EN ISO 6892-1:2009

SLOVENSKI STANDARD
01-marec-2010
1DGRPHãþD
SIST EN 10002-1:2002
Kovinski materiali - Natezni preskus - 1. del: Metoda preskušanja pri sobni
temperaturi (ISO 6892-1:2009)
Metallic materials - Tensile testing - Part 1: Method of test at room temperature (ISO
6892-1:2009)
Metallische Werkstoffe - Zugversuch - Prüfverfahren bei Raumtemperatur (ISO 6892-
1:2009)
Matériaux métalliques - Essais de traction - Partie 1: Méthode d'essai à température
ambiante (ISO 6892-1:2009)
Ta slovenski standard je istoveten z: EN ISO 6892-1:2009
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 6892-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 77.040.10 Supersedes EN 10002-1:2001
English Version
Metallic materials - Tensile testing - Part 1: Method of test at
room temperature (ISO 6892-1:2009)
Matériaux métalliques - Essai de traction - Partie 1: Metallische Werkstoffe - Zugversuch - Teil 1: Prüfverfahren
Méthode d'essai à température ambiante (ISO 6892- bei Raumtemperatur (ISO 6892-1:2009)
1:2009)
This European Standard was approved by CEN on 13 March 2009.

CEN 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 CEN Management Centre or to any CEN 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 CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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 Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6892-1:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 6892-1:2009) has been prepared by Technical Committee ISO/TC 164 "Mechanical
testing of metals" in collaboration with Technical Committee ECISS/TC 1 “Tensile testing” the secretariat of
which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2010, and conflicting national standards shall be withdrawn
at the latest by February 2010.
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 held responsible for identifying any or all such patent rights.
This document supersedes EN 10002-1:2001.
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, 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 the United Kingdom.
Endorsement notice
The text of ISO 6892-1:2009 has been approved by CEN as a EN ISO 6892-1:2009 without any modification.

INTERNATIONAL ISO
STANDARD 6892-1
First edition
2009-08-15
Metallic materials — Tensile testing —
Part 1:
Method of test at room temperature
Matériaux métalliques — Essai de traction —
Partie 1: Méthode d'essai à température ambiante

Reference number
ISO 6892-1:2009(E)
©
ISO 2009
ISO 6892-1:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2009
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
ISO's member body in 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 copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Terms and symbols.7
5 Principle.8
6 Test piece .8
7 Determination of original cross-sectional area.10
8 Marking the original gauge length.10
9 Accuracy of testing apparatus.11
10 Conditions of testing.11
11 Determination of the upper yield strength.15
12 Determination of the lower yield strength .15
13 Determination of proof strength, plastic extension.15
14 Determination of proof strength, total extension.16
15 Method of verification of permanent set strength .16
16 Determination of the percentage yield point extension .16
17 Determination of the percentage plastic extension at maximum force.16
18 Determination of the percentage total extension at maximum force.17
19 Determination of the percentage total extension at fracture.17
20 Determination of percentage elongation after fracture .18
21 Determination of percentage reduction of area .18
22 Test report.19
23 Measurement uncertainty.19
Annex A (informative) Recommendations concerning the use of computer-controlled tensile
testing machines .33
Annex B (normative) Types of test pieces to be used for thin products: sheets, strips and flats
between 0,1 mm and 3 mm thick .39
Annex C (normative) Types of test pieces to be used for wire, bars and sections with a diameter
or thickness of less than 4 mm.42
Annex D (normative) Types of test pieces to be used for sheets and flats of thickness equal to or
greater than 3 mm, and wire, bars and sections of diameter or thickness equal to or
greater than 4 mm .43
Annex E (normative) Types of test pieces to be used for tubes.47
Annex F (informative) Estimation of the crosshead separation rate in consideration of
the stiffness (or compliance) of the testing machine .49
ISO 6892-1:2009(E)
Annex G (informative) Measuring the percentage elongation after fracture if the specified value is
less than 5 % .50
Annex H (informative) Measurement of percentage elongation after fracture based on subdivision
of the original gauge length.51
Annex I (informative) Determination of the percentage plastic elongation without necking, A , for
wn
long products such as bars, wire and rods .53
Annex J (informative) Estimation of the uncertainty of measurement.54
Annex K (informative) Precision of tensile testing — Results from interlaboratory programmes.58
Bibliography .63

iv © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
Foreword
ISO (the International Organization 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 the 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.
International 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. Publication 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.
ISO 6892-1 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 1, Uniaxial testing.
This first edition of ISO 6892-1 cancels and replaces ISO 6892:1998.
ISO 6892 consists of the following parts, under the general title Metallic materials — Tensile testing:
⎯ Part 1: Method of test at room temperature
The following parts are under preparation:
⎯ Part 2: Method of test at elevated temperature
⎯ Part 3: Method of test at low temperature
The following part is planned:
⎯ Part 4: Method of test in liquid helium

