EN 10002-1:2001

SLOVENSKI STANDARD
01-junij-2002
Kovinski materiali - Natezni preskus - 1. del: Metoda preskušanja pri temperaturi
okolice
Metallic materials - Tensile testing - Part 1: Method of test at ambient temperature
Metallische Werkstoffe - Zugversuch - Teil 1: Prüfverfahren bei Raumtemperatur
Matériaux métalliques - Essai de traction - Partie 1: Méthode d'essai a température
ambiante
Ta slovenski standard je istoveten z: EN 10002-1:2001
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 10002-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2001
ICS 77.040.10 Supersedes EN 10002-1:1990
English version
Metallic materials - Tensile testing - Part 1: Method of test at
ambient temperature
Matériaux métalliques - Essai de traction - Partie 1: Metallische Werkstoffe - Zugversuch - Teil 1: Prüfverfahren
Méthode d'essai à température ambiante bei Raumtemperatur
This European Standard was approved by CEN on 12 May 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10002-1:2001 E
worldwide for CEN national Members.

Contents
page
Foreword.4
1 Scope .5
2 Normative references .5
3 Principle.5
4 Definitions.5
5 Symbols and designations .8
6 Test piece.10
6.1 Shape and dimensions.10
6.2 Types.11
6.3 Preparation of test pieces.11
7 Determination of original cross-sectional area (S ).11
o
8 Marking the original gauge length (L ).12
o
9 Accuracy of testing apparatus .12
10 Conditions of testing .12
10.1 Method of gripping .12
10.2 Test rate .12
11 Determination of percentage elongation after fracture (A) .13
12 Determination of the percentage total elongation at maximum force (A ).14
gt
13 Determination of proof strength, non proportional extension (R ).14
p
14 Determination of proof strength, total extension (R ) .15
t
15 Method of verification of permanent set strength (R ).15
r
16 Determination of percentage reduction of area (Z) .15
17 Test report .15
Annex A (informative) Recommendations concerning the use of computer controlled tensile testing
machines.28
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.33
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.35
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 .36
Annex E (normative) Types of test pieces to be used for tubes.39
Annex F (informative) Measuring the percentage elongation after fracture if the specified value is less
than 5 % .41
Annex G (informative) Measurement of percentage elongation after fracture based on subdivision of
the original gauge length .42
Annex H (informative) Manual method of determination of the percentage total elongation at maximum
force for long products such as bars, wire, rods .44
Annex J (informative) Precision of tensile testing and estimation of the uncertainty of measurement.45
Bibliography .56
Foreword
This European Standard has been prepared by Technical Committee ECISS/TC 1 "Steel - Mechanical 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 January 2002, and conflicting national standards shall be withdrawn at the latest
by January 2002.
This European Standard supersedes EN 10002-1:1990.
The European Standard EN 10002-1 "Metallic materials - Tensile testing - Part 1: Method of test (at ambient
temperature)" was approved by CEN on 27 November 1989.
After a first 5 years lifetime, ECISS decided to revise this standard.
The revised prEN 10002-1 was discussed during two meetings of ECISS/TC1/SC1 with the participation of 4 CEN
member countries (Belgium, France, Germany, United Kingdom).
EN 10002 was composed of five parts :
Part 1 : Method of test (at ambient temperature)
Part 2 : Verification of the force measuring system of the tensile testing machines
Part 3 : Calibration of force proving instruments used for the verification of uniaxial testing machines
Part 4 : Verification of extensometers used in uniaxial testing
Part 5 : Method of testing at elevated temperature
NOTE Part 2 has been already replaced by EN ISO 7500-1. Parts 3 and 4 will be replaced by corresponding ISO
standards.
The annexes B, C, D and E are normative. The annexes A, F, G, H and J are informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and the United Kingdom.
1 Scope
This European Standard specifies the method for tensile testing of metallic materials and defines the mechanical
properties which can be determined at ambient temperature.
NOTE Informative annex A indicates complementary recommendations for computer controlled testing machines. It is the
intention, based on further developments by manufacturers and users that annex A will become normative in the next revision of
this standard.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).
