1、Recommended Practices for the Design, Manufacture, and Examination of Critical Brazed ComponentsAWS C3.3:2008 (R2016)An American National StandardAWS C3.3:2008 (R2016)An American National StandardApproved byAmerican National StandardnullnullnullitnulleApril 21null 2008Reanullirmed: Anullnullt 22null
2、 2016Recommended nullacticenullnullor tnull nullnullnullnull nullnnullactnullenull and nullamination onullCritical nullanulled Componentnull3rd EditionSupersedes AWS C3.3:2002Prepared by theAmerican Welding Society (AWS) C3 Committee on Brazing and SolderingUnder the Direction of theAWS Technical Ac
3、tivities CommitteeApproved by theAWS Board of DirectorsAbnullractThis standard lists the necessary steps to assure the suitability of brazed components for critical applications. Although such applications vary widely, they have certain common considerations with respect to materials, design, manufa
4、cture, and inspection. It is the intent of this document to identify and explain these common considerations and the best tech-niques for dealing with them. It is beyond the scope of this document to provide specific details on these techniques, which the user must adapt to fit each particular appli
5、cation.AWS C3.3:2008 (R2016)iiInternational Standard Book Number: 978-0-87171-892-1American Welding Society. All rights reserved.2016 Printed in the United States of AmericaPhotocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in any form, incl
6、uding mechanical, photocopying, recording, or otherwise, without the prior written consent 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
7、the American Welding Society (AWS) provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923; tel: (978) 750-8400; Internet: http:/AWS C3.3:2008 (R2016)iiiStatement on the Use of American Welding Society StandardsAll standards (codes, specific
8、ations, 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 inco
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17、w.aws.org). Users should ensure that they have the latest edition, amendments, errata, and addenda.Publication of this standard does not authorize infringement of any patent or trade name. Users of this standard accept any and all liabilities for infringement of any patent or trade name items. AWS d
18、isclaims liability for the infringement of any patent or product trade name resulting from the use of this standard.AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so.Official interpretations of any of the technical requirements of this standa
19、rd 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 F). With regard to technica
20、l 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 gi
21、ving 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 revis
22、ion 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 requeste
23、d 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 Committees response to the comments. Guests are invited to attend all meetings of the AWS C3 Committ
24、ee 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
25、St, # 130, Miami, FL 33166.AWS C3.3:2008 (R2016)ivThis page is intentionally blank.AWS C3.3:2008 (R2016)vPersonnel (Reaffirmation)AWS C3 Committee on Brazing and SolderingR. W. Smith, Chair S-Bond TechnologiesG. L. Alexy, 1st Vice Chair Alexy MetalsC. M. Volpe, 2nd Vice Chair Senior Aerospace Metal
26、Bellows DivisionJ. R. Douglass, Secretary American Welding SocietyJ. J. Bassindale Woodward, IncorporatedD. E. Budinger General Electric AviationJ. A. Bush The Prince Annex B, which presents sample specifications that are intended as guides for the preparation of the users documents; Annex C, which
27、presents a discussion of brazing risk management; Annex D, which presents a table relating to the quantification of the scope and magnitude of braze-induced discontinuities; Annex E, which presents systematic criteria for design of brazed components; and Annex F, which presents guidelines for the re
28、questing of an official interpretation of an AWS standard.1.2 Units of Measurement. This standard does not require units of measure. Therefore, no equivalents or conversions are contained except when they are cited in examples.1.3 Safety. Safety and health issues and concerns are beyond the scope of
29、 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 Brazing Handbook(3) AW
30、S Safety and Health Fact Sheets(4) Other safety and health information on the AWS websiteMaterial or Equipment Manufacturers:(1) Safety Data Sheets supplied by the materials manufacturers(2) Operating Manuals supplied by equipment manufacturersApplicable Regulatory Agencies:(1) United States Departm
31、ent of Labor, Occupational Safety 3. Terms and DefinitionsAWS A3.0M/A3.0, Standard Welding Terms and Definitions, provides the basis for terms and definitions used herein. However, the following terms and definitions are included below to accommodate usage specific to this document.critical componen
32、t. A component whose primary failure would cause significant danger to persons or property or would result in a significant operational penalty.4. Brazing Materials4.1 Filler Metals. The brazing filler metal to be used as well as its quantity, dimensions, and placement should be specified on the eng
