Metallic materials - Tensile testing - Part 2: Method of test at elevated temperature (ISO 6892-2:2018)

ISO 6892-2:2018 specifies a method of tensile testing of metallic materials at temperatures higher than room temperature.

Metallische Werkstoffe - Zugversuch - Teil 2: Prüfverfahren bei erhöhter Temperatur (ISO 6892-2:2018)

Dieses Dokument legt ein Verfahren für den Zugversuch an metallische Werkstoffen bei Temperaturen, die
höher sind als Raumtemperatur, fest.

Matériaux métalliques - Essai de traction - Partie 2: Méthode d'essai à température élevée (ISO 6892-2:2018)

ISO 6892-2:2018 spécifie une méthode d'essai de traction des matériaux métalliques à des températures supérieures à la température ambiante.

Kovinski materiali - Natezni preskus - 2. del: Metoda preskušanja pri povišani temperaturi (ISO 6892-2:2018)

Ta dokument določa metodo za natezni preskus kovinskih materialov pri temperaturi, ki presega sobno temperaturo.

General Information

Status
Published
Publication Date
29-May-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
30-May-2018
Completion Date
30-May-2018

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SLOVENSKI STANDARD
SIST EN ISO 6892-2:2018
01-oktober-2018
1DGRPHãþD
SIST EN ISO 6892-2:2011
Kovinski materiali - Natezni preskus - 2. del: Metoda preskušanja pri povišani
temperaturi (ISO 6892-2:2018)

Metallic materials - Tensile testing - Part 2: Method of test at elevated temperature (ISO

6892-2:2018)

Metallische Werkstoffe - Zugversuch - Teil 2: Prüfverfahren bei erhöhter Temperatur

(ISO 6892-2:2018)

Matériaux métalliques - Essai de traction - Partie 2: Méthode d'essai à température

élevée (ISO 6892-2:2018)
Ta slovenski standard je istoveten z: EN ISO 6892-2:2018
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 6892-2:2018 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 6892-2:2018
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SIST EN ISO 6892-2:2018
EN ISO 6892-2
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2018
EUROPÄISCHE NORM
ICS 77.040.10 Supersedes EN ISO 6892-2:2011
English Version
Metallic materials - Tensile testing - Part 2: Method of test
at elevated temperature (ISO 6892-2:2018)

Matériaux métalliques - Essai de traction - Partie 2: Metallische Werkstoffe - Zugversuch - Teil 2:

Méthode d'essai à température élevée (ISO 6892- Prüfverfahren bei erhöhter Temperatur (ISO 6892-

2:2018) 2:2018)
This European Standard was approved by CEN on 3 May 2018.

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-CENELEC 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-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6892-2:2018 E

worldwide for CEN national Members.
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SIST EN ISO 6892-2:2018
EN ISO 6892-2:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 6892-2:2018
EN ISO 6892-2:2018 (E)
European foreword

This document (EN ISO 6892-2:2018) has been prepared by Technical Committee ISO/TC 164

"Mechanical testing of metals" in collaboration with Technical Committee ECISS/TC 101 “Test methods

for steel (other than chemical analysis)” 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 November 2018, and conflicting national standards

shall be withdrawn at the latest by November 2018.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 6892-2:2011.

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,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 6892-2:2018 has been approved by CEN as EN ISO 6892-2:2018 without any

modification.
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SIST EN ISO 6892-2:2018
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SIST EN ISO 6892-2:2018
INTERNATIONAL ISO
STANDARD 6892-2
Second edition
2018-03
Metallic materials — Tensile testing —
Part 2:
Method of test at elevated
temperature
Matériaux métalliques — Essai de traction —
Partie 2: Méthode d'essai à température élevée
Reference number
ISO 6892-2:2018(E)
ISO 2018
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and designations .......................................................................................................................................................................... 2

5 Principle ........................................................................................................................................................................................................................ 3

6 Test piece ...................................................................................................................................................................................................................... 3

7 Determination of original cross-sectional area (S ) ........................................................................................................ 3

8 Marking the original gauge length (L ) ......................................................................................................................................... 3

