AWS C3.4M/C3.4:2016

An American National Standard

Specification for Torch Brazing

AWS C3.4M/C3.4:2016

An American National Standard

Approved by the American National Standards Institute

December 15, 2015

Specification for Torch Brazing

4th Edition

Supersedes AWS C3.4M/C3.4:2007

Prepared by the American Welding Society (AWS) C3 Committee on Brazing and Soldering

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

This specification presents the minimum fabrication, equipment, and process procedure requirements, as well as inspec- tion requirements for the torch brazing of steels, stainless steels, copper, copper alloys, and heat- or corrosion-resistant alloys and other materials that can be adequately torch brazed (the torch brazing of aluminum alloys is addressed in AWS C3.7M/C3.7, Specification for Aluminum Brazing). This specification provides criteria for classifying torch brazed joints based on loading and the consequences of failure and quality assurance criteria defining the limits of acceptability in each class. The specification defines acceptable torch brazing equipment, materials, and procedures as well as the required inspection for each class of joint.

ISBN: 978-0-87171-874-7

© 2016 by American Welding Society

All rights reserved Printed in the United States of America

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Statement on 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 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 stan- dard must be by agreement between the contracting parties.

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This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition.

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On occasion, text, tables, or figures are printed incorrectly, constituting errata. Such errata, when discovered, are posted on the AWS web page (www.aws.org).

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 B). 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 C3 Committee on Brazing and Soldering. 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 C3 Committee on Brazing and Soldering 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 C3 Committee on Brazing and Soldering 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 NW 36 St, #130, Miami, FL 33166.

