AWS G2.3M/G2.3:2012

An American National Standard

Guide for the Joining of Solid Solution Austenitic Stainless Steels

AWS G2.3M/G2.3:2012

An American National Standard

Approved by the American National Standards Institute

October 16, 2012

Guide for the Joining of Solid Solution Austenitic

Stainless Steels

2nd Edition

Supersedes AWS G2.3M/G2.3:2009

Prepared by the American Welding Society (AWS) G2 Committee on the Joining of Metals and Alloys

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

This guide presents a description of solid solution austenitic stainless steels and the processes and procedures that can be used for the joining of these materials. This standard discusses the welding processes and welding parameters, qualifica- tions, inspection and repair methods, cleaning, and safety considerations. Practical information has been included in the form of figures, tables, and graphs that should prove useful in determining capabilities and limitations in the joining of austenitic stainless steels.

International Standard Book Number: 978-0-87171-824-2

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© 2012 by American Welding Society

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Official interpretations of any of the technical requirements of this standard may only be obtained by sending a request, in writing, to the appropriate technical committee. Such requests should be addressed to the American Welding Society, Attention: Managing Director, Technical Services Division, 8669 Doral Blvd., Suite 130, Doral, FL 33166 (see Annex F). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered. These opinions are offered solely as a convenience to users of this standard, and they do not constitute professional advice. Such opinions represent only the personal opinions of the particular individuals giving them. These individuals do not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or interpretations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.

This standard is subject to revision at any time by the AWS G2 Committee on the Joining of Metals and Alloys. It must be reviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard are required and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWS G2 Committee on the Joining of Metals and Alloys and the author of the comments will be informed of the Committee’s response to the comments. Guests are invited to attend all meetings of the AWS G2 Committee on the Joining of Metals and Alloys to express their comments verbally. Procedures for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 8669 Doral Blvd., Suite 130, Doral, FL 33166.

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Personnel

AWS G2 Committee on Joining Metals and Alloys

1. S. Babish, Chair Sandvik Materials Technology

2. Dunn, Vice Chair ExxonMobil Development Company

1. L. Diaz, Secretary American Welding Society

   1. E. Avery Consultant to Nickel Institute

   2. O. Luke Black & Veatch

1. C. Sutherlin ATI Wah Chang

   D. J. Tillack Consultant to Nickel Institute

   
   

   AWS G2E Subcommittee on Stainless Steel Alloys

2. O. Luke, Chair Black & Veatch

A. L. Diaz, Secretary American Welding Society

R. E. Avery Consultant to Nickel Institute

F. S. Babish Sandvik Materials Technology

R. D. Fuchs Böhler Welding Group USA, Incorporated

D. W. Haynie Kobelco Welding of America, Incorporated

W. E. Layo Midalloy

C. D. Ross ESAB Welding and Cutting Products

J. W. Sowards National Institute of Standards and Technology

D. J. Tillack Consultant to Nickel Institute

M. D. Yaple Böhler Welding Group USA, Incorporated

Advisor to AWS G2E Subcommittee on Stainless Steel Alloys

H. W. Record Böhler Welding Group USA, Incorporated

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Foreword

This foreword is not part of AWS G2.3M/G2.3:2012, Guide for the Joining of Solid Solution Austenitic Stainless Steels, but is included for informational purposes only.

The American Welding Society formed the G2 Committee on the Joining of Metals and Alloys in 1992 in response to an industry demand for information on welding the metals and alloys that have not been covered by other documents and com- mittees. This document is written by the G2 Committee on the Joining of Metals and Alloys.

Underlined text in clauses, tables, or figures indicates an editorial or technical change from the 2009 edition. A vertical line in the margin also indicates a revision from 2009 edition.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS G2 Committee on the Joining of Metals and Alloys, American Welding Society, 8669 Doral Blvd., Suite 130, Doral, FL 33166.

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Table of Contents

Page No.

