SANS 23279-2010 Non-destructive testing of welds - Ultrasonic testing - Characterization of indications in welds《焊缝的无损检验 超声波检验 焊缝的表示特征》.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-23355-6 SANS 23279:2010Edition 1ISO 23279:2007Edition 1SOUTH AFRICAN NATIONAL STANDARD Non-destructive testing of welds Ultrasonic testing

4、 Characterization of indications in welds This national standard is the identical implementation of ISO 23279:2007 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 000

5、1Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 23279:2010 Edition 1 ISO 23279:2007 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 135, Engineering materials Non-destructive testing, in acc

6、ordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in March 2010. Reference numberISO 23279:2007(E)ISO 2007INTERNATIONAL STANDARD ISO23279First edition2007-03-15Non-destructive testing of welds Ultrasonic test

7、ing Characterization of indications in welds Contrle non destructif des assemblages souds Contrle par ultrasons Caractrisation des indications dans les assemblages souds SANS 23279:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 23279

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11、w. ISO 2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form 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 i

12、n 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 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reservedSANS 23279:2010This s tandard may only be used and printed by approved s

13、ubscription and freemailing clients of the SABS .ISO 23279:2007(E) ISO 2007 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Criteria . 1 3.1 General. 1 3.2 Conventions used. 2 3.3 Location of indications. 2 3.4 Echo height criteria (Stages 1 a

14、nd 2) 2 3.5 Directional reflectivity criteria (Stage 3). 3 3.6 Echostatic pattern criteria (Stage 4) . 4 3.7 Echodynamic pattern criteria (Stage 5) 4 3.8 Complementary examination. 4 Annex A (normative) Classification of internal indications in welds Flowchart procedure 5 Annex B (informative) Exami

15、nation incidence 9 Annex C (informative) Basic echodynamic patterns of reflectors 10 SANS 23279:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 23279:2007(E) iv ISO 2007 All rights reservedForeword ISO (the International Organization

16、for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has t

17、he right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Interna

18、tional 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 International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publicatio

19、n 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 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

20、. ISO 23279 was prepared by Technical Committee ISO/TC 44, Welding and allied processes, Subcommittee SC 5, Testing and inspection of welds. Requests for official interpretations of any aspect of this International Standard should be directed to the Secretariat of ISO/TC 44/SC 5 via your national st

21、andards body. A complete listing of these bodies can be found at www.iso.org. SANS 23279:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 23279:2007(E) ISO 2007 All rights reserved vIntroduction Classification of indications as planar

22、or non-planar is based on several parameters: welding techniques; geometrical position of the indication; maximum echo height; directional reflectivity; echostatic pattern (i.e. A-scan); echodynamic pattern. The classification process involves comparing each parameter to all the others in order to a

23、rrive at an accurate conclusion. The flowchart in Annex A gives the classification of internal weld indications suitable for general applications. SANS 23279:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .SANS 23279:2010This s tandard ma

24、y only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO 23279:2007(E) ISO 2007 All rights reserved 1Non-destructive testing of welds Ultrasonic testing Characterization of indications in welds 1 Scope This International Standard defines a p

25、rocedure for classifying internal indications as planar or non-planar. This procedure is only suitable for indications located at least 5 mm below the unground surface of the joint. Annex A defines the procedure in the form of a flowchart. Figure 1 illustrates the location of indications. 2 Normativ

26、e references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1712, Non-destructive examination

27、 of welds Ultrasonic examination of welded joints Acceptance levels 3 Criteria 3.1 General The classification is carried out by the successive application of several discriminatory criteria, i.e. echo amplitude; directional reflectivity; echostatic pattern (A-scan); echodynamic pattern. The classifi

28、cation is carried out in accordance with EN 1712. The flowchart procedure is stopped as soon as one of the above criteria is fulfilled. The probes used for the classification are, as a general rule, the same as those specified for the detection. The flowchart procedure standardizes a quality control

29、 system of classification. Several levels are defined in decibels (dB) by a comparison with the distance amplitude curve (DAC) or by a comparison between the maximum echo heights from the discontinuity when tested at different angles of incidence. Proposed dB levels for the different stages in the f

30、lowchart procedure are given in Table 1. SANS 23279:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 23279:2007(E) 2 ISO 2007 All rights reservedTable 1 Proposed dB levels for the different stages in the flowchart procedure Reflectivit

31、y level S1 S2 S3 S4 Decibel DAC 10 dB DAC + 6 dB DAC 6 dB 9 dB a/15 dB ba Shear waves. b Between reflections obtained with a shear and a longitudinal wave.The flowchart procedure calls for five stages, each having a precise aim: Stage 1: to avoid the classification of indications with very low echo

