ISO 20064:2019

INTERNATIONAL ISO
STANDARD 20064
First edition
2019-07
Metallic materials — Steel — Method
of test for the determination of
brittle crack arrest toughness, K
ca
Matériaux métalliques — Acier — Méthode d'essai pour déterminer
la ténacité à la rupture fragile, K
ca
Reference number
©
ISO 2019
© ISO 2019
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 2019 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Test equipment. 3
5.1 General . 3
5.2 Testing machine . 3
5.2.1 Force implementation . 3
5.2.2 Calibration of the load cell . 3
5.2.3 Force measurement . 4
5.2.4 Method for force transfer to integrated test piece . 4
5.2.5 Loading direction . 4
5.2.6 Distance between the loading pins . 4
5.3 Impact equipment . 4
5.3.1 Impact methods . 4
5.3.2 Impact energy calculation. 6
5.3.3 Reaction force receivers . 6
6 Test pieces . 7
6.1 Test piece configurations . 7
6.2 Configurations of extension plates and tab plates . 9
6.2.1 General. 9
6.2.2 Extension plates .11
6.2.3 Tab plates .11
6.3 Welding of test piece and extension plates .11
7 Test methods .12
7.1 Temperature control method .12
7.1.1 Determination of temperature gradient .12
7.1.2 Method of temperature control and monitoring .13
7.2 Crack initiation methods .14
8 Test procedures .15
8.1 Pretest procedures .15
8.2 Impacting procedures .16
8.3 Post-test operations . .16
8.4 Observation of fracture surfaces .17
9 Determination of arrest toughness .22
9.1 Validation of arrested crack .22
9.2 Assessment of impact energy .23
9.3 Calculation of arrest toughness .24
10 Reporting .24
Annex A (informative) Devices and method for controlling and monitoring the temperature
of test pieces .28
Annex B (normative) Method for obtaining K at a specific temperature .31
ca
Annex C (normative) Calculation of stress intensity factors for a curved crack .33
Annex D (informative) Double tension type arrest test .34
Annex E (informative) Duplex type arrest test .37
Annex F (informative) Dynamic measurement methods .40
Bibliography .44
iv © ISO 2019 – All rights reserved

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 of 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 www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals,
Subcommittee SC 4, Fatigue, fracture and toughness testing.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
Introduction
This document provides a test method for determining the crack arrest toughness of steels. Experimental
[2]
methods of crack propagation and arrest are documented in Reference [1] Among these, ASTM E1221
is a test method to evaluate lower bound crack arrest toughness, K , under plane strain conditions. On
Ia
[3]
the other hand, crack arrest testing methods using wide plates were developed in the 1950s and have
[3] [4][5][6]
been used for assessing the crack arrest capabilities of cryogenic tanks and pressure vessels .
In recent years, these methods have been extensively used for evaluating the crack arrest toughness of
[7]
ship steels .
The wide plate crack arrest test is intended to evaluate the arrest toughness, K , of steel plate at
ca
its thickness of actual use and not the lower bound arrest toughness, K . However, the relationship
Ia
[4][6]
between the two arrest toughness values has been investigated . It was shown that K and
Ia
K values agreed at lower bound of K . Moreover, the wide plate crack arrest tests were shown to
ca ca
evaluate the arrest toughness at a higher temperature range at which K evaluation is impossible. The
Ia
theoretical background of crack arrest toughness testing with a temperature gradient is described in
References [8] and [9].
This document provides a test method for the determination of brittle crack arrest toughness of steel
by using wide plates with a temperature gradient.
The test method can be summarized as follows: after setting a temperature gradient across the width
of a test piece and applying uniform stress to the test piece, the test piece is struck to initiate a brittle
crack from a mechanical notch in either edge of the test piece and cause crack arrest after propagating
in the width direction (temperature gradient type arrest testing). Annex A describes typical devices
and a method of setting the temperature gradient on the piece. Using the stress intensity factor, the
arrest toughness, K , is calculated from the applied stress and the arrest
...