1、BSI Standards PublicationSuperconductivityPart 18: Mechanical properties measurement Room temperature tensile test of Ag- and/or Ag alloy-sheathed Bi-2223 and Bi-2212 composite superconductorsBS EN 61788-18:2013National forewordThis British Standard is the UK implementation of EN 61788-18:2013. It i
2、sidentical to IEC 61788-18:2013.The UK participation in its preparation was entrusted to TechnicalCommittee L/-/90, Super Conductivity.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provi
3、sions ofa contract. Users are responsible for its correct application. The British Standards Institution 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 70783 4ICS 29.050Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published und
4、er the authority of theStandards Policy and Strategy Committee on 31 January 2014.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN 61788-18:2013EUROPEAN STANDARD EN 61788-18 NORME EUROPENNE EUROPISCHE NORM December 2013 CENELEC European Committee for Electrotechn
5、ical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref.
6、 No. EN 61788-18:2013 E ICS 29.050 English version Superconductivity - Part 18: Mechanical properties measurement - Room temperature tensile test of Ag- and/or Ag alloy-sheathed Bi-2223 and Bi-2212 composite superconductors (IEC 61788-18:2013) Supraconductivit - Partie 18: Mesure des proprits mcaniq
7、ues - Essai de traction temprature ambiante des supraconducteurs composites Bi-2223 et Bi-2212 avec gaine Ag et/ou en alliage dAg (CEI 61788-18:2013) Supraleitfhigkeit - Teil 18: Messung der mechanischen Eigenschaften - Zugversuch von Ag und/oder Ag-Legierung ummantelten Bi-2223 und Bi-2212 Verbunds
8、upraleitern bei Raumtemperatur (IEC 61788-18:2013) This European Standard was approved by CENELEC on 2013-10-17. 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 an
9、y 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 CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other la
10、nguage made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, t
11、he Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the Uni
12、ted Kingdom. BS EN 61788-18:2013EN 61788-18:2013 - 2 - Foreword The text of document 90/326/FDIS, future edition 1 of IEC 61788-18, prepared by IEC/TC 90 “Superconductivity“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61788-18:2013. The following dates are fixed: lat
13、est date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-07-17 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-10-17 Attention is drawn to the possibi
14、lity 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. Endorsement notice The text of the International Standard IEC 61788-18:2013 was approved by CENELEC as a European Stand
15、ard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 61788-6 NOTE Harmonized as EN 61788-6. ISO 3611:2010 NOTE Harmonized as EN ISO 3611:2010 (not modified). BS EN 61788-18:2013- 3 - EN 61788-18:2013 Annex ZA (
16、normative) Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For
17、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. Publication Year Title EN/HD Year IEC 60050 series International Ele
18、ctrotechnical Vocabulary - - 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 - Tensile testing Part 1: Method of test at room temperature EN ISO 6892-1 - ISO 7500-1 - Metallic
19、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 - Metallic materials - Calibration of extensometer systems used in uniaxial testing EN ISO 9513 - BS EN 6178
20、8-18:2013 2 61788-18 IEC:2013 CONTENTS 1 Scope . 7 2 Normative references . 7 3 Terms and definitions . 7 4 Principle . 9 5 Apparatus . 9 5.1 General . 9 5.2 Testing machine 9 5.3 Extensometer 9 6 Specimen preparation . 9 6.1 General . 9 6.2 Length of specimen . 10 6.3 Removing insulation 10 6.4 Det
21、ermination of cross-sectional area (S0) 10 7 Testing conditions 10 7.1 Specimen gripping . 10 7.2 Setting of extensometer . 10 7.3 Testing speed 10 7.4 Test . 10 8 Calculation of results 12 8.1 Modulus of elasticity (E) 12 8.2 0,2 % proof strength (Rp 0,2) 13 8.3 Tensile stress at specified strains
