SIST EN 61788-6:2008
Superconductivity -- Part 6: Mechanical properties measurement - Room temperature tensile test of Cu/Nb-Ti composite superconductors
Superconductivity -- Part 6: Mechanical properties measurement - Room temperature tensile test of Cu/Nb-Ti composite superconductors
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 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). The sample covered by this test procedure has a round or rectangular cross-section with an area of 0,15 mm2 to 2 mm2 and a copper to superconductor volume ratio of 1,0 to 8,0 and without the insulating coating.
Supraleitfähigkeit -- Teil 6: Messung der mechanischen Eigenschaften - Messung der Zugfestigkeit von Cu/NbTi-Verbundsupraleitern bei Raumtemperatur
Supraconductivité -- Partie 6: Mesure des propriétés mécaniques - Essai de traction à température ambiante des composites supraconducteurs de Cu/Nb-Ti
Superprevodnost - 6. del: Meritve mehanskih lastnosti - Natezni preskus pri sobni temperaturi za superprevodnike iz kompozita Cu/Nb-Ti (IEC 61788-6:2008)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61788-6:2008
01-september-2008
Superprevodnost - 6. del: Meritve mehanskih lastnosti - Natezni preskus pri sobni
temperaturi za superprevodnike iz kompozita Cu/Nb-Ti (IEC 61788-6:2008)
Superconductivity - Part 6: Mechanical properties measurement - Room temperature
tensile test of Cu/Nb-Ti composite superconductors
Supraleitfähigkeit - Teil 6: Messung der mechanischen Eigenschaften - Messung der
Zugfestigkeit von Cu/NbTi-Verbundsupraleitern bei Raumtemperatur
Supraconductivité - Partie 6: Mesure des propriétés mécaniques - Essai de traction à
température ambiante des composites supraconducteurs de Cu/Nb-Ti
Ta slovenski standard je istoveten z: EN 61788-6:2008
ICS:
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN 61788-6:2008 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 61788-6:2008
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SIST EN 61788-6:2008
EUROPEAN STANDARD
EN 61788-6
NORME EUROPÉENNE
May 2008
EUROPÄISCHE NORM
ICS 29.050; 77.040.10 Supersedes EN 61788-6:2001
English version
Superconductivity -
Part 6: Mechanical properties measurement -
Room temperature tensile test of Cu/Nb-Ti composite superconductors
(IEC 61788-6:2008)
Supraconductivité - Supraleitfähigkeit -
Partie 6: Mesure des propriétés Teil 6: Messung der mechanischen
mécaniques - Eigenschaften -
Essai de traction à température ambiante Messung der Zugfestigkeit von
des composites supraconducteurs de Cu/NbTi-Verbundsupraleitern
Cu/Nb-Ti bei Raumtemperatur
(CEI 61788-6:2008) (IEC 61788-6:2008)
This European Standard was approved by CENELEC on 2008-04-01. 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 bibliographical 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 CENELEC 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, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61788-6:2008 E
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SIST EN 61788-6:2008
EN 61788-6:2008 - 2 -
Foreword
The text of document 90/207/FDIS, future edition 2 of IEC 61788-6, prepared by IEC TC 90,
Superconductivity, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61788-6 on 2008-04-01.
This European Standard supersedes EN 61788-6:2001.
EN 61788-6:2008 includes the following significant technical changes with respect to EN 61788-6:2001:
– the minimum distance between grips was changed from 100 mm to 60 mm;
– accuracy and precision statement were converted to uncertainty statements.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-04-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61788-6:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 61788-5 NOTE Harmonized as EN 61788-5:2001 (not modified).
__________
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SIST EN 61788-6:2008
- 3 - EN 61788-6:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
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
1)
IEC 60050-815 - International Electrotechnical Vocabulary - -
(IEV) -
Part 815: Superconductivity
1) 2)
ISO 376 - Metallic materials - Calibration of EN ISO 376 2004
force-proving instruments used for the
verification of uniaxial testing machines
1)
ISO 6892 - Metallic materials - Tensile testing at ambient - -
temperature
1) 2)
ISO 7500-1 - Metallic materials - Verification of static EN ISO 7500-1 2004
uniaxial testing machines -
Part 1: Tension/compression testing
machines - Verification and calibration of the
force-measuring system
1) 2)
ISO 9513 - Metallic materials - Calibration of EN ISO 9513 2002
extensometers used in uniaxial testing
1)
Undated reference.
2)
Valid edition at date of issue.
