SIST EN ISO 7438:2016

SLOVENSKI STANDARD
01-april-2016
1DGRPHãþD
SIST EN ISO 7438:2005
Kovinski materiali - Upogibni preskus (ISO 7438:2016)
Metallic materials - Bend test (ISO 7438:2016)
Metallische Werkstoffe - Biegeversuch (ISO 7438:2016)
Matériaux métalliques - Essai de pliage (ISO 7438:2016)
Ta slovenski standard je istoveten z: EN ISO 7438:2016
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.

EN ISO 7438
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2016
EUROPÄISCHE NORM
ICS 77.040.10 Supersedes EN ISO 7438:2005
English Version
Metallic materials - Bend test (ISO 7438:2016)
Matériaux métalliques - Essai de pliage (ISO Metallische Werkstoffe - Biegeversuch (ISO
7438:2016) 7438:2016)
This European Standard was approved by CEN on 21 November 2015.

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, 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: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7438:2016 E
worldwide for CEN national Members.

Contents
Page
European foreword . 3

European foreword
This document (EN ISO 7438:2016) 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 July 2016, and conflicting national standards shall be
withdrawn at the latest by July 2016.
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 ISO 7438:2005.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 7438:2016 has been approved by CEN as EN ISO 7438:2016 without any modification.
INTERNATIONAL ISO
STANDARD 7438
Third edition
2016-01-15
Metallic materials — Bend test
Matériaux métalliques — Essai de pliage
Reference number
ISO 7438:2016(E)
©
ISO 2016
ISO 7438:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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.
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 7438:2016(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Symbols and designations . 1
3 Principle . 1
4 Test equipment. 2
4.1 General . 2
4.2 Bending device with supports and a former . 3
4.3 Bending device with a V-block. 3
4.4 Bending device with a clamp . 4
5 Test piece . 4
5.1 General . 4
5.2 Edges of rectangular test pieces. 4
5.3 Width of the test piece . 4
5.4 Thickness of the test piece . 4
5.5 Test pieces from forgings, castings and semi-finished products . 5
5.6 Agreement for test pieces of greater thickness and width . 5
5.7 Length of the test piece . 5
6 Procedure. 5
7 Interpretation of results . 7
8 Test report . 7
Annex A (informative) Determination of the bend angle from the measurement of the
displacement of the former . 8
ISO 7438:2016(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 2, Ductility testing.
This third edition cancels and replaces the second edition (ISO 7438:2005), which has been technically
revised. The following changes have been made:
— Figure 3 has been revised;
— a note has been added in 4.2.2;
— Formula (A.4) and Figure A.1 have been revised.
iv © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 7438:2016(E)
Metallic materials — Bend test
1 Scope
This International Standard specifies a method for determining the ability of metallic materials to
undergo plastic deformation in bending.
This International Standard applies to test pieces taken from metallic products, as specified in the
relevant product standard. It is not applicable to certain materials or products, for example tubes in full
section or welded joints, for which other standards exist.
2 Symbols and designations
Symbols and designations used in the bend test are shown in Figures 1 and 2 and specified in Table 1.
Table 1 — Symbols and designations
Symbol Designation Unit
a Thickness or diameter of test piece (or diameter of the inscribed mm
circle for pieces of polygonal cross-section)
b Width of the test piece mm
L Length of the test piece mm
l Distance between supports mm
D Diameter of the former mm
α Angle of bend degrees
r Internal radius of bend portion of test piece after bending mm
f Displacement of the former mm
c Distance between the plane including the horizontal axis of sup- mm
ports and the central axis of the rounded portion of the former
before test
p Distance between the vertical planes including the central axis of mm
each support and the vertical plane including the central axis of
the former
R Radius of the supports mm
3 Principle
The bend test consists of submitting a test piece of round, square, rectangular or polygonal cross-
section to plastic deformation by bending, without changing the direction of loading, until a specified
angle of bend is reached.
The axes of two legs of the test piece remain in a plane perpendicular to the axis of bending. In the case of
a 180° bend, the two lateral surfaces may, depending on the requirements of the product standard, lie flat
against each other or may be parallel at a specified distance, an insert being used to control this distance.
ISO 7438:2016(E)
4 Test equipment
4.1 General
The bend test shall be carried out in testing machines or presses equipped with the following devices:
a) bending device with two supports and a former as shown in Figure 1;
b) bending device with a V-block and a former as shown in Figure 2;
c) bending device with a clamp as shown in Figure 3.
Figure 1 — Bending device with two supports and a former
Figure 2 — Bending device with a V-block and a former
2 © ISO 2016 – All rights reserved

ISO 7438:2016
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