1、BRITISH STANDARD BS EN 12797:2000 Incorporating Amendment No. 1 Brazing Destructive tests of brazed joints The European Standard EN 12797:2000, with the incorporation of amendment A1:2003 has the status of a British Standard ICS 25.160.50 BS EN 12797:2000 This British Standard, having been prepared
2、under the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 2000 BSI 11 February 2004 ISBN 0 580 36225 6 National foreword This British Standard is the official English language version of EN 12797:2000,
3、including amendment A1:2003. Together with BS EN 12799:2000 it supersedes BS 1723-3:1988 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee WEE/19, Brazing and bronze welding, which has the responsibility to: A list of organizations represented on this c
4、ommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using th
5、e “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from l
6、egal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK.
7、 Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 31 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments 14932 11 Febr
8、uary 2004 Modifications to contents and foreword pages and deletion of Annex ZA EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12797 July 2000 + A1 December 2003 ICS 25.160.50 English version Brazing Destructive tests of brazed joints (includes amendment A1:2003) Brasage fort Essais destructif
9、s des assemblages raliss par brasage fort (inclut lamendement A1:2003) Hartlten Zerstrende Prfung von Hartltverbindungen (enthlt nderung A1:2003) This European Standard was approved by CEN on 2 July 2000, and amendment A1:2003 was approved by CEN on 20 November 2003. CEN members are bound to comply
10、with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secret
11、ariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the offici
12、al versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden
13、, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.
14、Ref. No. EN 12797:2000 + A1:2003 EPage 2 EN 12797:2000 Contents Page Foreword 3 1 Scope 4 2 Normative references 5 3 General principles 6 4 Shear tests 7 5 Tensile tests 11 6 Metallographic examination 16 7 Hardness testing 17 8 Peel tests 19 9 Bend tests 21 Annex A (informative) Imperfections in br
15、azed joints 29 Page 3 EN 12797:2000 Foreword This European Standard has been prepared by Technical Committee CEN/TC 121 “Welding“, the secretariat of which is held by DS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorse
16、ment, at the latest by January 2001, and conflicting national standards shall be withdrawn at the latest by January 2001. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/CENELEC Internal Regulations
17、, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United
18、Kingdom. Foreword to amendment A1 This document EN 12797:2000/A1:2003 has been prepared by Technical Committee CEN/TC 121 “Welding“, the secretariat of which is held by DS. This Amendment to the European Standard EN 12797:2000 shall be given the status of a national standard, either by publication o
19、f an identical text or by endorsement, at the latest by June 2004, and conflicting national standards shall be withdrawn at the latest by June 2004. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/C
20、ENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
21、 Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Page 4 EN 12797:2000 B SI 000290 1 Scope This European Standard describes destructive test procedures and test piece types necessary to perform the tests on brazed joints. Brazed joints are used in a wide variety of assemblies and the des
22、ign requirements placed upon these joints will also vary widely; there will usually be some level of strength required but this may not be explicitly stated and is frequently of minor importance compared to some other criterion, e.g. hermeticity. It follows that a test which measures strength may be
23、 totally irrelevant in assessing a joint for a particular application where strength is a minor consideration. This situation is made more complicated because brazed joints are almost invariably designed to be loaded in shear and the dimensions of the joint affect the shear strength to a much greate
24、r extent than they do the tensile strength. The tests described in this standard have been used successfully to give information on specific properties and where such information is needed, it is recommended that one of them be specified. It is vital to recognize that for many fabrications none of t
25、hese tests will be suitable and specific tests will have to be devised, which do yield the requisite information (which may be qualitative rather then quantitative). The destructive test methods described are as follows: a) shear tests (see clause 4); b) tensile tests (see clause 5); c) metallograph
26、ic examination (see clause 6); d) hardness tests (see clause 7); e) peel test (see clause 8); f) bend tests (see clause 9). Details of burst tests are not included as these are not commonly used on brazed joints. The type of test piece described for each test can be quoted or incorporated in enginee
27、ring applications standards that deal with brazed assemblies. The results of the tests are used: 1) to determine basic data regarding filler metal performance; 2) to arrive at optimum brazing designs (including gaps) and brazing procedures; 3) to relate production results to results achieved in deve
28、lopment. This European Standard does not recommend the number of samples to be tested or the repeat tests allowed. Neither does it specify methods of sampling brazed joints, except to give guidance regarding the precautions necessary, nor does it comment on the acceptance criteria applicable to any
29、of the tests. No attempt is made to define which test or tests, if any, should be applied in any situation. This is a matter to be established before any particular method of test is selected.Page 5 EN 12797:2000 B SI 000290 2 Normative references This European Standard incorporates by dated or unda
