FABRICATION & RELATED TERMS

Carbon Steel / LTCS Materials With Electrode Selection

2023-12-17T14:10:00.005+05:30

Carbon Steel/LTCS Materials With Electrode Selection

(CS/LTCS Plates, Pipes, Tubes, Fittings, Forgings & Castings)

For Carbon Steel Plate Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate
1	CS	CS	1	A285 A515	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A516	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	-	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	A387 Gr.2	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	A387 Gr.12	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A387 Gr.11	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A387 Gr.22	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A387 Gr.5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	A387 Gr.7	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A387 Gr.9	E505	E8018-B8	ER505	241

For Carbon Steel Pipe Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate	Bare Electrode
1	CS	CS	1	A 53 A106	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A333 Gr. 1/6	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	A335 P1	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	A335 P2	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	A335 P12	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A335 P11	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A335 P22	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A335 P5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	A335 P7	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A335 P9	E505	E8018-B8	ER505	241

For Carbon Steel Tube Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate	Bare Electrode
1	CS	CS	1	A178 A179/192	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A334 Gr.1/6	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	A161 T1	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	A213 T2	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	A213 T12	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A213 T11	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A213 T22	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A213 T5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	A213 T7	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A213 T9	E505	E8018-B8	ER505	241

For Carbon Steel wrought Fittings Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate	Bare Electrode
1	CS	CS	1	A234 Gr. WPA/B	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A420 WPL6	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	A234 WPI	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	-	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	A234 WP12	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A234 W11	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A234 WP22	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A234 WP5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	A234 WP7	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A234 WP9	E505	E8018-B8	ER505	241

For Carbon Steel Forging Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate	Bare Electrode
1	CS	CS	1	A181 A105	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A350 LF 1/2	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	A182 F1	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	A182 F2	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	A182 F12	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A182 F11	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A182 F22	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A182 F5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	A182 F7	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A182 F9	E505	E8018-B8	ER505	241

For Carbon Steel Casting Materials :

Sr. No.	Base Metal		P No.	Material	AWS Specification			Hardness BHN Max.
					Covered Electrode		Bare Electrode
					Preferred	Aiternate
1	CS	CS	1	A216	E6010 Root E7018 F&F	E6013,E7015 E7028	ER70 S-2,S-3,S- 5 RG 60, 65	200
2	LTCS	LTCS	1	A352 LCB/C	E7018 G	E7018	E 70 S-1B	200
3	LTCS/ALLOY	C - 1/2Mo	3	A217 WC1	E7010-A1 E7018-A1	E7015-A1	E 70 S-1B	225
4	LTCS/ALLOY	1/2Cr-1/2Mo	3	-	E8018-B1	E8016-B1	-	225
5	LTCS/ALLOY	1Cr-1/2Mo	4	-	E8016-B2	E8018-B2	ER515	225
6	LTCS/ALLOY	1 1/4Cr-1/2Mo	4	A217 WC6	E8016-B2	E8018-B2	ER515	225
7	LTCS/ALLOY	2 1/4Cr-1Mo	5	A217 WC9	E9015-B3	E9018-B3	ER521	241
8	LTCS/ALLOY	5Cr-1/2Mo	5	A217 C5	E502	E8018-B6	ER502	241
9	LTCS/ALLOY	7Cr-1/2Mo	5	-	E7 Cr.	-	ER7 Cr	241
10	LTCS/ALLOY	9Cr-1Mo	5	A217 C12	E505	E8018-B8	ER505	241

INTRODUCTION OF ASME SEC. IX

2023-01-21T14:05:00.005+05:30

INTRODUCTION OF ASME SEC. IX

ASME SECTION IX deals with

- Part QW (Welding)

- Part QB (Brazing)

Each part divided into 4 articles as,

1. General Requirement.

2. Procedure Qualification.

3. Performance Qualification.

4. Data

LIMITATION :

1. To be referred only when the design code (Such as Section VIII Div. 1)

2. Does not guide the selection of electrode.

3. Does not guide the design of joints.

4. Does not specify the type and extend of radiography/NDT to be used.

5. Does not specify the acceptance criteria for extend of discontinuities acceptable.

WELDING PROCEDURE QUALIFICATION

When WPS/PQR Qualified,

Proves the quality and properties of weld joints prepared by a set of welding variables.

- Welding Process.

- Base Material.

- Welding Consumables.

- Welding parameters and techniques (Position, Polarity, preheat, Inter-pass Temperature etc)

- PWHT

Qualification is limited to the essential variables of the Specific Process

WPS :

Written document showing all the applicable welding variables
Provide direction for making production welds which will meet code requirements.

WELDING VARIABLES :

ESSENTIAL VARIABLE: significant effect on the weld properties if changed.

NON-ESSENTIAL VARIABLE: N0 significant effect on weld properties if changed.

SUPPLEMENTARY ESSENTIAL VARIABLE: When other Sections specify notch-toughness tests and are in addition to the essential variables.

Variables are listed for each welding process in QW-252 to QW-265

WPS should be available for reference and review by the inspector.It should also be made available with welding supervisors, welders

PROCEDURE QUALIFICATION RECORDS :

A mock up : Represent welding done in a shop under similar conditions.
Some codes call for a production weld coupons as an additional measure.
Production coupons also act as qualification tests for the PQR
Prepare A Weld Coupon Using an Preliminary WPS.
Weld Coupon Undergoes Destructive Test
Testing Requirements are specified in Sec IX
Acceptance norms shall be as per Construction Code.
PQR is limited to the essential variables of the Specific Process
Process of testing capability of the welder is known as "Welder Performance Qualification test"
Ascertain the skill of a welder or a welding operator to Produce defect free/Sound weld
Makes A Weld Coupon Using an Approved WPS
Weld Coupon Undergoes Soundness Test (NDT or DT)
Each Qualified Welder Shall be Assigned by A Unique Welder Number
Welders’ Qualifications Records Are Documented
Performance Qualification is limited to the essential variables of the Specific Welding Process

REQUIREMANTS OF ASME SECTION IX

Section has two parts : welding and brazing. [UW & UB]

Under Welding there are 4 chapters (Article I to V), in addition to initial introduction.

Article I: General.

- Positions of welding

- Examinations (Various Types of Tests, Testing Procedures, Specimen Details, Acceptance Criteria) etc.

Article II - Welding Procedure Qualifications.

- WPS, PQR

- Their contents, Format

- List of variables

- Qualification ranges

- Type and number of examinations required

Article III - Welding Performance Qualifications.

- WPQ

- List of Variables

- Qualification ranges

- Type and number of examinations required

Article IV

- Compiled welding data meant for using with articles I, II, III

Hence, for example, one who wants to qualify a welder can directly refer article III.

Article V – Standard Welding Procedure Specifications (SWPs).

- Useful for small manufacturers, whose knowledge of welding is miniscule

- SWPSs will have to purchase them from AWS

- Instead of performing more PQR tests, manufacturer to perform and document a demonstration weld following a typical SWPS.

- Manufacturer to demonstrate and document that he knows enough about welding to follow the SWPS.

- After welding and testing one demonstration coupon, many other SWPSs may typically be used without further demonstrations.

- Not permitted for construction where impact testing of the WPS is required

- The specific requirements of SWPSs are covered in Article V (i.e., QW-500)

- Sample form (QW 485) is demonstrated in non mandatory Appendix B.

- The permitted SWPSs are listed in Appendix E

- These SWPSs cover welding of P-1 and P-8 metals using SMAW, GTAW and GMAWFC. • Typi

- Typical thickness ranges permitted are 1/8” to 1-1/2” and both as-welded and post weld heat treated procedures (for P-1 metals) are available

Important points for reading the welding data:

- Never read the welding data given in article IV unless called upon to do so by articles I, II or III

- Normally adding "a new qualification shall be done when …" before reading data against essential variable given in the tables of Article II and III (such as QW 253), makes the reading easy

- Welding Data - Essential, Non Essential & Supplementary Essential Variables.

- Parent Metal Grouping - “P” No

- Filler Metal Grouping – “ F” No

- Weld Metal Composition Grouping – “A” No

- Welding Positions, Groove & Fillet

- Types of Tests – Tension, Guided Bend, Notch Toughness

- Test Requirements & Acceptance Limits

- Test Specimen – Location, Dimension & Testing Procedure

- Qualifications – Range in Thickness & Diameter

- Record & Documentation of WPS , PQR & WP

British Standards and Indian Standards

2022-03-09T22:41:00.007+05:30

British Standards and Indian Standards

A) British Standards : British Standards (BS) are the standards produced by the BSI Group which is incorporated under a royal charter and which is formally designated as the national standards body (NSB) for the UK. The most commonly referred British Standards in the Piping Industry are :

  BS 10 : Flanges
  BS 806 : Pipes and Fittings for Boilers
  BS 916 : Black Bolts, Nuts and Screws
  BS 970 : Steel for Forging, Bars, Rods, valve steel, etc.
  BS 1212 : Specification for Float Operated Valves
  BS 1306 : Copper and Copper alloy pressure piping system
  BS 1414 : Gate Valves for Petroleum Industry
  BS 1560 : Steel Pipe Flanges
  BS 1600 : Dimensions of Steel Pipes
  BS 1640 : Butt Welding Fittings
  BS 1740 : Wrought Steel screwed pipe fittings
  BS 1868 : Steel Check Valves for Petroleum Industry
  BS 1873 : Steel Globe and Check Valves for Petroleum Industry
  BS 1965 : Butt welding pipe fittings
  BS 2080 : Face to Face / End to End dimensions of Valves
  BS 2598 : Glass Pipelines and Fittings
  BS 3059 : Boiler and Super-heater Tubes
  BS 3063 : Dimensions of Gaskets for Pipe Flanges
  BS 3381 : Metallic Spiral Wound Gaskets
  BS 3600 : Dimensions of Welded and Seamless Pipes and Tubes
  BS 3601 : C.S. Pipes and Tubes for pressure purposes at room temperature
  BS 3602 : C.S. Pipes and Tubes for pressure purposes at high temperature
  BS 3603 : C.S. and Alloy Steel Pipes and Tubes for pressure purposes at low temperature
  BS 3604 : Alloy Steel Pipes and Tubes for high temperature
  BS 3605 : SS Pipes and Tubes for pressure purposes
  BS 3799 : Socket Weld / Screwed Fittings
  BS 3974 : Pipe hangers, Slides and Roller type supports
  BS 4346 : PVC pressure pipe – joints and fittings
  BS 4504 : Steel, Cast Iron and Copper alloy fittings
  BS 5150 : Cast Iron Wedge and Double Disc Gate Valves for general purposes
  BS 5151 : Cast Iron Gate (parallel slide) Valves for general purposes
  BS 5152 : Cast Iron Globe and Check Valves for general purposes
  BS 5153 : Cast Iron Check Valves for general purposes
  BS 5154 : Copper alloy Globe, Gate and Check Valves
  BS 5155 : Cast Iron and Cast Steel Butterfly Valves for general purposes
  BS 5156 : Diaphragm Valves for general purposes
  BS 5157 : Steel Gate (parallel slide) Valves for general purposes
  BS 5158 : Cast Iron and Cast Steel Plug Valves for general purposes
  BS 5159 : Cast Iron and Cast Steel Ball Valves for general purposes
  BS 5160 : Flanged Steel Globe and Check Valves for general purposes
  BS 5163 : Flanged Cast Iron Wedge Gate Valves for general purposes
  BS 5351 : Steel Ball Valves for Petroleum Industry
  BS 5352 : Steel Gate, Globe and Check Valves, smaller than 2″ NB
  BS 5353 : Specifications for Plug Valves
  BS 5391 : Specifications for ABS pressure pipes
  BS 5392 : Specifications for ABS fittings
  BS 5433 : Specifications for underground stop valves for water services
  BS 5480 : Specifications for GRP pipes and fittings
  BS 6364 : Specifications for Valves for Cryogenic services
  BS 6755 : Testing of Valves
  BS 6759 : Safety Valves

A) Indian Standards :

The Bureau of Indian Standards (BIS) is the National Standards Body of India under Department of Consumer affair. Some of the most commonly referred Indian Standards by Piping Engineers are :