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SIST EN 61788-6:2008
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SIST EN 61788-6:2008
IEC 61788-6
Edition 2.0 2008-01
INTERNATIONAL
STANDARD
Superconductivity –
Part 6: Mechanical properties measurement – Room temperature tensile test of
Cu/Nb-Ti composite superconductors
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 29.050; 77.040.10 ISBN 2-8318-9529-4
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SIST EN 61788-6:2008
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CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Principle .7
5 Apparatus.7
5.1 Conformity.7
5.2 Testing machine .7
5.3 Extensometer .8
6 Specimen preparation.8
6.1 Straightening the specimen .8
6.2 Length of specimen .8
6.3 Removing insulation .8
6.4 Determination of cross-sectional area (S ) .8
o
7 Testing conditions .8
7.1 Specimen gripping.8
7.2 Pre-loading and setting of extensometer .8
7.3 Testing speed.8
7.4 Test.9
8 Calculation of results .9
8.1 Tensile strength (R ) .9
m
8.2 0,2 % proof strength (R and R ) .9
p0,2A p0,2B
8.3 Modulus of elasticity (E and E ) .9
o a
9 Uncertainty.10
10 Test report.10
10.1 Specimen .10
10.2 Results.10
10.3 Test conditions.11
Annex A (informative) Additional information relating to Clauses 1 to 10 .13
Annex B (informative) Uncertainty considerations .18
Bibliography.21
Figure 1 – Stress-strain curve and definition of modulus of elasticity and 0,2 % proof
strengths .12
Figure A.1 – An example of the light extensometer, where R1 and R3 indicate the
corner radius .16
Figure A.2 – An example of the extensometer provided with balance weight and
vertical specimen axis.17
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SIST EN 61788-6:2008
61788-6 © IEC:2008(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
SUPERCONDUCTIVITY –
Part 6: Mechanical properties measurement –
Room temperature tensile test of Cu/Nb-Ti
composite superconductors
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-6 has been prepared by IEC technical committee 90:
Superconductivity.
This second edition cancels and replaces the first edition published in 2000. It constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– the minimum distance between grips was changed from 100 mm to 60 mm;
– accuracy and precision statement were converted to uncertainty statements.
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SIST EN 61788-6:2008
– 4 – 61788-6 © IEC:2008(E)
The text of this standard is based on the following documents:
FDIS Report on voting
90/207/FDIS 90/209/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be issued at a later date.
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SIST EN 61788-6:2008
61788-6 © IEC:2008(E) – 5 –
INTRODUCTION
The Cu/Nb-Ti superconductive composite wires currently in use are multifilamentary
composite material with a matrix that functions as a stabilizer and supporter, in which ultrafine
superconductor filaments are embedded. A Nb-40~55 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 superconductors 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 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, of which the windings are made.
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SIST EN 61788-6:2008
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SUPERCONDUCTIVITY –
Part 6: Mechanical properties 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 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).
The sample covered by this test procedure has a round or rectangular cross-section with an
2 2
area of 0,15 mm to 2 mm and 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 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.
IEC 60050-815, International Electrotechnical Vocabulary (IEV) – Part 815: Superconductivity
ISO 376, Metallic materials – Calibration of force-proving instruments used for the verification
of uniaxial testing machines
ISO 6892, Metallic materials – Tensile testing at ambient 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 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, as
well as the following, apply.
3.1
tensile stress
tensile force divided by the original cross-sectional area at any moment during the test
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SIST EN 61788-6:2008
61788-6 © IEC:2008(E) – 7 –
3.2
tensile strength
R
m
tensile stress corresponding to the maximum testing force
NOTE The symbol σ is commonly used instead of R .
UTS m
3.3
extensometer gauge length
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
L
g
length between grips that hold a test specimen in position before the test is started
3.5
0,2 % proof strength
R (see Figure 1)
p0,2
stress value where the copper component yields by 0,2 %
NOTE 1 The designated stress, R or R corresponds to point A or B in Figure 1, respectively. This
p0,2A p0,2B
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 of the composite where the Nb-Ti component yields by 0,2 %, of
which value corresponds to the point C in Figure 1 as described complementarily in Annex A (see Clause A.2).
NOTE 2 The symbol σ is commonly used instead of R .
0.2 p0.2
3.6
modulus of elasticity
E
gradient of the straight portion of the 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 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 strain rate shall be used. Grips
shall have a structure and strength 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 pneumatically or hydraulically actuated.
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SIST EN 61788-6:2008
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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 specimen (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 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 chemical 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 (S )
o
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 area of a rectangular wire shall be obtained from
the product of its thickness and width. Corrections to be made for the corners of the cross-
sectional area shall be determined through consultation among the parties concerned (see
Clause A.5).
7 Testing conditions
7.1 Specimen gripping
The test specimen shall be mounted on the grips of the tensile machine. At this time, the test
specimen and tensile loading axis must be on a single straight line. Sand paper may be
inserted as a cushioning material to prevent the gripped surfaces of the specimen from
slipping and fracturing (see Clause A.6).
7.2 Pre-loading and setting of extensometer
If there is any slack in the specimen when it is mounted, a force between one-tenth and one-
third of the 0,2 % proof strength of the composite shall be applied to take up the slack before
the extensometer is mounted. When mounting the extensometer, care shall be taken to
prevent the test specimen from being deformed. The extensometer shall be mounted at the
centre between the grips, aligning the measurement direction with the specimen axis
direction. After installation, loading shall be zeroed.
