SIST EN ISO 12737:2011
(Main)Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2010)
Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2010)
This International Standard specifies the ISO method for determining the plane-strain fracture toughness of homogeneous metallic materials using a specimen that is notched and precracked by fatigue, and subjected to slowly increasing crack displacement force.
Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand) (ISO 12737:2010)
Diese Internationale Norm legt das ISO Verfahren zur Bestimmung der Bruchzähigkeit homogener metallischer Werkstoffe im Fall des ebenen Dehnungszustands unter quasi statischer Belastung fest. Dazu werden gekerbte und mit einem Ermüdungsanriss versehene Proben einer langsam anwachsenden Riss¬öffnungskraft ausgesetzt.
Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO 12737:2010)
L'ISO 12737:2010 spécifie une méthode permettant de déterminer le facteur d'intensité de contrainte critique des matériaux métalliques homogènes sur une éprouvette entaillée et préfissurée par fatigue puis soumise à un écartement lent des lèvres de la fissure.
Kovinski materiali - Ugotavljanje lomne žilavosti pri ravninskem deformacijskem stanju (ISO 12737:2010)
Ta mednarodni standard določa metodo ISO za ugotavljanje lomne žilavosti pri ravninskem deformacijskem stanju homogenih kovinskih materialov z uporabo vzorca z utrujenostno zarezo in razpoko, ki se izpostavi počasi naraščajoči sili premika razpoke.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 12737:2011
01-november-2011
1DGRPHãþD
SIST EN ISO 12737:2005
Kovinski materiali - Ugotavljanje lomne žilavosti pri ravninskem deformacijskem
stanju (ISO 12737:2010)
Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2010)
Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand)
(ISO 12737:2010)
Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO
12737:2010)
Ta slovenski standard je istoveten z: EN ISO 12737:2010
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 12737:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 12737:2011
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SIST EN ISO 12737:2011
EUROPEAN STANDARD
EN ISO 12737
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2010
ICS 77.040.10 Supersedes EN ISO 12737:2005
English Version
Metallic materials - Determination of plane-strain fracture
toughness (ISO 12737:2010)
Matériaux métalliques - Détermination du facteur d'intensité Metallische Werkstoffe - Bestimmung der Bruchzähigkeit
de contrainte critique (ISO 12737:2010) (ebener Dehnungszustand) (ISO 12737:2010)
This European Standard was approved by CEN on 4 October 2010.
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, 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
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12737:2010: E
worldwide for CEN national Members.
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SIST EN ISO 12737:2011
EN ISO 12737:2010 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 12737:2011
EN ISO 12737:2010 (E)
Foreword
This document (EN ISO 12737:2010) 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 June 2011, and conflicting national standards shall be withdrawn at
the latest by June 2011.
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 12737:2005.
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, 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 12737:2010 has been approved by CEN as a EN ISO 12737:2010 without any modification.
3
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SIST EN ISO 12737:2011
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SIST EN ISO 12737:2011
INTERNATIONAL ISO
STANDARD 12737
Third edition
2010-12-15
Metallic materials — Determination
of plane-strain fracture toughness
Matériaux métalliques — Détermination du facteur d'intensité
de contrainte critique
Reference number
ISO 12737:2010(E)
©
ISO 2010
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SIST EN ISO 12737:2011
ISO 12737:2010(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.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2010
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.
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Published in Switzerland
ii © ISO 2010 – All rights reserved
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SIST EN ISO 12737:2011
ISO 12737:2010(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Symbols and designations.2
5 Principle .2
6 Apparatus.4
6.1 Testing machine and force measurement .4
6.2 Fatigue cracking machine .4
6.3 Displacement gauge.4
6.4 Testing fixtures.4
7 Test specimen size, configuration and preparation .5
7.1 Specimen size.5
7.2 Recommended specimen proportions.5
7.2.1 Recommended specimens .5
7.2.2 Alternative proportions.5
7.2.3 Alternative specimen configurations .5
7.2.4 Fatigue-crack starter notch .5
7.3 Specimen preparation and fatigue precracking.5
7.3.1 Material condition.5
7.3.2 Crack-plane orientation .7
7.3.3 Machining.7
7.3.4 Fatigue precracking .7
8 Procedure.8
8.1 Specimen measurement .8
8.2 Specimen test temperature .8
8.3 Fixture measurements for bend specimen.8
9 Test procedure.8
10 Calculation and interpretation of results .9
10.1 General .9
10.2 Residual stresses.9
11 Test report.9
Annex A (normative) Fatigue precracking of K fracture toughness specimens.11
Ic
Annex B (normative) Bend specimen.12
Annex C (normative) Compact specimen.14
Annex D (informative) Test fixtures .16
Bibliography.18
© ISO 2010 – All rights reserved iii
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SIST EN ISO 12737:2011
ISO 12737:2010(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 12737 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 4, Toughness testing — Fracture (F), Pendulum (P), Tear (T).
