accessible electric form of mobility for everyone.

The aim is to transform the environment, lives and businesses of every EV owner.

Altigreen

It’s a Bangalore based company, with a mission of accelerating carbon-free transport, and making it accessible and affordable, Altigreen has carved a niche for itself in the world of electric vehicles.

Loop moto

It’s EV conversion and retrofitting services are available all across India, for 2,3 & 4 wheeler vehicles.

Electric vehicle India

EVI is a fully-integrated solution that combines motors with an integrated inverter, control electronics and software – no separate large, heavy and costly inverter is required.

North way motor sport

Northway motorsport (Northway) is an electric vehicle division under Hemank Auto Parts Pvt Ltd. With over 35 years of technological, manufacturing & service expertise, the company, always been a leader of new emerging technologies through its multiple business ventures & products. Having developed its own drivetrains for ev’s, the company proudly presents high end technological solutions for everyday vehicle users. The main aim of the company has always been & shall continue to be, providing cost effective yet technologically advanced localized products & solutions for the Indian and International market, thus promoting 'Make in India' on a global scale.

Bharatmobi

BharatMobi to Electrify Conventional Vehicles. As an initial step to provide a sustainable solution to air pollution in Delhi, an Electric Vehicle startup, BharatMobi has launched a technology of EV conversions. The company said EV retrofitting or conversions can be the best choice for every individual’s capacity to contribute for a pollution-free India.

Rexnamo

It is a Ghaziabad-based company that takes the shells of old classic models and reconstructs them. Rexnamo’s auto shop has sold many retrofitted electric cars and DIY conversion kits in the past decade.

Folks Motors

Folk Motor's Retrofit xEV platform has been developed in conjunction with ARAI which has undertaken the design, engineering and validation.

The company has developed a twin-regeneration xEV platform that it aims to install on existing ICE vehicles, making them hybrid-electrics (xEVs) as well as capable of offering full-BEV functionality within city limits. The hybrid- electric (xEV) retrofit kit, which includes a motor, controller and battery, is integrated into the existing driveline of a manual-transmission car, also giving it automatic driving capability up to speeds of 80kph.

Bosch

The Bosch Retrofit Kit eAxle is a compact, cost-effective solution for electric drive systems. The advantage comes from the electric motor, power electronics, and transmission integrated to create a compact unit. It helps make electric drives less complex and more manageable. Additionally, the Bosch power-train is cost-effective and more efficient.

GOGOA1

GoGoA1.com is an Indian company, specializes in providing world-class OEM/ODM and Electric & Solar Powered Vehicles and their components. The company mainly concentrates on the transformation of existing fuel 2 wheeler, 3-wheeler, and cars into electric-powered technologies by creating hybrid and complete conversion kits for them.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

sheet metal processing and latest trends

noreply@blogger.com (Industrial age to information age) — Fri, 03 Dec 2021 11:28:00 +0000

Sheet metal

As the name suggests, the metal flats are converted in to thin sheets of different thickness with the mechanical property called "malleability". It is the property by virtue of which flat can be transferred in to thin sheets either by pressing / hitting or by industrial process of rolling.

Types of rolling

Cold rolling

The thick flats are passed through the series of rollers, reducing the thickness of the flat at each step and convert the thick cross section in to elongated long thin sheets.

As the name suggest, it is a cold working process that means the metals are processed at room temperature.

The concern is the more number of stages, as the ratio of change in thickness at each step is low, when performed at room temperature.

The pros are good surface quality and low hardness on the outer skin, suitable for more accurate precise components, lower thickness and close tolerance.

Hot rolling

In hot rolling the material is rolled in hot condition at very high temperature around 1700°F, which is above re-crystallization temperature for steel. The steel blocks so called billets are easier to roll at higher temperatures and are flattened to form sheet metal coils.

The main disadvantages are less control over shape, scaling and rounded edges, suitable for higher thickness and low precision parts.

The benefits are low processing cost, thus are cheaper than the cold rolled steels.

Sheet metal process:

Shearing

This process is used to make cut to length pieces from a slit coil, the slit coil is straightened by passing through numbers of rollers prior to shearing process. There is a large cutter blade on the both die and punch edges, normally high speed steel blade inserts are used. The cutting clearance is usually made to suit with wide range of thickness, to produce the right blend of fracture and shear edge with minimum burr.

Blanking

The metal cut out form the sheet or strip is the output in blanking process, generating web of symmetrical scrap called strip layout. The clearance is given to the punch and the die is the master, that means the die size is the same as the output. The output blank produced have the following main edges :

Edge rollover : The edge produced by punch when pushing the material against the walls of the die, mainly material is rollover due to clearance.

Shear edge : The shearing process is the actual cutting happens due to punch pushes the material against the narrow region (clearance), eventually cuts or shear the some portion of material identified by smooth shining band.

Fracture : When the material is forced to push against the walls of punch and die through narrow entrance so called clearance, the major portion of material around 70% is being fractured from the parent sheet or strip. This portion identified by coarse surface having draft angle, the amount of draft is directly proportional to the clearance.

Piercing or Punching

The process is same except the output, the outer part is the output in this case and the inner cut out is the scrap. The clearance is given to the die and the punch size is master, that means the punch size is same as of the output.

Why clearance given to punch in blanking process and to die in piercing process

Blanking process

The clearance is given to the punch and the die is the master, that means the die size is the same as the output.

Piercing process

The clearance is given to the die and the punch size is master, that means the punch size is same as of the output.

Drawing process

The process of making thin walled deep, hollow boxes etc. is called drawing. It can be further classified as shallow drawing or deep drawing. Mainly where there is more depth than the width is called deep drawing and where there width is more than the depth is called shallow drawing.

There is detailed article on deep drawing , refer link How to choose number of Draw process for deep drawn geometry

Bending

The bending the process in which, the material is folded against the small area at an angle of certain degree. The material flow is along with the axis of bending, where the inner area of the formed radius is subjected to compression and the outer area is subjected to tension or stretching. To read more about type of bending, you can refer the article Sheet Metal force calculation, mechanical engineering

Bending is a cost-effective near net shape process when used for low to medium quantities. Parts usually are lightweight with good mechanical properties. A disadvantage is that some process variants are sensitive to variations in material properties. For instance, differences in spring-back have a direct influence on the resulting bend angle. To mitigate this, various methods for in-process control have been developed.

Types of bending

V-Bending or Air bending

The metal piece called blank, is pressed between punch and die to form the shape of the part. The long parts are bend on the mechanical press known as Brake press, where length of the bed is quite long compared to width. The major problem faced in V bending is ‘’springback’’, which occurs due to elastic recovery of the material when subjected to plastic deformation beyond their yield limits. The springback is directly proportional to the tensile strength of the material, depending on material properties, the sheet may be overbent to compensate for springback.

U bending or Channel bending or Wiping

The material is pressed by the punch against the walls of the die, clearance plays the major role. Two main defects are the scratch and springback. The scratches are prevented by certain surface coatings such as chrome plating or PVD coating. The springback is non-controllable, either is allowed or punch size is reduced, generate slightly tapered face and outer face is the output size.

Double bending or offset bending

It is the condition where more than two bends are there, sheet is directly placed on the die and crash formed against the punch.