EN 10002-4, Metallic materials - Tensile testing - Part 4: Verification of extensometers used in uniaxial testing.
EN 20286-2, ISO system of limits and fits - Part 2 : Tables of standard tolerances grades and limits deviations for
holes and shafts (ISO 286-2:1988).
EN ISO 377, Steel and steel products - Location of samples and test pieces for mechanical testing (ISO 377:1997).
EN ISO 2566-1, Steel conversion of elongation values - Part 1 : Carbon and alloy steels (ISO 2566-1:1984).
EN ISO 2566-2, Steel conversion of elongation values - Part 2 : Austenitic steels (ISO 2566-2:1984).
EN ISO 7500-1, Metallic materials - Verification of static uniaxial testing machines – Part 1: Tension/compression
testing machines – Verification and calibration of force measuring (ISO 7500-1:1999).
3 Principle
The test involves straining a test piece in tension, generally to fracture, for the purpose of determining one or more
of the mechanical properties defined in clause 4.
The test is carried out at ambient 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.
4 Terms and definitions
For the purpose of this European Standard, the following terms and definitions apply :
4.1
gauge length (L)
length of the cylindrical or prismatic portion of the test piece on which elongation is measured. In particular, a
distinction is made between :
4.1.1
original gauge length (L )
o
gauge length before application of force
4.1.2
final gauge length (L )
u
gauge length after rupture of the test piece (see 11.1)
4.2
parallel length (L )
c
parallel portion of the reduced section of the test piece
NOTE The concept of parallel length is replaced by the concept of distance between grips for non-machined test pieces.
4.3
elongation
increase in the original gauge length (L ) at any moment during the test
o
4.4
percentage elongation
elongation expressed as a percentage of the original gauge length (L )
o
4.4.1
percentage permanent elongation
increase in the original gauge length of a test piece after removal of a specified stress (see 4.9), expressed as a
percentage of the original gauge length (L )
o
4.4.2
percentage elongation after fracture (A)
permanent elongation of the gauge length after fracture (L - L ), expressed as a percentage of the original gauge
u o
length (L )
o
1)
NOTE In the case of proportional test pieces, only if the original gauge length is other than 5,65 S where S is the
o o
original cross-sectional area of the parallel length, the symbol A should be supplemented by an index indicating the coefficient
of proportionality used, for example :
A = percentage elongation of a gauge length (L ) of 11,3 S .
11,3 o o
In the case of non-proportional test pieces, the symbol A should be supplemented by an index indicating the original gauge
length used, expressed in millimetres, for example :
A = percentage elongation of a gauge length (L ) of 80 mm.
80 mm o
4.4.3
percentage total elongation at fracture (A )
t
total elongation (elastic elongation plus plastic elongation) of the gauge length at the moment of fracture expressed
as a percentage of the original gauge length (L )
o
4.4.4
percentage elongation at maximum force
increase in the gauge length of the test piece at maximum force, expressed as a percentage of the original gauge
L )
length (
o
NOTE A distinction is made between the percentage total elongation at maximum force (A ) and the percentage non-
gt
proportional elongation at maximum force (A ) (see Figure 1).
g
4.5
extensometer gauge length (L )
e
length of the parallel portion of the test piece used for the measurement of extension by means of an extensometer
NOTE It is recommended that for measurement of yield and proof strength parameters L
L /2. It is further
e o
recommended that for measurement of parameters "at" or "after" maximum force, L is approximately equal to L .
e o
4.6
extension
increase in the extensometer gauge length (L ) at a given moment of the test
e
4S
o
1)
5,65 S = 5 .
o

4.6.1
percentage permanent extension
increase in the extensometer gauge length, after removal from the test piece of a specified stress, expressed as a
percentage of the extensometer gauge length (L )
e
4.6.2
percentage yield point extension (A )
e
in discontinuous yielding materials, the extension between the start of yielding and the start of uniform work
hardening
NOTE It is expressed as a percentage of the extensometer gauge length (L ).
e
4.7
percentage reduction of area (Z)
maximum change in cross-sectional area which has occurred during the test (S - S ) expressed as a percentage
o u
of the original cross-sectional area (S )
o
4.8
maximum force (F )
m
the greatest force which the test piece withstands during the test once the yield point has been passed
For materials, without yield point, it is the maximum value during the test.