Personnel v

Foreword vii

List of Tables xi

List of Figures xii

1. General Requirements 1

   1. Scope 1

   2. Units of Measure 1

   3. Safety 1

2. Normative References 1

3. Terms and Definitions 2

4. General Information 4

   1. History 4

   2. Properties 8

   3. Product Forms 8

   4. Specifications 8

5. Metallurgy 15

   1. Ferrite Discussion 15

   2. The Ferrite-Sigma Phase Relationship 21

   3. Corrosion Resistance Related to Welding 21

   4. Heat Tint 23

   5. Elevated Temperature Performance 24

6. Welding and Fabrication Considerations 26

   1. Weld Joint Design 26

   2. Cleaning Prior to Welding 27

   3. Thermal Arc Gouging and/or Grinding 28

   4. Distortion Control 29

   5. Welding Preheat and Maximum Interpass Temperature 29

   6. Welding Position 30

   7. Root Pass Welding 30

   8. Shielding Gas and Cleanliness 33

   9. Fixtures and Fitting Devices 33

7. Weldability Considerations 33

   1. Solidification Cracking 33

   2. Mitigation of Solidification Cracking with Ferrite Control 33

   3. Various Effects of Sulfur 34

   4. Reheat Cracking in Type 347-SS 34

   5. Other Forms of Weld Cracking and Prevention Strategies 34

   6. Welding Techniques to Minimize Weld Cracking 35

8. Welding Processes 35

   1. Shielded Metal Arc Welding (SMAW) 35

   2. Gas Tungsten Arc Welding (GTAW) 40

   3. Gas Metal Arc Welding (GMAW) 48

      Page No.

   4. Flux Core Arc Welding (GCAW) 52

   5. Submerged Arc Welding (SAW) 58

   6. Plasma Arc Welding (PAW) 60

   7. Laser Beam Welding (LBW) and Electron Beam Welding (EBW) 60

   8. Resistance Welding. 60

   9. Brazing 60

9. Postweld Operations 61

   1. Visual Inspection 61

   2. Weld Size 61

   3. Final Visual Inspection 62

   4. Weld Discontinuities. 62

   5. Slag Removal 62

   6. Grinding and Finishing 62

   7. Media Blasting. 63

   8. Cleaning, Pickling, and Passivation 63

   9. Electropolishing 65

10. Heat Treatment 66

    1. Solution Annealing 66

    2. Stress Relief 66

    3. Stabilization Anneal 67

11. Storage and Shipping Recommendations 67

12. Maintenance and Repair 67

    1. Maintenance 67

    2. Repair 68

Annex A (Informative)—Suggested Filler Metal Selection Chart 71

Annex B (Informative)—Informative References 79

Annex C (Informative)—ASTM Base Metal Specifications for Austenitic Stainless Steels 81

Annex D (Informative)—Estimating the Ferrite Content of Cast Base Materials 85

Annex E (Informative)—Engineering Terms, Common Conversions, and SMAW Electrode Diameters 87

Annex F (Informative)—Guidelines for the Preparation of Technical Inquiries. 91

List of AWS Documents on the Joining of Metals and Alloys 93

List of Tables

Table Page No.

