AWS A5.31M/A5.31:2012

An American National Standard

Specification for Fluxes for Brazing and Braze Welding

AWS A5.31M/A5.31:2012

An American National Standard

Approved by the American National Standards Institute

February 17, 2012

Specification for Fluxes for Brazing and Braze Welding

2nd Edition

Supersedes ANSI/AWS A5.31-92(R2003)

Prepared by the American Welding Society (AWS) A5 Committee on Filler Metals and Allied Materials

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

Eighteen fluxes for brazing and braze welding are classified according to the filler metal, form, and activity temperature range. Classification is in accordance with a classification system that employs the designator “FB” to indicate fluxes for brazing and braze welding applications. In addition to selected tests for each classification, major topics include general requirements, testing procedures, and packaging requirements. An annex listing general application guidelines is included.

This specification makes use of both the International System of Units (SI) and U.S. Customary Units. The measurements may not be exact equivalents; therefore, each system shall be used independently.

International Standard Book Number: 978-0-87171-807-5

American Welding Society 550 N.W. LeJeune Road, Miami, FL 33126

© 2012 by American Welding Society

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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 governmen- tal 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.

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This standard is subject to revision at any time by the AWS A5 Committee on Filler Metals and Allied Materials. 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 A5 Committee on Filler Metals and Allied Materials 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 A5 Committee on Filler Metals and Allied Materials 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, 550 N.W. LeJeune Road, Miami, FL 33126.

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Personnel

AWS A5 Committee on Filler Metals and Allied Materials

H. D. Wehr, Chair Arcos Industries LLC

1. J. DeLoach, Jr., 1st Vice Chair Naval Surface Warfare Center

   1. D. Fuchs, 2nd Vice Chair Bohler Welding Group USA, Incorporated

      1. Gupta, Secretary American Welding Society

         T. Anderson ITW Welding North America

         J. M. Blackburn Naval Sea Systems Command

         J. C. Bundy Hobart Brothers Company

         J. L. Caron Haynes International, Incorporated

         D. D. Crockett Consultant

         R. V. Decker Weldstar

         1. A. Del Signore Consultant

            J. DeVito Consultant

            H. W. Ebert Consultant

            D. M. Fedor The Lincoln Electric Company

            J. G. Feldstein Foster Wheeler North America

            S. E. Ferree ESAB Welding and Cutting Products

            D. A. Fink The Lincoln Electric Company

            G. L. Franke Naval Surface Warfare Center

            1. M. Henson Harris Products Group

            2. D. Kiser Special Metals

            P. J. Konkol Concurrent Technologies Corporation

            D. J. Kotecki Damian Kotecki Welding Consultants

            1. G. Kvidahl Ingalls Shipbuilding

               1. Y. Lau Canadian Welding Bureau

            1. S. Lee Chevron

               T. Melfi The Lincoln Electric Company

            2. M. Merlo Edison Welding Institute

            M. T. Merlo RevWires LLC

            B. Mosier Polymet Corporation

            1. K. Mukherjee Siemens Energy, Incorporated

               T. C. Myers Oceaneering Intervention Engineering

               C. L. Null Consultant

            2. A. Pletcher CB & I, Incorporated

K. C. Pruden Hydril Company

K. Roossinck Northrop Grumman Ship Systems

P. K. Salvesen Det Norske Veritas (DNV)

K. Sampath Consultant

W. S. Severance ESAB Welding and Cutting Products

M. F. Sinfield Naval Surface Warfare Center

M. J. Sullivan NASSCO-National Steel and Shipbuilding

R. C. Sutherlin ATI Wah Chang

R. A. Swain EuroWeld, Limited

M. D. Tumuluru US Steel Corporation

J. Zhang Indalco Alloys Inc. of Lincoln Electric

Advisors to the AWS A5 Committee Filler Metals and Allied Materials

R. L. Bateman Soldaduras West Arco Ltda.

J. E. Beckham Chrysler, LLC

M. L. Caruso Special Metals Welding Products Company

R. A. Daemen Consultant

B. S. Dauble Carpenter Technology Corporation

T. A. Davenport PRL Industries

C. E. Fuerstenau Lucas-Milhaupt, Incorporated

J. P. Hunt Special Metals

S. Imaoka KOBE Steel Limited

W. A. Marttila WAMcom Consulting LLC

R. Menon Stoody Company

D. R. Miller ABS

M. P. Parekh Consultant

J. W. Price DMI Industries

M. A. Quintana The Lincoln Electric Company

E. S. Surian National University of Lomas de Zamora

H. J. White Consultant

AWS A5H Subcommittee on Filler Metals and Fluxes for Brazing

R. M. Henson, Chair Harris Products Group

G. L. Alexy, Vice Chair The Prince & Izant Company

S. N. Borrero, Secretary American Welding Society

E. R. Boes Delta Faucet Company

D. Budinger General Electric Aviation

C. F. Darling Lucas-Milhaupt, Incorporated

W. J. Engeron Engeron Technology Group

T. P. Hirthe Kru-Mar Manufacturing Services, Incorporated

M. J. Lucas Jr. Belcan Corporation

J. C. Madeni Colorado School of Mines

R. P. McKinney The Prince & Izant Company

W. Miglietti Power Systems Manufacturing, LLC

C. R. Moyer Bodycote Thermal Processing

T. Oyama WESGO Metals

J. P. Sands Wolverine Joining Technologies

M. E. Scruggs Harris Products Group

A. E. Shapiro Titanium Brazing, Incorporated

C. M. Volpe Senior Aerospace–Metal Bellows Division

L. Wolfgram Lucas-Milhaupt, Incorporated

Advisors to the AWS A5H Subcommittee on Filler Metals and Fluxes for Brazing

R. Aluru Chromalloy Gas Turbine Corporation

P. A. Baskin The Superior Flux & Manufacturing Company

Y. Baskin The Superior Flux & Manufacturing Company

C. E. Fuerstenau Lucas-Milhaupt, Incorporated

M. J. Kuta Lucas-Milhaupt, Incorporated

Foreword

This foreword is not part of AWS A5.31M/A5.31:2012, Specification for Fluxes for Brazing and Braze Welding, but is included for informational purposes only.

