1、DEUTSCHE NORM December 2000 Brazing Non-destructive examination of brazed joints English version of DIN EN 12799 DIN EN 12799 - ICs 25.160.50 Hartlten - Zerstrungsfreie Prfung von Hartltverbindungen European Standard EN 12799 : 2000 has the status of a DIN Standard. A comma is used as the decimal ma
2、rker. National foreword This standard has been prepared by CEN/TC 121 Welding. The responsible German body involved in its preparation was the Normenausschuss Schweitechnik (Welding Standards Committee), Technical Committee Lten. EN comprises 33 pages. No pari of this standard may be reproduced with
3、out the prior permission of Ref. No. DIN EN 12799 : 2000-1 Y Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, s the exclusive right of sale for German Standards (DIN-Normen). English price group 11 Sales No. 11 11 05.01 EUROPEAN STANDARD NORME EUROPENNE EUROPISC
4、HE NORM EN 12799 July 2000 ICs 25.160.50 English version Brazing Non -d est ruc t ive exam i nation of brazed jo i n ts Brasage fort - Contrles non de- structifs des assemblages raliss par brasage fort Hartlten - Zerstrungsfreie Prfung von Harltverbindungen This European Standard was approved by CEN
5、 on 2000-07-02. CEN members are bound to comply with the CENKENELEC 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 stand- ards may
6、 be obtained on application to the Central Secretariat or to any CEN member. The European Standards exist 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 Centr
7、al Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the U
8、nited Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 2000. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No.
9、 EN 12799 : 2000 E Page 2 EN 12799 : 2000 Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 General principles 4 4 Visual examination 5 5 Ultrasonic examination 11 6 Radiographic examination 19 7 Penetrant detection 21 8 Leak testing 9 Proof testing 22 25 1 O Thermography 27 Annex A (inf
10、ormative) Imperfections in brazed joints 29 Annex ZA (informative) Clauses of this European Standard addressing essential requirements or other provisions of EU Directives 33 Foreword This European Standard has been prepared by Technical Committee CENKC 121 “Welding“, the secretariat of which is hel
11、d by DS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2001, and conflicting national standards shall be withdrawn at the latest by January 2001. This European Standard has been prepared
12、 under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this standard. According to the CENKENELEC Internal
13、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, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and
14、the United Kingdom. Page 3 EN 12799 : 2000 1 Scope This European Standard describes non-destructive examination procedures and test piece types necessary to perform the tests on brazed joints. The non-destructive examination methods described are as follows: a) b) c) d) e) f ) 9) thermography (see c
15、lause 10). visual examination (see clause 4); ultrasonic examination (see clause 5); radiographic examination (see clause 6); penetrant examination (see clause 7); leak testing (see clause 8); proof testing (see clause 9); The brazed joints to which these tests are applied can either be test samples
16、 manufactured to obtain brazed joint design data, or manufactured as part of the approval testing of a brazing procedure, or parts of a brazed assembly. The type of test piece described for each test can be quoted or incorporated in engineering application standards that deal with brazed assemblies.
17、 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 of the t
18、ests. 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. The methods of non-destructive examination are not associated with any particular type of brazed assembly but lay
19、down the general principles of the types of testing described. It is emphasised that a satisfactory examination method can only be developed and used after taking into account ail the relevant factors regarding the equipment to be used and the characteristics of the test piece being examined. 2 Norm
20、ative references This European Standard incorporates by dated or undated 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
21、 any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). Page 4 EN 12799 : 2000 EN 444 EN 473: 1993 EN 571-1 EN 583-1 11 998 prEN 583-2: 1
22、997 EN 583-3 EN 1593 EN 1779 EN 12668-1 Non-destructive testing - General principles for radiographic examination of metallic materials by X- and gamma-rays Non destructive testing - Qualification and certification of NDT personnel - General principles Non destructive testing - Penetrant testing - P
23、art 1 : General principles Non-destructive testing - Ultrasonic examination - Part 1 : General principles Non-destructive testing - Ultrasonic examination - Part 2: Sensitivity and range setting Non destructive testing - Ultrasonic examination - Part 3: Transmission technique Non-destructive testing
24、 - Leak testing - Bubble emission techniques Non-destructive testing - Leak testing - Criteria for method and technique selection Non-destructive testing - Characterization and verification of ultrasonic examination equipment - Part 1 : Instruments prEN 12668-2:1998 Non-destructive testing - Charact
25、erization and verification of ultrasonic examination equipment - Part 2: Probes EN 12668-3 Non-destructive testing - Characterization and verification of ultrasonic examination equipment - Part 3: Combined equipment prEN 131 84:1998 Non destructive testing - Leak test - Pressure change method prEN 1
26、31 851 998 Non destructive testing - Leak test - Tracer gaz method 3 General principles Imperfections may be observed when brazed joints are examined non-destructively. They may reduce the quality and performance characteristics of the joint or the brazed assembly. This European Standard does not gi
27、ve guidance regarding the cause of the imperfection or its effect upon the joint quality or the effects of single or multiple imperections upon the performance characteristics of the brazed assembly. This will Page 5 EN 12799 : 2000 depend upon the life-limiting processes to which the joint is subje
28、cted and the life requirements and performance specific to the brazed assembly. The majority of brazed joints are designed with the component 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 princi