Edge bending

In this case, the sheet is first pressed with some cushioned part and bend by punch against the die face. The main problem is material slippage and springback, the material slippage is due to friction between punch and material causing material to drag, the solution is to increase the holding force. The springback is killed by relieving the die edge by imparting the negative draft.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

All about patent

noreply@blogger.com (Industrial age to information age) — Sat, 06 Nov 2021 09:49:00 +0000

Patent

Patent is a legal document, serves as a mean to secure your idea in your parent country, which can be further extended to worldwide, however the duration of rights has been limited by the governments and the international bodies due to some reasons, such as the technology get changed with time or the inventor is subjected to take royalty or opportunity for a limited time. The time frame for the utility patent is 20 years and 15 years for the design patent. After the set time, everyone is free to use the patent as a free, however nobody can claim it, since the technology was already secured by the original inventor in the past.

Typical example of utility patent

Essential parts of patent application

The patent application called as Draft, is a combination of parts describes each and everything about the invention in details, the parts are discussed here segment wise :

1. Title

The title word is self explanatory, that is identical to the headline of the news, around which the whole story revolves, the half of the matter can be easily understand by the suitable headline. Therefore the suitable title is very important before designing the draft of your invention and it is the basis of search and examination by the patent officer, who will be going to grant you the patent number on your invention in near future.

2. Applicant

The applicant is the legal owner of the invention, to whom the legal rights of the patent would be granted by the law. The applicant and inventor may or may not be same in every application.

In the above example, the filing company is the applicant / legal owner of the patent.

3. Inventor

The inventor is the person, who has worked on the invention, in the above case the inventor are the employees of the Ford, who are being hired or being payed for their work. In case of individual inventor, the applicant may be the same as an inventor, as he is working for the self and affording all the expense related to the filing, therefore entitled to the legal rights and the whole benefits associated with the invention.

4. Abstract

Here the inventor is going to mention the whole summary of the patent such as what is the basis of patent, how it will serve the purpose of the invention and how it is going to be utilized in the real world.

5. Field of invention

This portion describes about the invention in details, the things like - what is the invention, what are objects included in the invention and how the mechanism of invention works. How new invention affect the overall performance of the object.

6. Background of the invention

In the background section, as the name suggest, the same type of things happening around us has been listed along with the past history of their origin. How the things has been improved / changed over the years has been briefly mentioned inside the segment.

7. Summary of the Invention

In the summary section, there are the certain things about the invention are defined, for instance - what is the invention, what aspect of the object it will cover or in which ways your invention affect the function of the object. what are the overall benefits your invention would provide in near future.

8. Ballooned drawings

The drawing is the representation of your invention or technology, which has a more practical value than the words mentioned in each segment. Without drawings your draft format is incomplete and not liable for any legal right. Drawings are like a map of the house you are going to construct, it is a formal plan either handmade or computer generated, is very essential part of the plan.

9. Description of ballooned articles

The above given is the drawing with all parts subdivided in to many objects, mentioned with unique number called balloon. The ballooned articles then are defined individually with their own function in the whole mechanism.

10. Claims made

The Claims made are the benefits by virtue of your invention or what benefits user is going to receive by using your invention. There are the two main types of claims - independent claims or direct claims, directly linked with your invention and Dependent claims - the benefits are not direct, but are indirectly received by virtue of direct benefits.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Essential parts of a Draw die

noreply@blogger.com (Industrial age to information age) — Sat, 06 Nov 2021 06:15:00 +0000

Brief function of a draw die or Forming die

The Draw die is basically a means or tool that is used to shape a sheet metal in to useful articles in a mass production. The main advantage is to produce identical parts in mass volumes, the dimensional stability of well designed tool is excellent, along with high degree of human safety and working ergonomics. The modern cad software offers very user friendly design tools, which offers flexibility to change modify and extremely vivid operations, easy to study manual as well as robotic movement study.

Section view of the assembly

Examples of draw or forming :

Sheet to first Forming

First to second forming

Base and Top housings

The base and top parts are the main parts contributes to the structure of the tool or die, the all parts are fitted / assembled on the both structures. The structure can be made from mild steel, however for bigger parts or panels the shape gets complicated, the custom made gravity castings are designed to lower / optimize the weight of the structure as well as to reduce the excessive machining.

Draw die casting - Front view

Draw die casting - Back view

The U-slots are provided to clamp the die with the bolster of the Power press machine. The mainly two types of press machines are there - 1. Mechanical 2. Hydraulic. The Hydraulic press is preferred for Draw or forming due to it's smooth / Jerk free function. The brief information on press machines are given in the article, refer the link - Brief Comparison of Hydraulic and Mechanical press.

The FG-250 or FG-300 grade is used for the both Base and top castings, used in the both draw or cutting dies.

Draw Punch

The draw punch is the part, around which the material is being wrapped or being formed. It should be enough hard and wear resistant to serve the at least 5 to 10 lac of parts. The main properties of the draw punch should include in order to long last for the desired service life.

Hardness

This is the first and foremost requirement, as it subjected to regular wear and tear due to abrasion of sheet against it. The surface hardness of at least 56~58 HRC is the fundamental requirement, sometimes additional surface coatings are preferred such as Chrome plating or PVD coating. For PVD coating, the vacuum heat treatment is preferred.

Toughness

Toughness is the required to absorb the heavy loads without cracking, which is the inverse function of hardness. Usually, when the material is more hard, it automatically being brittle and more prone to cracks when subjected to sudden loads.

Therefore, the material should be the blend of balance between the hardness and toughness, in order to achieve the desired service life.

Deformation after heat treatment

Sometimes the deformation / shrinkage is observed after heat treatment, which could be the result of unstable micro structure formed during hardening process. Some steels such as OHNS (oil hardened non shrinkable) offers excellent dimensional stability after hardening. The other way is go for vacuum hardening, which is very good for HCHCr material, D2 grade is preferred over D3.

Blank holder

The function of blank holder is to locate and hold material during forming process, again it should also be sufficiently hard to resist abrasion of metal skid over it's surface. The flatness of a blank holder has a vital role in maintaining accuracy of the part throughout the movement, guide pins are eventually provided to guide and maintain it's movement.

Guide Bush and Pins

The role of the guide pins is to maintain and guide the movement of blank holder throughout the process. It should be hard enough to resist regular wear and tear, along with tough enough to absorb the bending moments. The Case hardened materials such as EN-353 or EN-36 are preferred with min. case depth of 0.5 to 1 mm and hardness of 60~62 HRC.

Guide Bush and Pin set

Draw die Ring

Again, the draw die ring is the part, which is used to push / form the material against the walls of the punch, it is female part. It should be enough hard and wear resistant to serve the at least 5 to 10 lac of parts. The main properties of the draw punch should also include - Hardness, toughness and deformation free operation, in order to long last for the desired service life.

Ejector

The purpose of an ejector is to Hit the part, to make it flat. It also includes the letter punch for any additional marking such part number, identification code or batch marking. As it's name indicates, its main purpose is to eject the part with the help of some springs or elastomer, the gas spring is however being used as a preferred one due it's high success rate.

Ejector with Gas spring

Main Guide bush and pillar set

The purpose of main guide pillar and bush is to guide / align the tool throughout the stroke / motion of the press operation. Sometimes it absorb the play in press slides, thereby ensure the accuracy of the operation. The Case hardened materials such as EN-353 or EN-36 are preferred with min. case depth of 0.5 to 1 mm and hardness of 60~62 HRC. The design is the same in many cases, the diameter of the pillar increases with an increase of tool size, the tool size ratio is completely dependent function of the component to be produced, correspondingly the pillar size is required to balance the tool motion.