4.9
stress
force at any moment during the test divided by the original cross-sectional area (S ) of the test piece
o
4.9.1
tensile strength (R )
m
stress corresponding to the maximum force (F )
m
4.9.2
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. A distinction is made between :
4.9.2.1
R
upper yield strength ( )
eH
value of stress at the moment when the first decrease in force is observed (see Figure 2)
4.9.2.2
lower yield strength (R )
eL
lowest value of stress during plastic yielding, ignoring any initial transient effects (see Figure 2)
4.9.3
proof strength, non-proportional extension (R )
p
stress at which a non-proportional extension is equal to a specified percentage of the extensometer gauge length
(L ) (see Figure 3)
e
NOTE The symbol used is followed by a suffix giving the prescribed percentage, for example : R
p0,2.
4.9.4
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 ) (see Figure 4)
e
NOTE The symbol used is followed by a suffix giving the prescribed percentage for example : R
t0,5.
4.9.5
permanent set strength (R )
r
stress at which, after removal of force, a specified permanent elongation or extension expressed respectively as a
percentage of the original gauge length (L ) or extensometer gauge length (L ) has not been exceeded (see
o e
Figure 5)
NOTE The symbol used is followed by a suffix giving the specified percentage of the original gauge length (L ) or of the
o
extensometer gauge length (L ), for example : R
e r0,2.
4.10
fracture
phenomena which is deemed to occur when total separation of the test piece occurs or force decreases to become
nominally zero
5 Symbols and designations
Symbols and corresponding designations are given in Table 1.
Table 1 — Symbols and designations
Reference Symbol Unit Designation
a
number
Test piece
1 b mm Thickness of a flat test piece or wall thickness of a tube
a
2 b mm Width of the parallel length of a flat test piece or average width of the longitudinal strip
taken from a tube or width of flat wire
3 d mm Diameter of the parallel length of a circular test piece, or diameter of round wire or
internal diameter of a tube
4 D mm External diameter of a tube
L
5 mm Original gauge length
o
L A
- ' mm Initial gauge length for determination of (see annex H)
o g
6 L mm Parallel length
c
- mm Extensometer gauge length
L
e
7 L mm Total length of test piece
t
L
8 mm Final gauge length after fracture
u
L' Final gauge length after fracture for determination of A (see annex H)
- mm
u g
9 S mm Original cross-sectional area of the parallel length
o
10 S mm Minimum cross-sectional area after fracture
u
- k - Coefficient of proportionality
11 Z %
S  S
o u
Percentage reduction of area : 100
S
o
12 - - Gripped ends
Elongation
13 - mm Elongation after fracture :
L – L
u o
c
14 % Percentage elongation after fracture :
A
LL
uo
× 100
L
o
15 A % Percentage yield point extension
e
- L mm Extension at maximum force
m
16 A % Percentage non-proportional elongation at maximum force (F
g m)
17 A % Percentage total elongation at maximum force (F
gt m)
18 A % Percentage total elongation at fracture
t
19 - % Specified percentage non-proportional extension
20 - % Percentage total extension (see R )
t
21 - % Specified percentage permanent set extension or elongation
"continued"
Table 1 (concluded)
Reference Symbol Unit Designation
a
number
Force
22 F N Maximum force
m
Yield strength - Proof strength - Tensile strength
R d
23 Upper yield strength
eH MPa
R
24 MPa Lower yield strength
eL
25 R MPa Tensile strength
m
26 R MPa Proof strength, non-proportional extension
p
27 R MPa Permanent set strength
r
R MPa
28 Proof strength, total extension
t
- E MPa Modulus of elasticity
a
See Figures 1 to 13.
b The symbol T is also used in steel tube product standards.
c See 4.4.2.
d 1 MPa = 1 N/mm .
6 Test piece
6.1 Shape and dimensions
6.1.1 General
The shape and dimensions of the test pieces depend on 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 constant cross-section (sections, bars, wires, etc.) and also as cast test pieces (i.e. for cast irons 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, of some
other shape.