7.3 Testing speed
–4 –3
The strain rate shall be 10 /s to 10 /s during the test using the extensometer. After
–3
removing the extensometer, the strain rate may be increased to a maximum of 10 /s.
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7.4 Test
The tensile machine shall be started after the testing speed has been set to the specified
level. The signals from the extensometer and load cell shall be plotted on the abscissa and
ordinate, respectively, as shown in Figure 1. When the total strain has reached approximately
2 %, reduce the force by approximately 10 % and then remove the extensometer. The step of
removing the extensometer can be omitted in the case where the extensometer is robust
enough not to be damaged by the total strain and the fracture shock of this test. At this time,
care shall be taken to prevent unnecessary force from being applied to the test specimen.
Then, increase loading again to the previous level and continue testing until the test specimen
fractures. Measurement shall be made again if a slip or fracture occurs on the gripped
surfaces of the test specimen.
8 Calculation of results
8.1 Tensile strength (R )
m
Tensile strength R shall be the maximum force divided by the original cross-sectional area of
m
the wire before loading.
8.2 0,2 % proof strength (R and R )
p0,2A p0,2B
The 0,2 % proof strength of the composite due to yielding of the copper component is
determined in two ways from the loading and unloading stress-strain curves as shown in
Figure 1. The 0,2 % proof strength under loading R shall be determined as follows: the
p0,2A
initial linear portion under loading of the stress-strain curve is moved 0,2 % in the strain axis
(0,2 % offset line under loading) and the point A at which this linear line intersects the stress-
strain curve (point A) shall be defined as the 0,2 % proof strength under loading. The 0,2 %
proof strength of the composite under unloading R shall be determined as follows: the
p0,2B
linear portion under unloading is to be moved parallel to the 0,2 % offset strain point. The
intersection of this line with the stress-strain curve determines the point B that shall be
defined as the 0,2 % proof strength. This measurement shall be discarded if the 0,2 % proof
strength of the composite is less than three times the pre-load specified in 7.2.
Each 0,2 % proof strength shall be calculated using formula (1) given below:
R = F / S (1)
p0,2i i o
where
R is the 0,2 % proof strength (MPa) at each point;
p0,2i
F is the force (N) at each point;
i
S is the original cross-sectional area (in square millimetres) of the test specimen;
o
Further, i = A and B.
8.3 Modulus of elasticity (E and E )
o a
Modulus of elasticity shall be calculated using the following formula and the straight portion,
either of the initial loading curve or of the unloading one.
E = ΔF (1 + ε )/(S Δε) (2)
a o
where
E is the modulus of elasticity (MPa);
ΔF is the increments (N) of the corresponding force;
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SIST EN 61788-6:2008
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Δε is the increment of strain corresponding to ΔF;
ε is the strain just after unloading as shown in Figure 1.
a
E is designated as E when using the initial loading curve (ε = 0), and as E when using the
o a a
unloading curve (ε ≠ 0).
a
9 Uncertainty
Unless otherwise specified, measurements shall be carried out in a temperature range
between 280 K and 310 K. A force measuring cell with a combined standard uncertainty not
greater than 0,5 % shall be used. An extensometer with a combined standard uncertainty not
greater than 0,5 % shall be used. The dimension-measuring apparatus shall have a combined
standard uncertainty not greater than 0,1 %. The target combined standard uncertainties are
defined by root square sum RSS procedure, which is given in Annex B. The estimated
uncertainties for moduli of elasticity E and E , are 8 % and 2 % respectively. For 0,2 % proof
o a
strengths R and R smaller uncertainty values are expected due to the nearly 1/3 of
p0,2A p0,2B
the slope value of the stress strain curve in the region of intersections between shifted elastic
moduli slope line and stress versus strain curve (see Figure 1).
NOTE Uncertainties reported in present text if used for the purpose of practical assessment have to be taken
under the specific considerations with detailed caution as referred in Annex B.
10 Test report
10.1 Specimen
a) Name of the manufacturer of the specimen
b) Classification and/or symbol
c) Lot number
The following information shall be reported as necessary.
d) Raw materials and their chemical composition
e) Cross-sectional shape and dimension of the wire
f) Filament diameter
g) Number of filaments
h) Twist pitch of filaments
i) Copper to superconductor ratio
10.2 Results
a) Tensile strength (R )
m
b) 0,2 % proof strengths (R and R )
p0,2A p0,2B
c) Modulus of elasticity (E and E with ε )
o a a
The following information shall be reported as necessary.
d) Second type of 0,2 % proof strength (R )
p0,2C
e) Percentage elongation after fracture (A)
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61788-6 © IEC:2008(E) – 11 –
10.3 Test conditions
a) Strain rate
b) Distance between grips
c) Temperature
The following information shall be reported as necessary.
d) Manufacturer and model of testing machine
e) Manufacturer and model of extensometer
f) Gripping method
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SIST EN 61788-6:2008
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700
5
1
E
4
2
C
600
6
500
...
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