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 Measure. 1

   3. Safety 1

2. Normative References 1

3. Terms and Definitions 2

4. Introduction 3

   1. Elements that Influence Zirconium Weld Integrity 3

   2. Zirconium Metallurgy 3

   3. Zirconium Weld Discontinuities 4

5. Arc Welding Processes 4

   1. Gas Tungsten Arc Welding (GTAW) 4

   2. Gas Metal Arc Welding (GMAW) 4

   3. Plasma Arc Welding (PAW) 4

6. Equipment 5

   1. Power Source 5

   2. Welding Torch 5

   3. Tungsten Electrodes 6

7. Materials 6

   1. Base Metals 6

   2. Filler Metals 8

   3. Procedure Qualification 8

8. Workshop Practice 8

   1. Workshop Layout 8

   2. Material Identification and Storage 9

   3. Inert Gas Protection 9

   4. Inert Gas Distribution 9

   5. In-Chamber Welding 10

   6. Open Air Welding 11

   7. Shielding Gases 13

   8. Argon Safety 14

9. Joint Preparation 14

   1. Joint Design 14

   2. Cutting 15

   3. Preliminary Preparation 16

   4. Final Cleaning for Welding 16

   5. Fitup and Tack Welding 17

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      Page No.

10. Welding Technique 17

    1. Welding Parameters 17

    2. Preheating 18

    3. Filler Metal Practice 18

    4. Starting and Stopping the Arc. 18

    5. Electrode Practice 18

    6. Wire Feeding 18

    7. Interpass Cleaning 18

    8. Interpass Temperatures 19

11. In-Process Weld Quality Tests 19

    1. Visual Inspection 19

    2. Dew Point Testing 19

    3. Bend Testing 21

    4. Hardness Testing 21

12. Nondestructive Test 21

    1. Radiography 21

    2. Liquid Penetrant Testing 22

    3. Ultrasonic Inspection 22

13. Mandatory Heat Treatment of Zirconium Grade 705 22

1. Repair of Defects 22

   1. Fabrication Defects 22

   2. Repairs Following Service Failures 23

   3. Porosity 23

   4. Filler Metals for Welding Zirconium Alloy Metal Joints 23

Annex A (Informative)—Requirements of Base Metals 25

Annex B (Informative)—Requirements of Filler Metals 27

Annex C (Informative)—Informative References 29

Annex D (Informative)—Guidelines for the Preparation of Technical Inquiries 31

List of AWS Documents on Joining Metals and Alloys 33

x

List of Tables

Table Page No.

1. General Electrode Amperage Guidelines 7

2. ASTM/ASME Specifications for Product Forms 7

3. Recommended Shielding Gas Purity and Dew Point 9

4. Typical Joint Designs 15

5. Typical Parameters for GTAW of Zirconium 17

6. Surface Color in Zirconium Welds 20

7. Bend Test Requirements for Zirconium Alloys 21

1. Chemical Composition Requirements of Base Metals 25

2. Tensile Strength Requirements of Base Metals 26

B.1 Chemical Composition Requirements of Filler Metals—Weight Percent 27

List of Figures

Figure Page No.

1. Large Diameter Gas Cup and Lens for Zirconium Welding 5

2. Tungsten Electrode Tip Shape 6

3. Rigid and Collapsible Plastic Chambers Purged with Argon 10

4. Typical Trailing Shield Design 12

5. Examples of Back-Up Shields for Manual GTAW 13

6. Color Sequence in Zirconium 20

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xii

xii

Guide for the Fusion Welding

of Zirconium and Zirconium Alloys

1. General Requirements

   1. Scope. This guide provides information on welding processes and procedures that are recommended for use in zirco- nium fabrication. The document presents detailed and up-to-date technical information on the “best practices” to allow first time users of zirconium as well as established fabricators to join zirconium parts into high quality components.

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

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