ISO 6892-1:2009(E)
Introduction
During discussions concerning the speed of testing in the preparation of ISO 6892:1998, it was decided to
recommend the use of strain rate control in future revisions.
In this part of ISO 6892, there are two methods of testing speeds available. The first, method A, is based on
strain rates (including crosshead separation rate) and the second, method B, is based on stress rates. Method
A is intended to minimize the variation of the test rates during the moment when strain rate sensitive
parameters are determined and to minimize the measurement uncertainty of the test results.

vi © ISO 2009 – All rights reserved

INTERNATIONAL STANDARD ISO 6892-1:2009(E)

Metallic materials — Tensile testing —
Part 1:
Method of test at room temperature
1 Scope
This part of ISO 6892 specifies the method for tensile testing of metallic materials and defines the mechanical
properties which can be determined at room temperature.
NOTE Annex A indicates complementary recommendations for computer controlled testing machines.
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.
ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical
testing
ISO 2566-1, Steel — Conversion of elongation values — Part 1: Carbon and low alloy steels
ISO 2566-2, Steel — Conversion of elongation values — Part 2: Austenitic steels
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 following terms and definitions apply.
3.1
gauge length
L
length of the parallel portion of the test piece on which elongation is measured at any moment during the test
[3]
[ISO/TR 25679:2005 ]
3.1.1
original gauge length
L
o
length between gauge length (3.1) marks on the piece measured at room temperature before the test
[3]
NOTE Adapted from ISO/TR 25679:2005 .
ISO 6892-1:2009(E)
3.1.2
final gauge length after rupture
final gauge length after fracture
L
u
length between gauge length (3.1) marks on the test piece measured after rupture, at room temperature, the
two pieces having been carefully fitted back together so that their axes lie in a straight line
[3]
NOTE Adapted from ISO/TR 25679:2005 .
3.2
parallel length
L
c
length of the parallel reduced section of the test piece
[3]
[ISO/TR 25679:2005 ]
NOTE The concept of parallel length is replaced by the concept of distance between grips for unmachined test
pieces.
3.3
elongation
increase in the original gauge length (3.1.1) at any moment during the test
[3]
NOTE Adapted from ISO/TR 25679:2005 .
3.4
percentage elongation
elongation expressed as a percentage of the original gauge length, L (3.1.1)
o
[3]
[ISO/TR 25679:2005 ]
3.4.1
percentage permanent elongation
increase in the original gauge length (3.1.1) of a test piece after removal of a specified stress, expressed as
a percentage of the original gauge length, L
o
[3]
[ISO/TR 25679:2005 ]
3.4.2
percentage elongation after fracture
A
permanent elongation of the gauge length after fracture, (L − L ), expressed as a percentage of the original
u o
gauge length, L
o
[3]
[ISO/TR 25679:2005 ]
1)
NOTE For proportional test pieces, if the original gauge length is not equivalent to 5,65 S where S is the
o o
original cross-sectional area of the parallel length, the symbol A should be supplemented by a subscript indicating the
coefficient of proportionality used, e.g. A indicates a percentage elongation of the gauge length, L , of
11,3 o
AS= 11,3
11,3 o
For non-proportional test pieces (see Annex B), the symbol A should be supplemented by a subscript indicating the
original gauge length used, expressed in millimetres, e.g. A indicates a percentage elongation of a gauge length, L ,
80 mm o
of 80 mm.
1) 5,65SS=π5 (4 / ) .
oo
2 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
3.5
extensometer gauge length
L
e
initial extensometer gauge length used for measurement of extension by means of an extensometer
[3]
NOTE 1 Adapted from ISO/TR 25679:2005 .
NOTE 2 For measurement of yield and proof strength parameters, L should span as much of the parallel length of the
e
test piece as possible. Ideally, as a minimum, L should be greater than 0,50L but less than approximately 0,9L . This
e o c
should ensure that the extensometer detects all yielding events that occur in the test piece. Further, for measurement of
parameters “at” or “after reaching” maximum force, L should be approximately equal to L .
e o
3.6
extension
increase in the extensometer gauge length, L (3.5), at any moment during the test
e
[3]
[ISO/TR 25679:2005 ]
3.6.1
percentage extension
“strain”
extension expressed as a percentage of the extensometer gauge length, L (3.5)
e
3.6.2
percentage permanent extension
increase in the extensometer gauge length, after removal of a specified stress from the test piece, expressed
as a percentage of the extensometer gauge length, L (3.5)
e
[3]
[ISO/TR 25679:2005 ]
3.6.3
percentage yield point extension
A
e
in discontinuous yielding materials, the extension between the start of yielding and the start of uniform
workhardening, expressed as a percentage of the extensometer gauge length, L (3.5)
e
[3]
NOTE Adapted from ISO/TR 25679:2005 .
See Figure 7.
3.6.4
percentage total extension at maximum force
A
gt
total extension (elastic extension plus plastic extension) at maximum force, expressed as a percentage of the
extensometer gauge length, L (3.5)
e
See Figure 1.
3.6.5
percentage plastic extension at maximum force
A
g
plastic extension at maximum force, expressed as a percentage of the extensometer gauge length, L (3.5)
e
See Figure 1.
ISO 6892-1:2009(E)
3.6.6
percentage total extension at fracture
A
t
total extension (elastic extension plus plastic extension) at the moment of fracture, expressed as a percentage
of the extensometer gauge length, L (3.5)
e
See Figure 1.
3.7 Testing rate
3.7.1
strain rate
e
L
e
increase of strain, measured with an extensometer, in extensometer gauge length, L (3.5), per time
e
NOTE See 3.5.
3.7.2
estimated strain rate over the parallel length