9 Apparatus ..................................................................................................................................................................................................................... 3

10 Test conditions ....................................................................................................................................................................................................... 5

10.1 Setting the force zero point .......................................................................................................................................................... 5

10.2 Gripping of the test piece, fixing of the extensometer and heating of the test piece,

not necessarily in the following sequence ...................................................................................................................... 5

10.2.1 Method of gripping ........................................................................................................................................................ 5

10.2.2 Fixing of the extensometer and establishing the gauge length ............................................... 5

10.2.3 Heating of the test piece ............................................................................................................................................ 6

10.3 Testing rate based on strain rate control (Method A) ........................................................................................... 6

10.3.1 General...................................................................................................................................................................................... 6

10.3.2 Strain rate for the determination of the upper yield strength (R ) or

proof strength properties (R and, if required, R ) ............................................................................. 6

p t
10.3.3 Strain rate for the determination of the lower yield strength (R ) and

percentage yield point extension (A ), if required ............................................................................. 6

10.3.4 Strain rate for the determination of the tensile strength (R ), percentage

elongation after fracture (A), percentage reduction area (Z), and, if
required, percentage total extension at the maximum force (A ),

percentage plastic extension at maximum force (A ) ...................................................................... 7

10.4 Method of testing with expanded strain rate ranges (Method B) ............................................................... 7

10.4.1 General...................................................................................................................................................................................... 7

10.4.2 Rate for the determination of yield strength or proof strength properties .................. 7

10.4.3 Rate for the determination of tensile strength ...................................................................................... 7

10.5 Choice of the method and rates ................................................................................................................................................ 7

10.6 Documentation of the chosen testing conditions ...................................................................................................... 8

11 Determination or calculation of the properties................................................................................................................... 8

12 Test report ................................................................................................................................................................................................................... 8

13 Measurement uncertainty .......................................................................................................................................................................... 9

14 Figures ............................................................................................................................................................................................................................. 9

15 Annexes .......................................................................................................................................................................................................................10

Annex A (informative) Addition to ISO 6892-1:2016, Annexes B and D .......................................................................12

Annex B (informative) Measurement uncertainty ..............................................................................................................................18

Bibliography .............................................................................................................................................................................................................................21

© ISO 2018 – All rights reserved iii
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals,

Subcommittee SC 1, Uniaxial testing.

This second edition cancels and replaces the first edition (ISO 6892-2:2011), of which it constitutes a

minor revision.
The main changes compared to the previous edition are as follows:
— a note has been added after the first sentence of 10.2.1;
— some references to subclauses of ISO 6892-1 have been deleted.
A list of all parts in the ISO 6892 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
Introduction

In this document, two methods of testing speeds are described. The first, Method A, is based on strain

rates (including crosshead separation rate) with narrow tolerances (±20 %) and the second, Method B,

is based on conventional strain rate ranges and tolerances. 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.

The influence of the testing speed on the mechanical properties, determined by the tensile test, is

normally greater at an elevated temperature than at room temperature.

Traditionally, mechanical properties determined by tensile tests at elevated temperatures have been

determined at a slower strain or stressing rate than at room temperature. This document recommends

the use of slow strain rates but, in addition, higher strain rates are permitted for particular applications,

such as comparison with room temperature properties at the same strain rate.

During discussions concerning the speed of testing in the preparation of this document, it was decided

to consider deleting the stress rate method in future revisions.
© ISO 2018 – All rights reserved v
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SIST EN ISO 6892-2:2018
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SIST EN ISO 6892-2:2018
INTERNATIONAL STANDARD ISO 6892-2:2018(E)
Metallic materials — Tensile testing —
Part 2:
Method of test at elevated temperature

WARNING — This document calls for the use of substances and/or procedures that can

be injurious to health if adequate safety measures are not taken. This document does not

address any health hazards, safety or environmental matters associated with its use. It is

the responsibility of the user of this document to establish appropriate health, safety and

environmentally acceptable practices.
1 Scope

This document specifies a method of tensile testing of metallic materials at temperatures higher than

room temperature.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 6892-1 apply with the

following exceptions and supplements.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp

In general, all test piece geometries/dimensions are based on measurements taken at room temperature.

