1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSuperconductivityPart 6: Mechanical properties measurement Room temperature tensile test of Cu/Nb-Ti composite superconductorsBS EN 61788-6:2011National forewordThis British Stan
2、dard is the UK implementation of EN 61788-6:2011. It is identical to IEC 61788-6:2011. It supersedes BS EN 61788-6:2008,which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee L/-/90 Super Conductivity.A list of organizations represented on this committee can
3、be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011ISBN 978 0 580 65698 9 ICS 29.050; 77.040.10 Compliance with a British Standard cannot confer immunity from lega
4、l obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2011.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 61788-6:2011EUROPEAN STANDARD EN 61788-6 NORME EUROPENNE EUROPISCHE NORM Augus
5、t 2011 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserv
6、ed worldwide for CENELEC members. Ref. No. EN 61788-6:2011 E ICS 29.050; 77.040.10 Supersedes EN 61788-6:2008English version Superconductivity - Part 6: Mechanical properties measurement - Room temperature tensile test of Cu/Nb-Ti composite superconductors (IEC 61788-6:2011) Supraconductivit - Parti
7、e 6: Mesure des proprits mcaniques - Essai de traction temprature ambiante des supraconducteurs composites de Cu/Nb-Ti (CEI 61788-6:2011) Supraleitfhigkeit - Teil 6: Messung der mechanischen Eigenschaften - Messung der Zugfestigkeit von Cu/Nb-Ti-Verbundsupraleitern bei Raumtemperatur(IEC 61788-6:201
8、1) This European Standard was approved by CENELEC on 2011-08-15. CENELEC members are bound to comply 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 bibliographic
9、al references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC 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 C
10、ENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greec
11、e, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61788-6:2011EN 61788-6:2011 Foreword The text of document 90/267/FDIS, future edition 3 of IEC 6
12、1788-6, prepared by IEC TC 90, Superconductivity was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61788-6:2011. The following dates are fixed: latest date by which the document has to be implemented at national level by publication of an identical national standard or by
13、endorsement (dop) 2012-05-15 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2014-08-15 This document supersedes EN 61788-6:2008. EN 61788-6:2011 includes the following significant technical changes with respect to EN 61788-6:2008: specific exampl
14、e of uncertainty estimation related to mechanical tests was supplemented as Annex C. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. E
15、ndorsement notice The text of the International Standard IEC 61788-6:2011 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 61788-5 NOTE Harmonized as EN 61788-5. I
16、SO 3611:2010 NOTE Harmonized as EN ISO 3611:2010 (not modified). BS EN 61788-6:2011EN 61788-6:2011 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced documents are indispensable for the application of this d
17、ocument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. P
18、ublication Year Title EN/HD Year IEC 60050-815 - International Electrotechnical Vocabulary - Part 815: Superconductivity - - ISO 376 - Metallic materials - Calibration of force-proving instruments used for the verification of uniaxial testing machines EN ISO 376 - ISO 6892-1 - Metallic materials - T
19、ensile testing - Part 1: Method of test at room temperature EN ISO 6892-1 - ISO 7500-1 - Metallic materials - Verification of static uniaxial testing machines - Part 1: Tension/compression testing machines - Verification and calibration of the force-measuring system EN ISO 7500-1 - ISO 9513 - Metall
20、ic materials - Calibration of extensometers used in uniaxial testing EN ISO 9513 - BS EN 61788-6:201161788-6 IEC:2011 CONTENTS INTRODUCTION . 6 1 Scope . . 7 2 Normative references . 7 3 Terms and definitions . 7 4 Principle 8 5 Apparatus . 8 5.1 Conformity . . 8 5.2 Testing machine 8 5.3 Extensomet
21、er . 9 6 Specimen preparation. 9 6.1 Straightening the specimen . 9 6.2 Length of specimen . 9 6.3 Removing insulation . 9 6.4 Determination of cross-sectional area (So) . 9 7 Testing conditions . 9 7.1 Specimen gripping . 9 7.2 Pre-loading and setting of extensometer . . 9 7.3 Testing speed. 9 7.4
22、Test . 10 8 Calculation of results . . 12 8.1 Tensile strength (Rm) . 12 8.2 0,2 % proof strength (Rp0,2A and Rp0,2B) . 12 8.3 Modulus of elasticity (Eoand Ea) 12 9 Uncertainty . 12 10 Test report 13 10.1 Specimen . 13 10.2 Results 13 10.3 Test conditions 13 Annex A (informative) Additional informat