32、amplitudes; Stage 2: to classify all indications with high echo amplitude as planar; Stage 3: primarily to classify lack of fusion; Stage 4: primarily to classify inclusions; Stage 5: primarily to classify cracks. NOTE The “hybrid” indications resulting from the association of an inclusion and a lac

33、k of fusion are classified as planar by the flowchart procedure. An example of this type of flaw is given in Figure A.3. 3.2 Conventions used The reference echoes shall be obtained on 3 mm side drilled holes. By convention, a negative level value means that the indication has a lower echo amplitude

34、than the reference; a positive level value means that the indication has a higher echo amplitude than the reference. 3.3 Location of indications Figure 1 illustrates the location of indications. Dimensions in millimetres Key A ground weld Figure 1 Location of indications 3.4 Echo height criteria (St

35、ages 1 and 2) 3.4.1 Low amplitudes (Stage 1) It is accepted that an indication with a lower echo amplitude than level S1 (DAC 10 dB) is not significant. For special applications, this S1 value should be lowered if agreed between the contracting parties. SANS 23279:2010This s tandard may only be used

36、 and printed by approved subscription and freemailing clients of the SABS .ISO 23279:2007(E) ISO 2007 All rights reserved 33.4.2 High amplitudes (Stage 2) It is assumed that an echo height that is at least equal to the level S2 (DAC + 6 dB) comes from a planar indication. 3.5 Directional reflectivit

37、y criteria (Stage 3) This stage of the flowchart procedure shall be applicable either to all indications or, if agreed between the contracting parties, only to those indications exceeding a specified length. For the range of thicknesses 8 mm u t u 15 mm, this length is t, and for thicknesses over 15

38、 mm, this length is t/2 or 20 mm, whichever is the larger. For indications not exceeding the specified length, proceed to Stage 4. For the criteria below, the angle of incidence of examination which gives the highest echo amplitude relative to a DAC curve, Hdmax, is taken as reference. The minimum e

39、cho amplitude relative to a DAC curve, Hdmin, obtained from the other angles of incidence, is compared with Hdmax. To satisfy the directional reflectivity, the two conditions below shall be fulfilled simultaneously. a) The reflectivity of the indication, for at least one of the angles of incidence,

40、is higher than or equal to S3 (DAC 6 dB). b) There is a high directional reflectivity, i.e. 1) an imbalance of, at least, 9 dB between two angles of incidence of examination, if the examination is carried out with shear waves: Hdmax Hdmin W 9 dB, or 2) an imbalance of, at least, 15 dB between two an

41、gles of incidence of examination, where one of them is carried out with shear waves, the other with longitudinal waves: Hdmax Hdmin W 15 dB. The incidence of examination results from the association of a refraction angle and examination conditions (half skip, full skip). Some examples are given in A

42、nnex B. An example of the application of these criteria is given in Figure A.2. The attenuation of the weld could be taken into account. The following conditions apply. Normally, the wave length of the different angles of incidence of examination shall be almost the same (e.g. 4 MHz for longitudinal

43、 waves and 2 MHz for shear waves). In all cases, the differences between the compared angles of incidence are equal to or greater than 10 (the nominal refraction angles are taken into account). The comparison of reflectivities shall be made at the position on the indication which exhibits the highes

44、t reflectivity. Such comparisons make sense only if it is certain that the compared echoes come from the same reflectors. It shall be certain before the application of these criteria that: there is no segregation in the base metal; SANS 23279:2010This s tandard may only be used and printed by approv

45、ed subscription and freemailing clients of the SABS .ISO 23279:2007(E) 4 ISO 2007 All rights reserved there is no corrosion and the two sides are parallel if full skip is used; the materials are isotropic. 3.6 Echostatic pattern criteria (Stage 4) At this stage, the echostatic pattern (i.e. A-scan)

46、is considered. With the echo height requirements met (neither very high, nor very low) and a low directional reflectivity, if the echostatic pattern is single and smooth, the indication is classified as non-planar. If the echostatic pattern is not single and smooth, the next stage of the procedure i

47、s followed. The shape of the echostatic pattern depends on the transducer and equipment used. It is therefore imperative to compare the pattern of the indication with that obtained from the reference reflector (3 mm diameter side drilled hole). 3.7 Echodynamic pattern criteria (Stage 5) If the stati

48、c echo is not single and smooth, it shall be classified as single and jagged, or multiple. This point is made use of at Stage 5 of the flowchart procedure. The transverse echodynamic pattern of a reflector is the envelope of the resulting echoes when the ultrasonic beam passes it transversely. The a

49、nalysis takes into account not only the envelope of the curve, but also the behaviour of the echoes inside it. The pattern can be classified into four types, as given in Annex C. If the transverse echodynamic exhibits Pattern 3 (varial class) for at least two angles of incidence, the indication is classified as planar. Normally, the two angles of incidence chosen are those that give the highest reflectivities. If only one angle of incidence of examination