This document is the first of the A5.31 specifications that makes use of both the International System of Units (SI) and

1. Customary Units. The measurements are not exact equivalents; therefore each system must be used independently of the other, without combining values in any way. In selecting rational metric units, AWS A1.1, Metric Practice Guide for the Welding Industry, and International Standard ISO 544, Welding Consumables—Technical Delivery Conditions for Welding Filler Materials—Type of Product, Dimensions, Tolerances, and Markings, are used where suitable. Tables and figures make use of both SI Units and U.S. Customary Units, which with the application of the specified tolerances provides for interchangeability of products in both the SI Units and U.S. Customary Units.

   This is the second revision of the original specification issued in 1992. The first edition of the Brazing Manual, published in 1955, included a numerical list of fluxes. The next two editions, published in 10-year intervals, made numerous changes to the initial listings, but lacked the inclusion of the testing and restrictions normally incorporated in a specifica- tion. The Brazing Manual was revised again in 1991 and published as the AWS Brazing Handbook. The fifth edition of the Brazing Handbook was published in 2007.

   In 1978, the American Welding Society’s Brazing and Soldering Committee recognized the need for a flux specification. About two years later, collaboration between the Committee on Filler Metals and Allied Materials and the Subcommittee on Filler Metals and Fluxes for Brazing led to the initial preparation of the specification. At that point, the magnitude of the challenge to prepare a specification in an industry built on a foundation of proprietary products became apparent. After over a decade of activity by a dedicated group of brazing specialists, the first National Specification, AWS/ANSI A5.31–92, was issued. AWS A5.31M/A5.31:2012 represents over two decades of activity by a dedicated group of brazing specialists.

   The present edition, which supersedes ANSI/AWS A5.31–92 (R2003), includes the following updates: The International System of Units (SI) is used as the primary unit of measurement

   Three classes of dispensable fluxes: FB3-L, FB3-M, FB3-N

   Sodium Glare Test was removed

   Test base metal options added for select flux classifications Revised shelf life requirements

   Revised test specimen and preparation requirements Test lot definition

   Revised retest requirements

   Revised particle size test requirements Adherence Test title now reads as Adhesion Test Revised fluidity test requirements

   A flux viscosity test reference is included

   Supplemental Annexes—Informative references and safety considerations

   New substantive revisions are noted within the specification in italic font.

   Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS A5 Committee on Filler Metals and Allied Materials, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

   
   

   
   

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   Table of Contents

   
   

   Page No.

   Personnel v

   Foreword vii

   List of Tables xi

   List of Figures xi

   1. General Requirements 1

   2. Normative References 1

   3. Classification 2

   4. Acceptance 2

   5. Certification 3

   6. Rounding-Off Procedure 3

   7. Summary of Tests 3

   8. Retests 4

   9. Test Specimen 4

   10. Flux Sample 6

   11. Filler Metal 6

   12. Water Content Test 6

   13. Particle Test 7

   14. Adhesion Test 7

   15. Fluidity Test 8

   16. Fluxing Action Test 8

   17. Flow Test 9

   18. Life Test 9

   19. Viscosity Test 9

   20. Method of Manufacture 10

   21. Forms 10

   22. Packaging 10

   23. Marking of Packages 10

Annex A (Informative)—Informative References 11

Annex B (Informative)—Guide to AWS A5.31M/A5.31:2012, Specification for Fluxes for

Brazing and Braze Welding 13

Annex C (Informative)—Guidelines for the Preparation of Technical Inquiries 19

AWS Filler Metal Specifications by Material and Welding Process 21

AWS Filler Metal Specifications and Related Documents 22

List of AWS Documents on Brazing and Soldering 23

List of Tables

Table Page No.

1. Classification of Brazing Fluxes with Brazing or Braze Welding Filler Metals 3

2. Required Tests 4

3. Filler Metal and Base Metal for Tests, Flow and Life Test Temperature, and Flow Test

Minimum Area 5

List of Figures

Figure Page No.

1 Test Specimen Approximately 1.6 mm [0.062 in] Thick 6

B.1 Precautionary Information for Brazing and Welding Fluxes Containing Fluorides 18

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Specification for Fluxes for Brazing and Braze Welding

1. General Requirements

   1. Scope. This specification prescribes the requirements for the classification of brazing fluxes used with brazing or braze welding filler metals such as those classified in AWS A5.8M/A5.8, Specification for Filler Metals for Brazing and Braze Welding.

   2. Units of Measurement. This specification makes use of both the International System of Units (SI) and U.S. Customary Units. The measurements are not exact equivalents; therefore, each system must be used independently of the other without combining in any way when referring to material properties. The specification with the designation A5.31M uses SI Units. The specification A5.31 uses U.S. Customary Units. The latter are shown within brackets [ ] or in appropriate columns in tables and figures. Standard dimensions based on either system may be used for sizing of brazing fluxes or packaging or both under A5.31M or A5.31 specifications.

   3. Safety. Safety issues and concerns are addressed in this standard, although health issues and concerns are beyond the scope of this standard. Some safety and health information can be found in non-mandatory Annex Clauses B5 and B8.

      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 (see Annex Clause B8)

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

1. Material Safety Data Sheets supplied by the 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 devel- oping the safety program.