The adequate experience is thereby required to design a tool while maintaining the balance of human safety and ergonomics along with unmatched performance of service life, the spare parts should be easily exchangeable.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

How to choose number of Draw process for deep drawn geometry

noreply@blogger.com (Industrial age to information age) — Sun, 31 Oct 2021 12:32:00 +0000

Check for Draw to Height ratio

The D/H ratio is the basic ratio to have a look at the feasibility to perform a round / cylindrical draw process in a one or more than one process.

REFERENCE DEEP DRAWN PART

D = Outer dia. of the shell (15 inch, as shown in the sketch)

H = Height of the cylinder (20 inch, as shown in the sketch)

If D/H should be equal to or more than 1, there is a possibility to do it in a single draw.

In case, it is less than 1, then you have to go for a 2 or more draw operations.

For multiple draw process

In case D/H ratio is less than 1, then what is next. It is evident that it's more than one, but how much ?

The answer is complicated, there is no thumb rule, however based on my experience and compilation of years of experimental data, the following rules has been established.

For 1st draw, there should be the 60-70% reduction in diameter.

For 2nd draw, there should be the 40-45% reduction in diameter.

For 3rd draw, there should be the 20-25% reduction in diameter.

The base / original diameter with respect to whom, the reduction is applicable, that is the blank diameter.

Calculate the blank diameter

To calculate the blank dia. of the cylindrical part, the volume method to be used.

Volume of a cylinder is = ¶r²h

The volume of a blank, is also calculated by the same formula.

Volume of cylinder = volume of the calculated blank size

Let's say, the volume of cylinder is 108.6640 cubic inch.

Now for blank :

D = to be calculated

Thickness = 0.1 inch (same as thickness of the part)

108.6640 = 3.14 x R x R x 0.1

R = 18.6 and D = 37.2 inch

Decide the No. of Draw

Fore multiple draw process, there formula is same as mentioned earlier.

For First draw, the Final dia. of the part after draw is = (37.2 x 65%) = 24.18 inch

For Second draw, the possible reduction is = (24.18 x 40%) = 9.7 inch

Since our Target diameter is 15 inch, that means it's possible to draw the part in 2 draw stages.

Limitation of this basic method

This is a basic method, highly successful in the calculation of cylindrical deep drawn geometry.

Sometimes, other shapes such as square, pentagon and hexagon can be calculated. However, their blank size calculation is quite hard, since this is a volume based calculation best suited for round parts.

For more complex parts, the more advanced methods are being used given in the link at the end of the page ''Raw material calculation of Complex Deep drawn Geometry''

Defects of the metal forming process

The most painful and most frequent defects are wrinkles, thinning, springback and splits or cracks. Few methods are being used around the industry to cope with the main defects, based on the experience of the technicians. However, the correct process is the most vital, since it involves the correct geometry followed by number of steps to reach at final geometry. Which demands for specific experience or higher number of iterations, Nowadays the simulation software's comes under CAE (computer aided engineering), used the finite element analysis to predict the common defects in design stage, prior to die manufacturing.

Wrinkles : Wrinkling in a draw are series of ridges form radially in the drawn wall due to compressive buckling. Practically these are duo to low blank holder pressure due to which material slips and wrinkles formed. The optimum blank holding pressure is the key, however in certain cases it doesn't work. Then draw beads are the solutions, the location and shape of draw bead is the challenge, which can be analysed with FEA during design stage prior to tool manufacturing.

Cracks : Crack in the vertical wall due to high tensile stresses, some small radius block the material flow and results in excessive thinning at that point usually more than 40% of the sheet thk. result in cracks. In some cases it may happen due to excessive blank holder pressure, which restrict the metal flow. Somewhere it might be due to wrong process design, like try to make a more deep draws in a single stage, which otherwise feasible only in two stages.

Thinning : Excessive Stretching in the vertical wall due to high tensile stresses cause thickness reduction specifically on the small radius in the metal parts. The image highlights the thinning portions, however up to 20% thinning is allowed due to process limitations.

How FEA Helps : Nowadays FEA software's such as LS DYNA, AUTOFORM, HYPERFORM, PAMSTAMP are very good for virtual process simulations prior to product manufacturing. The defects such as Wrinkles, thinning and cracks can be seen in the design stage right just before the process design, results in correct process selection and reduction in lead time and save valuable money, which otherwise invested in hectic manufacturing iterations.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Process technology - how creativity results in major cost savings

noreply@blogger.com (Industrial age to information age) — Mon, 11 Oct 2021 12:29:00 +0000

how creativity results in major cost savings

Identify the area of improvement

The first and foremost process is in the development of ideas is to set the target or destination. Your road map may be misleading, in case you don't keep your eyes on the target or don't analyse your progress against the set goals. Milestones are the important gateways to measure your performance and keep you on the track.

In year 2008, i was working as an Engineer in agricultural tractor OEM based in INDIA. We were frequently receiving tractor model from different area of the world for bench-marking and analysis.

The one model aesthetically very appealing came from France, after dismantling it's body panels in the proto shop, me and my deputy manager were observing it's internal body parts. He was astonished to see the fuel tank and battery box were made out of carbon fiber and many more parts were optimized for weight reduction. Finally engine was being opened and it's oil sump was even made of carbon fiber.

At the moment, i suggested to my manager that the world is adopting the carbon fiber in many body parts, at least we should take initiative to convert the engine oil sump from casting to sheet metal.

Since carbon fiber is more more prone to cracks due to it's brittleness and it's implementation would not suit with the nature of Indian mechanic, who gradually uses hammer etc to loosen it's nut and might have cracks during such striking.

The idea sets its home in the mind of my manager and he eventually decided to take it further.

Sheet metal oil sump Casting oil sump

Set the target of improvement

Nevertheless, the target has been set, we are in the process of starting it's concept design mainly for weight calculations and difference among casting part and fabricated one.

After calculations, there was a major cost saving the weight has been reduced by almost one third.

Start the concept design

After the hard work of one week, Now it's time to present the idea before the management team in a presentable form. My team lead has made a presentation of concept design along with weight and cost saving, thanks to 3D cad packages which helped us to give shape to our idea in presentable form with realistic look. The tentative time plan has been developed for proto sample and testing activities.

During the presentation, the main bottle neck comes out as to maintain the flatness, since casting has a machined face and it should have been through metal stamping. As the gasket is being used in between both contact faces as dampener and to prevent oil leakage, it was decided to at least try out at testing level.

Generate your idea, Study the scope of potential failures

The idea has been generated and approved by the management for making at least proto samples and test it out for minimum 750 hours. The main big challenge is to make it's manufacturing flow diagram, since it was a deep and narrow part, never tried out in a sheet metal. At that time we were using FEA package to study the form-ability of skin panels, the same has been tested to make it's process flow.

After producing the part through incremental forming analysis, the defects like excessive thinning and wrinkles etc. were eliminated.

Now the only potential failure was to maintain the flatness, even though the metal spring back analysis has been done and appropriate actions were being taken, the risk was still present there.

Advance planning to overcome the failures

Although, the many issues were even resolved at the design stage, the nuances were still there, faced during trial phase such as material crack during forming. Which further has been eliminated by enlarging the radius and adding draft at certain places, shape optimization technique has been used with the help of FEA software. The final proto samples were made and eventually there was huge gap in the flatness values of machined and stamped part.

The stamped parts were appealed to be rejected, however have passed the fitment and oil leakage test after final assembly, the spring back killed by the pressure of bolt torquing.

