AWS G2.4/G2.4M:2014

An American National Standard

Guide for the Fusion Welding of Titanium and Titanium Alloys

AWS G2.4/G2.4M:2014

An American National Standard

Approved by the American National Standards Institute

May 5, 2014

Guide for the Fusion Welding of Titanium and Titanium Alloys

2nd Edition

Supersedes AWS G2.4/G2.4M:2007

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

The standard Guide for the Fusion Welding of Titanium and Titanium Alloys provides instructional guidance for the welding of titanium and titanium alloys. This guide explains processes, equipment, materials, workshop practices, joint preparation, welding technique, tests, and the repair of defects.

AWS G2.4/G2.4M:2014

Statement on the Use of American Welding Society Standards

All standards (codes, specifications, recommended practices, methods, classifications, and guides) of the American Welding Society (AWS) are voluntary consensus standards that have been developed in accordance with the rules of the American National Standards Institute (ANSI). When AWS American National Standards are either incorporated in, or made part of, documents that are included in federal or state laws and regulations, or the regulations of other govern- mental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWS standards must be approved by the governmental body having statutory jurisdiction before they can become a part of those laws and regulations. In all cases, these standards carry the full legal authority of the contract or other document that invokes the AWS standards. Where this contractual relationship exists, changes in or deviations from requirements of an AWS standard must be by agreement between the contracting parties.

AWS American National Standards are developed through a consensus standards development process that brings together volunteers representing varied viewpoints and interests to achieve consensus. While AWS administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, evalu- ate, or verify the accuracy of any information or the soundness of any judgments contained in its standards.

AWS disclaims liability for any injury to persons or to property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, or reliance on this standard. AWS also makes no guarantee or warranty as to the accuracy or completeness of any information published herein.

In issuing and making this standard available, AWS is neither undertaking to render professional or other services for or on behalf of any person or entity, nor is AWS undertaking to perform any duty owed by any person or entity to someone else. Anyone using these documents should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. It is assumed that the use of this standard and its provisions is entrusted to appropriately qualified and competent personnel.

This standard may be superseded by new editions. This standard may also be corrected through publication of amendments or errata or supplemented by publication of addenda. Information on the latest editions of AWS standards including amendments, errata, and addenda is posted on the AWS web page (www.aws.org). Users should ensure that they have the latest edition, amendments, errata, and addenda.

Publication of this standard does not authorize infringement of any patent or trade name. Users of this standard accept any and all liabilities for infringement of any patent or trade name items. AWS disclaims liability for the infringement of any patent or product trade name resulting from the use of this standard.

AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so.

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 NW 36 St, # 130, Miami, FL 33166 (see Annex E). 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 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. It must be reviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommen- dations, 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 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 to express their comments verbally. Procedures for appeal of an adverse decision concerning all such comments are pro- vided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

AWS G2.4/G2.4M:2014

Personnel

AWS G2 Committee on the Joining of 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

R. C. Sutherlin ATI Wah Chang

D. J. Tillack Consultant to Nickel Institute

AWS G2D Subcommittee on Reactive Alloys

R. C. Sutherlin, Chair ATI Wah Chang

A. L. Diaz, Secretary American Welding Society

S. S. Delmore CK Worldwide, Incorporated

B. Krueger Los Alamos National Laboratory

K. T. Tran Naval Surface Warfare Center

G. E. Trepus Boeing Commercial Airplanes

Advisors to the G2D Subcommittee on Reactive Alloys

1. D. Kellum Williamette Welding Supply Company

   H. Kotaki Consultant to The Japan Titanium Society

2. L. Luckowski United States Department of the Army

J. A. McMaster MC Consulting

J. Simpson International Titanium Association

S. D. Sparkowich Nerac, Incorporated

AWS G2.4/G2.4M:2014

Foreword

This foreword is not part of AWS G2.4/G2.4M:2014, Guide for the Fusion Welding of Titanium and Titanium Alloys, but is included for informational purposes only.

This specification makes use of both U.S. Customary Units and the International System of Units (SI). The measurements are not exact equivalents; therefore each system must be used independently of the other, without combining values in any way when referring to filler metal properties. In selecting rational metric units, the AWS A1.1, Metric Practice Guide for the Welding Industry, and the International Standard ISO 544, Welding consumables — Technical delivery conditions for welding filler metals — Type of product, dimensions, tolerances and markings, are used where suitable. Tables and figures make use of both U.S. Customary and SI Units, which, with the application of the specified tolerances, provide for interchangeability of products in both the U.S. Customary and SI Units.