e
L
c
L (3.2), of the test piece per time based on the
value of the increase of strain over the parallel length,
c
crosshead separation rate (3.7.3) and the parallel length of the test piece
3.7.3
crosshead separation rate
v
c
displacement of the crossheads per time
3.7.4
stress rate

R
increase of stress per time
NOTE Stress rate should only be used in the elastic part of the test (method B).
3.8
percentage reduction of area
Z
maximum change in cross-sectional area which has occurred during the test, (S − S ), expressed as a
o u
percentage of the original cross-sectional area, S :
o
SS−
ou
Z=× 100
S
o
3.9 Maximum force
NOTE For materials which display discontinuous yielding, but where no workhardening can be established, F is not
m
defined in this part of ISO 6892 [see footnote to Figure 8 c)].
3.9.1
maximum force
F
m
〈materials displaying no discontinuous yielding〉 highest force that the test piece withstands during the test
4 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
3.9.2
maximum force
F
m
〈materials displaying discontinuous yielding〉 highest force that the test piece withstands during the test after
the beginning of workhardening
NOTE See Figure 8 a) and b).
3.10
stress
at any moment during the test, force divided by the original cross-sectional area, S , of the test piece
o
[3]
NOTE 1 Adapted from ISO/TR 25679:2005 .
NOTE 2 All references to stress in this part of ISO 6892 are to engineering stress.
NOTE 3 In what follows, the designations “force” and “stress” or “extension”, “percentage extension” and “strain”,
respectively, are used on various occasions (as figure axis labels or in explanations for the determination of different
properties). However, for a general description or definition of a well-defined point on a curve, the designations “force” and
“stress” or “extension”, “percentage extension” and “strain”, respectively, are interchangeable.
3.10.1
tensile strength
R
m
stress corresponding to the maximum force, F (3.9)
m
[3]
[ISO/TR 25679:2005 ]
3.10.2
yield strength
when the metallic material exhibits a yield phenomenon, stress corresponding to the point reached during the
test at which plastic deformation occurs without any increase in the force
[3]
NOTE Adapted from ISO/TR 25679:2005 .
3.10.2.1
upper yield strength
R
eH
maximum value of stress (3.10) prior to the first decrease in force
[3]
NOTE Adapted from ISO/TR 25679:2005 .
See Figure 2.
3.10.2.2
lower yield strength
R
eL
lowest value of stress (3.10) during plastic yielding, ignoring any initial transient effects
[3]
[ISO/TR 25679:2005 ]
See Figure 2.
ISO 6892-1:2009(E)
3.10.3
proof strength, plastic extension
R
p
stress at which the plastic extension is equal to a specified percentage of the extensometer gauge length, L
e
(3.5)
NOTE 1 Adapted from ISO/TR 25679:2005, “proof strength, non-proportional extension”.
NOTE 2 A suffix is added to the subscript to indicate the prescribed percentage, e.g. R .
p0,2
See Figure 3.
3.10.4
proof strength, total extension
R
t
stress at which total extension (elastic extension plus plastic extension) is equal to a specified percentage of
the extensometer gauge length, L (3.5)
e
[3]
NOTE 1 Adapted from ISO/TR 25679:2005 .
NOTE 2 A suffix is added to the subscript to indicate the prescribed percentage, e.g. R .
t0,5
See Figure 4.
3.10.5
permanent set strength