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Personnel

AWS C3 Committee on Brazing and Soldering

R. W. Smith, Chair S-Bond Technologies

G. L. Alexy, 1st Vice Chair Alexy Metals

C. M. Volpe, 2nd Vice Chair Senior Aerospace – Metal Bellows Division

J. R. Douglass, Secretary American Welding Society

J. J. Bassindale Woodward, Incorporated

D. E. Budinger General Electric Aviation

J. A. Bush The Prince & Izant Companies

W. M. Coughlan Metglas, Incorporated

C. F. Darling Lucas-Milhaupt, Incorporated

W. J. Engeron Engeron Technology Group

1. L. Feldbauer Abbott Furnace Company

   Y. Flom NASA Goddard Space Flight Center

   B. Freund Millennium Industries

   Y. Gao Aerojet Rocketdyne

   R. A. Gourley Curtiss-Wright

2. D. Grohoske General Electric Aviation

1. R. Hazelbaker Consultant

2. P. Hirthe Kru-Mar Manufacturing Services

K. H. Holko Holko Consulting

J. R. Jachna Modine Manufacturing Company

D. A. Javernick Los Alamos National Laboratory

G. F. Kayser Aerojet Rocketdyne

J. A. Liguori SpaceX

J. Longabucco Lucas-Milhaupt, Incorporated

O. Mårs Höganäs AB

J. G. Matteau Indium Corporation

R. P. McKinney Harris Products Group

W. Miglietti ProEnergy

T. Oyama WESGO Metals

M. J. Pohlman Honeywell Aerospace

1. C. Profughi Hi TecMetal Group, Incorporated

   1. Rabinkin Brazing and Joining Consultant, LLC

S. S. Rajan Raytheon Space and Airborne Systems

J. P. Sands Bellman-Melcor, LLC

A. E. Shapiro Titanium Brazing, Incorporated

M. Stroiczek Höganäs GmbH

P. T. Vianco Sandia National Laboratories

C. Walker Sandia National Laboratories

1. Weinstein Wall Colmonoy Corporation

   R. R. Xu Rolls-Royce Corporation

   H. Zhao Creative Thermal Solutions

   Advisors to the AWS C3 Committee on Brazing and Soldering

   1. Aluru Progress Energy

      1. Barten Delphi Thermal & Interior

         1. Belohlav Lucas-Milhaupt, Incorporated

1. S. Bhargava American Axle & Manufacturing Company

D. W. Bucholz Consultant

S. Christy Pratt and Whitney

N. C. Cole NCC Engineering

1. E. Fuerstenau Lucas-Milhaupt, Incorporated

   P. K. Gupta Honeywell Aerospace

   1. M. Hosking Consultant

      1. N. Jain Lucas-Milhaupt, Incorporated

         1. Kay Kay & Associates

         2. Liguori Consultant

W. J. Loofboro Lucas-Milhaupt, Incorporated

E. Lugscheider Aachen University of Technology

J. C. Madeni Johns Manville

R. X. Reed Lucas-Milhaupt, Incorporated

W. D. Rupert Lucas-Milhaupt, Incorporated

AWS C3D Subcommittee on Brazing Specifications

M. J. Pohlman, Chair Honeywell Aerospace

C. M. Volpe, Vice-Chair Senior Aerospace – Metal Bellows Division

J. R. Douglass, Secretary American Welding Society

J. J. Bassindale Woodward, Incorporated

D. E. Budinger General Electric Aviation

J. A. Bush The Prince & Izant Companies

1. M. Coughlan Metglas, Incorporated

   1. F. Darling Lucas-Milhaupt, Incorporated

      1. P. Detty Ajax Tocco Magnethermic

         W. J. Engeron The Engeron Technology Group, Incorporated

      2. L. Feldbauer Abbott Furnace Company

         Y. Flom NASA Goddard Space Flight Center

         B. Freund Millennium Industries

         Y. P. Gao Aerojet Rockeydyne

         R. A. Gourley Curtiss-Wright

         M. T. Graham The Prince and Izant Company

      3. D. Grohoske General Electric Aviation

1. R. Hazelbaker Consultant

2. P. Hirthe Kru-Mar Manufacturing Services

K. H. Holko Holko Consulting

J. R. Jachna Modine Manufacturing Company

D. J. Jossick Lucas-Milhaupt, Incorporated

G. F. Kayser Aerojet Rockeydyne

J. A. Liguori SpaceX

J. Longabucco Lucas-Milhaupt, Incorporated

R. P. McKinney Harris Products Group

T. Oyama WESGO Metals

T. C. Profughi Hi TecMetal Group, Incorporated

S. S. Rajan Raytheon Space and Airborne Systems

J. P. Sands Bellman-Melcor, LLC

R. W. Smith S-Bond Technologies

M. Stroiczek Höganäs GmbH

P. T. Vianco Sandia National Laboratories

C. Walker Sandia National Laboratories

R. R. Xu Rolls-Royce Corporation

H. Zhao Creative Thermal Solutions

Advisors to the C3D Subcommittee on Brazing Specifications

G. L. Alexy Alexy Metals

R. Aluru Progress Energy

1. Barten Delphi Thermal & Interior

   N. C. Cole NCC Engineering

   M. Eliades Solvay Fluorides

2. E. Fuerstenau Lucas-Milhaupt, Incorporated

P. K. Gupta Honeywell Aerospace

F. M. Hosking Consultant

J. A. Jain Lucas-Milhaupt, Incorporated

T. A. Kern Consultant

E. Liguori Consultant

W. J. Loofboro Lucas-Milhaupt, Incorporated

J. C. Madeni Johns Manville

W. Miglietti ProEnergy

H. Mizuhara Consultant

R. X. Reed Lucas-Milhaupt, Incorporated

W. D. Rupert Lucas-Milhaupt, Incorporated

M. E. Sapp NAVAIR – In-Service Support Center

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Foreword

This foreword is not part of AWS C3.4M/C3.4:2016, Specification for Torch Brazing, but is included for informational purposes only.

This specification is one of a series prepared at the request of the Aerospace Materials Division (AMD) of the Society of Automotive Engineers (SAE) and a number of other organizations to replace the military specification MIL-B-7883, Brazing of Steels, Copper, Copper Alloys, Nickel Alloys, Aluminum, and Aluminum Alloys, which addressed all brazing processes. It became both obsolete and very cumbersome as brazing technology proliferated and became more complex.

Addressing all of the diverse brazing processes in one concise, easily understood document was found to be impractical; therefore, a series of five independent specifications on brazing have been written, all in the same format. These are the present document, AWS C3.4M/C3.4, Specification for Torch Brazing; AWS C3.5M/C3.5, Specification for Induction Brazing; AWS C3.6M/C3.6, Specification for Furnace Brazing; AWS C3.7M/C3.7, Specification for Aluminum Brazing; and AWS C3.9M/C3.9, Specification for Resistance Brazing.