Take expert help to overcome bottle necks, in case it is available

In our proto shop, there were some experienced tool makers, which have suggested the major shape modification in order to make it feasible to form. Such experts have a years of experience, enough to beat the calculations of the software, when he see the part it looks like if the metal part is telling him the way, how to produce me in the correct manner.

His suggested points produce excellent results when tested on FEA software. Such expert help wold boost your confidence and reduce your overall lead time.

Some problems are hidden and becomes visible during trial phase

During testing phase there was a minor leakage problem observed at nut welding area, where the oil is being drained out during servicing and changing engine oil. This was the hidden problem occurs suddenly during torture track test, every vehicle with any new part is subjected to torture track test for 400 hours, before launching in to mass production.

As a concrete action, the pressure leakage testing rig was introduced to prevent it in future mass supply.

Final mass production launch

After correcting all the problems faced during field trials and testing the product was finally launched in to mass production. It has not only saved a lots of money in current mass production models, but also open up the way to implement it in the future models as well.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

How cost reduction is the key factor to capture the market share

noreply@blogger.com (Industrial age to information age) — Mon, 11 Oct 2021 11:38:00 +0000

Benefits of Cost reduction

In the emerging Asian markets, inflation is on the peak and pay check of middle class people are not raising too much to cope with the increased rate of inflation.

They are therefore, spending money to manage their low cost budget and prefer to choose the balanced blend of cost and quality. The more competitive products with a perfect balance of cost and quality, captures the almost 70% market share.

The only way out to survival is to stay cost competitive.

To control the price of the product

The sale is totally dependent on the value of the product offered against the designated price, which is the main reason of price war at market place.

For example, today you would not be able to decide which SUV car to buy in an Indian market due to plenty of options available in the same price range. It is only competition which forces to control the price against the value offered.

To gain the competitive edge in the market

The old auto maker in India is making tie ups with the world top leaders, to capture the market share.

For instance, the Tata motor has gained the competitive edge in the market by launching series of cars in each segment with 5 star Ncap ratings. Which is the main reason to gain competitive edge in the market and leaving behind the giant Maruti Suzuki.

To increase the profit margin

The sales will create leverage, low margin with high volumes of sales create more profit margin and serves value against the price to the customers. In turns makes both, organization and customers happy.

To launch the variants

Tata motors has launched a series of cars covering low to high end variants, covering the 70% market share, which have forced the competition to lower their profit margins and offer value against the price.

Nowadays, competitors such as Suzuki, MG, Kia, huydai are forced to launch lower priced products, offering higher value against the price.

Performance improvement

Competition is the driving force, to continues performance improvement in the market.

For instance, Tata motors have launched vehicles with 5 star Ncap safety ratings in India. Acts as eye opener for the whole competition.

It becomes innovation, if timely protected

Tesla is the Giant automaker in EV segments, with millions of small patents preventing the competition to getting in, therefore creating monopoly based on the timely protected ideas.

Roadmap to the future new launches

The protected ideas of today becomes the path and roadmap to the upcoming innovations for the future products.

The firstly launched 5 star safety rated vehicle by Tata motors becomes road map to its own models as well as for the competition.

Improved brand image

The sales and brand building create Name and fame to build the concrete foundations of the business.

For instance, After take over of Jaguar Land rover, the Tata has improved its Brand value.

Robust research and development

Once you have launched the cutting edge technology, it will boost your research and development capabilities. Employee with high talents add up in the queue to join you, once you have a bigger brand value.

Open up the new world of opportunities

Success in launching new technologies will boost your confidence to the next level.

For example, Tesla has created a unique market share in Ev segment opens up new possibilities in Space ex. Which is a totally different and next level business.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Case study : How hastened decisions affect the business in the long term

noreply@blogger.com (Industrial age to information age) — Sun, 10 Oct 2021 06:17:00 +0000

How hastened decisions affect the business in the long term

Why there is a need for VA/VE in the running products

In the developing nations like India, the prices hikes are putting burden on the customers pockets, prevent them from buying thins which they can't afford. The option left behind is to produce economical, on the other hand raw material, labor, electricity prices are continuously going up generating hurdles in the way to produce economical. High govt. taxes leaving little margin in the pockets of OEM.

In such emerging situations, OEM's are adopting high VA/VE activities in order to prevent price hikes and tuned in line with the market competition.

No. One reason is competition

Competition is the driving force keeps alert the market against the price hikes, customers prefer lower prices with high features in every vehicle.

Second factor is the price war

Raw material, labor and electricity prices are going up, putting pressure on OEM to squeeze their margin or to find alternative ways in order to stay with in competition. Which has created a price war, that means to sell at lowest prices with high payout features.

3rd is high fuel prices

Govt. has imposed high taxes on the fuel, result in demand for high fuel efficient vehicles.

4th is to increase the sales

For a smaller business to grow into a big business, there is a need to generate the network of sales. The success of product and brand building plays major role in the course of actions.

5th is to grow your business

The secret of a growing business is to sell to the every layer of the community, the target of big business is not the 10% rich population, who demands luxury. But the 90% poor and middle class who need economy.

6th - employee justify their role

For a new business in domestic area, there is a continuous demand to keep your prices on the baseline.

In that case the main role of the employee is to continuously looking for the challenging ways to reduce the product cost to justify his job, whose salary is also counted as an overhead.

7th - employees growth

Some employees are forcing suppliers to forcefully reduce their part cost in any manner, no matter whether it should be inferior in quality function. Such employees gets a fair short term growth and many more incentives till the luck stay golden.

Pressure from the customer

In this post i am going to share with you the real time incident, which cost major OEM should have to cost on it's reputation in the market place, luckily they survived due to timely action and wise strategy.

The customer management was putting pressure on the supplier to forcefully do some value addition, which once they have refused due to amount of risk involved.

Squeezing development cycle

Once the supplier business was on stake, they have reduced the development time by skipping some major steps in development cycle. The value addition in the structural part was being asked about nearly 20% of price value.

Skipping testing and validation

Once the drawing was approved by the OEM,, they have planned their proto launching event in very hastened way. The supplier has submitted samples without testing validation. Even though the OEM has launched the vehicle without physically trying out or testing out.

Field failure start to receive just after 3rd month of launch

After the 3 months of product launch there was a big failure, the structural part undergoes crack with in one third time span of total warranty period from the one dedicated area of Punjab state. The incident reported by agency owner for two tractor models.

With in 15 days of time there were the warranties from the different areas such as Bihar, Uttarakhand. My team has visited the areas along with customer service teams, the issue was clear to us before it was being explained by anyone.

Part crack in circular periphery

1600 vehicles recalled

As a countermeasure, the sales data was taken from dealer network around the country. Finally, there were 1600 vehicles being sold all around, the road map was being made to replace the New parts with the old model. Since, the old model was running successfully before the launch of VA variant.

The tractors were called by the dealerships for free preventive checkup and faulty rims were being replaced free of cost.

Field failure investigation

The result of field investigation was that the New VA rim is suitable for agricultural applications, however failed to sustain the haulage applications and the areas where there is a sand mining, the parts were overloaded and being cracked. Since the old design has a more Factor of safety, therefore able to sustain overload.

Root cause investigation while comparing with similar vehicles in the market

Being hastened in launching was the key reason of failure

The failure could have been arrested, if the part was validated properly before launch. The hastened launching and skipping main milestones of testing was the key reason of failure.

The ignorance of supplier expertise leads to the launch of faulty products.