R
r
stress at which, after removal of force, a specified permanent elongation or extension, expressed respectively
as a percentage of original gauge length, L (3.1.1), or extensometer gauge length, L (3.5), has not been
o e
exceeded
[3]
[ISO/TR 25679:2005 ]
See Figure 5.
NOTE A suffix is added to the subscript to indicate the specified percentage of the original gauge length, L , or of the
o
extensometer gauge length, L , e.g. R .
e r0,2
3.11
fracture
phenomenon which is deemed to occur when total separation of the test piece occurs
NOTE Criteria for fracture which may be used for computer controlled tests are given in Figure A.2.
6 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
4 Terms and symbols
The symbols used in this part of ISO 6892 and corresponding designations are given in Table 1.
Table 1 — Symbols and designations
Symbol Unit Designation
Test piece
a
a , T mm original thickness of a flat test piece or wall thickness of a tube
o
original width of the parallel length of a flat test piece or average width of the longitudinal
b mm
o
strip taken from a tube or width of flat wire
original diameter of the parallel length of a circular test piece, or diameter of round wire or
d mm
o
internal diameter of a tube
D mm original external diameter of a tube
o
L mm original gauge length
o
L′ mm initial gauge length for determination of A (see Annex I)
wn
o
L mm parallel length
c
L mm extensometer gauge length
e
L mm total length of test piece
t
L mm final gauge length after fracture
u
L′ mm final gauge length after fracture for determination of A (see Annex I)
wn
u
S mm original cross-sectional area of the parallel length
o
S mm minimum cross-sectional area after fracture
u
k — coefficient of proportionality (see 6.1.1)
Z % percentage reduction of area
Elongation
A % percentage elongation after fracture (see 3.4.2)
A % percentage plastic elongation without necking (see Annex I)
wn
Extension
A % percentage yield point extension
e
A % percentage plastic extension at maximum force, F
g m
A % percentage total extension at maximum force, F
gt m
A % percentage total extension at fracture
t
∆L mm extension at maximum force
m
∆L mm extension at fracture
f
Rates
 −1
e
s strain rate
L
e
e −1
estimated strain rate over the parallel length
s
L
c
−1

R MPa s stress rate
−1
v mm s crosshead separation rate
c
ISO 6892-1:2009(E)
Table 1 — Symbols and designations (continued)
Symbol Unit Designation
Force
F N maximum force
m
Yield strength — Proof strength — Tensile strength
b
E MPa modulus of elasticity
m MPa slope of the stress-percentage extension curve at a given moment of the test
c
m MPa slope of the elastic part of the stress-percentage extension curve
E
R MPa upper yield strength
eH
MPa
R lower yield strength
eL
MPa
R tensile strength
m
MPa
R proof strength, plastic extension
p
MPa
R specified permanent set strength
r
MPa
R proof strength, total extension
t
a
Symbol used in steel tube product standards.
b −2
1 MPa = 1 N mm .
c
In the elastic part of the stress-percentage extension curve, the value of the slope may not necessarily represent the modulus of
elasticity. This value can closely agree with the value of the modulus of elasticity if optimal conditions (high resolution, double sided,
averaging extensometers, perfect alignment of the test piece, etc.) are used.