30、ted reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when
31、incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 910 Destructive tests on welds in metallic materials - Bend tests. EN 10002-1 Metallic materials - Tensile testing - Part 1: Method of test (at amb
32、ient temperature). EN 10003-1 Metallic materials - Brinell hardness test - Part 1: Test method. EN 10109-1 Metallic materials - Hardness test - Part 1: Rockwell test (scales A, B, C, D, E, F, G, H, K) and Rockwell superficial (scales 15N, 30N, 45N, 15T, 30T and 45T). EN 12799:2000 Brazing - Non-dest
33、ructive examination of brazed joints. ISO 4545 Metallic materials - Hardness test - Knoop test. ISO 5187 Welding and allied processes - Assemblies made with soft solders and brazing filler metals - Mechanical test methods. EN ISO 6507-1 Metallic materials - Vickers hardness test - Part 1: Test metho
34、d (ISO 6507-1:1997). ISO 7438 Metallic materials - Bend test. 3 General principles Imperfections may be observed when joints are examined by destructive tests. They may reduce the quality and performance characteristics of the joint or the brazed assembly. Destructive tests may be needed to determin
35、e the effects of the brazing process or any subsequent heat treatment on the properties of the joint (e.g. parent materials, filler metals, internal stresses). This European Standard does not give guidance regarding the cause of the imperfection or its effect upon the joint quality or the effects of
36、 single or multiple defects upon the performance characteristics of the brazed assembly. This will depend upon the life-limiting processes to which the joint is subjected and the life requirements and performance specific to the brazed assembly. The majority of brazed joints are designed with the co
37、mponent parts in a lap configuration. Because of the capillary nature of a brazed joint, most imperfections will be contained within the joint region, with the principal axes parallel to the plane of the joint. Any other imperfections are likely toPage 6 EN 12797:2000 B SI 000290 have been caused by
38、 stresses in the brazing metal or the parent materials, or were already present before brazing. Guidance is given regarding the types of imperfection that are observed when destructive tests are applied; these are defined diagrammatically in annex A. NOTE 1 The importance of tolerance to typical imp
39、erfections, the cause for rejection, the method of imperfection interpretation and the method of presentation of observations have to be established before a specific method of test is selected. The use of any method should always be considered in relation to testing as a whole. The benefits of usin
40、g any particular method can only be obtained by consideration of results in conjunction with results obtained by using other test methods. The most appropriate method or methods of testing should be selected. The methods of destructive examination are not associated with any particular type of test
41、piece but lay down the general principles of the types of testing described. It is emphasized that a satisfactory examination method can only be developed and used after taking into account all the relevant factors regarding the equipment to be used and the characteristics of the test pieces being e
42、xamined. The use of the methods of test described enables results from different organizations to have a greater validity when compared, and their use provides designers with basic data on the performance of brazing filler metals and brazed constructions. However, it is essential to appreciate that
43、the results achieved, as with all mechanical tests, are not fundamental, and that the values obtained depend upon the conditions of the test, the condition of the brazing filler metal, the design of the joint and the quality achieved by the brazing process. The brazing process produces joints that a
44、re not homogeneous as they are made up of parent materials and a filler metal. Many factors (such as the joint gap, brazing cycle, diffusion of the filler into the parent material, etc.) will affect the mechanical properties of the joint. Therefore expert knowledge is required to assess whether it i
45、s possible to repeat in production the mechanical properties achieved in test pieces. 4 Shear tests 4.1 General Many designs of test specimen have been used to produce shear data for brazed joints. The great majority of brazed joints are designed to be stressed in shear, and it is not possible to co
46、nvert the results obtained from butt brazed joints into shear strengths. Test pieces detached from brazed assemblies may be difficult to manufacture into standard shear test specimens; multi-jointed assemblies produce similar problems, where the presence of one defective joint may not reduce the ove
47、rall strength but can cause failure in service. The shear specimen should essentially be simple in design and economic to manufacture and test. In all cases, particularly if there is a wide scatter in the results, the effect of non-bonded areas and other imperfections observed by non-destructive exa
48、mination and the visual examination of the fracture surfaces should be considered.Page 7 EN 12797:2000 B SI 000290 4.2 Principle The principle of the test is to subject the test specimen to mechanical loading in shear to fracture and assess its mechanical properties when subjected to these methods o
49、f loading. 4.3 Test pieces and specimens The details of the test pieces and specimens to be used shall be established before any testing is undertaken, and may be, for example, one of the following types. a) Type I as shown in Figure 1; b) Type II as shown in Figure 2. The dimensions shown in Figures 1 and 2 are those typically used but it may be necessary to vary these to reflect specific applications. 4.4 Procedure The test shall be conducted generally in accordan