Test pieces, the original gauge length of which is related to the original cross-sectional area by the equation
L k S are called proportional test pieces. The internationally adopted value for k is 5,65. The original gauge
o = o
length shall be not less than 20 mm. When the cross-sectional area of the test piece is too small for this
requirement to be met with the coefficient k value of 5,65, a higher value (preferably 11,3) or a non-proportional test
piece may be used.
In the case of non-proportional test pieces, the original gauge length (L ) is taken independently of the original
o
cross-sectional area (S ).
o
The dimensional tolerances of the test pieces shall be in accordance with the appropriate annexes (see 6.2).
6.1.2 Machined test pieces
Machined test pieces shall incorporate a transition curve between the gripped ends and the parallel length if these
have different dimensions. The dimensions of this transition radius may be 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 parallel length (L ) or, in the
c
case where the test piece has no transition curve, the free length between the grips, shall always be greater than
the original gauge length (L ).
o
6.1.3 Non-machined 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 )
c
shall always be greater than the original gauge length (L ).
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.
Table 2 — Main types of test piece according to the product type
Type of product
Sheets – Plates – Wire - Bars – Sections
Flats
Corresponding
annex
With a thickness in with a diameter or side in millimetres of
millimetres of
-B
0,1  thickness < 3
-< 4 C
> 3 D

4
Tubes E
6.3 Preparation of test pieces
The test pieces shall be taken and prepared in accordance with the requirements of the relevant European
Standards for the different materials (e.g. EN ISO 377, etc.).
7 Determination of original cross-sectional area (S )
o
The original cross-sectional area shall be calculated from the measurements of the appropriate dimensions. The
accuracy of this calculation depends on the nature and type of the test piece. It is indicated in annexes B to E for
the different types of test pieces.
8 Marking the original gauge length (L )
o
Each end of the original gauge length shall be marked by means of fine marks or scribed lines, but not by notches
which could result in premature fracture.
For proportional test pieces, the calculated value of the original gauge length may be rounded off 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.
9 Accuracy of testing apparatus
The force-measuring system of the testing machine shall be calibrated in accordance with EN ISO 7500-1 and shall
be at least of class 1.
When an extensometer is used it shall be at least of class 1 (according to EN 10002-4) for the determination proof
strength (non-proportional extension) ; for other properties (with higher extension) a class 2 extensometer
(according to EN 10002-4) can be used.
NOTE For the determination of upper and lower yield strengths, the use of an extensometer is not necessary.
10 Conditions of testing
10.1 Method of gripping
The test pieces shall be held by suitable means such as wedges, screwed grips, parallel jaw faces, shouldered
holders, etc.
Every endeavour should be made to ensure that test pieces are held in such a way that the tension is applied as
axially as possible, in order to minimize bending. This is of particular importance when testing brittle materials or
when determining proof strength (non-proportional extension) or proof strength (total extension) or yield strength.
NOTE In order to obtain a straight test piece and assure 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 only be carried out to take into account the effect of the preliminary force.
10.2 Test rate
10.2.1 General
Unless otherwise specified in the product standard, the test rate shall conform to the following requirements
depending on the nature of the material.
NOTE The stress rates in Table 3 and the strain rates referred to throughout 10.2 do not imply specific modes of control by
the testing machine.
10.2.2 Yield and proof strengths
10.2.2.1 Upper yield strength (R )
eH
Within the elastic range and up to the upper yield strength, 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.
Table 3 — Stress rate
Modulus of elasticity of Stress rate
the material (E)
.
-1
MPa
MPa s
min max
< 150 000 2 20

150 000
10.2.2.2 Lower yield strength (R )
eL
If only the lower yield strength is being determined, the strain rate during yield of the parallel length of the test piece
-1 -1
shall be between 0,000 25 s and 0,002 5 s . The strain rate within the parallel length shall be kept as constant as
possible. If this rate cannot be regulated directly, it shall be fixed by regulating the stress rate just before yield
begins, the controls of the machine not being further adjusted until completion of yield.
In no case, the stress rate in the elastic range shall exceed the maximum rates given in Table 3.