22、(RA) 13 8.4 Fracture strength (Rf) 14 9 Uncertainty of measurement . 14 10 Test report 14 10.1 Specimen 14 10.2 Results 15 10.3 Test conditions 15 Annex A (informative) Additional information relating to Clauses 1 to 14 16 Annex B (informative) Uncertainty considerations 26 Annex C (informative) Spe
23、cific examples related to evaluation of uncertainties for Ag/Bi-2223 and Ag/Bi-2212 wires . 30 Figure 1 Typical stress-strain curve and definition of modulus of elasticity and 0,2 % proof strengths of an externally laminated Ag/Bi-2223 wire by brass foil . 11 Figure 2 Typical stress-strain curve of
24、an Ag/Bi-2223 wire where the 0,2 % proof strengths could not be determined and definition of tensile stresses at specified strains . 12 Figure A.1 Low mass Siam twin type extensometer with a gauge length of 12,3 mm (total mass 0,5 g) . 16 Figure A.2 Low mass double extensometer with a gauge length o
25、f 25,6 mm (total mass 3 g) . 17 Figure A.3 An example of the extensometer provided with balance weight and vertical specimen axis . 18 Figure A.4 Original raw data of an Ag/Bi-2223 wire measurement in form of load and displacement graph . 19 BS EN 61788-18:201361788-18 IEC:2013 3 Figure A.5 Typical
26、stress versus strain of an Ag/Bi-2223 wire up to the elastic limit corresponding to the transition region from elastic to plastic deformation (point G) . 20 Figure C.1 Measured stress versus strain curve for Bi-2223 wire . 31 Table A.1 Results of relative standard uncertainty values achieved on diff
27、erent Ag/Bi-2223 wires during the international round robin tests . 23 Table A.2 Selected data for F test for E0 of Sample E bare wire 24 Table A.3 Results of F-test for the variations of E0of four kinds of Bi-2223 wires 24 Table B.1 Output signals from two nominally identical extensometers 27 Table
28、 B.2 Mean values of two output signals . 27 Table B.3 Experimental standard deviations of two output signals 27 Table B.4 Standard uncertainties of two output signals 27 Table B.5 Coefficient of variations of two output signals . 28 Table C.1. Load cell specifications according to manufacturers data
29、 sheet 32 Table C.2 Uncertainties from various factors for stress measurement 33 Table C.3 Uncertainties with respect to measurement of strain measurement 35 Table C.4 Summary of evaluated uncertainties caused by various factors 35 Table C.5 Results of uncertainty evaluation for the modulus of elast
30、icity (E0= 86,1 GPa) as a function of initial cross head rate 36 Table C.6 Uncertainties from various factors for stress measurement 37 Table C.7 Results of uncertainty evaluation for the stress (R = 42,5 MPa) as a function of initial strain rate 37 BS EN 61788-18:2013 6 61788-18 IEC:2013 INTRODUCTI
31、ON Several types of composite superconductors have now been commercialised. Especially, high temperature superconductors such as Ag- and/or Ag alloy-sheathed Bi-2223 (Ag/Bi-2223) and Ag- and/or Ag alloy-sheathed Bi-2212 (Ag/Bi-2212) wires are now manufactured in industrial scale. Commercial composit
32、e superconductors have a high current density and a small cross-sectional area. The major applications of composite superconductors are to build electrical power devices and superconducting magnets. While the magnet is being manufactured, complicated stresses/strains are applied to its windings and,
33、 while it is being energized, a large electromagnetic 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 from which the windings are made. The Ag/Bi-2223 and Ag/Bi-2212 s
34、uperconductive composite wires fabricated by the powder-in -tube method are composed of a number of oxide filaments with silver and silver alloy as a stabilizer and supporter. In the case that the external reinforcement of Ag/Bi-2223 and Ag/Bi-2212 wires by using thin stainless or Cu alloy foils has
35、 been adopted in order to resist the large electromagnet force, this standard shall be also applied. BS EN 61788-18:201361788-18 IEC:2013 7 SUPERCONDUCTIVITY Part 18: Mechanical properties measurement Room temperature tensile test of Ag- and/or Ag alloy-sheathed Bi-2223 and Bi-2212 composite superco