The exception may be the extensometer gauge length (see 3.3 and 10.2.2).

NOTE The following properties are generally not determined at elevated temperature unless required by

relevant specifications or agreement:
— permanent set strength (R );
— percentage permanent elongation;
— percentage permanent extension;
— percentage yield point extension (A );
— percentage total extension at maximum force (A );
© ISO 2018 – All rights reserved 1
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
— percentage plastic extension at maximum force (A );
— percentage total extension at fracture (A ).
3.1
original gauge length

gauge length measured at room temperature before heating of the test piece and before application

of force
3.2
percentage elongation after fracture

permanent elongation at room temperature of the gauge length after fracture (L − L )

u o

Note 1 to entry: It is expressed as a percentage of the original gauge length (L ) (3.1).

Note 2 to entry: For further details, see ISO 6892-1.
3.3
extensometer gauge length

length within the parallel portion of the test piece used for the measurement of extension (3.4) by means

of an extensometer
3.4
extension

increase in the extensometer gauge length (L ) (3.3) at a given moment during the test

3.5
percentage extension

extension (3.4) expressed as a percentage of the extensometer gauge length (L ) (3.3)

3.6
percentage reduction of area

maximum change in cross-sectional area which has occurred during the test (S − S )

o u

Note 1 to entry: It is expressed as a percentage of the original cross-sectional area (S ), where S and S are

o o u
calculated from the dimensions at room temperature.
3.7
stress

force at any moment during the test divided by the original cross-sectional area (S ) of the test piece

Note 1 to entry: All stresses referred to in this document are engineering stresses, calculated using the cross-

sectional area of the test piece derived from dimensions measured at room temperature.

3.8
soaking time

time taken to stabilize the temperature of the test piece prior to mechanical loading

4 Symbols and designations

ISO 6892-1 provides an extensive listing of symbols and their related designations.

The additional symbols used in this document are given in Table 1.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
Table 1 — Symbols and designations
Symbol Unit Designation

T °C specified temperature or nominal temperature at which the test should be performed

T °C indicated temperature or measured temperature on the surface of the parallel length of

the test piece
t min soaking time
5 Principle

The test involves straining a test piece by tensile force for the determination of one or more of the

mechanical properties defined in Clause 3.

The test is carried out at a temperature higher than 35 °C, which means at temperatures higher than

room temperature as specified in ISO 6892-1.
6 Test piece
For requirements concerning test pieces, see ISO 6892-1.
NOTE Additional examples of test pieces are given in Annex A.
7 Determination of original cross-sectional area (S )

For requirements concerning determination of the original cross-sectional area, see ISO 6892-1.

NOTE This parameter is calculated from measurements taken at room temperature.
8 Marking the original gauge length (L )
For requirements concerning marking the original gauge length, see ISO 6892-1.
9 Apparatus
9.1 Force-measuring system.

The force-measuring system of the testing machine shall be calibrated in accordance with ISO 7500-1,

class 1, or better.
9.2 Extensometer.

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.

The extensometer gauge length shall be not less than 10 mm and shall correspond to the central portion

of the parallel length.

Any part of the extensometer projecting beyond the furnace shall be designed or protected from

draughts so that fluctuations in the room temperature have only a minimal effect on the readings. It

is advisable to maintain reasonable stability of the temperature and speed of the air surrounding the

testing machine.
© ISO 2018 – All rights reserved 3
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
9.3 Heating device.
9.3.1 Permitted deviations of temperature

The heating device for the test piece shall be such that the test piece can be heated to the specified

temperature, T.

The indicated temperatures, T , are the temperatures measured on the surface of the parallel length of

the test piece with corrections applied for any known systematic errors, but with no consideration of

the uncertainty of the temperature measurement equipment.

The permitted deviations between the specified temperature, T, and the indicated temperatures, T ,

and the maximum permissible temperature variation along the test piece are given in Table 2.

For specified temperatures greater than 1 100 °C, the permitted deviations shall be defined by previous

agreement between the parties concerned.

