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AWS C3.6M/C3.6:2008 An American National Standard

Specification for Furnace Brazing

AWS C3.6M/C3.6:2008 An American National Standard Approved by the American National Standards Institute September 12, 2007

Specification for Furnace Brazing
3rd Edition

Supersedes AWS C3.6:1999

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

550 N.W. LeJeune Road, Miami, FL 33126

AWS C3.6M/C3.6:2008

International Standard Book Number: 978-0-87171-080-2 American Welding Society 550 N.W. LeJeune Road, Miami, FL 33126 © 2007 by American Welding Society All rights reserved Printed in the United States of America Photocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in any form, including mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner. Authorization to photocopy items for internal, personal, or educational classroom use only or the internal, personal, or educational classroom use only of specific clients is granted by the American Welding Society provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet: <www.copyright.com>.

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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 governmental 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 the AWS administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, evaluate, 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 are entrusted to appropriately qualified and competent personnel. This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition. 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. Finally, the AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so. 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, 550 N.W. LeJeune Road, Miami, FL 33126 (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, 550 N.W. LeJeune Road, Miami, FL 33126.

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Personnel
AWS C3 Committee on Brazing and Soldering
P. T. Vianco, Chair R. W. Smith, Vice Chair S. N. Borrero, Secretary G. L. Alexy R. Aluru B. Barten D. W. Bucholz D. E. Budinger C. F. Darling W. J. Engeron S. L. Feldbauer Y. Flom D. Fortuna Y. Gao R. A. Gross Gourley S. R. Hazelbaker T. P. Hirthe F. M. Hosking J. R. Jachna D. A. Javernick D. Kane G. F. Kayser M. J. Kuta E. Liguori M. J. Lucas, Jr. R. P. McKinney C. R. Moyer T. Oyama C. A. Paponetti, Sr. R. L. Peaslee A. Rabinkin A. E. Shapiro C. Walker Sandia National Laboratories Materials Resources International American Welding Society The Prince & Izant Company Chromalloy Gas Turbine Corporation Delphi Thermal & Interior Conforma Clad, Incorporated General Electric Aviation Lucas-Milhaupt, Incorporated Engineered Alloy & Systems Support Abbott Furnace Company NASA Goddard Space Flight Center Sulzer Metco (U.S.), Incorporated Pratt & Whitney Rocketdyne Curtiss-Wright The Prince & Izant Company Kru-Mar Manufacturing Services Sandia National Laboratories Modine Manufacturing Company Los Alamos National Laboratory ADB Industries Pratt & Whitney Rocketdyne Lucas-Milhaupt, Incorporated Scarrott Metallurgical General Electric Aviation The Prince & Izant Company Bodycote Thermal Processing WESGO Metals Expert Brazing & Heat Treating, Incorporated Wall Colmonoy Corporation Metglas, Incorporated / Titanium Brazing Titanium Brazing, Incorporated Sandia National Laboratories

Advisors to the AWS C3 Committee on Brazing and Soldering A. Belohlav S. S. Bhargava S. Christy N. C. Cole C. E. Fuerstenau P. K. Gupta M. J. Higgins H. Lichtenberger E. Lugscheider W. D. Rupert Lucas-Milhaupt, Incorporated American Axle & Manufacturing Company Pratt and Whitney NCC Engineering Lucas-Milhaupt, Incorporated Honeywell Aerospace Pratt and Whitney Williams Advanced Materials Aachen University of Technology Wolverine Joining Technologies

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AWS C3D Subcommittee on Brazing Specifications
J. R. Jachna, Chair S. R. Hazelbaker, Vice Chair S. N. Borrero, Secretary R. Aluru D. E. Budinger S. L. Feldbauer Y. Flom C. E. Fuerstenau Y. P. Gao R. A. Gross Gourley T. P. Hirthe F. M. Hosking D. Kane G. F. Kayser M. J. Kuta E. Liguori J. A. Liguori M. J. Lucas, Jr. R. P. McKinney C. R. Moyer J. Newman T. Oyama C. A. Paponetti, Sr. R. L. Peaslee M. J. Pohlman R. W. Smith P. T. Vianco C. M. Volpe C. Walker C. Wohlmuth Modine Manufacturing Company The Prince & Izant Company American Welding Society Chromalloy Gas Turbine Corporation General Electric Aviation Abbott Furnace Company NASA Goddard Space Flight Center Lucas-Milhaupt, Incorporated Pratt & Whitney Rocketdyne Curtiss-Wright Kru-Mar Manufacturing Services Sandia National Laboratories ADB Industries Pratt & Whitney Rocketdyne Lucas-Milhaupt, Incorporated Scarrott Metallurgical Scarrott Metallurgical General Electric Aviation The Prince & Izant Company Bodycote Thermal Processing Laser Technology, Incorporated WESGO Metals Expert Brazing and Heat Treating, Incorporated Wall Colmonoy Corporation Honeywell Aerospace Materials Resources International Sandia National Laboratories Wolverine Joining Technologies Sandia National Laboratories Consultant

Advisors to the AWS C3D Subcommittee on Brazing Specifications B. Barten N. C. Cole P. K. Gupta M. J. Higgins T. A. Kern H. H. Lang H. Mizuhara W. D. Rupert K. P. Thornberry R. W. Walls Delphi Thermal & Interior NCC Engineering Honeywell Aerospace Pratt and Whitney Consultant York International Corporation Consultant Wolverine Joining Technologies Care Medical, Incorporated Walls Engineering

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Foreword
This foreword is not part of AWS C3.6M/C3.6:2008, Specification for Furnace 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 AWS C3.4M/C3.4, Specification for Torch Brazing; AWS C3.5M/C3.5, Specification for Induction Brazing; the present document, AWS C3.6M/C3.6, Specification for Furnace Brazing; AWS C3.7M/C3.7, Specification for Aluminum Brazing, and C3.8M/C3.8, Specification for the Ultrasonic Examination of Brazed Joints. 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. After the completion of the fourth brazing specification, 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 Examination of Brazed Joints, was written to complement this series. This third edition supersedes AWS C3.6:1999, bearing the same title. 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, 550 N.W. LeJeune Road, Miami, FL 33126.

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Table of Contents
Page No. Personnel......................................................................................................................................................................v Foreword ....................................................................................................................................................................vii 1. Scope.....................................................................................................................................................................1 2. Normative References .........................................................................................................................................1 3. Terms and Definitions.........................................................................................................................................2 4. Classification of Brazed Joints ...........................................................................................................................2 4.1 Method of Classification..............................................................................................................................2 4.2 Class A Joints ..............................................................................................................................................2 4.3 Class B Joints...............................................................................................................................................3 4.4 Class C Joints...............................................................................................................................................3 4.5 No Class Specified.......................................................................................................................................3 Process Requirements .........................................................................................................................................3 5.1 Process Description .....................................................................................................................................3 5.2 Equipment....................................................................................................................................................3 5.3 Materials ......................................................................................................................................................5 5.4 Procedure Requirements..............................................................................................................................5 5.5 Brazing Procedure Qualification .................................................................................................................6 5.6 Safety and Health.........................................................................................................................................6 Quality Assurance Provisions ............................................................................................................................7 6.1 Responsibility for Inspection.......................................................................................................................7 6.2 Requirements for Compliance .....................................................................................................................7 6.3 Sequence of Inspection and Manufacturing Operations..............................................................................7 6.4 Required Inspection of Brazed Joints ..........................................................................................................7 6.5 Acceptance Criteria .....................................................................................................................................9

5.

6.

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 Furnace Brazing

1. Scope
This specification presents the minimum fabrication and quality requirements for the furnace brazing of materials such as steels, stainless steels, nickel, nickel alloys, copper, copper alloys, and heat- or corrosion-resistant materials as well as other materials that can be adequately furnace brazed. Note that the furnace brazing of aluminum alloys is addressed in AWS C3.7M/C3.7, Specification for Aluminum Brazing. The purpose of this specification is to standardize furnace brazing process requirements and control brazed joint quality for all applications requiring brazed joints of assured quality. This document establishes minimum requirements for processes and products with a minimum of explanatory information so that sources of ambiguity are minimized. 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. Procedures for the protection of the safety and health of those performing resistance brazing and related operations are of great importance. However, safety and health issues and concerns are beyond the scope of this standard and therefore are not fully addressed herein. Safety and health information is available from other sources, including, but not limited to, ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes. This standard makes use of both the International System of Units (SI) and U.S. Customary Units. The latter are shown within brackets [ ], or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system shall be used independently.

visions 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. American Welding Society (AWS) standards:1 AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination; AWS A3.0, Standard Welding Terms and Definitions, Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting, and Thermal Spraying; AWS A5.8/A5.8M, Specification for Filler Metals for Brazing and Braze Welding; AWS A5.31, Specification for Fluxes for Brazing and Braze Welding; AWS B2.2, Standard for Brazing Procedure and Performance Qualification; AWS C3.3, Recommended Practices for the Design, Manufacture, and Examination of Critical Brazed Components; and AWS C3.8M/C3.8, Specification for the Ultrasonic Examination of Brazed Joints. American Society for Quality (ASQ) standard:2 ASQ Z1.4, Sampling Procedures and Tables for Inspection by Attributes. Society of Automotive Engineers (SAE)/Aerospace Materials Division (AMD) standards:3 SAE AMS 2403, Plating, General Purpose;
standards are published the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126. 2 ASQ standards are published by the American Society for Quality, 600 North Plankinton Avenue, Milwaukee, WI 532033005. 3 SAE standards are published the Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 150960001.
1 AWS

2. Normative References
The standards listed below contain provisions which, through reference in this text, constitute mandatory pro-

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SAE AMS 2424, Plating, Nickel, Low Stressed Deposit; SAE AMS 2451/1, Plating, Brush, Nickel General Purpose; and SAE AMS 2750, Pyrometry. American Society for Testing and Materials (ASTM) standards:4 ASTM E 230, Electromotive Force (EMF) Tables for Standardized Thermocouples; ASTM E 1742, Standard Practice for Radiographic Examination; and ASTM E 1417, Standard Practice for Liquid Penetrant Examination. National Conference of Standards Laboratories (NCSL) standard:5 NCSL Z540-1, General Requirements for Calibration Laboratories and Measuring and Test Equipment.

braze wetting. Brazing filler metal should be smooth, adherent, and exhibiting no evidence of repulsion of the brazing filler metal by the base metal surface. brazing procedure specification (BPS). A document specifying the required brazing variables for a specific application. joint dimensions. The joint length is the greater of the two dimensions of the joint parallel to the faying surfaces. The joint width is the lesser of these two dimensions of the joint. The clearance between the faying surfaces is the third dimension to be considered. lack of bond. A condition in a brazed joint where although brazing filler metal is present between the faying surfaces, the filler metal does not adhere or form a metallurgical bond with the base metal. It most commonly occurs when brazing filler metal is preplaced between contaminated faying surfaces. Organization Having Quality Responsibility. The organization responsible to the end user of the product for the quality of the product and its suitability for the intended use. This organization is usually the manufacturer and marketer of the final product in commercial business and the prime contractor in government procurement. Although such organizations may subcontract brazing and related operations to others, they cannot delegate the ultimate responsibility for the service suitability of the product to these subcontractors. surface porosity. A roughened or spongy appearance or open pores on the surface of the brazed fillet. Such pores are not sharply linear or crack-like in shape. Surface porosity is confined to the fillet and does not progress into the braze joint proper. void. Any area of the braze joint proper that is not completely filled with brazing filler material.

3. Terms and Definitions
AWS A3.0, Standard Welding Terms and Definitions, Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting, and Thermal Spraying, provides the basis for terminology used herein. For the purposes of this document, the following terms and definitions apply: braze joint. The total area, as defined by the engineering drawing, of the faying surfaces to be joined by brazing and the fillets that form at the edges of that area. braze joint proper. The total area, as defined by the engineering drawing, of the faying surfaces to be joined by brazing, excluding any fillets that form at the edges of that area. brazing symbol. The symbol on the engineering drawing designating the location, class, and configuration of the brazed joint. Such symbols shall be in accordance with AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination.
4 ASTM

4. Classification of Brazed Joints
4.1 Method of Classification. Furnace brazed joints are classified in this specification based on two criteria: the design requirements and the consequences of their failure. It is the responsibility of the Organization Having Quality Responsibility to evaluate these or other factors and assign the proper classification. This classification controls which inspection methods and limits are required. 4.2 Class A Joints. Class A joints are those joints subjected to high stresses, cyclic stresses, or both, the failure of which could result in significant risk to persons or property, or could result in a significant operational failure.

standards are published by the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. 5 NCSL standards are published by the National Conference of Standards Laboratories, 2995 Wilderness Place, Suite 107, Boulder, CO 80301-5404.

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4.3 Class B Joints. Class B joints are those joints subjected to low or moderate stresses, cyclic stresses, or both, the failure of which could result in significant risk to persons or property, or in significant operational failure. 4.4 Class C Joints. Class C joints are those joints subjected to low or moderate stresses, cyclic stresses, or both, the failure of which would have no significant detrimental effect. 4.5 No Class Specified. When no class is specified on the engineering drawing or other applicable document approved by the Organization Having Quality Responsibility, Class A requirements shall apply. However, because of the confusion that can result, all engineering drawings referencing this specification should state the class of the brazed joint in the brazing symbol. Symbols shall be in accordance with AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination.

assemblies being brazed. In equipment where SAE AMS 2750, Pyrometry, is not used in its entirety, the provisions of 5.2.2 shall apply. The instrument shall be of the potentiometer type or equivalent capable of measuring, recording, and providing a permanent record of the temperature through the entire brazing thermal cycle. In furnaces with multiple heating zones (i.e., preheat zone, braze zone, postheat zone), such instrumentation shall be provided for each zone. All instruments used to measure the temperature of assemblies being brazed or to control furnace temperature, or both, shall have an indicated temperature accuracy range of not more than 0.25% of the maximum for which the furnace is qualified over the entire operating range, including each furnace heat zone. The indicated temperature accuracy of the instrument shall be determined in accordance with the equipment manufacturer’s recommendations using a known electromotive force input traceable to the National Institute of Standards and Technology.6 All instruments shall be calibrated in accordance with SAE AMS 2750 and NCSL Z540-1, General Requirements for Calibration Laboratories and Measuring and Test Equipment. Instruments shall be calibrated on a regular schedule or whenever repairs or modifications are made to them. 5.2.3 Workload Control Thermocouples. Workload control thermocouples shall be of a type listed in ASTM E 230, Electromotive Force (EMF) Tables for Standardized Thermocouples. They shall be calibrated by comparison to a known calibrated test instrument traceable to the National Institute of Standards and Technology with the frequency specified by AMS 2750 and replaced as required. 5.2.4 Work-Zone Control Thermocouples. Workzone control thermocouples (furnace control) shall be of a type listed in ASTM E 230. They shall be calibrated by a comparison to a known calibrated instrument traceable to the National Institute of Standards and Technology with the frequency specified by SAE AMS 2750 and replaced as required. 5.2.5 Atmosphere-Controlling Instruments 5.2.5.1 Electronic Dew Point Measuring Devices. Electronic dew point measuring devices shall be calibrated in accordance with the manufacturer’s recommendations against reference devices traceable to the National Institute of Standards and Technology, or
6 National

5. Process Requirements
5.1 Process Description. Furnace brazing is a process in which assembled components, with brazing filler metal preplaced, are loaded into a furnace. The furnace is then purged with a neutral or reducing atmosphere, or evacuated of air, and heated to a certain temperature (generally above the liquidus of the brazing filler metal, but less than the melting point of the base metals). The brazements are then cooled or quenched at an appropriate rate so as to minimize distortion and produce the required properties in the brazing filler metal and base material. This cycle is designed to produce the melting and solidification of the brazing filler metal required to join the components without melting or damaging the base metals. 5.2 Equipment 5.2.1 General Furnace Requirements. All brazing furnaces shall have automatic temperature control and recording devices in good working order capable of controlling the temperature profile of the furnace to the requirements of this specification. Furnaces shall have adequate capacity to accomplish uniform heating of the workload at the rate required to prevent both unacceptable thermal distortion of the assemblies and liquation of the brazing filler metal. The furnace and associated equipment shall be properly maintained in good working order. 5.2.2 Temperature Measurement and Control Instruments. In closed, batch-type furnaces, suitable instrumentation and thermocouples (see 5.2.3) shall be provided to measure and control the temperature of

Institute of Standards and Technology (NIST), Office of Standard Reference Materials, 100 Bureau Drive, Stop 2300, Gaithersburg, MD 20899-2300.

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equivalent. Such gauges shall be calibrated before initial use and recalibrated at a frequency not to exceed six months. 5.2.5.2 Vacuum Measuring Devices. Thermocouple gages shall be used to measure pressure higher than 0.13 Pa [10–3 torr]. Suitable electronic gauges shall be used to measure pressures of 0.13 Pa [10–3 torr] or less. These gauges shall be so mounted as to measure the pressure within the work zone of the furnace. Suitable instruments for reading and recording the pressure within the furnace work zone shall also be provided. These instruments and gauges shall be calibrated in accordance with the manufacturer’s recommendations against reference standards traceable to the National Institute of Standards and Technology. Such gauges shall be calibrated before initial use and recalibrated at a frequency not to exceed six months. 5.2.6 Furnace Qualification. In equipment for which SAE AMS 2750 is not used in its entirety, the provisions of 5.2.6 shall apply. All furnaces shall be qualified for temperature uniformity and control prior to initial use for production brazing. Furnaces used for brazing above 1093°C [2000°F] shall be requalified at least every three months. Furnaces used only for brazing below 1093°C [2000°F] shall be requalified every six months. All furnaces shall be requalified after any repairs or alterations to the furnace that might affect furnace temperature control or uniformity (e.g., new heating elements, new control thermocouple(s), burner tubes, replacement of shielding burner tubes). Requalification is not required when the repair or alteration has previously been documented not to affect the temperature control or uniformity of the furnace. 5.2.6.1 Furnace Qualification Procedure. Temperature uniformity tests may be conducted with a furnace load representative of production parts, material, racks, or empty, and using a typical production atmosphere or vacuum level. The test shall be conducted using new or recalibrated thermocouples. The potentiometric measuring equipment or equivalent shall meet the requirements of 5.2.2. Instruments used to control the furnace during production brazing shall not be used to monitor the qualification thermocouples. A minimum of three thermocouples shall be used to determine the temperature uniformity of furnaces having a work zone volume of 0.085 m3 (cubic meters) [3 ft3 (cubic feet)] or less. A minimum of five thermocouples shall be used to determine the uniformity of furnaces having a work zone between 0.085m3 to 0.28m3 [3 ft3 to 10 ft3]. A minimum of nine thermocouples or one thermocouple per 0.71m3 [25 ft3] of working

zone, whichever is greater, shall be used to determine the uniformity of furnaces having a work zone larger than 0.28m3 [10 ft3]. No more than 40 thermocouples shall be required to determine the temperature uniformity in the work zone of any furnace. The thermocouples shall be symmetrically distributed within the work zone. Qualification shall be performed at the highest and lowest brazing temperature at which the furnace is used and at intermediate temperature such that the difference between qualification temperatures is not greater than 315°C [600°F]. The temperature of all test and furnace control thermocouples shall be recorded at intervals of no more than five minutes starting immediately after heating begins. Temperature measurement and recording shall continue at least 30 minutes after equilibrium has been reached to determine the temperature pattern of the furnace. The results of the test shall be posted at the furnace and shall include the date of testing, the due date of the next test, the size of the work zone, and the results of the tests, including the location within the work zone of the hottest and coldest location. Temperature uniformity may be run with a production load when all requirements are met. 5.2.6.2 Temperature Uniformity Requirements. Before temperature equilibrium has been reached, no temperature reading shall exceed the temperature for which the furnace is being qualified by more than 14°C [25°F]. After temperature equilibrium has been reached, the temperature recorded by any test thermocouple shall not vary from the selected furnace control temperature by more than 14°C [25°F]. 5.2.7 Atmosphere Furnace Requirements. Atmosphere controls shall be suitable for the intended purpose and in good working order. The gas supply and purification system shall be capable of supplying atmosphere gases in accordance with the approved brazing procedure specification (BPS) (see 5.5). 5.2.8 Vacuum Furnace Requirements. Vacuum furnaces shall comply with the following performance requirements: a cold and previously outgassed furnace shall leak no more than 2.6 Pa [20 × 10–3 torr] per hour when the vacuum chamber is isolated from the pumping system after being evacuated to 0.65 Pa [5 × 10–3 torr] or less. Such a leak rate test shall be performed at least once a week, or whenever there is reason to suspect that an unacceptable leak rate exists. The furnace should have the capability of introducing argon, hydrogen, helium, or nitrogen, if required, for rapid cooling or to backfill after evacuation to maintain a partial pressure, if required, to

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prevent sublimation of elements from the brazing filler metal. 5.2.9 Fixtures. When required, furnace brazing fixtures shall be made of suitable materials that will not contaminate the furnace or workload either upon contact or by vaporization. Fixtures shall be designed, built, and maintained to provide adequate support of assemblies, maintain proper braze joint clearance, and accommodate thermal expansion, all without adversely affecting mass load and uniformity. Coating with stop-off, ceramic, or other protective coating of the fixtures may be required to prevent or minimize brazing of the assembly to the fixtures. 5.3 Materials 5.3.1 Furnace Brazing Materials Requirements. As a minimum, the following furnace brazing materials (as required) shall be documented: 5.3.1.1 Brazing Filler Metals. The brazing filler metal to be used shall be specified on the engineering drawing or accompanying documents and shall meet the requirements of AWS A5.8/A5.8M, Specification for Filler Metals for Brazing and Braze Welding, unless otherwise specified by the engineering drawing or accompanying documents. There are brazing filler metal/base metal combinations that can cause severe service problems under certain circumstances, e.g., nickel-based alloys brazed with silver-bearing brazing filler metals and iron-based alloys brazed with silver or copper-based brazing filler metals containing high phosphorous. Care should be exercised to ensure that the brazing filler metal selected is metallurgically compatible with the base metal and the furnace brazing process. Also, measures may need to be taken to prevent bonding of the brazement to the fixture material. 5.3.1.2 Fluxes. Fluxes shall be used in combination with controlled atmospheres, other than in vacuum, only when specified on the approved BPS (see 5.5). Fluxes are specified in AWS A5.31/A5.31M, Specification for Fluxes for Brazing and Braze Welding. Other fluxes may be used if permitted by the Organization Having Quality Responsibility. 5.3.1.3 Cleaning Materials. Cleaning materials shall leave no residue that will interfere with the wetting or flow of the filler metal. For example, alumina, silica, zirconia, or other nonmetallic blast cleaning media may leave undesirable residue that could inhibit the braze wettability. Chemical cleaning solutions that are detrimental to the base metal or brazing process shall not be used (see 5.6 for Safety Precautions).

5.3.1.4 Furnace Atmosphere. Furnace atmospheres shall be compatible with the brazing filler metal and base metals and suitable for the particular application. 5.3.1.5 Braze Stopoff. Braze stopoff, if used, shall be suitable for the intended purpose and compatible with the base metal(s), brazing filler metal, and any protective atmospheres used. In certain specialized applications, residues from stopoff materials can produce unacceptable contamination of the product. If contamination is suspected, approval by the Organization Having Quality Responsibility should be obtained prior to use. 5.4 Procedure Requirements 5.4.1 Surface Preparation. The faying surfaces and adjacent areas of components to be brazed shall be free of oil, grease, dirt, oxides, paint, scale, or other foreign substances that can interfere with the brazing process or contaminate the braze joint. Burrs shall be removed as required prior to final cleaning to permit proper assembly and brazing filler metal flow. 5.4.2 Nickel Plating. Nickel plating is recommended on the braze joint areas of stainless, corrosion-, or heatresistant steels having equal or greater percentage by weight of the following alloying elements: (1) Titanium—0.40%, (2) Aluminum—0.40%, and (3) Titanium plus aluminum—0.70%. Electrolytic nickel plate 0.01 mm to 0.02 mm [0.0004 in to 0.0008 in] thick shall be applied in accordance with SAE AMS 2403, Plating, Nickel, General Purpose, SAE AMS 2424, Plating, Nickel Low-Stressed Deposit, or SAE AMS 2451/1, Plating, Brush, Nickel General Purpose. When the braze temperature is below 815°C [1500°F], SAE AMS 2404, Plating, Electroless Nickel, may be used. Other nickel plating methods per SAE AMS 2451/7, Plating, Brush, Nickel Low Stress, MediumHardness Deposit, may be used. The plating shall extend 2.5 mm [0.10 in] minimum beyond the brazed joint area indicated by the brazing symbol on the engineering drawing unless the part configuration does not permit this allowance. In addition, nickel plate may be specified by the Organization Having Quality Responsibility to cover any area or the entire surface of details or assemblies at its discretion. When the drawing or purchase documents do not specify localized plating, the components may be completely plated. CAUTION: When using nickel plating, phosphorus or sulfur—potential ingredients in the nickel plating—may interact with steel to form iron phosphides or sulfides when heated to over 815°C [1500°F]. Temperature mon-

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itoring shall be used, whenever possible, when heating to ensure the nickel plating will not interact with the base metals and form deleterious phases. 5.4.3 Joint Clearance. Joint clearance between faying surfaces to be furnace brazed shall be controlled by the assembly procedures so that proper joint clearance at the brazing temperature is provided. When one of the faying surfaces is cross-hatched or straight-line knurled in the direction of brazing filler metal flow into the joint, a line-to-line fit is permitted. The depth of such knurling shall not exceed 0.13 mm [0.005 in] below the original surface. Suggested joint clearances for typical materials may be found in the AWS Brazing Handbook. 5.4.4 Tack Welding. When tack welding is required to maintain proper positioning of components, the tack weld size, location, and welding filler metal shall be specified on the engineering drawing, or in writing by the Organization Having Quality Responsibility. Tack welds shall be applied with adequate inert gas shielding per the approved welding procedure to assure that oxide contamination of the braze joint surfaces does not occur. 5.4.5 Application of Brazing Filler Metal. Brazing filler metal specified by the engineering drawing may be applied as a paste mixture, slurry, wire, foil, transfer tape, cladding (braze sheet), or preformed shapes, as defined in the approved BPS. Brazing filler metal shall be applied to one side of the joint only or in slots machined within the joint area so that it flows through the joint by capillary action in order to facilitate visual inspection. Brazing filler metal placement between the joint faying surfaces of Class A and Class B joints shall be permitted only when authorized by the engineering drawing, with the prior written approval of the Organization Having Quality Responsibility, or if ultrasonic inspection or another approved inspection procedure per 6.4.3.4 is performed to assure proper metallurgical bonding between the braze filler metal and base metals. After the brazing filler metal application, assemblies shall be protected from contamination by suitable means. 5.4.6 Application of Stopoff. Braze stopoff, if used, shall be applied in the quantities and locations specified in the approved BPS to control brazing filler metal flow as required to meet the engineering drawing. It shall be applied so as to avoid contamination of the braze joint or the brazing filler metal. 5.4.7 Brazing Cycle. The brazing temperature and time shall be controlled depending on the chemical composition of the brazing filler metal and the degree of diffusion brazing desired. Heating and cooling rate shall be controlled to prevent distortion of the specific design of

the component being processed. These parameters may be defined on the engineering drawing or in writing by the Organization Having Quality Responsibility. 5.4.7.1 Rebrazing. Rebraze cycles shall be permitted only to a BPS meeting the requirements of 5.5. When the original brazing filler metal application side is closed, additional brazing filler metal may be added if needed to the opposite side of the joint. Brazed joints may be rebrazed by brazing to the original approved BPS without the specific written approval of the Organization Having Quality Responsibility, unless otherwise specified by that organization. Additional brazing filler metal of the same type used in the original procedure may be used. If the assembly is still not acceptable after having been rebrazed twice, or if a brazing process or brazing filler metal other than that approved by the qualified procedure is to be used, or if disassembly of the brazed assembly is required, then prior written approval of the procedures to be used shall be obtained from the Organization Having Quality Responsibility. If it is necessary to change the brazing process or brazing filler metal to accomplish the rebraze, then the new procedure shall be qualified as specified in 5.5. 5.4.8 Postbrazing Operations. Assemblies shall be cooled after brazing in such a manner that cracking of the brazing filler metal or base metals does not occur and residual stresses are minimized. Postbraze heat treatments, or combined brazing and heat treating cycles, if required, shall be performed per the engineering drawing. If required, flux or stopoff residues shall be removed by suitable means. 5.5 Brazing Procedure Qualification. Brazing equipment, procedures, and process parameters shall be qualified to establish the properties that are expected to result from its application to production brazements. The conditions used in making the test brazement (if required) or production assemblies, and the results of the required examination, shall be documented. Qualification procedures may be in accordance with AWS B2.2, Standard for Brazing Procedure and Performance Qualification, or as required by the Organization Having Quality Responsibility. If multiple brazing cycles are required for product fabrication, then all cycles shall be so qualified, documented, and approved. Prior to use, any modification of the approved procedure(s) shall be approved in writing. 5.6 Safety and Health. Brazing fluxes and brazing filler metals, particularly those containing cadmium, emit hazardous fumes during the brazing cycle. It is mandatory that all furnace brazing operations be properly and ade-

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quately ventilated or that operators be provided with an adequate breathing apparatus, or both, as required to ensure that all relevant federal, state, and local government safety and health requirements are met. In addition, there are other hazards involved in furnace brazing such as those relating to the use of corrosive fluxes, potentially explosive gases, and hot surfaces. The standard ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, provides further information on these and other safety and health concerns that must be controlled during furnace brazing. Information on the hazards associated with materials used in the brazing process may be found in the Material Safety Data Sheets (MSDSs) available from the manufacturer, as well as the AWS Safety and Health Fact Sheets available via www.aws.org.

is accessible for inspection. Brazements requiring postbraze heat treatment at the brazing house shall be inspected after heat treatment has been completed, unless otherwise specified on the engineering drawing. When brazed joints are inspected in process prior to the machining of joint edges, reinspection shall be required after machining to assure that the brazed joint has not been damaged in the machining operations. Inspection should be performed after postbraze cleaning. 6.4 Required Inspection of Brazed Joints 6.4.1 Destructive Testing. The destructive testing of assemblies or samples shall be performed as required for process qualification or corrective action. The destructive testing of samples or sample parts shall not be substituted for any nondestructive examination required by this specification except as part of an approved sampling in accordance with the requirements of this specification or as part of an inspection procedure complying with 6.4.3.4. 6.4.1.2 Burst Test. Burst testing shall be conducted when required by the Organization Having Quality Responsibility. 6.4.2 Visual Examination. All brazed joints shall be visually examined to the acceptance criteria specified in 6.5. 6.4.3 Nondestructive Examination. Class A and Class B brazed joints, except as specified in 6.4.3.3 and 6.4.3.4, shall be examined either radiographically or ultrasonically in accordance with the requirements of 6.5.2 unless otherwise specified on the engineering drawing. The choice of process is optional, except for the criteria established in 6.4.3.1 and 6.4.3.2. However, ultrasonic examination is generally the preferred method for examining brazed joints. 6.4.3.1 Radiographic Examination. Radiographic examination shall be performed in accordance with ASTM E 1742, Standard Practice for Radiographic Examination. When the joint clearance is less than 2% of the total thickness of the base metals or when the brazing filler metal is preplaced between the faying surfaces, the capability of the radiographic technique to detect the minimum discontinuity size required by the Organization Having Quality Responsibility shall be demonstrated. NOTE: When brazing filler metal is preplaced between the faying surfaces, unmelted filler metal may result in unreliable interpretations. Ultrasonic examination shall be required when the criteria for radiographic examination is not met, except as specified in 6.4.3.4.

6. Quality Assurance Provisions
6.1 Responsibility for Inspection. Unless otherwise specified in the contract or purchase order, the organization performing a brazing operation is responsible for all inspection of the brazed joints. This requirement includes a system of quality control and documentation that assures and can attest that all required operations and procedures have been performed. Suppliers may use their own facilities or any other facility acceptable to the Organization Having Quality Responsibility for the inspection of the final product. However, the Organization Having Quality Responsibility shall retain the right to perform or witness the required tests or to perform any other tests necessary to assure that the brazed assemblies conform to the requirements of this specification, and the engineering drawing. 6.2 Responsibility for Compliance. All products shall meet all requirements of this specification except when deviation is specifically approved in writing by the Organization Having Quality Responsibility, or is part of the engineering drawing. The braze inspections required shall become a part of the contractor’s overall inspection system or quality program. The absence of any inspection requirements in this specification shall not relieve a contractor of the responsibility of assuring that all products or supplies that the contractor produces under this specification meet all contractual obligations. The use of inspection sampling systems (see 6.4.4) does not authorize the shipment of known defective material nor does it obligate any person or organization to accept defective material. 6.3 Sequence of Inspection and Manufacturing Operations. Furnace brazed joints may be inspected at the assembly or subassembly level, provided the entire joint

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6.4.3.2 Ultrasonic Examination. Ultrasonic examination shall be performed in accordance with AWS C3.8M/C3.8, Specification for the Ultrasonic Examination of Brazed Joints. Ultrasonic examination shall be performed only when the following configuration and process criteria are met: (1) Surface through which the sonic pulse enters the material shall be parallel to the faying surfaces, and the assembly must be processed so that all brazing filler metal runover onto this surface is removed prior to ultrasonic inspection. Excess brazing filler metal must not be on the surfaces through which the ultrasound enters the test specimen; (2) A suitable ultrasonic reference standard shall be available. It shall be identical to the assemblies it represents with respect to joint configuration, joint clearance, and brazing filler material. The reference standard shall have defects of known size and location suitable for calibrating the ultrasonic apparatus; and (3) Ultrasonic apparatus shall produce a joint facsimile suitable for making quantitative measurements of the percentage of the brazed joint actually bonded and for documenting the testing of the assembly. Radiographic examination shall be required when any of these criteria are not met except as specified in 6.4.3.4. 6.4.3.3 Leak and Pressure Testing of Class A and Class B Joints. If specified on the engineering drawing or approved in writing by the Organization Having Quality Responsibility, pressure and leak testing to the following requirements may be substituted for radiographic and ultrasonic examination of Class A and Class B joints: (1) Class A joints shall be pressure tested at an internal pressure and according to procedures specified in writing by the Organization Having Quality Responsibility. No measurable leakage shall be allowed. They shall then be helium leak tested in accordance with the procedure outlined in AWS C3.3, Recommended Practices for the Design, Manufacture, and Examination of Critical Brazed Components. Leakage of not more than 3.0 × 10–5 cc3/s [2.0 × 10–6 in3/s] shall be detected with a suitable mass spectrometer leak detector in good working condition calibrated as specified by its manufacturer; and (2) Class B joints shall be air pressure tested at an internal pressure and according to procedures specified in writing by the Organization Having Quality Responsibility. Class B joints shall be bubble leak tested using a selected procedure defined in AWS C3.3 or as specified in writing by the Organization Having Quality Responsibility. No visually detected leaks shall be allowed.

NOTE: Internal pressure test fixtures and devices shall be suitable for the intended purpose and shall be adequately shielded to prevent injury to persons in case of catastrophic failure during pressure testing. 6.4.3.4 Alternate Examination Techniques. Certain specialized brazed components may not be inspectable using radiographic or ultrasonic techniques and may be unsuitable for leak or pressure testing in accordance with 6.4.3.3. In such cases, alternate examination techniques and acceptance limits shall be as specified in writing by the Organization Having Quality Responsibility. This organization is responsible for the suitability of the final product for service and of the selected inspection techniques to verify the suitability of the brazed joints. If no such special inspection techniques and acceptance limits have been specified in writing, all requirements of this specification shall be met. 6.4.3.5 Fluorescent or Dye Penetrant Examination. Fluorescent or dye penetrant examination techniques performed in accordance with ASTM E 1417, Standard Practice for Liquid Penetrant Examination, shall be used only on assemblies in which the brazed joint has been subjected to machining so as to ensure that the joint has not been damaged in machining or that internal voids or lack of bond has not been opened to the surface. These examination techniques are not suitable for the inspection of brazed fillets because they routinely give false results. 6.4.3.6 Other Nondestructive Tests. Additional nondestructive examination may be required by the Organization Having Quality Responsibility at its discretion. In such cases, the acceptance criteria shall be clearly defined in writing by this organization. 6.4.4 Inspection Sampling Plans 6.4.4.1 Class A Joints. Class A Joints require the inspection of every unit. No sample plans shall be used. 6.4.4.2 Class B Joints. Class B joints shall be inspected using a sample plan in accordance with ASQ Z1.4, Sampling Procedures and Tables for Inspection by Attributes, and only with the written permission of the Organization Having Quality Responsibility, provided the following criteria are met: (1) Sampling techniques are based upon the assumption that all of the products in a given batch or lot are identical; and (2) Proof of such identical processing is therefore a precondition for the approval of sample inspection plans. Such proof shall be documented and available to the Organization Having Quality Responsibility. No operation critical to the quality of the brazed joint shall be

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directly dependent upon the skill or care of an operator, except when a written record of the actual process variables controlled by the operator is automatically produced. When allowed, a random sample shall be selected from each inspection lot in accordance with ASQ Z1.4 acceptable quality levels (AQL) 2.5, C = 0 (i.e., no defects) and inspected in accordance with this specification. Lot sizes for the purposes of sampling shall consist of all brazed parts of the same design or kind manufactured using the same process from identical details, identically prepared during one continuous period, and submitted for acceptance at the same time. 6.4.4.3 Class C Joints. Class C joints may be inspected using sample plans in accordance with ASQ Z1.4. When allowed, a random sample shall be selected from each inspection lot in accordance with ASQ Z1.4 acceptable quality levels (AQL) 2.5, C = 0 (i.e., no defects) and inspected in accordance with this specification. Lot sizes for the purposes of sampling shall consist of all brazed parts of the same design or kind manufactured using the same process from identical details, identically prepared during one continuous period, and submitted for acceptance at the same time. NOTE: A single batch furnace run is considered one continuous period. 6.5 Acceptance Criteria. Unless otherwise specified by the engineering drawing or document referenced by it, the criteria specified below are the minimum acceptance criteria for inspection of furnace brazed joints. Any assembly failing to meet these minimum requirements shall be rejected. 6.5.1 External Discontinuities 6.5.1.1 Pinholes and Voids. Pinholes, voids, or brazing filler metal skips are allowed provided they shall not exceed the limits specified below. Discontinuities of less than 0.38 mm [0.015 in] are uninterpretable and are not considered as defects. Visual inspection of the fillet provides information about the wetting of the brazing filler metal to the base materials, adequate brazing filler metal volume, and proper brazing filler metal flow. Fillet voids, pinholes, and brazing filler metal skips are acceptable as long as they do not extend into the joint proper. Any fillet discontinuity that extends into the joint proper shall not exceed the following limits: (1) Class A—Maximum size 2.3 mm [0.090 in] with a total accumulated length less than 10% of the fillet length;

(2) Class B—Maximum size 2.3 mm [0.090 in] with a total accumulated length less than 25% of the fillet length; and (3) Class C—Maximum size 3.1 mm [0.120 in] with a total accumulated length less than 50% of the fillet length. 6.5.1.2 Cracks. Cracks are unacceptable. However, discontinuities with a major dimension of less than 0.38 mm [0.015 in], which are interpretable, are not considered defects as long as the assembly meets the applicable leak criteria and/or pressure test acceptance criteria. 6.5.1.3 Erosion. Any evidence of braze filler erosion of the exposed base metal surfaces is unacceptable if the erosion of either member exceeds 5% of the thickness for Class A and 15% for Class B or Class C of the thinnest component of the brazed joint. 6.5.1.4 Lack of Brazing Filler Metal Melting. Failure of the brazing filler metal to melt completely is unacceptable. 6.5.1.5 Edge Voids. For Class A and Class B joints, no through-voids (i.e., voids that extend through the entire brazed joint) are acceptable. For Class C, through voids are acceptable. There must be evidence of brazing filler metal penetration across the joint. Lack of such evidence of brazing filler metal penetration is unacceptable. When the assembly configuration makes inspection of the edge opposite that to which brazing filler metal was applied impossible, this requirement shall not apply. 6.5.1.6 Brazing Filler Metal Penetration. If the edge of the joint opposite that to which the brazing filler metal is applied is visible after brazing, the brazing filler metal shall be present at that edge of the joint. Brazing filler metal discontinuities at this edge are acceptable, as long as the criteria of 6.5.2 are met. This requirement shall not apply in cases where the edge of the joint opposite the edge to which filler material is applied is not accessible for inspection, because of the configuration of the assembly. 6.5.1.7 Flux or Flux Residue. Evidence of corrosive flux or corrosive flux residue is unacceptable (see 5.3.1.2). 6.5.1.8 Quality of Workmanship. The quality of workmanship shall be such that the assemblies are suitable for the intended purpose and that surfaces are free of excess braze filler material that could interfere with subsequent operations or the function of the product.

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6.5.2 Internal Discontinuities 6.5.2.1 Class A Joints. Radiographic film or ultrasonic facsimiles of Class A joints shall indicate that the total measured void, or unbonded area, of the joint does not exceed 15% of the total joint area. The width of the largest void or unbonded area as measured parallel to the joint width shall not exceed 60% of the total joint width. Any such void that is wider than 40% of the width of the joint shall extend no closer to either edge of the joint than 20% of the joint width.

6.5.2.2 Class B Joints. Radiographic film or ultrasonic facsimiles of Class B joints shall indicate that the total measured void, or unbonded area, of the joint does not exceed 25% of the total joint area. The width of the largest void, as measured parallel to the joint width, shall not exceed 70% of the total joint width. Any such area that is wider than 60% of the joint width or larger shall extend no closer to either joint edge than 15% of the joint width. 6.5.2.3 Class C Joints. Class C joints have no internal inspection requirements.

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Annex A (Informative) Informative References
This annex is not part of AWS C3.6M/C3.6:2008, Specification for Furnace Brazing, but is included for informational purposes only.

ANSI Z49.1:2005, Safety in Welding, Cutting, and Allied Processes, American Welding Society. AWS, 1991, Brazing Handbook, 4th ed., Miami: American Welding Society.

SAE AMS 2404:1997, Plating, Electroless Nickel, Society of Automotive Engineers. SAE AMS 2451/7:2000, Plating, Brush, Nickel Low Stress, Medium-Hardness Deposit, Society of Automotive Engineers.

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Annex B (Informative) Guidelines for the Preparation of Technical Inquiries
This annex is not part of AWS C3.6M/C3.6:2008, Specification for Furnace Brazing but is included for informational purposes only.

B1. Introduction
The American Welding Society (AWS) Board of Directors has adopted a policy whereby all official interpretations of AWS standards are handled in a formal manner. Under this policy, all interpretations are made by the committee that is responsible for the standard. Official communication concerning an interpretation is directed through the AWS staff member who works with that committee. The policy requires that all requests for an interpretation be submitted in writing. Such requests will be handled as expeditiously as possible, but due to the complexity of the work and the procedures that must be followed, some interpretations may require considerable time.

along with the edition of the standard that contains the provision(s) the inquirer is addressing. B2.2 Purpose of the Inquiry. The purpose of the inquiry shall be stated in this portion of the inquiry. The purpose can be to obtain an interpretation of a standard’s requirement or to request the revision of a particular provision in the standard. B2.3 Content of the Inquiry. The inquiry should be concise, yet complete, to enable the committee to understand the point of the inquiry. Sketches should be used whenever appropriate, and all paragraphs, figures, and tables (or annex) that bear on the inquiry shall be cited. If the point of the inquiry is to obtain a revision of the standard, the inquiry shall provide technical justification for that revision. B2.4 Proposed Reply. The inquirer should, as a proposed reply, state an interpretation of the provision that is the point of the inquiry or provide the wording for a proposed revision, if this is what the inquirer seeks.

B2. Procedure
All inquiries shall be directed to: Managing Director Technical Services Division American Welding Society 550 N.W. LeJeune Road Miami, FL 33126 All inquiries shall contain the name, address, and affiliation of the inquirer, and they shall provide enough information for the committee to understand the point of concern in the inquiry. When the point is not clearly defined, the inquiry will be returned for clarification. For efficient handling, all inquiries should be typewritten and in the format specified below. B2.1 Scope. Each inquiry shall address one single provision of the standard unless the point of the inquiry involves two or more interrelated provisions. The provision(s) shall be identified in the scope of the inquiry

B3. Interpretation of Provisions of the Standard
Interpretations of provisions of the standard are made by the relevant AWS technical committee. The secretary of the committee refers all inquiries to the chair of the particular subcommittee that has jurisdiction over the portion of the standard addressed by the inquiry. The subcommittee reviews the inquiry and the proposed reply to determine what the response to the inquiry should be. Following the subcommittee’s development of the response, the inquiry and the response are presented to the entire committee for review and approval. Upon approval by the committee, the interpretation is an official

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interpretation of the Society, and the secretary transmits the response to the inquirer and to the Welding Journal for publication.

obtained only through a written request. Headquarters staff cannot provide consulting services. However, the staff can refer a caller to any of those consultants whose names are on file at AWS Headquarters.

B4. Publication of Interpretations
All official interpretations will appear in the Welding Journal and will be posted on the AWS web site.

B6. AWS Technical Committees
The activities of AWS technical committees regarding interpretations are limited strictly to the interpretation of provisions of standards prepared by the committees or to consideration of revisions to existing provisions on the basis of new data or technology. Neither AWS staff nor the committees are in a position to offer interpretive or consulting services on (1) specific engineering problems, (2) requirements of standards applied to fabrications outside the scope of the document, or (3) points not specifically covered by the standard. In such cases, the inquirer should seek assistance from a competent engineer experienced in the particular field of interest.

B5. Telephone Inquiries
Telephone inquiries to AWS Headquarters concerning AWS standards should be limited to questions of a general nature or to matters directly related to the use of the standard. The AWS Board Policy Manual requires that all AWS staff members respond to a telephone request for an official interpretation of any AWS standard with the information that such an interpretation can be

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List of AWS Documents on Brazing and Soldering
Designation A2.4 A3.0 A5.8/A5.8M A5.31 B2.2 C3.2M/C3.2 C3.3 C3.4M/C3.4 C3.5M/C3.5 C3.6M/C3.6 C3.7M/C3.7 C3.8M/C3.8 C3.9M/C3.9 D10.13 BRH SHB Title Standard Symbols for Welding, Brazing, and Nondestructive Examination Standard Welding Terms and Definitions, Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting, and Thermal Spraying Specification for Filler Metals for Brazing and Braze Welding Specification for Fluxes for Brazing and Braze Welding Specification for Brazing Procedure and Performance Qualification Standard Method for Evaluating the Strength of Brazed Joints Recommended Practices for Design, Manufacture, and Examination of Critical Brazed Components Specification for Torch Brazing Specification for Induction Brazing Specification for Furnace Brazing Specification for Aluminum Brazing Recommended Practices for Ultrasonic Inspection of Brazed Joints Specification for Resistance Brazing (Forthcoming) Recommended Practice for the Brazing of Copper Pipe and Tubing for Medical Gas Systems Brazing Handbook Soldering Handbook

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