10.2.2.3 Upper and lower yield strengths (R and R )
eH eL
If the two yield strengths are determined during the same test, the conditions for determining the lower yield
strength shall be complied with (see 10.2.2.2).
10.2.2.4 Proof strength (non-proportional extension) and proof strength (total extension) (R and R )
p t
The stress rate shall be within the limits given in Table 3.
Within the plastic range and up to the proof strength (non-proportional extension or total extension) the strain rate
-1
shall not exceed 0,002 5 s .
10.2.2.5 If the testing machine is not capable of measuring or controlling the strain rate, a cross head
separation speed equivalent to the stress rate given in Table 3 shall be used until completion of yield.
10.2.3 Tensile strength (R )
m
After determination of the required yield/proof strength properties the test rate may be increased to a strain rate (or
-1
equivalent crosshead separation rate) to no greater than 0,008 s .
-1
If only the tensile strength of the material is required to be measured, the test rate shall not exceed 0,008 s
throughout the test.
11 Determination of percentage elongation after fracture (A)
11.1 Percentage elongation after fracture shall be determined in accordance with the definition given in 4.4.2.
For this purpose, the two broken pieces of the test piece are carefully fitted back together so that their axes lie in a
straight line.
Special precautions shall be taken to ensure proper contact between the broken parts of the test piece when
measuring the final gauge length. This is particularly important in the case of test pieces of small cross-section and
test pieces having low elongation values.
Elongation after fracture (L - L ) shall be determined to the nearest 0,25 mm with a measuring device with a
u o
sufficient resolution and the value of percentage elongation after fracture shall be rounded to the nearest 0,5 %. If
the specified minimum percentage elongation is less than 5 %, it is recommended that special precautions be taken
when determining elongation (see annex F).
This measurement is, in principle, valid only if the distance between the fracture and the nearest gauge mark is not
less than one third of the original gauge length (L ). However, the measurement is valid, irrespective of the position
o
of the fracture, if the percentage elongation after fracture is equal to or greater than the specified value.
11.2 For machines capable of measuring extension at fracture using an extensometer, it is not necessary to mark
the gauge lengths. The elongation is measured as the total extension at fracture, and it is therefore necessary to
deduct the elastic extension in order to obtain percentage elongation after fracture.
In principle, this measurement is only valid if fracture occurs within the extensometer gauge length (L ). The
e
measurement is valid regardless of the position of the fracture cross-section if the percentage elongation after
fracture is equal to or greater than the specified value.
NOTE If the product standard specifies the determination of percentage elongation after fracture for a given gauge length,
the extensometer gauge length should be equal to this length.
11.3 If elongation is measured over a given fixed length, it can be converted to proportional gauge length, using
conversion formulae or tables as agreed before the commencement of testing (for example as in EN ISO 2566-1
and EN ISO 2566-2).
NOTE Comparisons of percentage elongation are possible only when the gauge length or extensometer gauge length, the
shape and area of the cross-section are the same or when the coefficient of proportionality (k) is the same.
11.4 In order to avoid having to reject test pieces in which fracture may occur outside the limits specified in 11.1,
the method based on the subdivision of L into N equal parts may be used, as described in annex G.
o
12 Determination of the percentage total elongation at maximum force (A )
gt
The method consists of determining the extension at maximum force (L ) on the force-extension diagram
m
obtained with an extensometer.
The percentage total elongation at maximum force shall be calculated from the following equation :
L
m
A = × 100
gt
L
e
NOTE 1 For some materials which exhibit a flat plateau at maximum force, the percentage total elongation at maximum force
is taken at the mid-point of the flat plateau.
NOTE 2 A manual method is described in annex H.
13 Determination of proof strength, non proportional extension (R )
p
13.1 The proof strength (non-proportional extension) is determined from the force-extension diagram by drawing a
line parallel to the straight portion of the curve and at a distance from this equivalent to the prescribed non-
proportional percentage, for example 0,2 %. The point at which this line intersects the curve gives the force
corresponding to the desired proof strength (non-proportional extension). The latter is obtained by dividing this
force by the original cross-sectional area of the test piece (S ) (see Figure 3).
o
NOTE 1 Sufficient resolution in drawing the force-extension diagram is essential.