23、ion relating to Clauses 1 to 10 . 14 Annex B (informative) Uncertainty considerations . 19 Annex C (informative) Specific examples related to mechanical tests . 23 Bibliography . 32 Figure 1 Stress-strain curve and definition of modulus of elasticity and 0,2 % proof strengths . 11 Figure A.1 An exam
24、ple of the light extensometer, where R1 and R3 indicate the corner radius . . 15 Figure A.2 An example of the extensometer provided with balance weight and vertical specimen axis 16 Figure C.1 Measured stress versus strain curve of the rectangular cross section NbTi wire and the initial part of the
25、curve . . 23 Figure C.2 0,2 % offset shifted regression line, the raw stress versus strain curve and the original raw data of stress versus strain . 29 BS EN 61788-6:201161788-6 IEC:2011 Table B.1 Output signals from two nominally identical extensometers . 20 Table B.2 Mean values of two output sign
26、als . 20 Table B.3 Experimental standard deviations of two output signals 20 Table B.4 Standard uncertainties of two output signals 21 Table B.5 Coefficient of variations of two output signals. 21 Table C.1 Load cell specifications according to manufacturers data sheet . . 26 Table C.2 Uncertainties
27、 of displacement measurement 26 Table C.3 Uncertainties of wire width measurement 27 Table C.4 Uncertainties of wire thickness measurement 27 Table C.5 Uncertainties of gauge length measurement 27 Table C.6 Calculation of stress at 0 % and at 0,1 % strain using the zero offset regression line as det
28、ermined in Figure C.1b). 28 Table C.7 Linear regression equations computed for the three shifted lines and for the stress versus strain curve in the region where the lines intersect 29 Table C.8 Calculation of strain and stress at the intersections of the three shifted lines with the stress strain c
29、urve 30 Table C.9 Measured stress versus strain data and the computed stress based on a linear fit to the data in the region of interest . 31 BS EN 61788-6:2011 6 61788-6 IEC:2011 INTRODUCTION The Cu/Nb-Ti superconductive composite wires currently in use are multifilamentary composite material with
30、a matrix that functions as a stabilizer and supporter, in which ultrafine superconductor filaments are embedded. A Nb-4055 mass % Ti alloy is used as the superconductive material, while oxygen-free copper and aluminium of high purity are employed as the matrix material. Commercial composite supercon
31、ductors have a high current density and a small cross-sectional area. The major application of the composite superconductors is to build superconducting magnets. While the magnet is being manufactured, complicated stresses are applied to its windings and, while it is being energized, a large electro
32、magnetic force is applied to the superconducting wires because of its high current density. It is therefore indispensable to determine the mechanical properties of the superconductive wires, of which the windings are made. BS EN 61788-6:201161788-6 IEC:2011 7 SUPERCONDUCTIVITY Part 6: Mechanical pro
33、perties measurement Room temperature tensile test of Cu/Nb-Ti composite superconductors 1 Scope This part of IEC 61788 covers a test method detailing the tensile test procedures to be carried out on Cu/Nb-Ti superconductive composite wires at room temperature. This test is used to measure modulus of
34、 elasticity, 0,2 % proof strength of the composite due to yielding of the copper component, and tensile strength. The value for percentage elongation after fracture and the second type of 0,2 % proof strength due to yielding of the Nb-Ti component serves only as a reference (see Clauses A.1 and A.2)
35、. The sample covered by this test procedure has a round or rectangular cross-section with an area of 0,15 mm2to 2 mm2and a copper to superconductor volume ratio of 1,0 to 8,0 and without the insulating coating. 2 Normative references The following referenced documents are indispensable for the appli
36、cation 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. IEC 60050-815, International Electrotechnical Vocabulary Part 815: Superconductivity ISO 376, Metallic materials Ca
37、libration of force-proving instruments used for the verification of uniaxial testing machines ISO 6892-1, Metallic materials Tensile testing Part 1: Method of test at room temperature ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing
38、machines Verification and calibration of the force-measuring system ISO 9513, Metallic materials Calibration of extensometers used in uniaxial testing 3 Terms and definitions For the purposes of this document, the definitions given in IEC 60050-815 and ISO 6892-1, as well as the following, apply. 3.