CAUTION — The factor 100 is necessary if percentage values are used.
5 Principle
The test involves straining a test piece by tensile force, generally to fracture, for the determination of one or
more of the mechanical properties defined in Clause 3.
The test is carried out at room temperature between 10 °C and 35 °C, unless otherwise specified. Tests
carried out under controlled conditions shall be made at a temperature of 23 °C ± 5 °C.
6 Test piece
6.1 Shape and dimensions
6.1.1 General
The shape and dimensions of the test pieces may be constrained by the shape and dimensions of the metallic
product from which the test pieces are taken.
The test piece is usually obtained by machining a sample from the product or a pressed blank or casting.
However, products of uniform cross-section (sections, bars, wires, etc.) and also as-cast test pieces (i.e. for
cast iron and non-ferrous alloys) may be tested without being machined.
The cross-section of the test pieces may be circular, square, rectangular, annular or, in special cases, some
other uniform cross-section.
8 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
Preferred test pieces have a direct relationship between the original gauge length, L , and the original cross-
o
sectional area, S , expressed by the equation L = kS , where k is a coefficient of proportionality, and are
o o o
called proportional test pieces. The internationally adopted value for k is 5,65. The original gauge length shall
be not less than 15 mm. When the cross-sectional area of the test piece is too small for this requirement to be
met with, k = 5,65, a higher value (preferably 11,3) or a non-proportional test piece may be used.
NOTE By using an original gauge length smaller than 20 mm, the measurement uncertainty is increased.
For non-proportional test pieces, the original gauge length, L , is independent of the original cross-sectional
o
area, S .
o
The dimensional tolerances of the test pieces shall be in accordance with the Annexes B to E (see 6.2).
Other test pieces such as those specified in relevant product standards or national standards may be used by
[1] [2] [6] [7]
agreement with the customer, e.g. ISO 3183 (API 5L), ISO 11960 (API 5CT), ASTM A370 , ASTM E8M ,
[10] [13] [14]
DIN 50125 , IACS W2 , and JIS Z2201 .
6.1.2 Machined test pieces
Machined test pieces shall incorporate a transition radius between the gripped ends and the parallel length if
these have different dimensions. The dimensions of the transition radius are important and it is recommended
that they be defined in the material specification if they are not given in the appropriate annex (see 6.2).
The gripped ends may be of any shape to suit the grips of the testing machine. The axis of the test piece shall
coincide with the axis of application of the force.
The parallel length, L , or, in the case where the test piece has no transition radii, the free length between the
c
grips, shall always be greater than the original gauge length, L .
o
6.1.3 Unmachined test pieces
If the test piece consists of an unmachined length of the product or of an unmachined test bar, the free length
between the grips shall be sufficient for gauge marks to be at a reasonable distance from the grips (see
Annexes B to E).
As-cast test pieces shall incorporate a transition radius between the gripped ends and the parallel length. The
dimensions of this transition radius are important and it is recommended that they be defined in the product
standard. The gripped ends may be of any shape to suit the grips of the testing machine. The parallel length,
L , shall always be greater than the original gauge length, L .
c o
6.2 Types
The main types of test pieces are defined in Annexes B to E according to the shape and type of product, as
shown in Table 2. Other types of test pieces can be specified in product standards.
ISO 6892-1:2009(E)
Table 2 — Main types of test piece according to product type
Dimensions in millimetres
Corresponding
Type of product
Annex
Sheets — Plates — Flats Wire — Bars — Sections