This third edition cancels and replaces the second edition (ISO 12737:2005), of which it constitutes a minor
revision.
iv © ISO 2010 – All rights reserved
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SIST EN ISO 12737:2011
INTERNATIONAL STANDARD ISO 12737:2010(E)
Metallic materials — Determination of plane-strain fracture
toughness
1 Scope
This International Standard specifies the ISO method for determining the plane-strain fracture toughness of
homogeneous metallic materials using a specimen that is notched and precracked by fatigue, and subjected
to slowly increasing crack displacement force.
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 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
ASTM E399-09, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness K of Metallic
Ic
Materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
plane-strain stress intensity factor
K
I
magnitude of the elastic stress field at the tip of a crack subjected to opening mode displacement (mode I)
NOTE It is a function of applied force and test specimen size, geometry, and crack length, and has the dimensions of
-3/2
force times length .
3.2
plane-strain fracture toughness
K
Ic
measure, by the operational procedure of this method, of a material's resistance to crack extension when the
state of stress near the crack tip is predominantly plane strain and plastic deformation is limited
NOTE It is the critical value of K at which significant crack extension occurs on increasing load with high constraint to
I
plastic deformation.
© ISO 2010 – All rights reserved 1
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SIST EN ISO 12737:2011
ISO 12737:2010(E)
3.3
crack-plane orientation
method for relating the plane and direction of crack extension to the characteristic directions of the product
NOTE A hyphenated code is used wherein the letter(s) preceding the hyphen represent(s) the direction normal to the
crack plane, and the letter(s) following the hyphen represent(s) the anticipated direction of crack extension (see Figure 1).
For wrought metals, the letter X always denotes the direction of principal deformation (maximum grain flow in the product),
the letter Y the direction of least deformation, and the letter Z the direction normal to the X-Y plane. In the notation used in
ASTM E399-09, X corresponds to L, Y corresponds to T and Z corresponds to S.
If specimen directions do not coincide with the product's characteristic directions, then two letters are used to denote the
normal to the crack plane or the expected direction of crack extension, or both [see Figure 1 b)]. If there is no grain flow
direction (as in a casting), reference axes may be arbitrarily assigned but must be clearly identified.
3.4
notch opening displacement
V
displacement measured at or near the notch mouth
4 Symbols and designations
For the purposes of this document, the following symbols apply (see also Figures 1, 2 and 4).
Symbol Unit Designation
a mm Crack length
B mm Specimen thickness
E MPa Young's modulus
F kN Applied force
F kN Particular value of F (see Figure 4)
Q
F kN Particular value of F (see Figure 4)
5
1/2a
K MPa·m Maximum stress intensity factor during the final stage of fatigue cracking
f
1/2
K MPa·m Provisional value of K
Q Ic
1/2
K MPa·m Stress intensity factor (mode I)
I
1/2
K MPa·m Critical value of K (plane-strain fracture toughness)
Ic I
R — Ratio of minimum to maximum fatigue cracking force during any single cycle of
fatigue operation
R MPa 0,2 % offset yield strength
p0,2
S mm Span between outer loading points in case of bending
V mm Notch opening displacement
W mm Width of specimen
1/2
DK MPa·m Difference between maximum and minimum values of K during any single cycle of
I I
fatigue operation
a 1/2 -3/2 -3/2
0,031 6 MPa·m = 1 N·mm = 0,031 6 MN·m .
5 Principle
This method covers the determination of the plane-strain fracture toughness (K ) of metallic materials by
Ic
increasing-force tests of fatigue-precracked test specimens. Details of the test specimens and experimental
2 © ISO 2010 – All rights reserved
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SIST EN ISO 12737:2011
ISO 12737:2010(E)
procedures are given in Annexes B and C. Force versus notch opening displacement is recorded
autographically, or converted to digital form for accumulation in a computer information storage facility and
subsequent processing. The force corresponding to 2 % apparent crack extension is established by a
specified deviation from the linear portion of the test record. If certain validity requirements are satisfied, the
value of K is calculated from this force.