IS 210 : Grey Iron Castings
  IS 226 : Structural Steel (superseded by IS 2062)
  IS 554 : Dimensions of Pipe Threads
  IS 778 : Specification for Copper Alloy Gate, Globe and Check Valves
  IS 780 : Specification for Sluice Valves – 50 NB to 300 NB
  IS 1239 (Part I and II) : Specification for Mild Steel tubes and fittings
  IS 1363 : Hexagonal Bolts, Screws and nuts – Grade C
  IS 1364 : Hexagonal Bolts, Screws and nuts – Grade A and B
  IS 1367 : Technical supply conditions for threaded steel fastners
  IS 1536 : Centrifugally Cast Iron Pipes
  IS 1537 : Vertically Cast Iron Pipes
  IS 1538 : Cast Iron Fittings
  IS 1870 : Comparison of Indian and Overseas Standards
  IS 1879 : Malleable Iron Pipe Fittings
  IS 1978 : Line Pipe
  IS 1979 : High Test Line Pipe
  IS 2002 : Steel Plates
  IS 2016 : Plain Washers
  IS 2041 : Steel Plates for Pressure Vessels used at moderate and low temperature
  IS 2062 : Steel for general structural purposes
  IS 2379 : Color Code for Identification of Pipelines
  IS 2712 : Compressed Asbestos Fiber Jointing
  IS 2825 : Code for Unfired Pressure Vessels
  IS 2906 : Specification for Sluice Valves – 350 NB to 1200 NB
  IS 3076 : Specification for LDPE Pipes
  IS 3114 : Code of Practice for laying pipes
  IS 3516 : Cast Iron flanges and flanged fittings for Petroleum Industry
  IS 3589 : Seamless or ERW Pipes (150 NB to 2000 NB)
  IS 4038 : Specifications for Foot Valves
  IS 4179 : Sizes for pressure vessels and leading dimensions
  IS 4853 : Radiographic Examination of Butt Weld Joints in pipes
  IS 4864 to IS 4870 : Shell Flanges for vessels and equipments
  IS 4984 : Specification for HDPE Pipes
  IS 4985 : Specification for PVC Pipes
  IS 5312 : Specification for Check Valves
  IS 5572 : Classification of Hazardous area for Electrical Installation
  IS 5822 : Code of practice for laying welded steel pipes
  IS 6157 : Inspection and Testing of Valve
  IS 6286 : Seamless and Welded pipes for Subzero temperatures
  IS 6392 : Steel Pipe Flanges
  IS 6630 : Seamless alloy steel pipes for high temperature service
  IS 6913 : Stainless Steel tubes for food and beverage industry
  IS 7181 : Horizontally cast iron pipes
  IS 7240 : Code of Practice for Cold Insulation
  IS 7413 : Code of Practice for Hot Insulation
  IS 7719 : Metallic spiral wound gaskets
  IS 7806 : Stainless Steel Castings
  IS 7899 : Alloy Steel castings for pressure services
  IS 8008 : Specification for molded HDPE Fittings
  IS 8360 : Specification for fabricated HDPE Fittings
  IS 9890 : Ball Valves for general purposes
  IS 10221 : Code of Practice for coating and wrapping of underground MS pipelines
  IS 10592 : Eye wash and safety showers
  IS 10605 : Steel Globe Valves for Petroleum Industries
  IS 10611 : Steel Gate Valves for Petroleum Industries
  IS 10711 : Size of Drawing Sheets
  IS 10805 : Foot Valves
  IS 10989 : Cast / Forged Steel Check Valves for Petroleum Industry
  IS 10990 : Technical drawings – Simplified representation of pipelines
  IS 11790 : Code of Practice for preparation of Butt welding ends for valves, flanges and fittings
  IS 11791 : Diaphragm Valves for general purposes
  IS 11792 : Steel Ball Valves for Petroleum Industry
  IS 12709 : Specifications for GRP pipes
  IS 13049 : Specifications for Diaphragm type float operated valves
  IS 13095 : Butterfly Valves
  IS 13257 : Ring type joint gasket and grooves for flanges

API 660 REQUIREMENTS VS TEMA REQUIREMENTS FOR HEAT EXCHANGERS

2022-02-27T22:39:00.008+05:30

API 660 REQUIREMENTS VS TEMA REQUIREMENTS FOR HEAT EXCHANGERS

For Shell & Tube heat exchangers employed in refineries & petrochemical complexes, the applicability of API 660 (ISO 16812) in addition to TEMA has becoming mandatory by most end users and consultants. API 660 lays down most requirements based on practical considerations & past experience.

Point No. 01

Tubesheet Cladding Thickness

API 660 Requirement :

Minimum 10 mm for expanded tube to tubesheet joints. Minimum 5 mm for welded tube to tubesheet joints.

TEMA Requirement :

For TEMA Class R & B, minimum 7.8 mm for expanded tube to tubesheet joints and 3.2 mm for welded tube to tubesheet joints.

For TEMA Class, minimum 4.8 mm for expanded tube to tubesheet joints and 3.2 mm for welded tube to tubesheet joints.

Point No. 02

Type of Exchangers

API 660 Requirement :

TEMA types “P” (Outside packed floating head) and “W” (Externally sealed floating tubesheet) are not allowed.

TEMA Requirement :

As per TEMA RCB-5.2, Type “P” exchangers are allowed for all classes R, C & B.

Type “W” (Externally sealed floating tubesheet) exchangers shall be used only for water, steam, air, lubricating oil, or similar service. For other limitations refer TEMA.

Point No. 03

Minimum Tube OD

API 660 Requirement :

The minimum outside diameter of the tubes shall be 19.05 mm (3/4”).

TEMA Requirement :

As per TEMA minimum tube outside diameter can be 6.4 mm also.

Point No. 04

Tube Thickness

API 660 Requirement :

Minimum tube thicknesses are defined with reference to tube material of construction.

TEMA Requirement :

No specific guidelines (numbers) are given in TEMA for minimum tube thickness with reference to tube material of construction

Point No. 05

Backing Device Corrosion Allowance

API 660 Requirement :

Shell side corrosion allowance shall be included on the back side of the floating[1]head backing device

TEMA Requirement :

As per TEMA floating head backing devices are not required to have corrosion allowance.

Point No. 06

Tubesheet Extension

API 660 Requirement :

A full-diameter stationary tubesheet shall be provided for removable bundle exchangers with Bonnets (TEMA “B”).

TEMA Requirement :

No specific guideline is given in TEMA for consideration of tubesheet extension.

Point No. 07

Impingement Plate Thickness

API 660 Requirement :

Minimum thickness of the impingement plate shall 6 mm (1/4”).

TEMA Requirement :

No specific guidelines (numbers) are given in TEMA for minimum thickness of impingement plates.

Point No. 08

Impingement Plate

API 660 Requirement :

Perforated impingement plate baffles shall not be used.

TEMA Requirement :

Use of perforated distribution device is allowed as per TEMA recommended good practice.

Point No. 09

Baffle Thickness

API 660 Requirement :

The thickness of carbon steel or low[1]alloy steel (max. 9 % chromium) transverse baffles and support plates shall be not less than twice the specified shell side corrosion allowance.

TEMA Requirement :

Thickness of baffles and support plates for all materials is given with reference to various shell diameters and plate spacing. Also as per TEMA, baffles and support plates does not require corrosion allowance.

Point No. 10

Seal Strips Thickness

API 660 Requirement :

Minimum thickness of seal strips shall be the nominal thickness of the transverse baffles or 6 mm (1/4”), whichever is less.

TEMA Requirement :

No specific guideline is given in TEMA for the thickness of seal strips.

Point No. 11

Washer Requirement for Studs

API 660 Requirement :

Hardened washers shall be provided under nuts for all bolts having diameters of 38 mm (1½”) or larger. The washers shall be at least 6 mm (1/4”) thick.

TEMA Requirement :

No specific guideline is given in TEMA.

Point No. 12

Gasket Construction

API 660 Requirement :

Gasket construction (Welded or Non[1]welded) is defined with respect to size and type of gaskets. Requirements for serrated gasket, jacketed gasket, corrugated gasket, and Spiral wound gasket are specified separately.

TEMA Requirement :

No specific guideline is given in TEMA.

Q. What is Flanges ? Which Types of Flanges used In Fabrication...?

2021-04-27T09:50:00.003+05:30

Q. What is Flanges ? Which Types of Flanges used In Fabrication...?

Flanges : A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed. Flanged joints are made by bolting together two flanges with a gasket between them to provide a seal.

Types :

1) WNRF Flanges (Weld Neck Flanges) :

The Welding Neck Flanges (WNRF) are often used for high-pressure applications. To order a weld neck flange, it is important to specify the pipe is being used for. This is because the inside diameter of the flange will match the inside diameter of your pipe or Fitting. Weld Neck Flanges are ideal for extreme fluctuations of temperature and in environments where there may be a lot of bending and handling of the flanges.Welding Neck Flanges are easy to recognize at the long tapered hub, that goes gradually over to the wall thickness from a pipe or fitting. The long tapered hub provides an important reinforcement for use in several applications involving high pressure, sub-zero and / or elevated temperatures. These flanges are bored to match the inside diameter of the mating pipe or fitting so there will be no restriction of product flow. This prevents turbulence at the joint and reduces erosion. This flange type will be welded to a pipe or fitting with a single full penetration, V weld (Butt weld).

Standards :

ANSI/ASME B16.5, B16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, GOST Flange, ASME/ANSI B16.5/16.36/16.47A/16.47B, MSS S44, ISO70051, JISB2220, BS1560-3.1, API7S-15, API7S-43, API605, EN1092

Dimensional Tolerance As Per B16.5 and B16.47 as,

Outside Diameter ≤ 24 = 1.6 mm \| > 24 = ± 3.2 mm	Inside Diameter not applicable
Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm 6.35 mm Raised Face, Tongue & Groove / Male-Female = ± 0.4 mm	Outside Diameter of Hub ≤ 12 = + 2.4 mm / - 1.6 mm \| ≥ 14 = ± 3.2 mm
Diameter of Counterbore not applicable	Drilling Bolt Circle = 1.6 mm \| Bolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle with Respect to Facing ≤ 2½ = 0.8 mm max. \| ≥ 3 = 1.6 mm max.
Thickness ≤ 18 = + 3.2 mm / - 0 \| ≥ 20 = + 4.8 mm / - 0	Length thru Hub ≤ 18 = + 3.2 mm / - 0.8 mm \| ≥ 20 = + 4.8 mm / - 1.6 mm

Material :

For SS Material : ASTM/ASME A/SA182 F304, F304L, F316, F316L, ASTM/ASME A/SA351 CF8, CF3, CF8M, CF3M

For CS Material : ASTM/ASME A/SA105 A/SA105N & A/SA216-WCB, ASTM A105 / ASME SA105, A105N, ASTM A350 LF2 / ASME SA350, High Yield CS ASTM A694 / A694 (F52 F56 F60 F65 F70 F80)

For Alloy Steel Material : ASTM A182 / ASME SA182 F5, F9, F11, F12, F22, F91

The diagrammatic view of WNRF Flanges as shown below,

Pic.001

2) Slip On Flange :

The calculated strength from a Slip On flange under internal pressure is of the order of two-thirds that of welding neck flanges, and their life under fatigue is about one-third that of the latter. The connection with the pipe is done with 2 fillet welds, as well at the outside as also at the inside of the flange. A disadvantage of the flange is, that principle always firstly a pipe must be welded and then just a fitting. A combination of flange and elbow or flange and tee is not possible, because named fittings have not a straight end, that complete slid in the Slip On flange. Slip on flange are slipped over the pipe and welded to provide strength and prevent leakage. This SORF flange can sometimes have a boss or hub and can be made with a bore to suit either pipe or tube. The Slip on Flanges is at the low-cost end of the scale. SORF flanges are not required high accuracy when cutting the pipe to length.

Standard : ANSI/ASME B16.5, B16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, GOST Flange, ASME/ANSI B16.5/16.36/16.47A/16.47B, MSS S44, ISO70051, JISB2220, BS1560-3.1, API7S-15, API7S-43, API605, EN1092

Material :

For SS Material : ASTM/ASME A/SA182 F304, F304L, F316, F316L, ASTM/ASME A/SA351 CF8, CF3, CF8M, CF3M, DIN 1.4301, DIN 1.4306, DIN 1.4401, DIN 1.4404, DIN 1.4308, DIN 1.4408, DIN 1.4306, DIN 1.4409

For CS Material : ASTM/ASME A/SA105 A/SA105N & A/SA216-WCB, DIN 1.0402, DIN 1.0460, DIN 1.0619, Die Steel, ASTM A105 / ASME SA105, A105N, ASTM A350 LF2 / ASME SA350, High Yield CS ASTM A694 / A694 (F52 F56 F60 F65 F70 F80)

For Alloy Steel Material : ASTM A182 / ASME SA182 F5, F9, F11, F12, F22, F91

The diagrammatic view of WNRF Flanges as shown below,

Pic.002

3) Socket Weld Flange :

Socket Weld flanges were initially developed for use on small, size high pressure piping. Their static strength is equal to Slip On flanges, but their fatigue strength 50% greater than double-welded Slip On flanges. The connection with the pipe is done with 1 fillet weld, at the outside of the flange. But before welding, a space must be created between flange or fitting and pipe. The purpose for the bottoming clearance in a socket weld is usually to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal. The image shows you the X measure for the expansion gap.

The diagrammatic view of WNRF Flanges as shown below,

Pic.003

4) Stud-Bend Flange :

A Stub End always will be used with a Lap Joint flange, as a backing flange. This flange connections are applied, in low-pressure and non critical applications, and is a cheap method of flanging. In a stainless steel pipe system, for example, a carbon steel flange can be applied, because they are not come in contact with the product in the pipe.