36、nductors 1 Scope This International Standard specifies a test method detailing the tensile test procedures to be carried out on Ag/Bi-2223 and Ag/Bi-2212 superconductive composite wires at room temperature. This test is used to measure the modulus of elasticity and to determine the 0,2 % proof stren
37、gth. When the 0,2 % proof strength could not be determined due to earlier failure, the stress level at apparent strains of 0,05 %, 0,1 %, 0,15 %, 0,2 %, 0,25 % with increment of 0,05 % is measured. The values for elastic limit, fracture strength, percentage elongation after fracture and the fitted t
38、ype of 0,2 % proof strength serve only as a reference (see Clauses A.4, A.5, A.6 and A.10). The sample covered by this test procedure should have a round or rectangular cross-section with an area of 0,3 mm2to 2,0 mm2(corresponding to the tape-shaped wires with width of 2,0 mm to 5,0 mm and thickness
39、 of 0,16 mm to 0,4 mm). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced docum
40、ent (including any amendments) applies. IEC 60050 (all parts), International Electrotechnical Vocabulary (available at ) ISO 376, Metallic materials Calibration of force-proving instruments used for the verification of uniaxial testing machines ISO 6892-1, Metallic materials Tensile testing Part 1:
41、Method of test at room temperature 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 ISO 9513, Metallic materials Calibration of extensometer systems used in uniaxial
42、 testing 3 Terms and definitions For the purposes of this document, terms and definitions given in IEC 60050-815 and ISO 6892-1, as well as the following terms and definitions apply. BS EN 61788-18:2013 8 61788-18 IEC:2013 3.1 tensile stress R tensile force divided by the original cross-sectional ar
43、ea at any moment during the test 3.2 tensile strain A displacement increment divided by initial gauge length of extensometers at any moment during the test 3.3 extensometer gauge length LGlength of the parallel portion of the test piece used for the measurement of displacement by means of an extenso
44、meter 3.4 distance between grips Lolength between grips that hold a test specimen in position before the test is started 3.5 modulus of elasticity E gradient of the straight portion of the stress-strain curve in the elastic deformation region SEE: Figure 1. Note 1 to entry: It can be determined diff
45、erently depending upon the adopted procedures: a) one from the initial loading curve by zero offset line expressed as E0, b) the other one given by the slope of line during the elastic unloading, expressed as EU. 3.6 0,2 % proof strength Rp0,2stress value when the superconductive composite wire yiel
46、ds by 0,2 % SEE: Figure 1. Note 1 to entry: The designated stress, Rp0,2-0or Rp0,2-Ucorresponds to point A or B obtained from the initial loading or unloading curves in Figure 1, respectively. This strength is regarded as a representative 0,2 % proof strength of the composite. 3.7 tensile stress at
47、specified strains RAtensile stress corresponding to different specified strain (A) 3.8 fracture strength Rftensile stress at the fracture Note 1 to entry: In most cases, the fracture strength is defined as tensile stress corresponding to the maximum testing force BS EN 61788-18:201361788-18 IEC:2013
48、 9 3.9 tensile stress at elastic limit Reltensile stress at elastic limit corresponding to transition instant from elastic to plastic deformation 3.10 tensile strain at elastic limit Aelstrain at elastic limit Note 1 to entry: The stress Reland the corresponding strain Aelrefer to point G in Figure
49、A.5, respectively and are regarded as the transition point from elastic to plastic deformation. 4 Principle The test consists of straining a test piece by a tensile force, generally to fracture, in principle for the purpose of determining the mechanical properties defined in Clause 3. Depending on the employed strain measuring method, however, the quantities determined by the present test should be limited. When using the conventional single extensomete
