1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 1971-2:2011Copper and copper alloys Eddy current test formeasuring defects on seamlessround copper and copper alloytubesPart 2: Test with an internal probe on theinner surf
2、aceBS EN 1971-2:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 1971-2:2011.Together with BS EN 1971-1:2011, it supersedes BS EN 1971:1999which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee NFE/34/1, Wrought and un
3、wrought copper and copperalloys.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution
4、 2012ISBN 978 0 580 70541 0ICS 77.150.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 January 2012.Amendments issued since publicationDate Text affectedBS EN
5、1971-2:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1971-2 December 2011 ICS 23.040.15; 77.150.30 English Version Copper and copper alloys - Eddy current test for measuring defects on seamless round copper and copper alloy tubes - Part 2: Test with an internal probe on the inner surface
6、Cuivre et alliages de cuivre - Mthode de contrle par courants de Foucault pour le mesurage des dfauts des tubes ronds sans soudure en cuivre et alliages de cuivre - Partie 2: Essai avec un capteur interne sur la paroi interneKupfer und Kupferlegierungen - Wirbelstromprfung an Rohren zur Messung von
7、Fehlern an nahtlos gezogenen runden Rohren aus Kupfer und Kupferlegierungen - Teil 2: Prfung mit Innensonde auf der Innenseite This European Standard was approved by CEN on 5 November 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for g
8、iving 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 CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three o
9、fficial 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 CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies
10、 of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingd
11、om. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1971-2:2011: EBS EN
12、1971-2:2011EN 1971-2:2011 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Terms and definitions .54 General requirements 54.1 Personnel qualification .54.2 Condition of tube to be tested 54.3 Equipment 65 Reference standard tube .66 Acceptance criteria 76.1 Detection
13、of local discontinuities by internal probes systems 76.2 Detection of non-local discontinuities by internal probes systems with lower detection levels .76.3 Other test methods 87 Instrument adjustment 8Bibliography 9Figures Figure 1 Simplified representation of eddy current testing using internal pr
14、obe .6 BS EN 1971-2:2011EN 1971-2:2011 (E) 3 Foreword This document (EN 1971-2:2011) has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication
15、 of an identical text or by endorsement, at the latest by June 2012, and conflicting national standards shall be withdrawn at the latest by June 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be
16、 held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Est
17、onia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Within its programme of work, Technical Committee CEN/TC 133 requeste
18、d CEN/TC 133/WG 3 “Copper tubes (installation and industrial)“ to prepare the following document: EN 1971-2, Copper and copper alloys Eddy current test for measuring defects on seamless round copper and copper alloy tubes Part 2: Test with an internal probe on the inner surface This is one of two pa
19、rts of the standard for the eddy current test for measuring defects on seamless round copper and copper alloy tubes. The other part is: EN 1971-1, Copper and copper alloys Eddy current test for measuring defects on seamless round copper and copper alloy tubes Part 1:Test with an encircling test coil
20、 on the outer surface BS EN 1971-2:2011EN 1971-2:2011 (E) 4 Introduction The eddy current test with internal probe described in this standard has the objective of detecting potential leaks and serious defects in seamless round copper and copper alloy tubes. The eddy current test is able to detect ma
21、terial inhomogeneities and their positions throughout the length of tubes. The eddy current signals of material inhomogeneities are compared with reference signals of artificially produced test defects. It is possible to identify these inhomogeneities on the inner and outer surfaces as well as withi
22、n the tube wall. Since the distribution of eddy currents decreases as the distance from the test coil increases, the amplitude of defect signals also decreases with increasing distance from the test coil. Thus the eddy current test with internal probe on the inner surface is less sensitive to defect
23、s on the outer surface. The purpose of this standard is not to define a method of measuring the actual extent of the material inhomogeneities as the signal amplitude is dependent on, amongst other factors, volume, form and position of the inhomogeneity. Due to end effects, it is not possible to effe
24、ctively test the ends of the tubes. The purchaser and the supplier could agree that the end effect may be overcome by cutting to length after testing. BS EN 1971-2:2011EN 1971-2:2011 (E) 5 1 Scope This European Standard specifies a procedure for the eddy current test with an internal probe for measu
25、ring defects on the inner surface of seamless round copper and copper alloy tubes. This European Standard applies particularly for finned tubes with high fins according to EN 12452. NOTE The eddy current test method(s) required, together with the size range and acceptance level, are defined in the r
26、elevant product standard. The choice of the method for eddy current test: with an encircling test coil on the outer surface according EN 1971-1 or with an internal probe on the inner surface according EN 1971-2 is at the discretion of the manufacturer if there are no other agreements between the pur
27、chaser and the supplier. Especially for finned tubes according to EN 12452 with high fins, it is recommended to use eddy current test with internal probe as described in this standard. 2 Normative references The following referenced documents are indispensable for the application of this document. F
28、or dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 473, Non-destructive testing Qualification and certification of NDT personnel General principles EN ISO 12718, Non-destructive testing Edd