The diagrammatic view of WNRF Flanges as shown below,

Pic.004

5) Lap-Joint Flange :

Lap Joint Flanges have all the same common dimensions as any other flange named on this page however it does not have a raised face, they used in conjunction with a "Lap Joint Stub End". These flanges are nearly identical to a Slip On flange with the exception of a radius at the intersection of the flange face and the bore to accommodate the flanged portion of the stub end. Their pressure-holding ability is little, if any, better than that of Slip On flanges and the fatigue life for the assembly is only one tenth that of welding neck flanges. They may be used at all pressures and are available in a full size range. These flanges slip over the pipe, and are not welded or otherwise fastened to it. Bolting pressure is transmitted to the gasket by the pressure of the flange against the back of the pipe lap (Stub End).

The diagrammatic view of WNRF Flanges as shown below,

Pic.005

6) Threaded Flange :

Threaded Flanges are used for special circumstances with their main advantage being that they can be attached to the pipe without welding. Sometimes a seal weld is also used in conjunction with the threaded connection. Although still available in most sizes and pressure ratings, screwed fittings today are used almost exclusively in smaller pipe sizes. A threaded flange or fitting is not suitable for a pipe system with thin wall thickness, because cutting thread on a pipe is not possible. Thus, thicker wall thickness must be chosen...what is thicker ?

The diagrammatic view of WNRF Flanges as shown below,

Pic.006

7) Blind Flange :

Blind Flanges are manufactured without a bore and used to blank off the ends of piping, valves and pressure vessel openings. From the standpoint of internal pressure and bolt loading, blind flanges, particularly in the larger sizes, are the most highly stressed flange types

The diagrammatic view of WNRF Flanges as shown below,

Pic.007

Q. Types of Flange Faces...?

Different types of flange faces are used as the contact surfaces to seat the sealing gasket material. ASME B16.5 and B16.47 define various types of flange facings, including the raised face, the large male and female facings which have identical dimensions to provide a relatively large contact area. Other flange facings covered by these standards include the large and small tongue-and-groove facings, and the ring joint facing specifically for ring joint type metal gaskets.

Types :

1) Raised Face (RF) :

The raised face flange face is the most common type used in process plant applications, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face This face type allows the use of a wide combination of gasket designs, including flat ring sheet types and metallic composites such as spiral wound and double jacketed types.The purpose of a RF flange is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint.

2) Flat Face (FF) :

The flat face flange has a gasket surface in the same plane as the bolting circle face. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting. Flat face flanges are never to be bolted to a raised face flange.

3) Ring Type Joint (RTJ):

This type is typically used in the most severe duties, for example, in high-pressure-gas pipe work. Ring-type metal gaskets must be used on this type of flange facing The ring type joint flanges are typically used in high pressure and/or high temperature services above 800°F (427°C). They have grooves cut into their faces which steel ring gaskets. The flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or Coining) the gasket to make intimate contact inside the grooves, creating a metal to metal seal.

Q. What Is WPS/PQR...?

2021-03-20T19:55:00.007+05:30

Q. What Is WPS/PQR...?

Q. What is Welding Procedure Specification (WPS)?

A Welding Procedure Specification (WPS) is the formal written document describing welding procedures, which provides direction to the welder or welding operators for making sound and quality production welds as per the code requirements . A WPS is a document that describes how welding is to be carried out in production. Its purpose is to aid the planning and quality control of the welding operation. They are recommended for all welding operations and most application codes and standards make them mandatory.

Q. What is Procedure Qualification Record (PQR)?

A PQR is a record of a test weld performed and tested (more rigorously) to ensure that the procedure will produce a good weld. A PQR is required when it is necessary to demonstrate that your company has the ability to produce welds possessing the correct mechanical and metallurgical properties. A welding procedure must be qualified in accordance with the requirements of an appropriate welding procedure standard, such as ASME Sec IX, as follows:

1. Produce a welding procedure specification (WPS) as stated above.

2. Weld a test piece in accordance with the requirements of your specification. The joint set up, welding and visual examination of the completed weld should be witnessed by a certified welding inspector such as an AWS certified CWI or an Inspection Body. The details of the test such as the welding current, pre-heat etc., must be recorded during the test.

3. Once the welding is complete the test piece must be subject to destructive and non destructive examination such as radiography and mechanical tests as defined by the welding procedure standard. This work must be carried out in a qualified laboratory but the Inspection Body may require witnessing the tests and viewing any radiographs.

4. If the test is successful you or the test body completes the appropriate documents which the test body’s surveyor signs and endorses.

Q. What is Welder Performance Qualification Record (WPQR)?

Once the procedure is approved it is necessary to demonstrate that all your welders working to it have the required knowledge and skill to put down a clean sound weld. If the welder has satisfactorily completed the procedure test then he is automatically approved but each additional welder must be approved by completing an approval test to an appropriate standard such as ASME Sec IX as follows:

1. Complete a weld test as stated above. The test should simulate production conditions and the welding position should be the position that the production welds are to be made in or one more severe.

2. For maximum positional approval a pipe inclined at 45 degrees (referred to as the 6G position) approves all positions except vertical down.

3. Test the completed weld in accordance with the relevant standard to ensure that the weld is clean and fully fused.

4. For a butt weld this is normally a visual examination followed by radiography or bend tests.

5. Once the test is completed the necessary forms have to be completed by you or the test body and signed by the test body’s surveyor.

6. Note that any changes that require a new welding procedure (WPS) may also apply to the welders approval, refer to the referencing code/ standard for precise details

Typical Items That Should Be Recorded On W.P.S:-

Procedure number
Process type
Consumable Size, Type and full Codification.
Consumable Baking Requirement if applicable
Parent material grade and spec.
Thickness range.
Plate or Pipe, Diameter range
Welding Position
Joint Fit Up, Preparation, Cleaning, Dimensions etc.
Backing Strip, Back Gouging information.
Pre-Heat (Min Temp and Method)
Inter-pass If Required (Maximum Temperature recorded )
Post Weld Heat Treatment. If Required (Time and Temp)
Welding Technique (weaving, max run width etc.)
Arc Energy Limits should be stated if impact tests are required or if the material being welded is sensitive to heat input.

As per ASME SEC.X the following parameters consisting in WPS as,

QW-402 : JOINT

1) Type of joint (Single "V" Double "V", Single "J" Double "J" Etc.

2) Root Facing, Root Gap Etc.

3) Backing Strip if required.

QW-403 : BASE METAL

1) P-Numbers, Group Numbers Etc.

2) Grade Specification.

3) Base Metal Thickness.(Qualifying Thickness)

QW-404 : FILLER METALS

1) SFA Numbers

2) AWS Numbers.

3) F-Numbers.

4) A-Numbers.

5) Size of Filler Metal.

6) Groove, Fillet Etc.

QW-405 : POSITIONS

1) Position of Groove.

2) Welding Position.

3) Position of Filet.

QW-406: PREHEAT

1) Preheat Temperature.

2) Inter-pass Temperature.

3) Preheat Maintenance.

QW-407: PWHT

1) Temperature Range.

2) Time Range.

QW-408: GAS

1) Only for GTAW Welding.

QW-409: ELECTRIC CHARACTIRISTICS

1) Weld Pass (Either Single or Multiple)

2) Process of Welding.

3) Filler Metal - Classification & Dia.

4) Current - Type of Polarity, Amp Range & Volt Range.

5) Travel Speed Range (mm/min).

6) Heat Input.

7) Additional Technique Etc.

QW-410 : TECHNIQUE

1) String or Wave bead.

2) Method of Back Gauging, electrode facing, single/multiple electrodes, peening, initial or inter-pass cleaning Etc.

PQR/ WPQR Testing

The following tests by Independent Test Laboratory may be required on your PQR and WPQR Coupons:

Weld Visual Examination by a AWS Certified Welding Inspector
Bend Test
Hardness Test
Transverse Tensile Test
All Weld Metal Tensile Test
Charpy Impact Test
Weld Metal Chemical Analysis
Macro-etch Test
Torque Test
Peel Test
Nick Break Test
Radiography Test
Ultrasonic Test

What is P numbers,Group Numbers, F-Numbers and A-Numbers in Welding...?

2021-02-28T21:55:00.012+05:30

What is P numbers, Group Numbers, F-Numbers and A-Numbers in Welding...?

ASME boiler and pressure vessel Code (BPVC) has assigned Certain numbers to base metals in order to minimize the number of procedure and qualification in WPS and PQR.

Base Metal : Base metal is parent metal It is that metal in the welding practice that has been cut by the various forms of cutting and other activities, then prepared and is to be welded. Base metal is categorized as P Number and P number is further divided in group numbers based on base metal characteristics.

The diagrammatical view of base metal as shown in Pic.001

Pic.001

Filler Metals : A filler metal is a metal added in the making of a joint through welding, brazing, or soldering. Filler Metals - Electrodes are as categorized as per F- Number same as per the characteristics of filler metal.

Weld Metal : Weld Metal is the composition designated on PQR to form of A-Number.

The diagrammatical view of P-Number, F-Number,A-Number as shown in Pic.000

Pic.002

The categorization of P-Numbers, Group Numbers, F-Numbers and A-Numbers can be found in ASME Section IX in different tables as shown the below,

For P-Number - See Table QW-422 In ASME SEC IX

For Group Number - See Table QW-422 In ASME SEC IX

For F-Number - See Table QW-432 In ASME SEC IX

For A-Number - See Table QW-442 In ASME SEC IX

P-Number :

To reduce the number of Procedure Qualification Required ASME has assigned P-Numbers to different types of materials. This numbers are assigned as per base metal characteristics , this characteristics consisting Mechanical properties, Weldability, Composition and other different parameters. Same type of P-Numbers allows us to use the one qualified PQR on different grades of material which process same type of P-Number on which PQR is qualified.

Any change P-Number shall be required to requalification of WPS.

We can obtain the P-Numbers for different metals from the Table mentioned in ASME SEC IX QW-422 so the PQR shall be determined as per ASME table. One thing is noted that before using qualified PQR on other grade material on shall consider the other different properties like Heat Treatment, mechanical properties, design considerations etc.

Example : PQR qualified for P-Number 1 (SA 106 GR.B to SA 106 GR.B) the welding procedure shall qualify for P-Number 1 (SA 333 GR.6 or SA 234 GR. WPB or SA 516 GR. 60/70 to any of the same P-Number. Different material have different P-Numbers for ex for SA 106 GR, B P-Number 1 and for SA 312 TP 304 P-Number is 8.

Same materials with P-Numbers shown below,

P-Number Material

1 Carbon Steel

3 Low alloy steel (Up to 1/2% Cr and up to 1/2% Mo)

4 Low alloy steel (1 to 2% Cr and up to 1/2% Mo)

5A Low alloy steel (2 to 3% Cr, 1% Mo Alloy Steel)

5B Intermediate Allot Steel (5 to 10% Cr, 1% Mo)

5C All 5A and 5B Materials heat treated to 85ksi+

6 Martensitic Stainless Steel

7 Ferritic Stainless Steel

8 Austenitic Stainless Steel

9 2 to 5% Ni Alloy Steel

10 Mn-V, Cr-V, 9%Ni, High Cr Alloy Steels

11 Low Alloy Steel, Quenched and Tempered to 95ksi+

21 1.2% Mg or Mn alloy Aluminum

22 1.2% Mn, 2,5% Mg, 0.25% Cu Aluminum

23 1.3% Mg, 0.7% Si, 0.25% Cr Aluminum

25 1.5% Mg, 0.8% Mn, 0.15% Cr Aluminum

31 Copper

32 Admiralty, Naval, Aluminum Brass, Muntz Metal

33 Cu-Si Alloys

34 Cu-Ni Alloys

41 Nickel

51 Titanium

61,62 Zirconium

Group Number : The P-Number are further categorized as Group Number. Group number is applicable when toughness requirements applies to materials. This is sub-grouping of the P-Number materials by the similarity of metallurgical properties except impact requirements.

Shown below the examples of different grades to understand the group subgrouping under P-Numbers from the Table from ASME SEC IX Table QW-422 as

Grade P-Number Group Number

For SA 516 Gr. 60 1 1

For SA 516 Gr. 70 1 2

F-Number : The grouping of electrodes and welding rods is mentioned in ASME SEC IX Table QW-432 is based essentially on their usability characteristics, which fundamentally determine the ability of welders to make satisfactory welds with a given filler metal. This grouping is made to reduce the number of welding procedure and performance qualifications, where this can logically be done.