Thickness Diameter or side
a
0,1 u a < 3 — B
— < 4 C
a W 3 W 4 D
Tubes E
6.3 Preparation of test pieces
The test pieces shall be taken and prepared in accordance with the requirements of the relevant International
Standards for the different materials (e.g. ISO 377).
7 Determination of original cross-sectional area
The relevant dimensions of the test piece should be measured at sufficient cross-sections perpendicular to the
longitudinal axis in the central region of the parallel length of the test piece.
A minimum of three cross-sections is recommended.
The original cross-sectional area, S , is the average cross-sectional area and shall be calculated from the
o
measurements of the appropriate dimensions.
The accuracy of this calculation depends on the nature and type of the test piece. Annexes B to E describe
methods for the evaluation of S for different types of test pieces and contain specifications for the accuracy of
o
measurement.
8 Marking the original gauge length
Each end of the original gauge length, L , shall be marked by means of fine marks or scribed lines, but not by
o
notches which could result in premature fracture.
For proportional test pieces, the calculated value of the original gauge length may be rounded to the nearest
multiple of 5 mm, provided that the difference between the calculated and marked gauge length is less than
10 % of L . The original gauge length shall be marked to an accuracy of ± 1 %.
o
If the parallel length, L , is much greater than the original gauge length, as, for instance, with unmachined test
c
pieces, a series of overlapping gauge lengths may be marked.
In some cases, it may be helpful to draw, on the surface of the test piece, a line parallel to the longitudinal axis,
along which the gauge lengths are marked.
10 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
9 Accuracy of testing apparatus
The force-measuring system of the testing machine shall be calibrated in accordance with ISO 7500-1, class 1,
or better.
For the determination of proof strength (plastic or total extension) the used extensometer shall be in
accordance with ISO 9513, class 1 or better, in the relevant range. For other properties (with higher extension)
an ISO 9513, class 2 extensometer in the relevant range may be used.
10 Conditions of testing
10.1 Setting the force zero point
The force-measuring system shall be set to zero after the testing loading train has been assembled, but
before the test piece is actually gripped at both ends. Once the force zero point has been set, the force-
measuring system may not be changed in any way during the test.
NOTE The use of this method ensures, that on one hand the weight of the gripping system is compensated for in the
force measurement and on the other hand any force resulting from the clamping operation does not affect this
measurement.
10.2 Method of gripping
The test pieces shall be gripped by suitable means, such as wedges, screwed grips, parallel jaw faces, or
shouldered holders.
Every endeavour should be made to ensure that test pieces are held in such a way that the force is applied as
[8]
axially as possible, in order to minimize bending (more information is given in ASTM E1012 , for example).
This is of particular importance when testing brittle materials or when determining proof strength (plastic
extension), proof strength (total extension) or yield strength.
In order to obtain a straight test piece and ensure the alignment of the test piece and grip arrangement, a
preliminary force may be applied provided it does not exceed a value corresponding to 5 % of the specified or
expected yield strength.
A correction of the extension should be carried out to take into account the effect of the preliminary force.
10.3 Testing rate based on strain rate control (method A)
10.3.1 General
Method A is intended to minimize the variation of the test rates during the moment when strain rate sensitive
parameters are determined and to minimize the measurement uncertainty of the test results.
Two different types of strain rate control are described in this section. The first is the control of the strain rate
itself, e , that is based on the feedback obtained from an extensometer. The second is the control of the
L
e
estimated strain rate over the parallel length, e , which is achieved by controlling the crosshead separation
L
c
rate at a velocity equal to the desired strain rate multiplied by the parallel length.
If a material shows homogeneous deformation behaviour and the force remains nominally constant, the strain
rate, e , and the estimated strain rate over the parallel length, e , are approximately equal. Differences
L L
e c
exist if the material exhibits discontinuous or serrated yielding (e.g. some steels and AlMg alloys in the yield
point elongation range, or materials which show serrated yielding like the Portevin-Le Chatelier effect) or if
ISO 6892-1:2009(E)
necking occurs. If the force is increasing, the estimated strain rate may be substantially below the target strain
rate due to the compliance of the testing machine.
The testing rate shall conform to the following requirements.

a) In the range up to and including the determination of R , R or R , the specified strain rate, e (see
eH p t
L
e
3.7.1), shall be applied. In this range, to eliminate the influence of the compliance of the tensile testing
machine, the use of an extensometer clamped on the test piece is necessary to have accurate control
over the strain rate. (For testing machines unable to control by strain rate, a procedure using the

estimated strain rate over the parallel length, e , may be used.)
L
c

b) During discontinuous yielding, the estimated strain rate over the parallel length, e (see 3.7.2), should
L
c
be applied. In this range, it is impossible to control the strain rate using the extensometer clamped on to
the test piece because local yielding can occur outside the extensometer gauge length. The required
estimated strain rate over the parallel length may be maintained in this range sufficiently accurately using
a constant crosshead separation rate, v (see 3.7.3);
c
vL= e (1)
cc
L
c
where