Further action to conclude

The customers which have faced major breakdown, lost confidence in the brand. Even though the concrete action has taken to replace the faulty parts by any means. Still there are many steps missing, there is a need to refine the whole process of product launch.

Long term impact on the business

Loosing confidence in launching next VA/VE activities

After the incident, the all ongoing VA/VE activities has been put on hold, which are even more genuine in nature. Some customers have lost their faith, management has lost the confidence in their launching process and supplier has been put in red category. It may takes years of time to revive from such incidents.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

Proud of being granted with your first patent

noreply@blogger.com (Industrial age to information age) — Sun, 10 Oct 2021 05:43:00 +0000

Generating new and rare idea

If you suppose to be a big picture thinker, having a unique and rare idea, then the first and foremost step is to cross check, whether is it protected by someone else in the past history. In case it is, then think of something else or if it is not protected by anyone in the past, then you are going to make it yours intellectual property.

THOUGHT PROCESS

Make it in a presentable form

Once your idea is created in presentable form, which is easy to understand. You can make a free hand sketch and convert it into professional 3D cad model with the help of paid professionals, in case you are not a designer.

The professional people makes your idea in presentable form, this is very easy to understand.

Search for previous history of the similar ideas, before it infringes with any

Next step is to search for the previous history of similar ideas already protected in the past. For the first time user, i will highly recommend to take the help of expert agent.

Agents are expert people, who have a advanced software to search among the database, even they are expert in making a proper draft of your idea, less prone to rejection or objection.

When i have filed for my first patent, i have only my concept and no idea about the procedures of the intellectual filing system. I have discussed my plan with my friend, who has given me further reference of the agent dealing with trademarks and referred me the patent attorney working in the same organization he is.

Working on the feasibility

Once you know there are already protected ideas, which are not similar with yours, however infringes in the near future.

The professional attorney may help with a advice to change or modify your idea. My first idea, which i think was unique was already similar to the already protected one. Then my agent suggested me to make necessary changes in the draft to avoid any infringement.

Filing your Patent

Next step is to file your patent application with the help of your agent or attorney.

After submission of your application, you will receive FER (first examination report) with in six months. In the report, details of findings are mentioned by the examiner or controller of patent and designs.

It is not advisable to submit a response by yourself, instead you should take the help of your attorney. As it may ask for some additional information or there may be any objection against infringement.

The legally careful and professional reply boost your chances of granting a patent.

Looking for the scope of implementation

My idea was unique and complicated design of wheel rim for heavy duty agricultural haulage applications. Which in near future might be in use by the any OEM, since tractor may replace the commercial trucks in mining and loading applications due to it's low cost and usage in wide applications. It may create a royalty income for me in the near future, You have to think in the same way.

Search for potential markets to launch your idea

Once you know the area of application, it's now time to make a advance plan to launch your idea in to the potential markets. This is applicable, in case you are engaged in similar business.

Sometimes, after getting your idea or design protected, you can approach to someone already engaged in similar business and ask for royalty to use your intellectual property.

Your intellectual property is your asset and you should utilize it with in 15 years, after that it's free to use by anyone.

Build a road map to launch your idea

Big business can utilize the idea due to its potential of leveraging and required complicated road map or plan to build a network for sales and distribution.

For individual, the plan is to simply approach to someone who is ready to sponsor your idea or already engaged in similar business and willing to pay royalty to you.

Why you need to secure your idea before launching

Your idea is your intellectual property, if you don't secure it others will do.

My team has generated one great idea to optimize the weight of agriculture tractor rim through the process of flow forming.

We have added the process in the presentation before securing the idea, even though we were working on its proto type samples. The idea was being presented to the one of our esteemed customer by our marketing executive director. With in six months of time, the idea was being patented by our competitor, while we were testing it's proto type samples. It is of no use for us.

From that learning, it is being advised to protect your idea before it is exposed to the real world.

Feeling of granted with your first patent

I had an excellent idea, which i had been offered to my organization first. They didn't take it seriously, then i decided to secure it for my own.

The feeling of granted with your first patent, is nothing less happier than a new born baby in your hands. You would soon start to plan its future like the future of your kid.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Case study : How i have resolved the major warranty problem

noreply@blogger.com (Industrial age to information age) — Fri, 01 Oct 2021 10:00:00 +0000

Correctly define the problem

We were informed about the severe cracks in the parts reported by leading agricultural OEM in India and team has to report back as soon as the issue escalate further. Warranty hazards in a structural members are very severe due to their life threatening nature. Up on investigating, there were the signs of severe damage, such as an accidental situation. Service teams are creating panic situations; however, engineers should stay calm before reaching to any conclusion in hastened way.

Failed part

Try to figure out the source of problem

There might be the several reasons, such as improper usage, accidental condition, applying excessive torque to tighten, sudden deflation of air resulting in imbalance of vehicle.

Physical presence at the site of application is highly appreciated to understanding the loading conditions and usage patterns.

Conditions under which your part failed

After you reach at the site and the usage patterns are vivid to you, try to access the capture the maximum information in the form of pictures, videos, notes. Since this is your running part, being supplied throughout the years. The sudden failures are the result of change, here ‘’change’’ is the key thing which you have to co-relate. Whether it is the new area where vehicle was never sold or tested or the evolution of new application or change in application or change in mating part or change in vehicle model, where your part was never tested.

Check with the mating part

Here in my part there are the three possibilities: Change in tire size or change in axle hub design or change in vehicle model.

Up on conclusion it was found that the customer has changed the Hub-axle design as VA-VE initiative without intimation to the supplier, whose part is being suffered from severe failures.

Mating part

Any change in mating part would adversely affect the function of your part

The hub design has been changed to the extent that should have not been there, New engineers take initiatives of VA-VE in the greed of appreciation in terms of money and their idea eventually get approved by their in-experienced managers without understanding the severity of the function. Which therefore imparting pressure to modify the mating part, that otherwise makes no sense.

Old Hub Design New Hub Design

Use of bench marking techniques

By blue matching with the mating part, the problem becomes more vivid, as the definition of pressure works here (force acting on per unit area). The contact area here is negligible and pressure/load is same as in the case of old mating part, causing the more stress concentration and weakening of the area.

Blue impression with the mating part

Arresting the problem

More concrete is the foundation of your analysis, more accurate is the way out to arrest the problem. Here as we can see, the problem is more vivid after the analysis. The reduced contact is the key area to focus and with the help of cad data of the changed hub axle, we have further taken up the analysis at our work premises and ask the customer team for sometime and committed to come up with detailed analysis and final conclusion.

Brainstorming to find out the final solution

Once upon studying and mating the cad model, the picture becomes as it is like blue matching with the physical part, as you can see the yellow area is the key contact.

With the series of iterations and brainstorming sessions we have developed the concept design with increased contact area.

Now, next challenge is to validate its effectiveness.

Contact area study - Old design vs New design

Take the help of engineering techniques / Finite element analysis

To validate the effectiveness of modification, there are two methods - the first and most accurate is to physically test the sample under given loading conditions, which is the most accurate, however longest time taking.

Second is the, FEA method is effective to just have a brief comparison of stress levels of both conditions, low realibility, however quickest and easiest.

Lots of experience required to choose such methods, risky for people with little know how.

FEA study for Stress analysis - Old design vs New design

Solid foundation of your analysis is the key to success / Not plan A or B

As the description predict, the more concrete your foundation of analysis is, more reliable your solution is. Realistic people doesn't need plan B or further plans, it is the speculators who are not confident on their way of working, therefore having lots of inconsistency around them and looking for way out to eascape in the dark.