A vertical line in the margin or underlined text in clauses, tables, or figures indicates an editorial or technical change from the 2007 edition.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS G2 Committee on Joining Metals and Alloys, American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

AWS G2.4/G2.4M:2014

Table of Contents

Page No.

Personnel v

Foreword vii

List of Tables xi

List of Figures xi

1. General Requirements 1

   1. Scope 1

   2. Units of Measurements 1

   3. Safety 1

2. Normative References 1

3. Terms and Definitions 2

4. Introduction 4

   1. Oxygen, Nitrogen, Carbon, Iron, and Titanium 5

   2. Surface Oxide Film 5

5. Arc Welding Processes 6

   1. Gas Tungsten Arc Welding (GTAW) 6

   2. Gas Metal Arc Welding (GMAW) 6

   3. Plasma Arc Welding (PAW) 6

6. Equipment 7

   1. Power Source 7

   2. Welding Torch 7

   3. Tungsten Electrodes 8

7. Materials 10

   1. Base Metals 10

   2. Filler Metals 10

   3. Procedure Qualification 12

8. Workshop Practice 12

   1. Workshop Layout 12

   2. Material Identification and Storage 12

   3. Inert Gas Protection 12

   4. Inert Gas Distribution 13

   5. In-Chamber Welding 13

   6. Open-Air Welding 14

   7. Shielding Gases 17

   8. Argon Safety 17

9. Joint Preparation 17

   1. Joint Design 17

   2. Cutting 18

   3. Preliminary Preparation 19

   4. Cleaning for Welding 20

   5. Fitup and Tack Welding 20

      AWS G2.4/G2.4M:2014

      Page No.

10. Welding Technique 21

    1. Welding Parameters 21

    2. Preheating 21

    3. Filler Metal Practice 21

    4. Starting and Stopping the Arc 21

    5. Electrode Practice 22

    6. Wire Feeding 22

    7. Interpass Cleaning 22

    8. Interpass Temperatures 22

11. In-Process Weld Quality Tests 22

    1. Visual Inspection 22

    2. Dew Point Testing 24

    3. Bend Testing 24

    4. Hardness Testing 24

12. Nondestructive Test 25

    1. Radiography 25

    2. Liquid Penetrant Testing 25

    3. Ultrasonic Inspection 26

13. Repair of Defects 26

    1. Fabrication Defects 26

    2. Repairs Following Service Failures 26

    3. Porosity 26

    4. Filler Metals for Welding Titanium Alloys Metal Joints 26

Annex A (Informative)—Requirements of Base Metals 27

Annex B (Informative)—Requirements of Filler Metals 31

Annex C (Informative)— Informative References 35

Annex D (Informative)—Classifications for Titanium and Titanium Alloys 37

Annex E (Informative)—Guidelines for the Preparation of Technical Inquiries 41

List of AWS Documents on Joining Metals and Alloys 43

AWS G2.4/G2.4M:2014

List of Tables

Table Page No.

1. Approximate Current Ranges Depending upon the Electrode Diameter 9

2. ASTM Specifications for Product Forms 10

3. Recommended Filler Metals 11

4. Recommended Shielding Gas Purity and Dew Point 13

5. Typical Joint Designs 18

6. Typical Parameters for GTAW, GMAW, and PAW 21

7. Surface Color in Titanium Welds 23

8. Bend Test Requirements for Titanium Alloys 25

1. Chemical Composition Requirements of Base Metals (from ASTM B265) 27

2. Tensile Strength Requirements of Base Metals 29

B.1 Symbols for Chemical Composition and Composition Requirements 32

1. Guidelines for Compatible Filler Materials 37

2. Base Material Grouping S-51 38

3. Base Material Grouping S-52 38

4. Base Material Grouping S-53 39

5. Base Material Grouping S-54 40

6. Filler Material Grouping A-51B 40

7. Filler Material Grouping A-52B 40

8. Filler Material Grouping A-53B 40

List of Figures

1. Body-Centered Cubic (BCC) Structure. 3

2. Hexagonal Close-Packed (HCP) Structure 3

3. Interstitial Elements 4

4. Substitutional Elements 4

5. Titanium Surface Oxide Formed by Heating in Air 5

6. Large-Diameter Gas Cup and Lens for Titanium Welding 7

7. Tungsten Electrode Tip Shape 8

8. Collapsible Plastic Chamber Purged with Argon 14

9. Typical Trailing Shield Design 15

10. Examples of Backup Shields for Manual GTAW 16

11. Color Sequence in Titanium 23

12. Contamination of Tungsten Electrode from Air Entrainment 24