33、ineering drawing or accompanying documents and should meet the requirements of AWS A5.8M/A5.8, Specification for Filler Metals for Brazing and Braze Welding, unless otherwise specified by the engineering drawing or accompanying documents. Each incoming lot, batch, or heat of brazing filler metal sho
34、uld be verified to the specification. Identification and traceability should be provided.4.2 Form. Brazing filler metals are available in several different physical shapes and sizes that should be specified by the user as follows:(1) Wire: Diameter, length, and dimensions of the formed shapes; tempe
35、r, if for use in automatic feeding equipment;(2) Foil: Thickness, width, and length; temper, if for use in automatic feeding equipment;(3) Powder: Particle size or size distribution, or both;(4) Paste: Binder type and percentage, and powder particle size;(5) Plasticized tape: Thickness, width, perce
36、nt density, and binder type;(6) Brazing sheet: Cladding thickness and composition; and(7) Plating: Electrolytic or electroless, and thickness.4.3 Fluxes. For information on fluxes, refer to AWS A5.31M/A5.31, Specification for Fluxes for Brazing and Braze Welding.4.4 Packaging and Storage. The method
37、s of packaging to prevent contamination or the loss of identification should be specified. Storage conditions and shelf life should be specified, when appropriate.4.5 Identification. Procedures should be established to maintain the integrity of the identification of materials during use.5. Design5.1
38、 Basic Considerations. Reliability requires deliberate steps during the design phase to assure the effective control of quality. Quality control procedures must not be afterthoughts that are specified once the design is finalized, they should AWS C3.3:2008 (R2016)3be developed concurrently with the
39、design and verified as appropriate. Consideration should be given to the practical aspects of brazing, the characteristics of the filler and base materials involved, and the limitations of the inspection procedures.The requirements of the brazing and inspection operations should be given equal weigh
40、t. For example, the completed assembly may not provide accessibility for the inspection of each joint; therefore, the step brazing of various subassemblies may be nec-essary to permit inspection at intermediate stages and should be considered during the design of the component.Designs for critical b
41、razed components should be conservative and assure that the joints are inspected in the condition in which they will enter service. The design activity should consider the items listed below to ensure that the final brazed component is suitable for the intended critical service.5.2 Qualification of
42、Brazers and Processes. While destructive qualification tests of sample joints or specimens are useful to demonstrate the ability of processes and operators to produce the required joints, they do not in themselves assure the quality of the components produced. Qualification procedures should not be
43、used as a substitute for inspection and nondestructive examination procedures that directly indicate the quality of the actual hardware to be used in service. For further information, see AWS B2.2/B2.2M, Specification for Brazing Procedure and Performance Qualification.5.3 Application. The design ac
44、tivity is responsible for deciding which products and which brazed joints in these products are critical.These recommended practices are neither a general brazing specification nor an inspection specification. Because of the great diversity of brazed joints, one universal set of criteria cannot appl
45、y to all specific cases. The basic premise of these recommended practices is that each component having critical brazed joints should be completely defined by an engi-neering drawing and pertinent specifications.5.4 Documentation. Critical components should be controlled by documents specifying the
46、following:(1) The materials required and their minimum acceptable properties;(2) The complete design configuration and the dimensions of the product;(3) All required factors controlling the manufacture, including facilities, equipment, and detailed work instructions, must be specified so that no imp
47、ortant factors are left to the discretion of persons involved in the fabrication (e.g., specific detail dimensions and tolerances or techniques that control braze joint clearances, or the locations and resulting accessi-bility for the inspection of pipe joints in complex plumbing systems);(4) The in
48、spection procedures required and the minimum acceptance limits; and(5) A procedure for the disposition of materials or products not meeting the minimum acceptance limits.All requirements should be specified as limits for acceptance of the product.5.5 Materials. Materials include the base metals as w
49、ell as the brazing filler metals. Each should be suitable, and its suitability should be proven, if necessary, by the preparation of appropriate sample specimens and the performance of mechanical, corrosion, and service tests. In addition to the usual factors considered in any material selection, the following are particularly important in the designing of brazed joints:(1) Effects of the filler metal on the base metal during brazing (e.g., the dissolution, diffusion, or embrittlement of the base metal);(2) Hardness changes and the gradient of ductility in the heat-affec
