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1、 Reference number ISO 18279:2003(E) ISO 2003 INTERNATIONAL STANDARD ISO 18279 First edition 2003-12-15 Brazing Imperfections in brazed joints Brasage fort Dfauts dans les assemblages raliss par brasage fort Copyright International Organization for Standardization Provided by IHS under license with I
2、SO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be
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5、e is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2003 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
6、or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47
7、 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2003 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or n
8、etworking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normall
9、y carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the
10、work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare In
11、ternational Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of
12、 the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 18279 was prepared by the European Committee for Standardization (CEN) in collaboration with Technical Committee ISO/TC 44, Welding and allied proc
13、esses, Subcommittee SC 12, Soldering and brazing materials, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). Throughout the text of this document, read “.this European Standard.” to mean “.this International Standard.”. Copyright International Organiz
14、ation for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) iv ISO 2003 All rights reserved Contents Page Forewordv Intr
15、oductionvi 1Scope 1 2Terms and definitions2 3Symbols3 4Classification4 4.1General4 4.2External imperfections4 4.3Internal imperfections .4 Annex A (informative) Guidelines for practical evaluation of imperfections16 Annex B (informative) Evaluation17 Bibliography24 Copyright International Organizati
16、on for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved v Foreword This document (EN ISO 1
17、8279:2003) has been prepared by Technical Committee CEN/TC 121 “Welding“, the secretariat of which is held by DS, in collaboration with Technical Committee ISO/TC 44 “Welding and allied processes”. This European Standard EN ISO 18279:2003 shall be given the status of a national standard, either by p
18、ublication of 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. Annexes A and B are informative. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following co
19、untries 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, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Copyright International
20、 Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) vi ISO 2003 All rights reserved Introduction Brazed
21、joints usually contain imperfections of various types, some of which will be detrimental in almost every case but others may be detrimental or harmless, depending entirely on the service requirements of the joint in question. Therefore it will frequently be necessary to classify the imperfections in
22、 a brazed joint and then try to assess the significance of their effects on the behaviour of the joint in service. The classification is, relatively, easy and Table 1 describes the imperfections that most commonly occur. The assessment of significance is not easy (see also Annex A). For welded joint
23、s, there has been extensive work carried out for many years on the significance of imperfections in service but such work has not been carried out on brazed joints. Moreover the work on welded joints is only rarely relevant to brazed joints, mainly because of differences in geometry and stressing. T
24、herefore this standard cannot give definitive quality levels for brazed joints. These can only be produced as experience is gained from industrial applications. However, Annex B gives some suggestions for quality levels for general applications, which may be of help where detailed information is not
25、 available. It has to be emphasized that the use of quality levels can only be successful if the imperfections that are relevant to the application of the brazed joint are determined. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Techni
26、cal Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved 1 1 Scope This European Standard details a classification of imperfections that can occur in brazing joints. In addi
27、tion guidance is provided on quality levels and suggested limits for imperfections are detailed. For requirements not covered by this standard, reference is to be made to other sources, e.g. statutory regulations, codes of practice and technical delivery conditions. No information is given on how im
28、perfections are to be assessed in individual cases because this depends on the requirements for the particular brazed joint. These imperfections are not always detectable by the use of non- destructive testing alone. The standard covers only imperfections that can occur in connection with brazing wi
29、thout the effect of any additional service loads. Only the type, shape and position of such imperfections are covered; no indication is given of the conditions of occurrence or causes. For requirements for brazed joints which are relevant and essential to the particular function of the component, re
30、ference should be made to the relevant documentation, e.g. manufacturing documents or procedure sheets. NOTE It is important that these requirements be precisely prescribed and that compliance with them be verifiable. Compliance may be established by testing either the brazed assembly itself or a te
31、st piece produced under comparable conditions. The requirements should be established and fully documented before any classification is undertaken. This European Standard does not lay down requirements for acceptance levels for imperfections since these will differ very markedly, depending on the ap
32、plication, but it does suggest some quality levels which may be of value in the absence of more detailed information. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDT
33、No reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) 2 ISO 2003 All rights reserved a) Simple brazed assembly Key Parent material Parent material affected by brazing (heat affected zone (HAZ) Diffusion-transition zone Braze metal NOTEExtent of HAZ will vary with m
34、aterials and brazing process. b) Section through assembly in a) Figure 1 Schematic of brazed assembly 2 Terms and definitions For the purposes of this European Standard the areas of a brazed assembly are defined as shown schematically in Figure 1. In addition the following term and definition apply.
35、 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved
36、 3 2.1 imperfections irregularities in the brazed joint, deviations from the intended relative positions of the parts joined by brazing and from the intended shape of the brazed component, where such deviations are dependent on the brazing 3 Symbols The following symbols are used: ? llength of the b
37、razed overlap; ? lrrequired brazed length; ? lulength of overlap before brazing; ? l1, 2dimensions of the brazed imperfection; ? tjthickness of brazed joint; ? t1, 2wall or plate thickness or thicknesses. t t t l l l l l 1 j 2 1 2 r u NOTEThis figure illustrates a planar imperfection. Figure 2 Symbo
38、ls used for dimensions Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) 4 ISO
39、2003 All rights reserved 4 Classification 4.1 General The imperfections are classified into six groups as follows: ? group ICracks; ? group II Cavities; ? group III Solid inclusions; ? group IV Bonding imperfections; ? group V Shape and size imperfections; ? group VI Miscellaneous imperfections. Imp
40、erfections are identified by designations. A further distinction can be made between the external and internal imperfections that may occur in brazed joints. 4.2 External imperfections External imperfections in brazed joints include: ? underfill; ? cracks; ? surface-breaking porosity; ? incomplete f
41、illet; ? overlap; ? localized melting; ? rough surface of seam; ? flux seepage; ? discoloration; ? spatter; ? residual flux; ? surface erosion of parent material. 4.3 Internal imperfections Internal imperfections in brazed joints include: ? cracks; ? filling imperfections; Copyright International Or
42、ganization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved 5 ? solid inclusions; ? ga
43、s entrapment; ? flux inclusion; ? lack of fusion; ? excessive alloying of filler material and parent material (sometimes called erosion). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/
44、12/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) 6 ISO 2003 All rights reserved Table 1 Classification of imperfections DesignationDescriptionRemarksDrawing I Cracks 1AaAAAcrackLimited separation of the material, predominantly two- dimensio
45、nal extension. A crack may be longitudinal or transverse It can lie in one or more of the following : 1AaAABin the braze metal 1AaAAC at the interface and including the diffusion zone 1AaAADIn the HAZ 1AaAAEin the unaffected parent material 1AAAD1AAAE 1AAAC 1AAAB a - In the case of an intergranular
46、crack, change this second symbol A to the symbol F. - In the case of a transgranular crack, change this second symbol A to the symbol H. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/1
47、2/2007 22:46:01 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 18279:2003(E) ISO 2003 All rights reserved 7 Table 1 Classification of imperfections (continued) DesignationDescriptionRemarksDrawing II Cavities 2AAAAcavity 2BAAAgas cavityGas-filled cavity 2BAAA 2BGAAgas poreSpheroidal gas inclusion. It can occur as : 2BGGAuniformly distributed porosity 2BGMAlocalized (clustered) porosity 2BGHAlinear porosity 2LIAAlarge gas pocketsLarge voids may be the width of the joint with elongated shape Copyright International Organization for Standardization Pro