If the straight portion of the force-extension diagram is not clearly defined, thereby preventing drawing the parallel
line with sufficient precision, the following procedure is recommended (see Figure 6).
When the presumed proof strength has been exceeded, the force is reduced to a value equal to about 10 % of the
force obtained. The force is then increased again until it exceeds the value obtained originally. To determine the
desired proof strength a line is drawn through the hysteresis loop. A line is then drawn parallel to this line, at a
distance from the corrected origin of the curve, measured along the abscissa, equal to the prescribed non-
proportional percentage. The intersection of this parallel line and the force-extension curve gives the force
corresponding to the proof strength. The latter is obtained by dividing this force by the original cross-sectional area
of the test piece (S ) (see Figure 6).
o
NOTE 2 Several methods can be used to define the corrected origin of the force-extension curve. A method which may be
used is to construct the line parallel to that determined by the hysteresis loop so that it is tangent to the force-extension curve.
The point where this line crosses the abscissa is the corrected origin of the force-extension curve (see Figure 6).
13.2 The property may be obtained without plotting the force-extension curve by using automatic devices
(microprocessor, etc.), see annex A.
14 Determination of proof strength, total extension (R )
t
14.1 The proof strength (total extension) is determined on the force-extension diagram by drawing a line parallel
to the ordinate axis (force axis) and at a distance from this equivalent to the prescribed total percentage extension.
The point at which this line intersects the curve gives the force corresponding to the desired proof strength. The
latter is obtained by dividing this force by the original cross-sectional area of the test piece (S ) (see Figure 4).
o
14.2 The property may be obtained without plotting the force-extension diagram by using automatic devices (see
annex A).
(R )
15 Method of verification of permanent set strength
r
The test piece is subjected to a force for 10 s to 12 s corresponding to the specified stress and it is then confirmed,
after removing the force, that the permanent set extension or elongation is not more than the percentage specified
for the original gauge length.
16 Determination of percentage reduction of area (Z)
Percentage reduction of area shall be determined in accordance with the definition given in 4.7.
The two broken pieces of the test piece are carefully fitted back together so that their axes lie in a straight line. The
minimum cross-sectional area after fracture (S ) shall be measured to an accuracy of ± 2 % (see annexes B to E).
u
The difference between the area (S ) and the original cross section (S ) expressed as a percentage of the original
u o
area gives the percentage reduction of area.
17 Test report
The test report shall contain at least the following information :
 reference to this standard : EN 10002-1 ;
 identification of the test piece ;
 specified material, if known ;
 type of test piece ;
 location and direction of sampling of test pieces, if known ;
 test results.
In the absence of sufficient data on all types of metallic materials it is not possible, at present, to fix values of
uncertainty for the different properties measured by the tensile test.
NOTE 1 For consideration of uncertainty, see annex J, which provides guidance for the determination of uncertainty related
to metrological parameters and values obtained from the interlaboratory tests on a group of steels and aluminium alloys.
NOTE 2 Results should be presented to at least the following :
- strength values to the nearest whole number in MPa;
- percentage elongation values to 0,5%;
- percentage reduction of area to 1%.
Key
AStress
B Percentage elongation
NOTE See Table 1 for explanation of reference numbers.
Figure 1 - Definitions of elongation
b)
a)
c)
d)
Key
AStress
B Percentage elongation
C Initial transient effect
NOTE See Table 1 for explanation of reference numbers.
Figure 2 - Definitions of upper and lower yield strengths for different types of curves
Key
AStress
B Percentage elongation or percentage extension
Figure 3 - Proof strength, non-proportional extension (R )
p
Key
Key
AStress A Stress
B Percentage extension B Percentage elongation or percentage extension
NOTE See Table 1 for explanation of reference numbers.
Figure 4 - Proof strength, total extension (R ) Figure 5 - Permanent set strength (R )
t r
Key
Key
A Force A Stress
B Percentage extension B Percentage extension
D Force corresponding to R
p
E Specified non-proportional extension
Figure 6 - Proof strength, non-proportional Figure 7 - Percentage yield point extension (A )
e
extension (R ) (see 13.1)
p
Key
AForce
B Elongation
NOTE See Table 1 for explanation of reference numbers.