F-Numbers of filler metals can be found in ASME Section IX’s Number Table QW-432 an extract is shown as following:

Electrodes/Welding rods F-Number

Steel and steel Alloys F-Number 1 To F-Number 6

Aluminum and Aluminum Base Alloys F-Number 21 to 23 7 F-Number 25,26

Copper and Copper Base Alloys F-Number 31 to F-Number 37

Nickel and Nickel Base Alloys F-Number41 to F-Number46

Titanium and Titanium Base Alloys F-Number 51 to F-Number 56

Zirconium and Zirconium base Alloys F-Number 61

Hard Facing Weld Metal Weld Overlay F-Number 71 to F-Number 72

A-Number : For Identification of Chemical Composition of weld metal the another type of grouping consisting in welding on PQR and WPS is done as per A-Number. The A-Number can be found in ASME SEC. IX Table QW-442.Please note the A number in WPS does not refer to the filler wire or electrode chemical composition; it refers to the deposited weld metal chemical composition.

RADIOGRAPHY EXAMINATION - IDENTIFICATION OF DISCONTINUITIES IN WELD

2021-02-25T22:18:00.006+05:30

IDENTIFICATION OF DISCONTINUITIES IN WELD

Discontinuities is basically interruption in the structure of material. This discontinuities may occur in base metal, on weld of material or on HAZ (Heat Affected Zone). The number of discontinuities that is acceptable for given material is depend on type of discontinuities and different parameters so it is important to identify the given discontinuity and either acceptable or not as per given applicable codes. So the different types of general discontinuities as shown below,

1) Lack of Fusion : The Lack of Fusion is the type of discontinuity which may appears on between rungs of weld on at the edges of weld. Basically Lack of Fusion is where the weld filler metal does not properly fuse with the base metal or previous weld pass material. The arc does not melt the base metal sufficiently and causes the slightly molten puddle to flow into base material without bonding.

Lack of fusion is most serious weld discontinuity occur on weld joint. If lack-of-fusion defects and cracks are compared, it is evident that much more attention is paid to cracks than to lack of fusion although lack of fusion is as serious a defect as a crack. On the basis of position the lack of fusion classified as,

1) lack of side-wall fusion,

2) lack of inter-run fusion,

3) lack of fusion at the root of the weld.

The Diagrammatic view and the view on RT Film of Lack of Fusion as shown below,

Pic.001

2) Cracks : Crack is tight linear separations of metal that can be very short to very long indications. Cracks are grouped as hot or cold cracks. Hot cracks usually occur as the metal solidifies at elevated temperatures. Cold cracks occur after the metal has cooled to ambient temperatures. Cracks can be detected in a radiograph only when they are propagating in a direction that produces a change in thickness that is parallel to the x-ray beam. Cracks will appear as jagged and often very faint irregular lines. Cracks can sometimes appear as "tails" on inclusions or porosity.

Different types of cracks occurs in weld as,

1) Longitudinal Cracks.

2) Transverse Cracks.

3) Centre Cracks.

4) Throat Cracks.

5) Root Cracks.

6) Under bead Cracks.

7) Root Cracks.

8) Hot Cracks.

9) Toe Cracks.

10) Cold Cracks.

11) Crater Cracks.

The Diagrammatic view and the view on RT Film of Cracks as shown below,

Pic.002

3) Porosity : Porosity is the result of gas entrapment in the solidifying metal. Porosity is actually black round or irregular spot in clusters or in rows. All porosity is a void in the material it will have a radiographic density more than the surrounding area. Porosity is caused by the absorption of nitrogen, oxygen and hydrogen in the molten weld pool which is then released on solidification to become trapped in the weld metal.

The Diagrammatic view and the view on RT Film of Porosity as shown below,

Pic.003

4) Cluster porosity: Cluster porosity is caused when flux coated electrodes are contaminated with moisture. The moisture turns into gases when heated and becomes trapped in the weld during the welding process.

The Diagrammatic view and the view on RT Film of Cluster Porosity as shown below,

Pic.004

5) Root Concavity: Root or Internal concavity or suck back is condition where the weld metal has contracted as it cools and has been drawn up into the root of the weld. Root concavity is caused by shrinkage of the weld pool in the through-thickness direction of the weld. Melting of the root pass by the second pass can also produce root concavity. On a radiograph it looks similar to lack of penetration but the line has irregular edges and it is often quite wide in the center of the weld image.

The Diagrammatic view and the view on RT Film of Root Concavity as shown below,

Pic.005

6) Incomplete penetration (IP): Incomplete penetration (IP) or lack of penetration (LOP) occurs when the weld metal fails to penetrate the joint. It is one of the most objectionable weld discontinuities. Lack of penetration allows a natural stress riser from which a crack may propagate. The appearance on a radiograph is a dark area with well-defined, straight edges that follows the land or root face down the center of the weldment. Incomplete root fusion is when the weld fails to fuse one side of the joint in the root. Incomplete root penetration occurs when both sides root region of the joint are unfused due to,

A) Excessive Root Face in Butt Weld

B) Misplaced Weld

C) Too small Root Gap

D) Too small Bevel Angle

E) Use of Too large diameter Electrode.

The Diagrammatic view and the view on RT Film of Incomplete Penetration as shown below,

Pic.006

7)Slag inclusions: Slag inclusions are non metallic particles trapped in the weld metal or at the weld surface. Slag inclusions result from faulty welding technique, improper access to the joint or both. Tungsten inclusions are tungsten particles trapped in weld metal deposited with the gas tungsten arc welding process. In a radiograph, dark, jagged asymmetrical shapes within the weld or along the weld joint areas are indicative of slag inclusions.

The Diagrammatic view and the view on RT Film of Slag Inclusion as shown below,

Pic.007

8) Undercut: Internal or root undercut is an erosion of the base metal next to the root of the weld. In the radiographic image it appears as a dark irregular line offset from the centerline of the weldment. Undercutting is not as straight edged as LOP because it does not follow a ground edge.

The Diagrammatic view and the view on RT Film of Undercut as shown below,

Pic.008

9) Mismatch or Offset : Offset or mismatch are terms associated with a condition where two pieces being welded together are not properly aligned. The radiographic image is a noticeable difference in density between the two pieces. The difference in density is caused by the difference in material thickness. The dark, straight line is caused by failure of the weld metal to fuse with the land area.

The Diagrammatic view and the view on RT Film of Mismatch or Offset as shown below,

Pic.009

10) Inadequate weld reinforcement: Inadequate weld reinforcement is an area of a weld where the thickness of weld metal deposited is less than the thickness of the base material. It is very easy to determine by radiograph if the weld has inadequate reinforcement, because the image density in the area of suspected inadequacy will be more (darker) than the image density of the surrounding base material.

The Diagrammatic view and the view on RT Film of Inadequate Weld Reinforcement as shown below,

Pic.010

11) Excess weld reinforcement : Excess weld reinforcement is an area of a weld that has weld metal added in excess of that specified by engineering drawings and codes. The appearance on a radiograph is a localized, lighter area in the weld. A visual inspection will easily determine if the weld reinforcement is in excess of that specified by the engineering requirements.

The Diagrammatic view and the view on RT Film of Excess Weld Reinforcement as shown below,

Pic.011

12) Tungsten Inclusions : Tungsten inclusions are tungsten particles trapped in weld metal deposited with the gas tungsten arc welding process. Dipping the tungsten electrode in the molten weld metal or using too high current that melts the tungsten can cause inclusions. Tungsten is a brittle and inherently dense material used in the electrode in tungsten inert gas ( TIG ) welding. If improper welding procedures are used, tungsten may be entrapped in the weld. Radiographically, tungsten is denser than aluminum or steel; therefore, it shows as a lighter area with a distinct outline on the radiograph.

The Diagrammatic view and the view on RT Film of Tungsten Inclusions as shown below,

Pic.012

UNIT CONVERSIONS

2021-02-04T18:50:00.001+05:30

UNIT CONVERSIONS

Sr. No. To Change To Multiply By

01 Inches Millimeters 25.4

02 Inches Centimeters 2.54

03 Inches Meters 0.0254

04 Feet Meters 0.3048

05 Miles Kilometers 1.609347

06 Square Inches Square Centimeters 6.452

07 Square Feet Square Meters 0.0929

08 Cubic Inches Cubic Centimeters 16.3872

09 Pounds Kilograms 0.45359

10 BTU Calories 252

11 Millimeters Inches 0.03937

12 Centimeters Inches 0.39371

13 Meters Inches 39.371

14 Meters Feet 3.281

15 Kilometers Miles 0.62137

16 Square Centimeters Square Inches 0.1550

17 Square Meters Square Feet 10.7649

18 Cubic Centimeters Cubic Inches 0.061

19 Cubic Meters Cubic Feet 35.314

20 Kilograms Pounds 2.20462

21 Grams Ounces Avoir 0.03527

22 Calories BTU 0.003968

23 Cubic Feet Cubic Inches 1728

24 Cubic Inches Cubic Feet 0.00058

25 Cubic Feet Gallons 7.480

26 Square Feet Square Inches 144

27 Square Inches Square Feet 0.00695

28 Long Tons Pounds 2240

29 Short Tons Pounds 2000

30 Long Tons Short Tons 1.12

31 Pounds per Square Inch Pascals 6.895 x 10³

32 Pounds per Square Inch Kilograms per Square CM 7.03 x 10-2

33 Pascals Pounds per Square Inch 1.45 x 10-4

34 Kilograms per Square CM Pounds per Square Inch 1.422 x 101

35 Centigrade Kelvin 1.0 + 273

36 Centigrade Fahrenheit 1.8 + 17.78

37 Fahrenheit Centigrade -32 x 0.555

38 Fahrenheit Kelvin -32 x 0.555 + 273.15

TYPES OF FITTINGS

2021-01-03T19:23:00.003+05:30

TYPES OF FITTINGS

Fittings is the pipping component used to change the direction of flow and other dimensions basically fitting used in pipping and plumbing industries. generally large variety of fittings used in different industries as per requirement and type of work.some types of fitting shown below,

1) ELBOW :

Elbow is one type of industrial fittings which change the direction of piping. Elbow is key part of piping system that change the direction of flow in piping. Elbow is used to connect two pipes with different diameters and we can change the direction of flow in piping system the standard elbows comes in few different angles as 45 Degree,90 Degree, 180 Degree commonly also 60 Degree and 120 Degree for some special cases. Different types of with sizes as per requirement with different types of grades are available in market.

Basically, Standard the Elbows classified as,

i) 45 Degree Elbows

ii) 90 Degree Elbows

45 Degree Elbow: This elbow is functioned to change the fluid direction by 45 Degree

90 Degree Elbow: This Elbow is functioned to change the fluid direction by 90 degree and most common used elbows.

90 Degree Elbows & 180 Degree Elbow again classified as,

i) Long Radius Elbows

ii) Short Radius Elbows

i) Long Radius Elbows:

The curvature radius means elbow radius if in some cases the radius is larger than pipe diameter that is R ≥ 1.5 Diameter then such elbows called Long Radius Elbows.

ii) Short Radius Elbows:

The curvature radius is same as pipe diameter then such elbows called Short Radius Elbows.

On the basis of connections, the elbow are classified as Butt Weld Elbows, Socket Welded Elbow and Threaded Elbows.

(Note: The advantages of butt weld elbows over socket weld elbows and Threaded elbows is Butt welded elbows used with higher pressure and temperature.

Materials:

Carbon Steel Elbows: ASTM A234 GR. WPB and WPC, ASTM 420 WPL6.

Stainless Steel Elbows: ASTM A403 WP304/304L, 316/316L,ASTM A270.

Dimensional Tolerances:

For the dimensions like nominal pipe size, outside diameter, weight, schedule etc for standard Elbows refer Standard ASME B16.5

REDUCER:

Reducer is a one type of fitting used in pipelines in order to reduce its size from large to small boar. Reducer used as Nozzle or diffuser depend on type of application.

ECCENTRIC REDUCER:

Eccentric reducer is comical shaped but not symmetrical about the centre line or axis. The Eccentric Reducer is one type of fittings used in piping system between two pipes of different diameters. In Eccentric Reducer reduction in pipe size achieve by decreasing the diameter of the fittings. Eccentric Reducer used as diffuser or nozzle.

CONCENTRIC REDUCER:

Concentric Reducer is in symmetrical and conical shaped in which the reduced the diameter equally about the centre line or axis .

Note : Concentric Reducer removes noice pollution over Eccentric Reducer.)

Materials :

Carbon steel : ASTM A 234 GR. WPB, A420 WPL6

Stainless Steel : ASTM A403 WP 304/304L, A403 316/316L 317/317L, 321, 310, 904L etc.

Alloy : ASTM A234 WP1, WP5, WP9, WP11, WP22, WP9 etc.

Dimensional standard :

ASME B16.9 , DIN 2615, JIS B2312 and ASME B16.11.

EQUAL TEE :

Equal Tee is one type of fitting in which three opening in “T” formed . equal tee consisting in various sizes, two openings of same size. An equal tee has dragged to attach the fitting to a divider or stud. Equal tee is one of strong type of fittings which available in various sizes

The dimensions of equal tee as shown below,

Pic.01

The standard size of Equal Tee specify in ASME B16.9 specification Factory-Made Wrought Steel Buttwelding Fittings as mentioned nominal pipe size, outside diameter, Centre to end and length of equal tees.

Materials :

Carbon steel: ASTM/ASME A234 WPB-WPC

Alloy steel: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP 911

Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N

ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti

ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H

Low temperature steel: ASTM/ASME A402 WPL 3-WPL 06

High performance steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70

Applications of pipe tee:

Pipe Tees are widely used in various commercial and industrial applications. Industrial applications include:

1) Pulp/paper

2) Refining

3) Textile

4) Waste treatment, Marine

5) Petroleum

6) Utilities/power generation

7) Automotive

8) Gas compression and distribution industries

9) Industrial equipment

10) Chemical processing

THREADOLET:

Threadolet is the one of self-reinforced branch fittings which is used whenever threaded branch connection required from the pipe header.

Threadolet available in different sizes as either full size or reducing size.

While dimensional inspection of threadolet the following dimensions checked as,

a) Outer and inner diameter of the body.

b) Length of the Hub.

c) Thread Dimensions.

Basically threadolet is design for specific conditions based on process pipping ASME CODE B13.3. Different class of threadolet available in market as per requirement

Material :

Stainless Steel: ASTM a182 F 304, 304L, 304H, 309S, 309H, 310S, 310H, 316, 316TI, 316H, 316L, 316LN, 317, 317L, 321, 321H, 347, 347H, 904L

Duplex Steel: duplex 2205 2507 s31803 s32750 s32760 s31254 254smo smo254 904l uns no8904 astm a182 f51 f53 f44 f55 f60 f62 s31050 s32205 s32550

Carbon Steel: ASTM A105, A694 F42/46/52/56/60/65/70,A350 LF1 LF2 LF3

Alloy Steel: ASTM A182 F5/F9/F11/F22/F91

Longitudinal Submerged Arc Welding (LSAW)

2020-11-20T08:45:00.003+05:30

Longitudinal Submerged Arc Welding (LSAW)

Longitudinal Submerged Arc Welding is the type of welding basically used for pipe which manufactured with weld. This is a specific welding technique used in pipe production. Production from longitudinal submerged arc welding is required high high wall thickness due to high internal and external pressure. The longitudinal Submerged Arc Welding is popular welding process used for longitudinal seam welding of large diameter pipes . This process also called as LSAW.

The longitudinal Submerged Arc Welding find their application in Oil lines, gas lines, water supply etc.

Steel pipes is long and hollow tubes used basically to transfer product from one location to other. The transportation of product from one location to another by with help of pipes which pipes mainly consisting two types, one is seamless pipes and othe welded pipes. During manufacturing of both of the pipes steel cast into more workable from hot billet or slab . By stretching the hot billet into a seamless pipes . For transporting large quantities of hydrocarbons over long distances, longitudinal submerged arc welded (LSAW) pipes have been used for decades.

When we required high wall thickness due to high internal or external pressure the most economical process is The longitudinal Submerged Arc Welding (LSAW).

The ERW (Electric Resistance Welding) differ from LSAW (The longitudinal Submerged Arc Welding) is that the LSAW type used for large diameter size of pipe as compared to ERW process. The LSAW type process used for pipe having diameter 16 inch. To 60 inch, low temperature resistance. Also Double Submerged Arc Welded (DSAW) steel pipe is available in straight and spiral welded formats and used in a variety of applications

The material used for LSAW type process is heavy or middle thickness sheet which coiled in forming machine and welded by The longitudinal Submerged Arc Welding.

In the longitudinal Submerged Arc Welding. Hot rolled coils used to formed the steel pipes by bending and welding process.

The typical example of production of longitudinal welded large diameter pipes as shown below,

Firstly Longitudinal edges of steel plates beveled using carbide milling equipment , after that beveled plates formed into U-Shaped press subsequence into o Shape using O-Shaped press the whole process shown below,

Pic.01

The inspection purpose in LSAW Welding is to check Chemical analysis, Flattening Test Bending Test X-Ray testing, Yield Strength, Ultimate Tensile Test, Hydrostatic Test etc.

The photograph of pipes manufactured by LSAW (longitudinal Submerged Arc Welding) as shown below,

Pic.02

Specification : ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.

Advantages : contamination of impurities in the air is protected by this type of process.

welds would penetrate 100% of the pipe wall and formed very string bond this is main advantage of LSAW process.

ALIGNMENT CHECKING

2020-11-02T20:25:00.003+05:30

ALIGNMENT CHECKING

Basically, arrangement in s straight line is called as alignment

1 1) Axis Alignment.

2 2) Surface Alignment.

1) AXIS ALIGNMENT:

The axis alignment used for pressure vessel, column, storage tank for proper straightness of whole job. Axis Alignment is checked with axis of job. The axis alignment checked on respective four orientation of vessel by rotating the shells of vessel. In axis alignment measure the perpendicular distance between plumb line and horizontal line (See Pic.001) and record.

Diagrammatical view of checking of Axis Alignment as shown below,

Pic.001

The reading record as per table shown below,

Pic.002

The axis alignment of vessel check by following method,

1) Firstly, plot the points on Graph paper with suitable scale

2) Draw the best fit line to pass through all points on graph.

3) The maximum distance measured from the line is the maximum Out of Alignment.

4) Find out maximum out of alignment in both the planes and note as (A) 0-180 Degree. Readings 90-270 degree. Readings

Pic.003

5) Repeat the process for the same 90-270-degree orientation by rotating the shell of vessel

2) SURFACE ALIGNMENT:

The typical example of measurement of vessel dimensions for surface alignment as shown below,

Pic.004

The method of checking surface alignment as shown below,

1) Firstly, level the shell at main degrees orientation (0,90,180 & 270 Degrees) vertically or horizontally.

2) Drop the pair of plumbs near each Circular seam and on both ends.

3) Put twins horizontally on both sides of shell.

4) Maintain equal distance at both ends of sections between horizontal twins and plumb.

5) Then measure the perpendicular distance between other plumbs and horizontal twins and records the reading in table (See Pic.005) as shown below,

6) Rotate the job 90 degree and repeat the same process for the other orientations and record the readings.

Surface Alignment = Maximum Reading – Minimum Reading.

Pic.005

Surface alignment for different shell Thickness:

The dimension settings at ends and decided taking in to consideration of shell thickness (See Pic.006) and for remaining repeat the same procedure.

Pic.006

Important Note : The shell or ovality of the shell shall be controlled within the limit in order to get better alignment of Job.

AWS SPECIFICATIONS FOR ELECTRODES & CONVERSION TABLE OF UNITS FOR PROPERTIES USED IN WELDING.

2020-10-25T21:09:00.004+05:30

AWS SPECIFICATIONS FOR ELECTRODES.

A) For Mild Steel Electrodes.

AWS SPECIFICATION

1) E-6012

2) E-6013

3) E-6013

4) E-6013

5) E-7014

B) For Heat and Creep Resistance Steel Electrodes.

AWS SPECIFICATION

1) E-7018 A1

2) E-8018 B2

3) E-8018 B2L

4) E-9018 B3

5) E-9018 B3L

C) For Low Hydrogen and Low Alloy Steel Electrodes.

AWS SPECIFICATION

1) E-7016

2) E-7018

3) E-7018

4) E-7018-1

5) E-7018G

6) E-7018CIL

7) E-8018G

8) E-9018G

9) E-9018M

10) E-10018M

11) E-11018M

D) For Heat Resistance Steel and Stainless Steel.

AWS SPECIFICATION

1) E-308-16

2) E-308L-16

3) E-308H-16

4) E-347-16

5) E-316-16

6) E-316L-16

7) E-309-16

8) E-309Mo-16

9) E-310-16

10) E-2209-16

E) For Cast Iron.

AWS SPECIFICATION

1) E-NiCi

2) E-NiCuB

3) E-NiFeCi

CONVERSION TABLE OF UNITS FOR PROPERTIES USED IN WELDING.

PROPERTY MULTIPLE BY

1) Area

Inch² to mm² 6.451 x 10²

Mm² to Inch² 1.550 033x10^-3

2) Current Density

A/Inch² to A/Inch² 003x10^-3

A/mm² to A/Inch² 6.451 600x10²

3) Deposition Rate

lb/h to Kg/h Approx. 0.45

Kg/h to lb/h Approx. 2.2

4) Flow Rate

ft³/h to Litre per Minute 4.719 475x10^-1

Gallon per HR to Litre per Minute 6.309 020x10^-2

Gallon per min to Litre per Minute 3.785 412

cm³/min to Litre per Minute 1.000 000x10^-3

Litre per Minute to ft³/h 2.118 880

cm³/min to ft³/h 2.118 880x10^-3

5) Heat Input

J/inch to J/m 3.937 008x10

J/m to J/inch 2.540 000x10^-2

Inch to mm 2.540 000x10^-2

Ft. to mm 3.048 000x10^-2

mm to Inch 3.937 008x10^-2

mm to ft. 3.280 840x10^-3

6) Tensile Strength

psi to Pa 6.894 757x10^-3

lb/ft² to Pa 4.788 026x10

N/mm² to Pa 1.000 000x10⁶

Pa to psi 1.450 377x10^-4

Pa to lt/ft² 2.088 543x10^-2

Pa to N/mm 1.000 000x10^-6

7) Travel speed of Wire(mm/s)

In./mm to mm/s² 4.233 333x10^-1

mm/s to Inch./min 2.362 205

J to ft.lb.f 0.737

J to Kgfm 0.102

INSPECTION AND WELDING OF CIRCULAR SEAM (CIR-SEAM)

2020-10-14T22:07:00.002+05:30

INSPECTION AND WELDING OF CIRCULAR SEAM (CIR-SEAM)

As we discussed earlier Long Seam Set-Up and Inspection the circular seam is also similar lightly in inspection point of view. Circular Seam is called Cir-Seam. We can check the Cir-Seam of individual shell or number of shells combined in fabrication of pressure vessel or in column.

The following parameters checked during inspection of individual Cir-Seam as,

1) Identification mark on plate of respective Cir-Seam.

2) Profile Verification with template.

3) NDT of Long Seams Carried out or not.

4) Weld Edge Preparation.

5) DPT (Dye Penetration Testing)/ MPT (Magnetic Particle Testing carried out or not as per client requirement.

6) Orientation marking as per engineering drawings or not.

7) Off-set within tolerance limit or not.

8) Ovality checking.

9) PTC (Production Test Coupon) Results only if applicable.

PIC.01: Checking of Off-set During inspection of Cir-Seam.

During inspection of Cir-Seam following parameters considered,

A) Align the two pairs of rotators and one of them is drive unit.

B) Match the orientation of all offered shells with engineering drawing by rotating the shell sections.

C) Checking of overall length of offered Shell sections as Cir-Seams.

D) Keep proper full off-set in between each Cir-seams.

E) Lock the equipment at main Degrees (Orientation so that checking for orientation as per engineering drawing is easy)

F) Checking of alignment of offered seams at main four orientations.

G) Checking of visual inside outside of equipment, remove all internal cleats.

H) Verification of Weld Edge Preparation (WEP), Root Face and Root Gap as per drawing engineering drawing or not.

I) Check PTC requirement

Following table shown maximum Off-Set in Butt Weld for Cir-Seam.

PIC.02

Following table shown Reinforcement limit in Butt Weld for Cir-Seam.

PIC.03

INSPECTION & WELDING OF LONG SEAM

2020-09-27T14:03:00.009+05:30

INSPECTION & WELDING OF LONG SEAM

In fabrication area the fabrication of storage tank, pressure vessels etc. the plates is rolled and make a joint as per required inside diameter of vessel or storage tank called long seam.

The Typical Photograph of Long-Seam for information shown below,

PIC.01

The parameters which considered while inspection of Long Seam is listed below,

1) First step of inspection of long seam is check whether the long seam which plate is identified or not with inspectors stamp and other job details like part no material grade etc.

2) Punching the seam number along the seam at every 1000mm apart and highlighted also the seam no on each seam.

3) Cleanness of Weld Edge Preparation (WEP) and cleaning of nearest area of long seam & performing DPT (Dye Penetration Testing) on WEP as shown below,

PIC.02

4) All Tack Welds free from cracks.

5) The Joint Details of Joint like Weld Edge Preparation (WEP), Groove Angle Root Gap, Root Face is required to check as per engineering Drawings or not.

6) Weld edge required to check visually properly, free from arc strikes, spatters, gas cutting marks, dent marks etc.

7) Profile Checking at Joint of Shell i.e.. At Long Seam Is perfectly Matching with template profile or not, shown below,

PIC.03

8) Check offset within a limit or not. Shown below the typical Maximum Offset Limits below,

PIC.04

9) Running IN and OUT coupons attached or not with matching Wels Edge Preparation. Shown below photograph,

PIC.05

10) PTC as an extension to the seam if applicable (PTC : Production Test Coupon).Shown below the PTC attached with long-seam.

PIC.06

11) Profile Checking and Ovality checking which is within limit or not.

12) Circumference at both ends of Long Seams is checked recorded the value and checked with limit or not as per specification. Typical Diagrammatical view of Long seam with measuring parameter shown below,

PIC.07

WELDING OF LONG SEAM

1) Firstly, the seam is inspected from inspection department.

2) Make preheat arrangement if Preheat required and preheat the Long-seam edge at at temperature mentioned in Specification (WPS/PQR).

3) Welding done as per welding Test Plan (WTP). WTP consisting the welding paraments like type of welding, type consumables/filler wires, Preheat, Inter-pass Temperature, Post Weld temperature etc. Shown below Typical V Groove long seam set-up.

PIC.08

4) Performing Back-chip DPT (Dye Penetration Test).

5) Maintain Weld Reinforcement Within Limit (Tolerances as per specification) Typical Tolerances of reinforcement for But Weld as per ASME SEC.8 DIV.1 UW-35 For Long-Seam shown below,

PIC.09

6) Weld Seam free from visible Surface Defects

7) Re-Rolled the Shell if Shape is out.

8) Clear all NDT as mentioned in specification or in Weld And Test Plan (WTP).

9) If applicable PTC proceed for Mechanical Testing and other tastings as per requirements pensioned in Respective code or in specification.

CASTING DISCONTINEUTIES IN RADIOGRAPHY.

2020-09-20T12:01:00.002+05:30

CASTING DISCONTINEUTIES IN RADIOGRAPHY.

Casting is a manufacturing process in which liquid material is pored into mold the mold contain hollow cavity of a desire shape and then allow to solidify, the solidify part is called as Casting.

In radiography the casting product have different types of discontinuities found as shown below,

1) Micro-Porosity Defect :

The micro-porosity is the defect found in Casting due to evolution of gas very fine gas pores form around grain boundaries . The micro-porosity occurs in those places of the casting products which solidify last. Miro-Porosity is not always immediately visible to the human eye. The least micro-porosities occur in Die-Casting Products and their causes originate in a shrinkage porosity.

Micro-Porosity mainly effects Non-Ferrous metals such as Magnesium & Aluminum.

Pic.01 : Micro-Porosity.

For Prevention

i) Avoidance of sharp-cross-sections and joints.

ii) Keep binder contents in mold materials.

iii) Adjust optimum castings temperatures.

iv) Reduce gas contents in the melt.

v) Reduce solidification interval.

2) GAS HOLE DEFECT:

We know that Rounded cavities generally greater than 1 mm Diameter, quite large and after more randomly dispred through the casting due to gas involve from the metal during solidification. Appears as dark areas with a smooth outline which is either circular or in elonged shape.

Generally Gas Hole porosity occurs when the metal traps gas (Nitrogen, Oxygen or Hydrogen) during casting. When casting solidify there is formation of bubbles This bubbles appears on casting as rounded, circular or hole type.

Pic.02 : Gas Hole

3) PIN-HOLE POROSITY:

Small rounded in shape cavities in casting generally less than 1 mm Diameter cause by same evolution of gases during solidification of molten metal of casting products is called Pin-Hole Porosity. Pin-Hole Porosity sometimes occurs below the surface of casting products and such type of discontinuities called Sub-Cutaneous pinhole porosity. Which type of porosity appears on radiograph in dark rounded images.

Basically, Pinholes are very tiny holes found in upper part of mold. This type of porosity appears in large numbers together.

Pic.03 : Pin-Hole Porosity.

4) WORMHOLES:

Wormholes is Tube like cavities similar to the gas hole discontinuities generally located just below the surface of casting products. The Wormhole discontinuity is caused by progressive expansion of entrapped superheated steam from moisture in a mold.

In order to prevent The Wormhole , eliminating the gas and cavities to prevent wormholes in casting. Avoid joint geometry which creates the cavity.

5) SHRINKAGE CAVITY :

Shrinkage Cavity is the defect or depression in casting which formed during solidification process. As compared to the Rounded Gas Porosity the Shrinkage Cavity appears with angular edges.

In other words, the Shrinkage Cavity is caused by centration of metal during solidification.

6) AIRLOCK DEFECT :

Airlock is basically a large cavity formed by air is entrapped in the mold during pouring of the metal. Airlock is appears as a generally smooth and often irregular shaped.

7) FILAMENTARY STRINKAGE :

The continuous cracks of various dimensions and different densities observed usually under thick part of the material is called filamentary shrinkage . The filamentary shrinkage is difficult to detect. As compared to Filamentary Cracks the filamentary Shrinkage is less dense. Appears as a network of branched irregular shapes.

8) HOT TEAR :

Hot Tears is also called as Hot Cracking. The Hot Tear defect occurs when casting cools. It is one type ofd fracture which cause in metal during contraction as it cools during the early edges after solidification. Hot Tear is appears as dark lines. It is plane type discontinuity.

Pic.08 : Hot Tear.

9) COLD SHUT :

Cold Shut is a discontinuity formed when a stream of liquid metal flows through a mold fails to fused with other metal in the mold. A smooth dark line appears as cold shut on radiograph. Cold Shut is planner type discontinuity . It is detect by visually even visible by naked eye.

Pic.09 : Cold Shut

10) INCLUSION :

Sand from mold can be washed into the stream of metal as enters as flows through a mold and become trapped in the metal as it solidifies. It may appear as a light or dark irregular shaped image in a radiograph and may difficult to distinguish from a void. Such type of discontinuity is generally not acceptable.

Inclusions is usually impurities in a pour metal. Inclusions are mostly a problem in aluminum casting but their are issues in zinc and magnesium also.

Pic.10 Inclusion :

11) STRESS CRACK :

A sharper more well define fracture of a meterial during the later stages of cooling from solidification is called Stress Crack. May appears like dark line . They also can formed when casting is cold or during heat treatment. Stress Crack is most common source of failure at molds made of maragging steels.

Pic.11 : Stress Crack

12) SEGREGATION :

This continuity comprises particular component of a metal composition that have different solidification temperatures and tend formed by solidification of metal and segregation at particular areas particularly at central zones of casting products. May appear as a dark or light area on radiograph. Generally when casting an alloy Segregation occurs.

Pic.12 : Segregation.

HYDROSTATIC TESTING

2020-09-05T21:52:00.005+05:30

HYDROSTATIC TESTING

Hydro-static testing is also called as hydro-test is the test in which piping components, gas cylinders, storage tank, vessels etc is tested for the leaks and strength of that component. The Hydro-static test is done after the all activities like radiography of welding joints, required NDT, welding of all pressure parts etc in order to the given object operate under desired condition. This process in which the water filled in the component and pressurised as per requirements of client which depend on service and other factors.

The Typical Diagram for pressure vessel during hydrostatic test shown below,

Pic.01 : Diagrammatic view of Pressure Vessel during Hydrostatic Testing.

The hydro-static test is performed by firstly filling the components such as tank, pipes etc with water after filling removing the air inside the component and after that pumping or pressurized by pump up to pressure of that component mentioned on engineering drawing . After pressurized at component hold at specific pressure for specific amount of time which depend on clients criteria or approved hydrostatic procedure from client after holding period the all weld joints and whole component is inspected with help of lamp for tracing of liquid to determine the crack and any kind of leaks.

Hydrostatic test is plays very important role in inspection. The pressure at which hydrostatic test to be performed is as per design calculation of that particular object but normally 4 times of design pressure.

One thing is noted that the Hydrostatic testing is the non destructive testing method which used for testing leaks and performance of that component.

Every testing consisting certain type of procedure and the testing is done as per the procedure. The pressure at which the hydrostatic test to be performed is given in the engineering drawing the pressure is measure by pressure gauge and the gauge should be in service & calibrated condition up to date. The range of pressure gauge is mentioned in appropriate procedure, as per ASME section viii code the required ranging is 1.2 to 4 times for example if the components hydro pressure 32 kg/cm²then the minimum range of pressure gauge as per code 1.2 that means 1.2 x 32 is 38.4 kg/cm² and maximum range that is 4 x 32 is 128 kg/cm² that means the pressure gauge to be used is in between the range from 38.4 to 128 kg/cm².

Different types of hydrostatic tests perform as per components and as per requirement as Direct Expansion Method, Proof Pressure Method, Water Jacket Method etc. But basic procedure is same. For example if we performing the hydrostatic test of pressure vessels then the following points must be consider in inspector point of view as,

1) Proper blanking of all Nozzles.

2) All Original blind flanges used Properly or not.

3) Completion of welding on pressure parts.

4) Vessel is kept on hydrotest saddles in the specified orientation as per engineering drawings issued by design department.

5) Clearance of all pending NCR’S (Non Conformity Report) if any.

6) All Long Seams / Cir-seams are more visible for inspection.

7) Gaskets and gasket seats checked for any damages.

8) Inside surface properly clean or not.

9) Testing of PTC/MTC If any to the acceptable test results.

10) Check outside diameter circumference (ODCF) before pressurized, during pressurized and after release of pressure ODCF values is to be reported.

11) All weld joints to be visually checked with lamp or apply DPT testing on Weld joints.

12) Ensure that for original blinds the original fasteners provided or not with required material grade and tightened to required torque or not.

13) All dimensions check within acceptable limit.

14) The water used is portable or other. (As per procedure)

15) Measure the Metal temperature of vessel before Hydrostatic test.

16) Exact Ranging of pressure gauge is used or not.

) 17) Pressure gauges calibrated during the service and calibration certificate of calibration agency.

18) Arrangement for pressuring shall be through one of the nozzle for bottom.

19) Hydro Pump for pumping of water is available or not.

20) Inlet valve shall remain closed till water filling.

21) And most important parameter that is all activities like str Heat treatments stress relieving (S.R.) if applicable is done or not, required NDT performed or not in other word all required activities as per approved QAP.

After the hydrostatic test the Hydrostatic test Report is prepared as per procedure the positioning of component, acceptance criteria, test temperature, pressure application, type of inspection, rejection and documentation all mentioned in approved procedure.

Acceptance Criteria.

For Section VIII Division 1 type Pressure Vessels Reduce the test pressure above design pressure and inspect all joints for leackage (As Per UG-99).

Design Pressure x 1.3 x Ratio of stress value of material at test temperature to Design Temperature.

For Section VIII Division 1 type Pressure Vessels Reduce the test pressure above design pressure or 3/4^th Test pressure whichever is more and inspect all joints for leakage (As Per AT-355 & at-300 ).

Design Pressure x 1.25 x Ratio of stress value of material at test temperature to Design Temperature.

Rejection :

If any leakage is observed from weld or parent metal or any joint, drain the water repair the leak and reoffer for the hydrostatic testing.

If any leakage observed through Gasket connection, depressurized the vessel and tighten the Stud/Nuts.

Arrangement of Inlet pressure gauge & arrangement of Outlet pressure gauge as shown below,

Pic.02 : Arrangement of Inlet Pressure Gauge.

Pic.0 : Arrangement of Inlet Pressure Gauge.

Safety points :

1) Drain the water from vessel only when top outlet is kept open.

2) Never pressurised vessel above required or mensioned pressure in given engineering drawings.

3) Use minimum 2 pressure gauges for hydrotest.

4) Never use High discharge pumps for hydrotest.

TYPES OF THERMPCOUPLE'S

2020-09-04T20:15:00.002+05:30

TYPES OF THERMPCOUPLE'S

Thermocouple is the one type of sensor which used to measure the temperature. Thermocouple is one type of thermoelectric device. Thermocouple is made up of two different dissimilar metals joined together to form a junction.

The basic principle of thermocouple is to develops an EMF which is a function of the difference in temperature of its measuring junctions. One junction is placed on surface or in air that is being measured and this junction is called hot junction in other hand the other junction is called cold junction and at cold junction the temperature is remains constant. These two points also known as measuring junction and reference junction. If the temperature of measuring junction is known then we can determine temperature at measuring junction by measuring the EMF generated in the circuit.

For reference point of view the diagrammatic view of thermocouple shown below,

Pic.01

Material Requirements of Thermocouple,

I) High coefficient of thermal EMF.

II) Resistance to oxidation, resistance & corrosion.

III) Continuously increasing relation of EMF to temperature over a long range.

Types of Thermocouples,

Basically two types of thermocouples as,

1) Base Metal Thermocouples.

2) Nobel Metal Thermocouples.

In Base Metal Thermocouples there are five types as

1) J Type

2) K Type

3) T Type

4) E Type

5) N Type

In Nobel Metal Thermocouples there are three types as,

1) B Type

2) R Type

3) S Type

1) J Types Thermocouple :

This type of thermocouples is commonly used thermocouples. The temperature measuring range of J Type thermocouple is in between 0 to 750 Degree C. Out of two legs for positive leg Iron material is used while for negative leg constantan material is used. Accuracy of such type of thermocouple is +/- 2.2 Degree C.