e is the estimated strain rate over the parallel length;
L
c
L is the parallel length.
c
c) In the range following R or R or end of yielding (see 3.7.2), e or e can be used. The use of e is
p t
L L L
e c c
recommended to avoid any control problems which may arise if necking occurs outside the extensometer
gauge length.
The strain rates specified in 10.3.2 to 10.3.4 shall be maintained during the determination of the relevant
material property (see also Figure 9).
During switching to another strain rate or to another control mode, no discontinuities in the stress-strain curve
should be introduced which distort the values of R , A or A (see Figure 10). This effect can be reduced by a
m g gt
suitable gradual switch between the rates.
The shape of the stress-strain curve in the workhardening range can also be influenced by the strain rate. The
testing rate used should be documented (see 10.6).
10.3.2 Strain rate for the determination of the upper yield strength, R , or proof strength properties,
eH
R , and R
p t
The strain rate, e , shall be kept as constant as possible up to and including the determination of R or R
eH p
L
e
or R . During the determination of these material properties the strain rate, e , shall be in one of the two
t
L
e
following specified ranges (see also Figure 9).
−1
Range 1: e = 0,000 07 s , with a relative tolerance of ±20 %
L
e
−1
Range 2: e = 0,000 25 s , with a relative tolerance of ±20 % (recommended unless otherwise
L
e
specified)
If the testing machine is not able to control the strain rate directly, the estimated strain rate over the parallel

length, e , i.e. constant crosshead separation rate, shall be used. This rate shall be calculated using
L
c
Equation (1).
12 © ISO 2009 – All rights reserved

ISO 6892-1:2009(E)
The resulting strain rate on the test piece will be lower than the specified strain rate because the compliance
of the testing machine is not considered. An explanation is given in Annex F.
10.3.3 Strain rate for the determination of the lower yield strength, R , and percentage yield point
eL
extension, A
e
Following the detection of the upper yield strength (see A.4.2), the estimated strain rate over the parallel
length, e , shall be maintained in one of the following two specified ranges (see Figure 9) until discontinuous
L
c
yielding has ended.
−1
Range 2:  = 0,000 25 s , with a relative tolerance of ±20 % (recommended, when R is determined)
e
eL
L
c
−1
Range 3:  = 0,002 s , with a relative tolerance of ±20 %
e
L
c
10.3.4 Strain rate for the determination of the tensile strength, R , percentage elongation after fracture,
m
A, percentage total extension at the maximum force, A , percentage plastic extension at maximum
gt
force, A , and percentage reduction area, Z
g
After determination of the required yield/proof strength properties, the estimated strain rate over the parallel
length,  , shall be changed to one of the following specified ranges (see Figure 9).
e
L
c
−1
Range 2:  = 0,000 25 s , with a relative tolerance of ±20 %
e
L
c
−1
Range 3:  = 0,002 s , with a relative tolerance of ±20 %
e
L
c
−1 −1
Range 4: e = 0,006 7 s , with a relative tolerance of ±20 % (0,4 min , with a relative tolerance of
L
c
±20 %) (recommended unless otherwise specified)
If the purpose of the tensile test is only to determine the tensile strength, then an estimated strain rate over the
parallel length of the test piece according to range 3 or 4 may be applied throughout the entire test.
10.4 Testing rate based on stress rate (method B)
10.4.1 General
The testing rates shall conform to the following requirements depending on the nature of the material. Unless
otherwise specified, any convenient speed of testing may be used up to a stress equivalent to half of the
specified yield strength. The testing rates above this point are specified below.
10.4.2 Yield and proof strengths
10.4.2.1 Upper yield strength, R
eH
The rate of separation of the crossheads of the machine shall be kept as constant as possible and within the
limits corresponding to the stress rates in Table 3.
NOTE For information, typical materials having a modulus of elasticity smaller than 150 000 MPa include magnesium,
aluminium alloys, brass, and titanium. Typical materials with a modulus of elasticity greater than 150 000 MPa include
wrought iron, steel, tungsten, and nickel-based alloys.
ISO 6892-1:2009(E)
Table 3 — Stress rate
Modulus of elasticity of the material Stress rate

E R
−1
MPa MPa s
min. max.
< 150 000 2 20
W 150 000 6 60
10.4.2.2 Lower yield strength, R
eL
If only the lower yield strength i
...