29、y current testing Vocabulary (ISO 12718:2008) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN ISO 12718 apply. 4 General requirements 4.1 Personnel qualification The eddy current test shall be made by operators trained in this technique and it shall b
30、e done under the responsibility of qualified staff. When agreed upon between the purchaser and the supplier, qualification of the personnel shall be certified according to EN 473. 4.2 Condition of tube to be tested Tubes shall be sufficiently clean and straight to permit satisfactory operation of op
31、tionally drive mechanism and eddy current test equipment. BS EN 1971-2:2011EN 1971-2:2011 (E) 6 4.3 Equipment The internal probe shall be moved through the tubes as vibration-free as possible. The variation in test sensitivity due to changes of speed and internal probe position within the tubes shal
32、l be maintained within 2 dB. The internal probe can be moved manually or by using a drive mechanism (see Figure 1). Key 1 tube with fins on the outside 2 internal probe Figure 1 Simplified representation of eddy current testing using internal probe Test speed over the length of the tube shall be as
33、constant as possible. The distance between the probe and the inner surface of the tube shall be kept as small as possible so that the sensitivity of the test is sufficient. NOTE For internal probes, the usual frequencies are in the range 1 kHz to 125 kHz. 5 Reference standard tube Unless otherwise s
34、pecified in the relevant product standard, a reference standard tube is made of a defect-free tube of the same dimensions and specified properties as the tube to be tested. During the reference test, the influence of dynamic conditions shall be taken into account. NOTE The producer can ensure that t
35、his requirement is met by the appropriate option subject to the type of the installation, such as: a) for control devices not in-line with production, the reference tube should be long enough to ensure the same dynamic conditions for the reference test as for normal line operating speed; or b) the c
36、ontrol devices should include a dynamic effect compensating unit to take into account the speed differences between the reference tube throughput speed and the normal line operating speed. Either the reference standard tube shall have three holes located on three generating lines at 120, or only one
37、 hole. If a reference standard tube with three holes is used, the holes shall be spaced from each other and from each end, sufficiently to obtain separate signals from each hole without interference from the tube ends. If a reference standard tube with only one hole is used, then this tube shall be
38、used three times being turned by 120. BS EN 1971-2:2011EN 1971-2:2011 (E) 7 The maximum drill diameter for the various dimension ranges is defined in the relevant product standards. Other reference standard tube types may be considered if they are demonstrated as more relevant for certain products;
39、they shall be defined in the relevant product standards. 6 Acceptance criteria 6.1 Detection of local discontinuities by internal probes systems Local discontinuities of the tubes, including beginning and end of long regular discontinuities and variations of long discontinuities, are detected as def
40、ects with internal probes systems. The sorting limit shall be the smallest amplitude of the three signals produced by the hole or holes in the reference standard tube. 6.2 Detection of non-local discontinuities by internal probes systems with lower detection levels Non-local discontinuities of the t
41、ube could be identified as defects by one of the methods defined for this purpose, according to the requirements of the relevant product standards. Some discontinuities of the tube, which individually are not considered as defective, might cause signals lower than the detection threshold of the norm
42、al sorting limit for local defects but higher than a second selected lower detection threshold Sl. The signals for the lower and normal detection thresholds are related by a ratio K2, which shall be determined by the manufacturer of the tube, as follows: SS= Knl2(1) where Slis the signal for the low
43、er detection threshold; Snis the signal for the normal detection threshold. A maximum density of defects d0shall be calculated as follows: LN= d000(2) where N0is the maximum permissible number of discontinuities in a pre-set length; L0is the pre-set length. NOTE Both N0and L0should be determined by
44、the tube manufacturer if they are not specified in the relevant product standard. Discontinuity signals ranging between the two sorting limits of the lower and normal detection thresholds along the pre-set length L0shall be counted as N. When the real density d = N/L0exceeds d0, the entire pre-set l
45、ength affected shall be considered defective. BS EN 1971-2:2011EN 1971-2:2011 (E) 8 6.3 Other test methods For other test methods the acceptance criteria shall be defined specifically, such as for a system involving relative rotational motion between the tube and the surface probe. Equal or higher s
46、ensitivity shall be demonstrated. 7 Instrument adjustment The test system shall be adjusted, using a reference standard tube in accordance with Clause 5. If the test instrument operates with phase selection, the signals from the defects to be detected shall lie within the determined phase ranges. Th
47、e sensitivity of the instrument shall be adjusted so that the smallest of the three signals exceeds the response threshold of the sorting limit. Adjustment of the instrument shall be carried out and checked for each change of product and at regular intervals of not more than 8 h during periods of co
48、ntinuous operation. If any check shows that a loss of sensitivity exceeding 2 dB has occurred, all the tubes tested since the last check shall be considered as not tested. BS EN 1971-2:2011EN 1971-2:2011 (E) 9 Bibliography EN 12452, Copper and copper alloys Rolled, finned, seamless tubes for heat ex
49、changers This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standards and other standards-related publications, information and services. It presents the UK view on standards in Europe and at the international level. BSI is incorporated by Royal Charter. British Standards and other standardisation products are published by BSI Standards Limited.British Standards Institution (BSI)raising standards worldwideBSI389 Chiswick High Roa