# Sensitivity: 50 µV/Degree C

J Type thermocouple is find there application in vacuum and most commonly used for general purpose of applications.

2) K Type Thermocouple :

This type of thermocouple is most commonly used thermocouple. The J Type thermocouple is more accurate with wide range the range in between -200 Degree C to +1250 Degree C. Accuracy of such type of thermocouple is +/- 2.2 Degree C.

# Sensitivity: 41 µV/Degree C

Wire is made up of Comel and Alumel material and composition as,

Comel : 90% Nickel + 10% Chromium

Alumel : 95% Nickel + 2%

Manganese + 2% Aluminium + 1% Silicon.

On positive leg cromel material used and on negative leg alumel material is used.

K Types Thermocouple is find their applications where tempreture range 500 Degree C, in nuclear applications

3) E Type Thermocouple:

Type E thermocouples is generating Highest EMF per degree as compared to other type of thermocouples. Type E Thermocouple gives stronger accuracy as compared to K & J type thermocouples. Temperature range in between -50 Degree C to +740 Degree C. Accuracy is about +/- 1.7 Degree C.

#Sensitivity: 68 µV/Degree C

In E type Thermocouples at +ve leg Chromel material used while at -ve leg Constantan material is used. The E Type thermocouple find their applications in aerospace Industries.

4)T type Thermocouple :

For requirement of low temperature the T Type thermocouple is used because T type thermocouple stable at extremely low temperature. Temperature range in between -250 Degree C to +350 Degree C. In such type of thermocouple at +ve leg copper material is used while at -ve leg constantan material is used. The composition of material constantan is about 55% Copper & 45% Nickel. Accuracy for the T type thermocouple is +/- 1.0 Degree C.

#Sensitivity: 43 µV/Degree C

T Type thermocouple is find there application in Bllod Banks and Laboratories.

5) N Type thermocouple:

Type N thermocouple is slightly expensive as compared to K Typethermocouple. N Type thermocouple gives same accuracy and tempreture range as in K Type thermocouple type thermocouple is made up of Nicrosil and Nisil material. Temperature range as in between -270 Degree C to 1300 Degree C. Accuracy is about +/- 2.2 Degree C .

#Sensitivity: 39 µV/Degree C

6) B Type Thermocouple:

This type of thermocouples extremely used for high temperature applications. They give good accuracy at very high temperature. Temperature range in between 0 to 1800 Degree C. B Type thermocouple made of of 1 leg 70% Platinum and 30% rhodium while second leg 94% platinum and 6% Rhodium. Such type of thermocouple gives accuracy about +/- 0.5%.The main advantage of B type of thermocouple is high accuracy as compared to other thermocouples.

7) S Type Thermocouple:

The S type of thermocouple is used at very high temperature applications. Temperature range of 0 to 1600 Degree C. The first leg made up of 90% Platinum and 10% Rhodium while second leg platinum only. Accuracy is about +/- 1.5 Degree C.

8) R Type Thermocouple :

Such type of thermocouples expensive because consisting high % of rhodium. Temperature range in between 0 to 1482 Degree C. The first leg made up of 87% of platinum an 13% of rhodium while second leg made up of platinum only. Accuracy is about +/- 1.5 Degree C.

TYPES OF HEAT TREATMENTS - Overview

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TYPES OF HEAT TREATMENTS

1) NORMALIZING.

2) ANNEALING.

3) STRESS RELIEVING.

4) SOLUTION ANNEALING.

5) AGEING.

6) TEMPERING.

7) HARDENING.

1) NORMALIZING. :

Normalizing is the process in which heating a material at elevated temperature and then allow it to cool back to the room temperature by exposing it to room temperature air after it heated. In normalizing the steel is heated to 40 Degree C above upper critical temperature followed by cooling in the still air in order to achieve,

i) Uniform structure of material

ii) To refine grain structure.

iii) Change in UTS (Ultimate Tensile Strength)

iv) Change in YS (Yield Strength)

v) Impact Properties

vi) Relieving internal stresses

vii) Hardness

The stages involve in Normalizing shown with diagram as shown below

Pic.01

The main aim of normalizing is to increase the toughness of steels. It is the type of heat treatment which applicable to ferrous material only.

Advantages over annealing process:

i) It is faster than annealing process

ii) Normalizing is less expensive than annealing process.

Disadvantages:

i) As increases the cooling rate results in high hardness.

ii) Cooling rate in normalizing is different at different depths so the formed structure is depending on thickness of material.

2) ANNEALING. :

Annealing is one of the heat treatments which change the mechanical and physical properties of material in order to increase the ductility and reduce the hardness. In annealing steel is heated at 10 to 50 degree C above the upper critical temperature and held for the desired length of time followed by very slow cooling in furnace in order to achieve softness of material and better ductility.

Advantages:

i) It increases toughness of material.

ii) It increases the ductility of the material.

iii) It reduces the brittleness of the material.

iv) Helps to increase machinability of the material.

3) STRESS RELIEVING. :

The steel is heated at temperature below or close to the lower critical temperature with specific rate of heating call stress relieving process. In this heat treatment metal is held at temperature for specific length of time and then cooling with specific rate of temperature. One thing is noted that in stress relieving there is no change grain structure of the material. Stress Relieving done in order to soften the material partially, reduce internal stresses also soften HAZ (Heat Affected Zone).

The temperature range in stress relieving is in order to 593 degree C , 600 degree C -640 degree C, 650 degree C – 690 degree C

The time is 1 Hr/ inch Thick.

Heating Rate: Normally 300 C per Hr Per Inch.

Cooling Rate: Normally 300 C per Hr Per Inch.

4) SOLUTION ANNEALING.:

In Solution annealing heat treatment, the austenitic stainless steel is heated above 1050 degree C and held for the desire time followed by cooling to the room temperature within few minutes by quenching process or blowing the air.

Basically solution annealing is done on non-ferrous alloys and stainless steel in order to soften the material , to improve corrosion resistance & in order to remove carbide precipitation formed at grain boundaries during the process of manufacturing.

5) AGEING. :

Aging is the simple heat treatment in which the material heated at a certain temperature and held for desire time followed by the process of quenching or cooling in air. The aging heat treatment done on material susceptible for ageing characteristics like maraging steels. The ageing heat treatment is increasing the strength of the material, also improve toughness of the material.

6) TEMPERING. :

Tempering is the process which improve the characteristics of steel by heating at high temperature below the melting point of material and then cooling it normally in air Tempering process reduces the internal stresses in the material. Tempering process used to increase toughness of iron-base alloys.

7) HARDENING. :

Hardening is the process is used to increase hardness of metal. The hardening process in which heating the material above critical temperature holding at this temperature for one hour per inch of thickness and cooling fast in order to material much harder and string structure.

WELD IMPERFECTIONS AND CODES IN RADIOGRAPHY.

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WELD IMPERFECTIONS AND CODES IN RADIOGRAPHY

Weld Discontinuities are designated by standard abbreviations.In radiography the weld imperfection either surface or internal type,

A) Surface Imperfections

B) Internal Imperfections.

Standard abbreviations for weld discontinuities as listed below,

Imperfections Code

1) Spatter. SSP

2) Excessive Penetration. SXP

3) Incompletely Filled Groove. SGI

4) Undercut. SUG

5) Grinding Mark. SMG

6) Hammer Mark. SMH

7) Surface Pitting. SPT

8) Linear Misalignment. HiLo

9) Root Concavity. SRC

10) Shrinkage Groove. SGS

11) Torn Surface. STS

12) Tool Mark. SMT

13) Excessive Dressing. SED

Abbreviations for internal Imperfection as listed below,

1) Longitudinal Crack KL

2) Lack of Root Fusion LR

3) Crater Crack KC

4) Incomplete Root Penetration LP

5) Linear Inclusion IL

6) Tungsten Inclusions IT

7) Gas Pore GP

8) Crater Pipe CP

9) Linear Porosity PL

10) Diffraction Mottling DM

11) Uniform Porosity PU

12) Lack of Side Fusion LS

13) Lack of Inner-Run Fusion LI

14) Inclusion IN

15) Oxide inclusion IC

16) Transverse Crack KT

17) Copper Inclusion IC

18) Burn Through BT

19) Elongated Cavity EC

20) Localized Porosity PG

All Radio-graphs should be interpreted to determine their compliance with a code or standard.

Activities to checked during inspection of Forging, Valves & Pressure Vessels.

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Activities to checked during inspection of Forging, Valves & Pressure Vessels.

Inspection consisting large number of activities some activities require to witnessed by Third Party Inspection Agencies and some activities internally checked by manufacturer. In the field of inspection large variety of components with different material and with different dimensions of component checked so it is too matters that what kind of inspection done as per code and client requirements so inspector should know what to check, how much check, acceptance criteria, record and documentation.

Any component is inspected with help of acceptance standard of specific standards code and specification of clients such as ASTM,API,DIN,IS etc.

Generally during Inspection of Forging components involve following activities as,

Verify the forging processes.
Identification of Raw Material.
Verify forging shop records
Verify Heat Treatments cycles and records with respective applicable code.
Identification of Test Specimen whatever is required.
Dimensional Inspection
Visual inspection of components
Witness of NDT as Ultrasonic Test (UT), Dye Penetration Test (DPT) Etc.
Witness of repairs and after repairs Witness of NDT if required.

During Inspection of valves involve following activities as,

Verification of Test Certificates Raw Material.
Verification of construction feature match with respective Code standards of specification or not.
Verification of WTP/WPS records.
Witness of hydrotesting if required.
Any additional or special tightness test.
Dimensional Inspection.
Any additional testing whatever as per requirements of code of specification.

during Inspection of Pressure Vessels involve following activities as,

Review if Material test Reports.
Material Identification and stamp transfer of Raw Material as per code and specification requirements.
Procedure for the activities during process NDT procedure like UT/MT/RT/DPT or Heat Treatment procedure etc.
Welder Qualification and checking of WPS and PQR.
In-process inspection, fit-up inspection, inspection of weld and application of NDT examination.
Review or witness of Heat Treatment Charts.
Visual Dimension and inspection.
Hydrostatic testing and stamping.
Painting and surface preparation of the component.
Dispatch of component.

THINGS REQUIRED TO CHECK DURING INSPECTION OF TEST CERTIFICATES OF THE MATERIAL

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THINGS REQUIRED TO CHECK DURING INSPECTION OF TEST CERTIFICATES OF THE MATERIAL

As we know inspection is main activity in fabrication and any other field so during inspection large numbers of factors which is considered lets we discuss the parameters to be checked during inspection of different grades of Plates, Pipes and Flanges.

Checking of mill test certificates:

Mill Test certificates or MTC’s (Material Test Certificates) is also known as Mill Test Report (MIR) is the certificate of that particular product like plates, pipes etc provided by manufacturer who certify the mechanical and chemical properties and other additional technical specifications of the respective items. Basically Material Test Certificates is the quality assurance document. All items like Forging, Plates, Pipes MTC’s is provided by the manufacturer with the product. So, we discuss about the things that required to check in MTC or Mill Test Certificate during inspection.

When The vendor required the material of plates, pipes, forge etc, The vendor provide TDC (Technical Data Sheet) to manufacturer. The TDC is the document on the basis of that document the material is order this data sheet consisting all necessary data required as per client or the code requirement of the specification so manufacturer provided the material on the basis of TDC.

Material Test Certificate provides all necessary data about the product for example, If we purchase plates from manufacturer, the manufacturer provides MTC’s of that respective product and which is required to review by inspection agency before processing for further process so following parameters are present in MTC’s as,

Manufacturer’s Name: First, the Manufacturer name is shown on MTC’S at Top with address of the plant. Manufacturer is one which making the material, some well-known manufacturer’s named as ESSAR STEEL, SAIL, METINVST, MAHARASHTRA SEAMLES, R.D. FORGE etc.

Test Certificate Number : Test Certificate Number is one unique number for particular test certificate for transability of the certificate’s.

Process Route: The Process Route of the material is the process through which material is making which consisting different stages, For example.

VD (Vacuum Degassing)

CCM (Continuous Casting Method)

RHF (Rotary Hearth Furnace)

Plate Rolling

Furnace Normalizing. Etc

NDT requirements: UT (Ultrasonic Testing) as per code requirements is required or not is checking while review if Test Certificate’s.

P.O. Number: The P.O. Number is Purchase Order Number an unique assigned number against that P.O. Number material is supplied. The Purchase Order Number will be referenced throughout the transaction process by both vendor and manufacturer.

Customer Name: On material Test Certificate the customer no is mentioned.

Product Specification: Different grades of material required for fabrication for example For Plates: SA 516 Gr.60/70, SA 537 CL.1,IS 2062 E250

For Pipes: SA 333 Gr. 3/6, SA 106 GR. B Etc.

Certification : Test Certificate also mentioned certification consisting as 2.1,2.2,3.1,3.2,3.1A/B/C Each have specific meaning.