Here in this case, after successfully analyzing the design via FEA method, i have chosen to proceed with the tooled up samples for physical validation on internal test rig with the replica of the hub axle part, same as the modified by the customer.

It takes around 30 days to get the tooled up samples and the results were astonishing with huge gap in performance between old (1.5 lac cycles) and new (12.5 lac cycles) design. Based on which, we had successfully pass on our best proposal to the customer for their validation and testing.

Based on our study, they opt for direct implementation in to mass production.

Even today after 2 years of implementation, there are no field issues or complaints.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Meshing Basics - Solid meshing

noreply@blogger.com (Industrial age to information age) — Thu, 20 Aug 2020 04:29:00 +0000

Meshing Basics - Solid meshing

Why to choose solid mesh

Sometimes we need visual aspect to see the exact/realistic look of the thickened part after forming process or for realistic look of the effect of special Iteration/modification after forming.

First step is to produce the correct 2d Meshing

There are two ways to create the perfect quard mesh - first is the conventional method, most suitable for square or rectangular sheet without hole or contour.

Second is the radial meshing, by dividing the geometry and meshing the segments individually, however ensure the connectivity of the elements.

The quality of mesh directly impacting the accuracy of the results, since the solver is solving each node, better connectivity among elements, more reliable are the results.

See the video for Radial meshing method :

Importance of correct element size:

It's very important to choose the correct element size, since the results are directly affected due to this, for instance with the min. radius value of 5mm on the final product, the mesh size should be the 1/4th of the min. radius to obtain the correct thinning results, at least 4-elements should be there on that radius during analysis for realistic output.

How to generate the solid mesh:

The solid mesh is created from the 2D mesh from the multiple 3d meshing options, preferably drag option, for instance i have created quard mesh on the simple square sheet via. conventional method or by creating a quard mesh on the complex curved surface via. radial meshing method.

See the video tutorial on the solid meshing:

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Meshing basics- radial meshing on square sheet with round edges

noreply@blogger.com (Industrial age to information age) — Wed, 29 Jul 2020 08:15:00 +0000

How to mesh a surface with square sheet with round edges :

Conventional Meshing :

In conventional meshing, we are directly mesh the geometry with a Either mixed mesh or pure quard mesh. The accuracy of results depend upon size and accuracy/quality of meshing. The quard mesh is perfect for a square or rectangular sheets, however the method demands change with respect to shape change. In this video you will see the elements error produced while direct meshing on the surface.

Customized method of Meshing :

Here you can see, how i have prepared the geometry by splitting it in to various equal segments due to make it perfectly fit for the quard and radial mesh. The center portion is scrap, therefore i have divide it with a circle and mesh it with quard meshing/conventional method.
The segment with round edges to mesh first, the technique is called radial meshing, the only thing to remember is to make no's of elements equal in center and outer periphery.
Mesh all segments likewise as shown in video, would prepare a geometry with perfect quard mesh with high element quality index.

Keep practicing and enjoy.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

How to modify the product to make it aesthetically better and more cost effective

noreply@blogger.com (Industrial age to information age) — Tue, 30 Jun 2020 10:51:00 +0000

How I have modified my product to make it aesthetically better and cost effective

Old Product

Optimized product

Study and analysis of current Product

Current product is not very appealing, however functionally perfect, since the all tire and vehicle fitment profile/dimensions are within tolerance. There are many way-outs to change the product, however the changes might not contradict with the customer drawing or specification, so that it should meet the critical parameters to avoid any functional defects.

Therefore, the scope of change/modifications is a daunting task, that require full know-how of the product and there should be the calculated impact of change, based on that generate the best possible alternative ideas, like in my case I have just added the best possible shapes to meet the mini. Material input and max. endurance strength to meet the physical test requirements.

Generate Ideas

There are many potential ideas comes out from the studies such as Raw material thickness change, Shape change (wherever allowed), RM grade change. Process these ideas for further screening criteria like, Raw material thickness and grade are in contradiction with the requirements of the drawing and in shape you can only manipulate non-functional shape, since it should not affect any fit and function which might have adverse effect on the mass supplies.

Nevertheless, consider the final one idea and again make alternatives out of that, like I have chosen the shape change idea, the question is how much change is optimum to meet both targets, that is performance and cost effectiveness.

After identify your subject of change, even highly professionals are advised to re-check for any contradiction with in the drawings or specifications.

Prepare designs and calculate the Raw material

Out of alternate ideas, prepare the design of all and calculate the blank size/ raw material size. Which is again an expert task, see the topics blank size calculation of bend parts and raw material calculation of the complicated shapes.

Next step is to validate the calculated material size, either physically or best alternate is the cad geometry with FEA technique, there are software available such as Siemens NX with one step analysis, in brief it requires cad geometry with mid-surface, the thickness and material grade to put separately in input column. Mesh the geometry, the accuracy of your output shape is directly depends upon your mesh quality.

or there is another high end software like ‘Hyperworks’ with one step forming analysis, there is same method, it’s requires more inputs and more professional with more settings and options, thereby the results are more accurate and reliable.

Technology make things easier, eventually you should know how to use it correctly.

The simulation example of the best developed blank option, the simulation was performed with the help of Hyperworks with solid mesh.

Forming Simulation
Apart from the forming simulation, there is one unseen potential failure taken care during design was the material bulging at the corner of bending, which might cause wear/abrasion with the mating part during assembly. It's always easy to understand the basics, but it takes years to find nuances. For more clarity the points are marked in the below image :

Corner Relieving

Make proto samples and validate

Don’t be hastened in decision making, since it’s very crucial step, so proto sample is always the best alternative. Make proto samples – 3 or 4 types to match with your ideas. Compare from every aspect such as Aesthetically by careful self-observation as well as from others perspectives.

From material savings, note the optimum shape with max. utilization.

From Endurance strength, by putting it on the test rigs and verify after physical testing. Never be hastened in decision making, since decision can’t be made on the basis of single test results, so it’s essential to repeat the tests with more specimen to be sure of performance.

Select the best alternative

Now you have a full data/information of the potential rivals, make a clean comparison data in terms of utilization, aesthetics, test results.

Decision making is a crucial step and everyone has its own viewpoint, therefore it’s always better to discuss with your team mates and CFT (cross functional teams) in your organization. The suggestions from everyone are welcome and to be deeply analyzed, however the key decision making is the sole responsibility of the Engineering Team lead.

Experience matters in the final process of decision making, consult your seniors or managers who are enough experienced to guide you about any potential demerits which could remain hidden from you. In some cases, you can offer it to your customer as a better rival/alternative of your existing products with all the evidence of validation and request him to check the fitment jointly along with final sign off to reduce any final risk.

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.
Buy the book from Amazon.
Or
Buy from here at 20% discount.
Or
Buy the book from Flipkart
Or
Buy the book from Notion press
Or
Buy from apple store
Or
Buy from Smashwords
Or
Buy from Barnes and noble
Or
Buy from kobo books
Or
Buy from scribd

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Raw material calculation of Complex Deep drawn Geometry

noreply@blogger.com (Industrial age to information age) — Thu, 04 Jun 2020 10:35:00 +0000

Raw material calculation of Complex Deep drawn Geometry :

The complex automotive parts such as chassis cross members have complicated shapes that are not easy to handle for process engineers. Certain things to be considered while calculating their raw material size, which is a major factor and value addition to the cost estimation and cost accounting.