(F )
Figure 8 - Maximum force
m
Figure 9 - Machined test pieces of rectangular cross section (see annex B)
NOTE 1 The shape of the test piece heads is given only as a guide.
NOTE 2 See Table 1 for explanation of reference numbers.
Figure 10 – test pieces comprising a non-machined portion of the product (see annex C)
NOTE The shape of the test piece heads is given only as a guide.
Figure 11 - Proportional test pieces (see annex D)
NOTE See Table 1 for explanation of reference numbers.
Figure 12 - Test pieces comprising a length of tube (see annex E)
NOTE 1 The shape of the test piece heads is given only as a guide.
NOTE 2 See Table 1 for explanation of reference numbers.
Figure 13 - Test piece cut from a tube (see annex E)
Annex A
(informative)
Recommendations concerning the use of computer controlled tensile
testing machines
A.1 General
This annex contains recommendations for the determination of mechanical properties by using a computer
controlled tensile testing machine. In particular it provides the recommendations which should be taken into
account in the software and testing conditions.
These recommendations are related to the design, the software of the machine and its validation and to the
operating conditions of the tensile test.
A.2 Terms and definitions
For the purposes of this annex, the following term and definition applies :
A.2.1
Computer controlled tensile testing machine
machine for which the control and monitoring of the test, the measurements and the data processing are
undertaken by computer
A.3 Tensile testing machine
A.3.1 Design
The machine should be designed in order to provide outputs giving analogue signals untreated by the software. If
such outputs are not provided, the machine manufacturer should give raw digital data with information how these
raw digital data have been obtained and treated by the software. They should be given in basic Sl units relating to
the force, the extension, the time and the test piece dimensions. These data should be revised if the machine is
modified.
A.3.2 Data sampling frequency
The frequency bandwidth of the mechanical and electronic components of each of the measurements channels
and the data sampling frequency should be sufficiently high as to be able to record the material characteristics
required to be measured.
For example to capture R , the following formula may be used to determine the minimum sampling frequency :
eH




f = × 100 (A.1)
min
R  q
eH
where
-1
f is the minimum sampling frequency in s ;
min
.
-1



is the stress rate in MPa s ;
R is the upper yield strength in MPa ;
eH
q is the relative accuracy error of the machine (according to EN ISO 7500-1).
NOTE 1 The choice of R in the formula (A.1) is due to the fact that it corresponds to a transient characteristic during the
eH
test. If the material tested has no yield phenomena, the proof strength Rp0,2 should be used.
NOTE 2 In case where the machine is operating in strain rate control, the stress rate should be calculated taking into account
the modulus of elasticity of the material.
A.4 Determination of the mechanical properties
A.4.1 General
The following requirements should be taken into account by the software of the machine.
A.4.2 Upper yield strength (R )
eH
R as defined in 4.9.2.1 should be considered as the stress corresponding to the highest value of the force prior to
eH
a reduction of at least 0,5 % of the force and followed by a region in which the force should not exceed the previous
maximum over a strain range not less than 0,05 %.
A.4.3 Lower yield strength (R )
eL
R is defined in 4.9.2.2. However, for productivity of testing a nominal value of R may be reported as the lowest
eL eL
stress within the first 0,25 % strain after R , not taking into account any initial transient effect. When this procedure
eH
is used, it should be recorded in the test report. After determining R by this procedure, the test rate may be
eL
increased as per 10.1.3.
NOTE This clause only applies to materials having yield phenomena and when A is not required to be determined.
e
A.4.4 Proof strength at non-proportional extension (R ) and proof strength at total extension (R )
p t
These values, see 4.9.3 and 4.9.4, can be determined by interpolation between two points of the smoothed curved.
A.4.5 Tensile strength (R )
m
It is the stress corresponding to the maximum force (F ), see 4.9.1.
m
A.4.6 Percentage elongation at fracture (A )
t
A.4.6.1 A should be determined with reference to the definition of fracture in Figure A.1.
t
The fracture is considered to be effective when the force between two measuring points decreases more than 5
times the value of the previous two points followed by a decrease
...