29、pal axes parallel to the plane of the joint. Any other imperfections are caused by stresses in the brazing metal or the parent materials, or were already present before brazing. Guidance is given regarding the types of imperfections that are observed when non-destructive tests are applied; these are
30、 defined diagrammatically in annex A. NOTE The importance of tolerances to typical imperfections, 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 meth
31、od should always be considered in relation to testing as a whole. The benefits of using any particular method can only be obtained by consideration of the results in conjunction with results obtained by using other test methods. The most appropriate method or methods of examination should be selecte
32、d. 4 Visual examination 4.1 General Simple visual examination is the most fundamental and commonly used method of non-destructive examination. The examination described in this clause relates to the quality of the joint and does not include dimensional inspection. Consideration shall be given at the
33、 design stage to the provision of adequate access to permit visual examination. Before any visual examination is undertaken it shall be established which joints (and fillets of joints) are accessible for inspection; a suggested criterion for accessibility for satisfactory inspection, either directly
34、 by eye or viewed in a mirror, is shown in Figure 1, 4.2 Principle The brazed joint and adjacent parent material are visually examined (unaided and aided) to check the appearance, soundness and contour. 4.3 Qualification of personnel Personnel who carry out visual examination shall: a) be informed a
35、bout the braze process used and the possible imperfections; Page 6 EN 12799 : 2000 b) c) d) have vision tested in accordance with 6.3 of EN 473 : 1993; have received instruction in the specific requirements in accordance with 4.4; have received instruction in the general application standard. When t
36、raining records are kept, they shall verify compliance with items a) to d) and contain a supervisors statement that an acceptable level of attainment has been achieved. Visual examination does not require personnel with qualifications in addition to that detailed in items a) to d). 4.4 Requirements
37、specific to the examination The following shall be established before any examination is undertaken. a) b) Manufacturing stage at which visual examination is to be carried out; this should include consideration as to whether inspection is carried out on-line; Requirements for surface preparation for
38、 inspection; NOTE 1 There is usually no such preparation after fluxless brazing processes. After brazing, flux and flux residues are normally removed (see 4.8). c) Minimum relevant imperfection size; NOTE 2 The recommended minimum relevant imperfection size for visual examination is 0,5 mm as define
39、d in 4.8 b), unless otherwise specified. Extent of visual examination as defined in 4.7; Any requirements for a written inspection procedure; Any aids to visual inspection additional to those listed in 4.6. d) e) Acceptance criteria (see 4.8); f ) 9) Reporting requirements; h) 4.5 information to be
40、supplied for visual inspection Before commencing examination, the following shall be available to the operator. a) b) All the information required in 4.4; A written inspection procedure, if applicable. 4.6 Inspection aids and equipment The following are likely to be required. a) Suitable illuminatio
41、n; Page 7 EN 12799 : 2000 b) A wide-angle low-magnification (x5) viewer, e.g. a standard universal bench- mounted device that leaves both hands free and may also incorporate illumination; A comparison gauge for the minimum relevant imperfection size, e.g. either: 1) c) a mounted wire of this diamete
42、r to hold alongside the imperfection, the end of which may be bent for easy alignment with the major axes of the imperfection; or an x8 loupe with graticule; 2) A plain small mirror, e.g. a dental mirror, for partially accessible joints: Means of locally illuminating areas in shadow, e.g. optic fibr
43、e lightguides; Approved methods of marking individual joints if detailed in 4.9, e.g. certain types of waterproof felt marker pens. d) e) f ) Page 8 EN 12799 : 2000 4.7 Extent of visual inspection on each workpiece As many work pieces have a proportion of fillets that eith hav difficult ccess or be
44、examined only by special techniques, the extent of inspection shall be defined for each workpiece and shall be established before the examination is undertaken and not left to the discretion of the inspector. The specified inspection sites shall be shown on the assembly drawing or, in complex cases,
45、 on a drawing prepared for this purpose. The drawing shall also state, or reference, the acceptance criteria. 1 Key 1 Axis 2 Viewing angle I Figure 1 - Access for visual inspection: joints to be viewable within a stated angle of joint axis or exit plane Page 9 EN 12799 : 2000 - T- Detail X )io 1 Bot
46、tom of recess to be visible at 45 O to the joint axis Figure 2 - Access for visual inspection: recessed fillet, when recessed fillets are permitted 4.8 Acceptance guidelines The following points should be considered. a) F/ux and flux residues (when appropriate to the brazing process used). The exten
47、t of removal of flux and flux residues to permit inspection should be detailed; Minimum relevant imperfection size. Imperfections having a maximum dimension smaller than an agreed minimum size are to be disregarded. It is recommended that the minimum relevant imperfection size is 0,5 mm; b) NOTE The
48、 acceptability for service of brazed assemblies which may require greater integrity should be determined by additional tests, e.g. leaktightness. Continuity of filets. It should be stated whether complete or incomplete fillets are acceptable. Where incomplete fillets are acceptable, the description
49、should be as direct as possible and avoid possible errors. For example, incomplete fillets with xgaps maximum each not exceeding ymm is preferable to incomplete fillets with gaps not exceeding 20 o/o of total length; c) Page 10 EN 12799 : 2000 Recessed fiiiets. Recessed fillets may be due to brazing gaps at the upper limit for the braze process employed or insufficient filler metal. It is difficult to estimate the depth of recess and if the condition is acceptable it is suggested the criterion shown in Figure 2 is adopted; Excess fillermetal. When it is