Why accurate raw material cost is the Key factor to control cost

The raw material contributes a 70% cost of the product cost and 30% are the processing, finishing and packaging, which therefore makes it most critical part of the final product costing. The process engineers should be trained enough to calculate the optimum material cost, wherever possible to combine/manipulate the process layout to save the material.

Why Right process selection is important :

The correct sequence of process is the key factor, since the raw material input would be the different based on the process selection. For instance, let's take example of the following Geometry with trimming Margin.

Extra raw material taken for trimming, that is to control the outer shape and could be avoided in case it's has no significance or not fouling with surrounding parts in the assembly.

Use of CAE to select first time right process :

The Computer aided engineering help to create the right process, since the manual calculations have high chances of errors, even with experienced engineers have mistakes which proves costly for the project deadlines.

The CAE helps in creating accurate process mapping with least errors along with optimum process and material input.

Blank calculation process through conventional method :

The one of the method to exact blank size is to cut out sections at various points and calculate the length to obtain the final blank shape, however there are high chances of errors if not done by professional. Eventually the final results are not that much accurate, nearly 60% accuracy obtained, even for expert cad users. Refer the article Blank size calculation of a sheet metal for calculating the length along sections.

Blank calculation process through CAE method :

CAE help the engineers to calculate the 90% accurate blanks with a blink of an eye, however the expertise of engineers is quite important. Since the output is directly proportional to the input such as mesh quality, material database, process inputs like press speed, pressure, tonnage etc.

Blank (Material) size Calculation of Cup Draw :

CUP DRAW

The best and accurate method to calculate the blank size of Cup/Hat shaped draw is by Volume method, however there are 5~7% error due to process thinning at radius point. Let's learn to calculate the blank size, Since we know the volume of blank should be equal to the volume of drawn part :

Volume of Blank = Volume of Cup (Calculate from the CAD geometry)

𝚷 X R X R X Thickness = 336009 ⇏ 3.14X R X R X 4 = 336009

R X R = 336009 / (3.14X4) ⇏ R = SQ RT (26752.3)

R = 163.5 and correspondingly Diameter = 327mm

This cup has to be drawn in to three stages, Draw-1, Draw-2 and Final Draw.

To make sure the final flange to be straight and dimensionally controlled, the part has to be trimmed before final Draw, therefore optimum Trimming margin has to be added and the final material size to be taken as circle of Diameter - 340mm

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Press Tonnage calculation for processing of sheet metal

noreply@blogger.com (Industrial age to information age) — Wed, 03 Jun 2020 05:27:00 +0000

Bending Force Calculation :

There are various ways to calculate the bending force of a sheet metal parts, most basic is to use the formula. Since it's a basic and everyone should know about theory, however there may be some variations in results due to error in input values such as Tensile strength, coeff. of friction (not considered in formulas), press type (Mechanical or hydraulic) and other practical aspects which are not possible to measure. Therefore these force values to be taken as reference and sufficient factor of safety to be considered, minimum 20% to be added to select the final press. 100% correlation of formula and actual press force is impossible, even FEA softwares have certain limitations.

Bending in a V-die with rectangular cross-section:

where kV = die opening factor, 0.75 to 2.5 (larger values are for smaller R/t ratios and vice
versa). A 1.33 value is used for a die opening of 8 times metal thickness.
W = width of the bent-up portion
L = distance between material supports
S = ultimate tensile strength

For instance, Let's assume a sheet part with thickness 3mm, Kv =2.5, more than 8x of thk., L=60, W=75, S=41

Force = (2.5 x 41 x 75 x 3 x 3) / 60 ⇒ 1153 Kgf

To check the accuracy of the formula, the co-relation has been made with the FEA force calculation :

FEA force is 10231N = 1044 kfg (almost nearby the formula)

Bending in a U-die, equipped with a spring-loaded pressure pad:

where kU = die opening factor, 0.4 to 10
RE = radius, die edge (see Fig. 8-53)
RD = radius, bottom of U channel
Ppad = pressure of spring-loaded support

Bending with bottoming (coining):

Bottoming force (F) = A X S
where S = Tensile strength
A = area of part, subjected to coining

Wipe bending dies pressure calculation:

where L = distance between supports of the material
W = width of the bent-up portion
S = ultimate tensile strength
t - Sheet Thickness

FORCE CALCULATION IN ROTARY BENDING

F = 2.25 x S x (PL x t / L)

where L = distance between Die and roll radius
PL = width of the bent-up portion
S = ultimate tensile strength
t - Sheet Thickness

If you want to learn the Metal forming simulation, read the book "Practical guide to forming simulation"

The book is available via. the following links.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards

Lean Manufacturing Terminologies

noreply@blogger.com (Industrial age to information age) — Wed, 27 May 2020 08:45:00 +0000

Lean Manufacturing Tools and Techniques

The article below outlines some of the key lean manufacturing tools and techniques.

Quality Function Deployment (QFD)

QFD is a helpful lean manufacturing tool for quality planning, which is also known as the "House of Quality". This is used in lean manufacturing environments to identify the outputs required by customers, and then trace these outputs to causal inputs which can be controlled by the organisation. This will typically include product design and manufacturing process characteristics. As such, QFD can be used to identify which manufacturing process characteristics are key drivers of product and service quality for the customer. The output of QFD Phase 1 is Design Requirements. This is the input into QFD Phase 2, whose output is Critical Part Characteristics, which is the input to QFD Phase 3 whose output is Key Process Parameters, which is the input to QFD Phase 4 whose output is Production Requirements.

Process Failure Modes and Effects Analysis (FMEA)

Closely related to the Design FMEA, is another lean manufacturing tool: Process FMEA studies can be used by a lean manufacturing consulant to size the relative risks of a range manufacturing quality failure modes. It is a formalized analytical technique which lists all potential sources of failure and then allocates a weighted points score according to the expected frequency, the likelihood of being able to detect the failure and the severity of the consequences. It is used to ensure that all manufacturing failure modes have been evaluated. This priorities design risks with a view to them being eliminated.

Poka Yoke or (Fool-Proofing)

Often an extremely cost-effective lean manufacturing tool, using very simple devices to prevent the production of defective products. There are typically three types: 1. Contact Type, 2. Constant Number Type, 3. Performance Sequence Type.

Statistical Process Control (SPC)

In lean manufacturing environments this is considered to be an extremely effective quality tool, requiring only periodic measurement of system output variables, and thus low administrative costs, yet because it is preventive, also reduces process non-conformance dramatically. SPC is a core element within the six-sigma toolkit. It involves establishing the limits of statistical variability for a system output parameter in steady state conditions (see Machine Capability Studies). Limits for the variability of the process are calculated and control limits set, which mean that when not under steady state conditions and the output variable either falls below the lower control limit, or climbs above the upper control limit the process, the process can be halted and remedial action taken. If the system is "capable", then the upper and lower control limits will be within the tolerance required of the system and the remedial action can be taken before the output variable is out of tolerance.

Machine Capability Studies

Another extremely important preventive quality approach in the lean manufacturing toolkit. SPC techniques are used establish the statistical variability of an output parameter from a machine in steady state conditions. If the engineering tolerances required by products produced by the machine are within its steady state limits of variability, the machine is said to be "capable" of the tolerances. Process capability studies are broader than machine capability studies, in that they typically also take account of the intervention of other actors (e.g. a human operator) in addition to the capability of a machine.