1. The Chemical Composition Limits of Common Wrought Austenitic Stainless Steel Base Materials 5

2. The Chemical Composition Limits of Common Cast Austenitic Stainless Steel Base Materials 9

3. Mechanical Properties of Wrought Annealed Stainless Steel Alloys 12

4. Minimum Mechanical Properties of Common Cast Austenitic Stainless Steel Base Materials 14

1. Ferrite Diagram Comparisons of Chrome and Nickel Equivalencies 18

2. Typical Physical Property Comparisons of Austenitic Stainless Steels versus Carbon Steels 26

6.1 Purging Guidelines for Piping 32

1. Chemical Analysis of Stainless Steel SMAW Electrodes 36

2. SMAW Electrodes (AWS A5.4/A5.4M) (specified tensile properties) 38

3. SMAW Electrodes: Welding Current, Position of Welding, and Operating Characteristics 39

4. SMAW Electrodes: Suggested Amperage Ranges for E3xx-15, -16, and -17 Type Electrodes 40

5. Suggested Welding Parameters, Manual GTAW 42

6. Suggested Argon Torch Flow Rates, Manual GTAW 42

7. Suggested Gas Cup Size versus Maximum Welding Amperage, Manual GTAW 42

8. GTAW (TIG) Shielding Gas Selection 43

9. Chemical Compositions of Bare and Metal Cored Filler Metals (AWS A5.9/A5.9M) 45

10. Nickel-Based Consumables, Chemical Composition Ranges 47

11. Nickel-Based SMAW Electrodes, Specified Tensile Properties 48

12. GMAW (MIG) Shielding Gas Selection 50

13. GMAW Parameters (Short Circuit, DCEP, He + 7.5%Ar + 2.5%CO2 Shielding Gas) 51

14. GMAW Parameters (Spray Transfer, DCEP, 98%Ar + 2%O2 Shielding Gas) 51

15. FCAW Electrodes Classification Scheme (AWS A5.22/A5.22M:2010) 54

16. FCAW Electrodes: Chemical Composition Requirements 55

17. AWS A5.22/A5.22M FCAW Electrodes and Rods (specified tensile properties) 57

18. Shielding Gas Selection for Flux Core Arc Welding 57

19. Typical Submerged Arc Welding Parameters, DCEP 59

1. Suggested Filler Metal Selection Chart—Wrought Standard Grades 73

2. Suggested Filler Metal Selection Chart—Wrought Proprietary Grades 76

3. Filler Selection for Stainless Steel Castings 77

1. Common Engineering Terms 87

2. Data 87

3. Common Welding-Related Conversion Factors 88

List of Figures

Figure Page No.

4.1 Alloying Variations of Common Austenitic Stainless Steels 7

1. The Schaeffler Diagram 16

2. The DeLong Diagram 17

3. WRC-1992 Diagram for Stainless Steel Weld Metal 19

4. a Carbide Precipitation in Type 304 Austenitic Stainless Steel 22

1. b Carbide Reaction Temperature Ranges 23

2. The Effects of Chromium, Nickel, and Other Elements on the Oxidation Resistance of Steels and

Stainless Steels 25

8.1 Waveform Components and Arc and Burn-Off Rate 53

D.1 The Schoefer Diagram 85

Guide for the Joining of

Solid Solution Austenitic Stainless Steels

1. General Requirements

   1. Scope. This guide presents a description of solid solution austenitic stainless steels and the most commonly used welding processes and procedures for joining these materials. The most commonly used welding processes, including shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), submerged arc welding (SAW), and flux core arc welding (FCAW), are discussed in detail; laser beam, electron beam, plasma arc, resistance, and braze welding are not covered in great detail.

      The welding processes discussed in this guide include recommended welding parameters, filler metals, shielding gases, and fluxes. Procedure qualifications, inspection and repair considerations and methods, and cleaning and safety con- siderations are also discussed. Practical information has been included as figures, tables, and graphs that should prove useful for determining the capabilities and limitations in the joining of austenitic stainless steels. This guide does not address martensitic, ferritic, or duplex stainless steels.

   2. Units of Measure. This standard uses both the International System of Units (SI) and U.S. Customary Units. The latter are shown with brackets ([ ]) or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system should be used independently.

   3. Safety. Safety and health issues and concerns are beyond the scope of this standard; some safety and health infor- mation is provided, but such issues are not fully addressed herein. Safety and health information is available from the following sources:

      American Welding Society:

      1. ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes

      2. AWS Safety and Health Fact Sheets

      3. Other safety and health information on the AWS website Material or Equipment Manufacturers:

         (1) Material Safety Data Sheets supplied by materials manufacturers (2) Operating Manuals supplied by equipment manufacturers

         Applicable Regulatory Agencies

         Work performed in accordance with this standard may involve the use of materials that have been deemed hazardous, and may involve operations or equipment that may cause injury or death. This standard does not purport to address all safety and health risks that may be encountered. The user of this standard should establish an appropriate safety program to address such risks as well as to meet applicable regulatory requirements. ANSI Z49.1 should be considered when developing the safety program.

         
         

2. Normative References

The standards listed below contain provisions, which through reference in this text, constitute mandatory provisions of this AWS standard. For undated references, the latest edition of the referenced standard shall apply. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply.