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TitleSABP-A-022
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Total Pages40
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Page 1

Previous Issue: New Next Planned Update: TBD Page 1 of 40

Primary contacts: Lobley, Graham R. on 966-3-8746678; Niemeyer, Dennis C. on 966-3-8736700


Copyright©Saudi Aramco 2008. All rights reserved.



Best Practice
SABP-A-022 25 August 2008

Stainless Steel Fabrication, Testing and Installation

Document Responsibility: Materials & Corrosion Control Standards Committee












Saudi Aramco DeskTop Standards

Table of Contents

1 Scope and Purpose............................................ 2
2 Conflicts and Deviations..................................... 2
3 References......................................................... 2
4 Definitions and Abbreviations............................. 5
5 Introduction to Stainless Steels.......................... 6
6 Classes of Stainless Steel.................................. 6
7 Composition, Corrosion Resistance
and Sensitization..................................... 9
8 Materials Selection........................................... 11
9 Castings .......................................................... 12
10 Fabrication....................................................... 13
10.1 Welding and Corrosion Resistance....... 13
10.2 Welding of Stainless Steels................... 14
10.3 Storage.................................................. 32
10.4 Shop Fabrication................................... 32
10.5 Pickling, Passivation & Iron Removal.... 33
10.6 Field Fabrication.................................... 34
11 Hydrostatic Testing.......................................... 36
12 Microbiologically Influenced Corrosion (MIC)... 37
13 Coating Stainless Steel.................................... 38
14 Summary.......................................................... 39

Page 2

Document Responsibility: Materials and Corrosion Control Standards Committee SABP-A-022

Issue Date: 25 August 2008

Next Planned Update: TBD Stainless Steel Fabrication, Testing and Installation





Page 2 of 40



1 Scope and Purpose

Stainless steels are more expensive than carbon and low alloy steels and are normally

selected for their superior corrosion or heat resistance. For the austenitic stainless

steels, good low temperature toughness is also a key mechanical property. However,

improper fabrication and testing procedures can seriously degrade corrosion resistance

and directly lead to premature failures.

This SABP provides guidelines to optimize performance of stainless steels, particularly

austenitic, duplex and martensitic grades. It identifies specific procedures and

specifications to be followed, during manufacturing, fabrication and commissioning, in

order to achieve optimum performance of stainless steel equipment and piping.

This SABP is based on current industry experiences and is intended for internal Saudi

Aramco operations and maintenance applications. It also provides guidance for

inspection in fabrication facilities.

2 Conflicts and Deviations

If there is a conflict between this Best Practice and a Saudi Aramco standard then the

Standard shall govern. If there is a conflict between this Best Practice and an approved

welding procedure then the approved welding procedure shall govern. If there is a

conflict between this Best Practice and other standards and specifications, please

contact the Coordinator of ME&CCD/CSD.

3 References

3.1 Saudi Aramco References

Saudi Aramco Engineering Standards

SAES-A-007 Hydrostatic Testing Fluids and Lay-Up

Procedures

SAES-G-005 Centrifugal Pumps

SAES-H-001 Coating Selection & Application Requirements for

Industrial Plants and Equipment

SAES-L-132 Material Selection for Piping Systems

SAES-W-010 Welding Requirements for Pressure Vessels

SAES-W-011 Welding Requirements for On-Plot Piping

SAES-W-014 Weld Overlays and welding of Clad Materials

SAES-W-016 Welding of Special Corrosion Resistant Materials

http://standards/docs/Saes/PDF/SAES-A-007.PDF
http://standards/docs/Saes/PDF/SAES-G-005.PDF
http://standards/docs/Saes/PDF/SAES-H-001.PDF
http://standards/docs/Saes/PDF/SAES-L-132.PDF
http://standards/docs/Saes/PDF/SAES-W-010.PDF
http://standards/docs/Saes/PDF/SAES-W-011.PDF
http://standards/docs/Saes/PDF/SAES-W-014.PDF
http://standards/docs/Saes/PDF/SAES-W-016.PDF

Page 20

Document Responsibility: Materials and Corrosion Control Standards Committee SABP-A-022

Issue Date: 25 August 2008

Next Planned Update: TBD Stainless Steel Fabrication, Testing and Installation





Page 20 of 40

can buildup pressure on the inside of the pipe and cause the root to be

defective or unweldable.



Purge Times for Stainless Steel Pipe


Diameter
Purging time

Minute

2 and less 0.5

4 1

6 2

8 3

10 4

12 6

16 10

18 12

24 22



Minimum purging time based on pipe size and 6 volume changes of
gas

The above table assumes use of argon gas at a flow rate of 50 CFH

(22.5 L/H). Listed times are for each 300 mm of pipe length to be

purged (multiply by actual length). Use the above values for 300 mm for

any shorter length.

Preheat, Interpass Temperature, Heat Input and Post Weld Heat
Treatment (PWHT)

The following section provides general information on the preheat,

interpass temperature, heat input and PWHT for stainless steel materials.

The governing code, Saudi Aramco Standards and approved welding

procedure must be followed.

Austenitic, Super-Austenitic, Duplex and Precipitation Hardening
Stainless

Austenitic, super-austenitic, duplex and precipitation hardening stainless

steels are susceptible to sensitization and secondary phase embrittlement

when exposed to temperatures in the range of 450°C to 850°C. For this

reason preheat is not used for these materials. They can be heated to

remove moisture prior to welding if required.

To limit sensitization and embrittlement, the maximum interpass

temperature is restricted for these materials. For types 304L and 316L

Page 40

http://standards/docs/Saes/PDF/SAES-A-007.PDF

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