39、1 tensile stress tensile force divided by the original cross-sectional area at any moment during the test BS EN 61788-6:2011 8 61788-6 IEC:2011 3.2 tensile strength Rmtensile stress corresponding to the maximum testing force NOTE The symbol UTSis commonly used instead of Rm. 3.3 extensometer gauge l
40、ength length of the parallel portion of the test piece used for the measurement of elongation by means of an extensometer 3.4 distance between grips Lglength between grips that hold a test specimen in position before the test is started 3.5 0,2 % proof strength Rp0,2(see Figure 1) stress value where
41、 the copper component yields by 0,2 % NOTE 1 The designated stress, Rp0,2Aor Rp0,2Bcorresponds to point A or B in Figure 1, respectively. This strength is regarded as a representative 0,2 % proof strength of the composite. The second type of 0,2 % proof strength is defined as a 0,2 % proof strength
42、of the composite where the Nb-Ti component yields by 0,2 %, the value of which corresponds to the point C in Figure 1 as described complementarily in Annex A (see Clause A.2). NOTE 2 The symbol 0,2is commonly used instead of Rp0,2. 3.6 modulus of elasticity E gradient of the straight portion of the
43、stress-strain curve in the elastic deformation region 4 Principle The test consists of straining a test piece by tensile force, generally to fracture, for the purpose of determining the mechanical properties defined in Clause 3. 5 Apparatus 5.1 Conformity The test machine and the extensometer shall
44、conform to ISO 7500-1 and ISO 9513, respectively. The calibration shall obey ISO 376. The special requirements of this standard are presented here. 5.2 Testing machine A tensile machine control system that provides a constant cross-head speed shall be used. Grips shall have a structure and strength
45、appropriate for the test specimen and shall be constructed to provide an effective connection with the tensile machine. The faces of the grips shall be filed or knurled, or otherwise roughened, so that the test specimen will not slip on them during testing. Gripping may be a screw type, or pneumatic
46、ally or hydraulically actuated. BS EN 61788-6:201161788-6 IEC:2011 9 5.3 Extensometer The weight of the extensometer shall be 30 g or less, so as not to affect the mechanical properties of the superconductive wire. Care shall also be taken to prevent bending moments from being applied to the test sp
47、ecimen (see Clause A.3). 6 Specimen preparation 6.1 Straightening the specimen When a test specimen sampled from a bobbin needs to be straightened, a method shall be used that affects the material as little as possible. 6.2 Length of specimen The total length of the test specimen shall be the inward
48、 distance between grips plus both grip lengths. The inward distance between the grips shall be 60 mm or more, as requested for the installation of the extensometer. 6.3 Removing insulation If the test specimen surface is coated with an insulating material, that coating shall be removed. Either a che
49、mical or mechanical method shall be used, with care taken not to damage the specimen surface (see Clause A.4). 6.4 Determination of cross-sectional area (So) A micrometer or other dimension-measuring apparatus shall be used to obtain the cross-sectional area of the specimen after the insulation coating has been removed. The cross-sectional area of a round wire shall be calculated using the arithmetic mean of the two orthogonal diameters. The cross-sectional a