Six Sigma

Six Sigma has grown to become an entire range of quality tools and techniques in its own right. In environments like GE, the six sigma approach has broadened to include such things as programme and project management tools and rules all of which are complementary to lean manufacturing. The original concept however is that embodied by SPC and Capability Studies - that is; the need for ever tighter consistency of process variables.

Taguchi

When the interactions between a large number of input parameters are complex, yet their combined effect causes a range of outcomes for output parameters, normally the only way to understand the combined effect of differing input parameter values would be to conduct an experiment for every possible combination (full factorial) of input parameter values. By contrast the Taguchi (design of experiments) methodology enables a much smaller number of experiments on the input variables to be conducted, which nevertheless provide an equivalent understanding as if the full factorial range of experiments had been conducted. Its statistical validity has been questioned by some, but exponents of the approach cite its noticeable successes in enabling complex quality problems to be solved. This is a very valuable lean manufacturing tool.

Shainin

In some ways like Taguchi, but a range of statistical tools and techniques for developing an understanding regarding the complex interactions between a significant number of input variables and output variables. Again a powerful means of eliminating waste - a fundamental principle of lean manufacturing. Examples of techniques include "Multi-vari Charts".

Reducing Cycle Times/Reducing Lead Times - Cellular Manufacturing Architecture

Since in many organisations, the sum of machine cycle times is typically only 5% of the entire lead time for the manufacturing of that product, (best practice is 50%) the driver of product lead times is not the speed at which machines process components. Often the most significant driver of lead times (and therefore work in progress & cash) is the number of changes in ownership during a component's manufacturing route. This is often the case in "process" or "functional" manufacturing architectures, where similar processes are grouped together and components travel many times between groups of processes, changing ownership throughout. On the other hand, a "Cellular" manufacturing architecture, can be introduced to minimize changes of ownership; grouping disparate processes together for components with similar characteristics. Moving from a "functional" to a "cellular" manufacturing architecture can reduce WIP and lead times by at least 50%, and can also reduce the need for substantial indirect labour (e.g. expediters, material handlers, supervisory staff etc). Typically headcount reductions of between 20-30% are reliable.

Kanban

Kanban means "sign" in Japanese, and is a visual reactive re-order point control system. Reactive in the sense that without intervention it cannot anticipate peaks or troughs in demand and adjust accordingly, and a re-order point system because when a minimum inventory level is reached, a reorder Kanban is launched. A lean manufacturing consultant can select an optimum design from a number of variations on the theme; single card Kanbans (move and make card), dual card Kanbans (move card and make card). True Kanban however, can be applied to components of any value, but is most reliable when demand is predictable and flat. As with any reactive reorder point system Kanban can be caught out by peaks in demand, and can hold unnecessary costly work-in-progress if demand drops. As such, it works best in an environment which is subject to Level Scheduling. A two-bin system is a variation on the Kanban theme, used for low value components, where inventory value is negligible and level scheduling isn't necessary.

Level Scheduling

Ask any lean manufacturing consultant and they'll tell you that Level Scheduling is a very under-rated technique, because it is often a major cost driver and is a key pre-requisite for robust and low WIP Kanban implementations. It relies heavily upon quick changeovers (SMED) to ensure that manufacturing processes can make say components A, B & C in smaller quantities every day of the week, rather than A for 3 days, then B for 2 days and then C for 2 days. This ensures that demand throughout the manufacturing system for upstream specialist resources (e.g. a special process for component B) doesn't come in peaks, but is spread evenly. This enables the number of scarce specialist resources in a lean manufacturing system to be minimized (e.g. reduced labour, machines etc), and Kanbans to recirculate more frequently and for their re-order point levels to be dropped (reducing WIP). It is a key means of driving out variability in a lean manufacturing environment.

Quick Changeovers or Single Minute Exchange of Die (SMED)

A core tool for a lean manufacturing consultant, SMED is often used by because of its multi-faceted impact. Primarily it enables a manufacturing organisation to move from a "minimum batch quantity" approach to a "batch of one" approach, but this also facilitates Level Scheduling, which in turn facilitates robust and low WIP Kanban implementations. Changeovers are analysed into "external" elements, those which can be performed off-line whilst the machine is running and "internal" elements which have to be performed when the machine is stopped. As many internal elements are converted to external elements as possible and then both internal and external elements are streamlined as far as possible.

Mixed Mode Manufacture

Involves the development of tooling which rather than performing an operation on multiples of one type of component (e.g. an eight cavity plastic injection moulding tool for salt shaker lids and another for pepper shaker lids) can be replaced by an eight cavity tool split into four cavities for salt shakers and four cavities for pepper shakers. This eliminates changeovers and ensures that production schedules can be "levelled".

Bottleneck Process Management

Unfortunately bottlenecks move depending upon mix, but because they govern the output from the entire system, if capacity is stretched multi-shift them, work them through breaks, minimize changeover times and minimize downtime using Total Productive Maintenance techniques etc.

Total Productive Maintenance (TPM)

Another lean manufacturing tool, which is focused on the objective of zero breakdowns. Significant emphasis is on first line preventive maintenance by operators, which is then supported by a regime of preventive maintenance provided by specialists. In order to make planned or preventive maintenance work successfully, it is often necessary to separate it organizationally from breakdown maintenance.

Nagare

Operators "walk" products around a "U-shaped" cell of simple machines manually loading products from previous processes into the next. Each machine once loaded operates automatically. Cell capacity can be increased by adding more workers into the cell. Benefits include: improved labour productivity, lower capital expenditure, flexibility, lower level skill requirements. A technique still not seen so often in UK manufacturing facilities.

Simulation

There are two types of manufacturing system simulation: computer and manual. Whilst real-time computer graphics are great fun to watch, but lean manufacturing specialists find the greatest value is achieved when manual simulations are played by operators (like a board game) to test the robustness of a manufacturing system design and in particular to design Kanban systems. This approach enables operators to "buy-in" to the design of the manufacturing system.

5S

5S is a series of five simple lean manufacturing tools to improve the workshop environment. Whilst the benefits that 5S can bring are not "step change" in nature, the approaches can significantly reduce losses in productive time for example by ensuring that tools are not mislaid, but are readily to hand on say shadow boards. The approaches can also be helpful in lean manufacturing environments in establishing cleanliness and tidiness norms for an organisation and therefore making a contribution towards limited cultural change.

SOME MORE HELPFUL TOPICS :

Bending Force Calculation

Forming Limit Diagram

Sheet Metal blank size calculation

Lean Manufacturing Terminologies

Brief Comparison of Hydraulic and Mechanical press

TECHNICAL TERMINOLOGY OF WHEEL TIRE

Raw material calculation of Complex Deep drawn Geometry

Modify the product to make it aesthetically better and more cost effective

How creativity results in major cost savings

How concrete analysis resolve warranty issues

Proud of being Granted with your first patent

How hastened decisions affect the business in the long term

How cost reduction is the key factor to capture the market share

How to choose number of Draw process for deep drawn geometry

Essential parts of a draw die

Everything about patent

sheet metal processing and latest trends

Electric vehicle (EV) – Future of Transport

Surface coatings to increase the tool wear life

Mechanical Properties of Cast Carbon and Low Alloy Steels

HYDRAULIC PRESS - BRIEF TERMINOLOGY

A TO Z TERMINOLOGY OF AUTOMOTIVE CONTROL SYSTEMS

A to Z Terminology of surface treatment and heat treatment

Raw material standards