The decision to subdivide the technology in this way was based on a survey of production brazing applications conducted by the AWS C3 Committee on Brazing and Soldering. The survey demonstrated that these five specifications would cover the vast majority of brazing performed today.

There is not a direct conversion of the MIL-B-7883 Grades and the AWS Classes and the quality assurance requirements differ. The cancellation of MIL-B-7883 was not intended to add additional inspection requirements to legacy hardware (i.e., MIL-B-7883 Grade B with only external inspection was not intended to become AWS Class B with internal NDT requirements). Each Organization Having Quality Responsibility must provide instructions on how or if the cancellation is to be handled for their hardware.

After the completion of the brazing specifications, it was determined that a document providing specific criteria and requirements for the application of ultrasonic testing to brazed joints was needed. Therefore, AWS C3.8M/C3.8, Specification for the Ultrasonic Pulse-Echo Examination of Brazed Joints, was written to complement this series.

This fourth edition supersedes AWS C3.4M/C3.4:2007, bearing the same title. Revisions made to this edition were coor- dinated with changes in AWS C3.5M/C3.5 and AWS C3.6M/C3.6, incorporating many of the improvements in the 2011 edition of AWS C3.7M/C3.7, and coordinating the wording between the three documents. Revisions were made through- out the document.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS C3 Committee on Brazing and Soldering, American Welding Society, 8669 NW 36 St, #130, Miami, FL 33166.

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Table of Contents

Page No.

Personnel v

Foreword ix

1. General Requirements 1

   1. Scope 1

   2. Units of Measurement 1

   3. Safety 1

   4. Ordering Information 2

2. Normative References 2

3. Terms and Definitions 3

4. Classification of Brazed Joints 4

   1. Method of Classification 4

   2. Class A Joints 4

   3. Class B Joints 4

   4. Class C Joints 4

   5. No Class Specified 4

5. Process Requirements 4

   1. Process Description 4

   2. Equipment 4

   3. Materials 5

   4. Procedure Requirements 5

   5. Brazing Procedure Specification (BPS) Qualification 7

   6. Safety and Health 7

6. Quality Assurance Provisions 7

   1. Responsibility for Inspection 7

   2. Requirements for Compliance 7

   3. Inspection Personnel Qualification 7

   4. Sequence of Inspection and Manufacturing Operations 7

   5. Required Inspection of Brazed Joints 8

   6. Acceptance Criteria 9

   7. Process Completion 10

Annex A (Informative)—Informative References 11

Annex B (Informative)—Guidelines for the Preparation of Technical Inquiries 13

List of AWS Documents on Brazing and Soldering 15

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Specification for Torch Brazing

1. General Requirements

   1. Scope. This specification presents the minimum fabrication and quality requirements for the torch brazing of materials such as steels, stainless steels, copper, copper alloys, and heat- and corrosion-resistant alloys as well as other materials that can be adequately torch brazed. Note that the torch brazing of aluminum alloys is addressed in AWS C3.7M/C3.7, Specification for Aluminum Brazing.

      The purpose of this specification is to standardize torch brazing process requirements and brazed joint quality requirements for all applications requiring brazed joints of assured quality. This document establishes minimum require- ments for processes and products with a minimum of explanatory information so that sources of ambiguity are mini- mized. It assigns responsibility for the ultimate quality of the brazed product to a single organization and permits that organization to modify requirements if appropriate to the application. It requires proper documentation of any such modifications.

   2. Units of Measurement. This standard makes use of both the International System of Units (SI) and U.S. Customary Units; the latter are shown within brackets [ ]. 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 information 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. Safety Data Sheets supplied by the materials manufacturers

2. Operating Manuals supplied by equipment manufacturers Applicable Regulatory Agencies:

1. United States Department of Labor, Occupational Safety & Health Administration (OSHA)

2. Equivalent agencies of other countries and individual states

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.

See 5.6 for additional safety and health information.