Table 2 — Permitted deviations between T and T and maximum permissible temperature

variations along the test piece
Maximum permissible

Specified temperature, T Permitted deviation between T and T temperature variation along

°C °C the test piece
T ≤ 600 ±3 3
600 < T ≤ 800 ±4 4
800 < T ≤ 1 000 ±5 5
1 000 < T ≤ 1 100 ±6 6
9.3.2 Measurement of temperature

When the gauge length is less than 50 mm, one temperature sensor shall measure the temperature at

each end of the parallel length directly. When the gauge length is equal to or greater than 50 mm, a

third temperature sensor shall measure near the centre of the parallel length.

This number may be reduced if the general arrangement of the furnace and the test piece is such that,

from experience, it is known that the variation in temperature of the test piece does not exceed the

permitted deviation specified in 9.3.1. However, at least one sensor shall be measuring the test piece

temperature directly.

Temperature sensor junctions shall make good thermal contact with the surface of the test piece and be

suitably screened from direct radiation from the furnace wall.
9.3.3 Verification of the temperature-measuring system

The temperature-measuring system shall have a resolution equal to or better than 1 °C and an accuracy

of ±0,004 T °C or ±2 °C, whichever is greater.

NOTE The temperature-measuring system includes all components of the measuring chain (sensor, cables,

indicating device and reference junction).

All components of the temperature-measuring system shall be verified and calibrated over the

working range at intervals not exceeding 1 year. Errors shall be recorded on the verification report.

The components of the temperature-measuring system shall be verified by methods traceable to the

international unit (SI unit) of temperature.
4 © ISO 2018 – All rights reserved
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
10 Test conditions
10.1 Setting the force zero point

The force-measuring system shall be set to zero after the testing equipment has been assembled but

before the test piece is actually placed in the gripping jaws. 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 the weight of the gripping system is compensated in the force

measurement and that any force resulting from the clamping operation does not affect the force zero point.

10.2 Gripping of the test piece, fixing of the extensometer and heating of the test piece,

not necessarily in the following sequence
10.2.1 Method of gripping
For requirements concerning the method of gripping, see ISO 6892-1.

NOTE Maintaining a very small tensile load (e.g. test machine in load control) during heating period and

soaking time can prevent possible compressive stresses due to thermal expansion.
10.2.2 Fixing of the extensometer and establishing the gauge length
10.2.2.1 General

Different methods of establishing the extensometer gauge length are used in practice. This can lead to

minor differences in the test results. The method used shall be documented in the test report.

10.2.2.2 L based on room temperature (Method 1)

The extensometer is set on the test piece at room temperature with nominal gauge length. The extension

is measured at test temperature and the percentage extension is calculated with the gauge length at

room temperature.
The thermal extension is not considered.
10.2.2.3 L based on test temperature (Method 2)
This L includes the thermal extension of the test piece.
10.2.2.3.1 Nominal L at test temperature (Method 2 a)

The extensometer is set on the test piece at the test temperature with nominal gauge length before

mechanical loading.
10.2.2.3.2 Reduced L at room temperature (Method 2 b)

An extensometer with reduced gauge length is set on the test piece at room temperature such that at

test temperature, the nominal gauge length is achieved.
For the calculation of percentage extension, the nominal gauge length is used.
10.2.2.3.3 Corrected L at test temperature (Method 2 c)

The extensometer is set on the test piece at room temperature with the nominal gauge length.

For the calculation of percentage extension, the corrected nominal gauge length at test temperature

(gauge length at room temperature and thermal expansion) is used.
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SIST EN ISO 6892-2:2018
ISO 6892-2:2018(E)
10.2.3 Heating of the test piece

The test piece shall be heated to the specified temperature, T, and shall be maintained at that

temperature for at least 10 min before loading (soaking time). The loading shall only be started after

the output of the extensometer has stabilized.

Quite often, longer times can be required to bring the entire cross-section of the material up to the

specified temperature.

During heating, the temperature of the test piece shall not exceed the specified temperature with its

tolerances, except by special agreement between the parties concerned.
10.3 Testing rate based on strain rate control (Method A)
10.3.1 General
This method is intend
...

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