So, the specification is mentioned on Material Test Certificate as per the product specification of the material.

Heat No./Plate No./Batch No.: Every product like plates, pipes flanges the each product have heat no and plate no same to be mentioned on actual material .One heat number have no of plates.

For Example: H-C98128 H-C98128

P-RG782125/1 P-RG782125/1

Size,Qty and Weight of Product: Size with quantity and the weight is mentioned on Material Test Certificate’s so its required to check the given material with size which is mentioned in Test Certificate.

For Example For Plates, Size(mm) Weight (Mt.) Qty.

T X W X L 7.238 5

30 X 2500 X 12000

Mechanical Properties: This factor is most important while review of Material Test Certificates Mechanical Properties contain

1) Yield Strength. (YS)

2) Ultimate Tensile Strength. (UTS)

3) % of Elongation. (%EL)

4) Impact Testing (If required)

Other any additional testing’s as per specification mentioned on respective material and grades in Material Test Certificate’s.

Chemical Analysis: Chemical Analysis obtained from a sample during the poring of material. Chemical Analysis is mentioned in percentages (% of element) . Two types of analysis as LA (Ladle Analysis) or Heat Analysis and PA (Product Analysis) consisting % of elements as C (Carbon), Mn (Manganese), S(Sulphur), P (Phosphorus), Si (Silicon), Cr(Chromium), Ni(Nickel), Cu(Copper), Ti(Titanium),V (Vanadium), Nb(Niobium), Mo(Molybdenum), Al(Aluminum), etc and Carbon Equivalent so the all % of elements as per respective code grade of specification acceptable or not is checked while review of Test Certificate.

The Carbon Equivalent (CE) is generally calculated by formula,

CE = C+Mn/6+(Cr+Mo+V)/5+9Ni+Cu)/15

Typical example of Sample of Test Certificate for reference shown below,

Pic.01

Other required additional testing's and requirements as per code specification mentioned on test certificates as shown below for reference,

Pic.02

For example, for If if want to review the Material Test Certificate of SA 516 Gr.60 then we go to ASME SEC. II part B as see the SA516 and all mechanical testing’s and Chemical Compositions either in limit or not required to check as Review of Test Certificate before processing the product in process.

Other data and testing’s like Grain Structure, Surface conditions, Hardness testing, killed or semi-killed or other client tolerances is mentioned as per requirements of the material.

The monogram (Symbol) of manufacturer, Plate Number, Heat Number, Size, Specification, UT Code is hard punched on the material and same to be mentioned in Material Test Certificate’s so during inspection or identification of the material its Quality Inspectors Duty to check all the given material’s Test Certificate’s Heat No Plate No, and other data is matched or not.

INSPECTIONS OF NOZZLES OF PRESSURE VESSELS.

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INSPECTIONS OF NOZZLES OF PRESSURE VESSELS

The inspection during setup (In process Inspection) and inspection during final dimensions is two different activities. In process Inspection is the inspection before welding in which checking of given setup is to be correctly set-up as per given engineering drawing or not and final inspection is the inspection after welding so this are two different activities. The pressure vessels or column is closed container and design in order to hold different gasses, liquids so the inspection is main parameter in design and fabrication point of view in pressure vessels.

Basically, inspection is main activity in pressure vessels, because in inspection consisting large number of activities includes different attachments like (Pipe Cleats, Platform Cleats, Lugs, Nozzles, Openings Welding of parts, Insulation Rings etc.) So the dimension is the main part of inspection of pressure vessel or column.

The Picture of nozzle welded on vessel shown below for reference,

Pic.01

We learn about how to check nozzles during in-process and final dimensions. So first thing is that during inspection of nozzles following main parameters to be checked as,

1) Projections

2) Nozzles data

3) Orientation

4) Elevations

1) Projections of Nozzles:

Projections is checked simply with help of measuring tape from nozzle flange face to the center-line of the vessel or column and the required projections are given in engineering drawings. For example, if we want to check the projections of the nozzles (For example N-1A) see below figure,

Pic.02

In above figure we see the projections given as 1650mm from flange face to V.C.L. (Vessels Center Line) Generally required projections given in appropriate engineering drawings

In above figure the S.R. Neck(Self Reinforced Nozzle) Welded with WNRF Flange (Weld Neck Raised Face) and the projections are given so we can check the projection of given nozzle named as N-1A by measuring tape from flange face of nozzle to center-line of the vessel or column.

i) Tolerance for Projections of Nozzles :

The acceptance for measuring projections of nozzles is not addressed in ASME SECTION VIII DIV. 1 but as per Pressure Vessel handbook it is to be considered as ±6mm so as per above figure or dimensions from engineering drawings the required projections is 1650mm so if the actual measurement is vary between ±6mm then only the given nozzle projections is acceptable otherwise required to rectify and reoffer for the inspection.

2) Nozzles Data :

During inspection or Final dimensions of the nozzle it is quality inspector’s duty to check either correct nozzle is attached/welded to the vessel or not, the things to check is that, nozzle Material Identification Mark, ProperSize, Schedule or Thickness, Rating and Type of nozzle (WNRF/S.R. NECK/LWNRF) and all parameters are mentioned in form of table in engineering drawing for reference see below figure for the data of nozzles,

Pic.03

Above table is typical view of nozzle data in engineering drawing so its inspector’s duty to check all data like correct rating of nozzle is to be setup/welded or not and other parameters as shown in table. One thing is noted that the nozzle is already inspected by inspection department as material identification so during inspection of nozzles its Quality Control department's duty to check the correct type of nozzle is to be setup/welded or not.

In above table Mark column contein 1A, Qty as 1, 16mm Thk.,size 400NB (NB:Nominal Bore) 150# Rating and type of nozzle as S.R.+WN.

3) Orientation of Nozzles :

Basically orientation of nozzles it means the degrees on which nozzle to be attached/welded on vessel or column. The Orientation of nozzles is measure simply by measuring tape. The typical measurement of outside diameter of vessel as shown below,

Pic.04

So the orientation of nozzle checked simply by measuring tape from centre-line of nozzle to the nearest main degree of vessel or column.The orientation of nozzles given in engineering drawing.

For reference Typical view of Orientation of nozzles given in Engineering Drawing like this as shown below figure,

Pic.05

In above figure Nozzles N-1A is at 20 degree so for checking the orientation of N-1A we measure distance between nearest main degree of vessel as 0 degree to degree of nozzle that is 20 degree. so difference between this is 20-0 = 0 degree.

Firstly We calculate the ODCF (Outside Diameter Circumference) of the Vessel for example if The vessel of ID 2000mm and Thickness 24mm or OD (Outside Diameter) 2024mm.

firstly

If Inside Diameter given adding the 2 times of thickness to ID to get O.D.

So, (ID + 2 X Thk. of Shell)

(2000 + 2 x 24) = 2000+48 = 2048mm

If Outside Diameter is given Or O.D. = 2048mm

Now we multiply OD to π because we calculate circumference,

so ODCF = 2048 x 3.142 = 6434.81mm

So ODCF divide by 360 to get measurement of 1 degree as,

6434.81 / 360 = 17.87mm Degree so the measurement of 1 degree is 17.87mm

The distance Between main degree of vessel as from 0 degree to Nozzle 1A ie 20 Degrees

20 x 17.87 = 357.40mm.

i) Tolerance for Orientation of Nozzles:

The acceptance for measuring the Orientation of nozzles is not addressed in ASME SECTION VIII DIV. 1 but as per Pressure Vessel handbook it is to be considered as ±1 Degree so if measured readings within tolerance limit then only acceptable otherwise required to rectify.

4) Elevation of Nozzles :

The elevation of nozzles means at certain placement on which nozzle is attached in other-words the measurement between nozzles to other attachment or center line or nozzle center-line to T.L. (Tangent Line). The elevations of all nozzles specified in appropriate engineering drawings. The typical sample for elevation of nozzle N-1A shown below figure,

Pic.06

In above figure the elevation given is 1080mm From T.L. (Tangent Line) So during inspection for checking elevation we required to check distance from center-line of nozzle to T.L.(Tangent Line) by measuring Tape.The elevations given in appropriate engineering drawings.

i) Tolerance for Orientation of Nozzles:

The acceptance for measuring Elevation of nozzles is not addressed in ASME SECTION VIII DIV. 1 but as per Pressure Vessel handbook it is to be considered as ±6mm so if measured readings and found within tolerance then only acceptable otherwise required to rectify.

So the Tolerance sheet provided by client as per requirements or code requirements but if not then by practice we take tolerance as per vessel handbook.

TENSILE TESTING - OVERVIEW

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TENSILE TESTING

As per name the tensile word consisting different types of loading as ,

1) Tensile Loading.

2) Compressive Loading.

3) Shear Loading.

4) Torque Loading.

5) Bending Moment Loading

Tensile test is also known as tension test. The tensile test is one of the most common mechanical testing is used to measure tensile strength and ductility of the material. In tensile test the material is pulled and measure the stress. Tensile testing is related to mechanical behavior of the material and in this testing checking the response of the specimen during loading.

By tensile testing we can measure the yield strength, modulus of elasticity, reduction in areas, elongation till fracture and ultimate tensile strength of the specimen. The measurement of tensile testing of the material is very important for find out maximum force absorbed by the material before change its molecular structure. With help of tensile testing we can plotted the data on graph on stress-strain curve which gives results of how the material reacted to forces being applied.

The Tensile Testing Specimen as shown below,

PIC.01

Types of Tensile Tastings:

1) Adhesion/Bond strength Testing.

2) Crimp joint pull-off Joint Testing.

3) Peel Testing.

4) Tear Resistance Testing.

Acceptance criteria for tensile testing is as per ASME SECTION IX The test specimens should be break less than minimum specified tensile strength in weld or weld interface. However, if it breaks in the area out of weld or weld interface will be acceptable 5% below the minimum specified tensile strength.

Advantages:

1 1) Tensile testing is the destructive testing in which the sample is made in standard size

2 2) The tensile test is done at constant strain rate and constant temperature

3 3) Quick way to determine the problem in the material

4 4) We get poisons ration which is helpful for FEA (finite element analysis)

Disadvantages:

1 1) Tensile testing does not provide the information of materials at different temperatures.

2 2) At different strain rates the straight of the material can’t find by tensile method.

3 3) Restricted to ductile materials.

4 4) Tensile Testing is destructive testing so material gets wasted every time after testing.

ASME BOILER AND PRESSURE VESSELS CODES

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ASME BOILER AND PRESSURE VESSELS CODES

SECTION I : Rules For Construction of power boilers.

SECTION II : Materials.

Part A : Ferrous Material Specification.

Part B: Non-Ferrous Material Specification.

Part C : Specification For Welding, Rods, Electrodes and Filler Metals.

SECTION III : Rules For Construction of Nuclear Facility Components.

Subsection NCA. General Requirements

For Divisions 1 and Division 1

Subsection NB : Class 1 components

Subsection NC : Class 2 Components

Subsection ND : Class 2 components

Subsection NE : Class MC components

Subsection NF : Supports

Subsection NG : Core Supports Structures.

Subsection NH : Class 1 Components in elevated tempreture service appendices.

Division 2 Code For Concrete Containment's

Division 3 Containment System For Storage and Transport Packaging of spent nuclear fuel and high level radioactive material and waste.

SECTION IV : Rules For Construction of Heating Boilers.

SECTION V : Non-Destructive Examination

SECTION VI : Recommended Rules For Care and Operation of Heating Boilers.

SECTION VII : Recommended Guidelines for the Care of Power Boilers.

SECTION VIII : Rules for Construction of pressure vessels.

Division 1 : Pressure Vessels.

Division 2 : Alternative Rules for Pressure Vessels.

Division 3 : Alternative Rules for Construction of Pressure Vessels.

SECTION IX : Welding and Brazing Qualifications.

SECTION X : Fiber-Reinforced Plastic Pressure Vessels.

SECTION XI : Rules for Inservice Inspection of nuclear powerplant Components.

SECTION XII : Rules for Construction and Continued Service of Transport Tank.

SECTION XIII : Boiler and Pressure Vessels.

Outside Diameter ≤ 24 = 1.6 mm \| > 24 = ± 3.2 mm	Inside Diameter not applicable
Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm 6.35 mm Raised Face, Tongue & Groove / Male-Female = ± 0.4 mm	Outside Diameter of Hub ≤ 12 = + 2.4 mm / - 1.6 mm \| ≥ 14 = ± 3.2 mm
Diameter of Counterbore not applicable	Drilling Bolt Circle = 1.6 mm \| Bolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle with Respect to Facing ≤ 2½ = 0.8 mm max. \| ≥ 3 = 1.6 mm max.
Thickness ≤ 18 = + 3.2 mm / - 0 \| ≥ 20 = + 4.8 mm / - 0	Length thru Hub ≤ 18 = + 3.2 mm / - 0.8 mm \| ≥ 20 = + 4.8 mm / - 1.6 mm