Ic
а) Basic identification b) Non-basic identification
c) Radial grain flow, axial working direction d) Axial grain flow, radial working direction
a
Grain flow.
Figure 1 — Crack-plane identification
The property K characterizes the resistance of a material to fracture in the presence of a sharp crack under
Ic
severe tensile constraint, such that
a) the state of stress near the crack front approaches plane strain, and
b) the crack-tip plastic zone is small compared to the crack size, specimen thickness, and ligament ahead of
the crack.
K is believed to represent a lower limiting value of fracture toughness in the environment and at the
Ic
temperature of test.
© ISO 2010 – All rights reserved 3
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SIST EN ISO 12737:2011
ISO 12737:2010(E)
Cyclic or sustained loads can cause crack extension at K values less than K . Crack extension under cyclic
I Ic
or sustained loads can be influenced by temperature and environment. Therefore, when K is applied to the
Ic
design of service components, differences between laboratory test and field conditions should be considered.
With plane-strain fracture toughness testing, there can be no advance assurance that a valid K will be
Ic
determined in a particular test.
6 Apparatus
6.1 Testing machine and force measurement
The testing machine shall be calibrated in accordance with ISO 7500-1 and shall be of at least grade 1. The
testing machine shall have provisions for the autographic recording of the force applied to the specimen;
alternatively, a computer data acquisition system may be used to record force and displacement for
subsequent analysis. The combination of force-sensing device and recording system shall permit the force F
Q
(as defined in Clause 10) to be determined from the test record to ± 1 %.
6.2 Fatigue cracking machine
When possible, the fatigue machine and force-indicating device shall be calibrated statically in accordance
with ISO 7500-1 and shall have a grade of at least 2. If the machine cannot be calibrated statically, the applied
force shall be known to ± 2,5 %. Careful alignment of the specimen and fixturing is necessary to encourage
straight fatigue cracks. The fixturing shall be such that the stress distributio
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kovinski materiali - Ugotavljanje lomne žilavosti pri ravninskem deformacijskem stanju (ISO/FDIS 12737:2010)Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand) (ISO/FDIS 12737:2010)Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO/FDIS 12737:2010)Metallic materials - Determination of plane-strain fracture toughness (ISO/FDIS 12737:2010)77.040.10Mehansko preskušanje kovinMechanical testing of metalsICS:Ta slovenski standard je istoveten z:FprEN ISO 12737kSIST FprEN ISO 12737:2010en,fr,de01-september-2010kSIST FprEN ISO 12737:2010SLOVENSKI
STANDARD
kSIST FprEN ISO 12737:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN ISO 12737
June 2010 ICS 77.040.10 Will supersede EN ISO 12737:2005English Version
Metallic materials - Determination of plane-strain fracture toughness (ISO/FDIS 12737:2010)
Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO/FDIS 12737:2010)
Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand) (ISO/FDIS 12737:2010) This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee ECISS/TC 101.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Croatia, 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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. FprEN ISO 12737:2010: EkSIST FprEN ISO 12737:2010
FprEN ISO 12737:2010 (E) 2 Contents Page Foreword .3 kSIST FprEN ISO 12737:2010
FprEN ISO 12737:2010 (E) 3 Foreword This document (FprEN ISO 12737:2010) 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 document is currently submitted to the Unique Acceptance Procedure. This document will supersede EN ISO 12737:2005. Endorsement notice The text of ISO/FDIS 12737:2010 has been approved by CEN as a FprEN ISO 12737:2010 without any modification.
kSIST FprEN ISO 12737:2010
kSIST FprEN ISO 12737:2010
Please see the administrative notes on page iii
RECIPIENTS OF THIS DRAFT ARE INVITED TOSUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICHTHEY ARE AWARE AND TO PROVIDE SUPPORT-ING DOCUMENTATION. IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-LOGICAL, COMMERCIAL AND USER PURPOSES,DRAFT INTERNATIONAL STANDARDS MAY ONOCCASION HAVE TO BE CONSIDERED IN THELIGHT OF THEIR POTENTIAL TO BECOME STAN-DARDS TO WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
Reference numberISO/FDIS 12737:2010(E)© ISO 2010 FINAL DRAFT ISO/TC 164/SC 4 Secretariat: ANSI Voting begins on: 2010-06-03 Voting terminates on: 2010-08-03
INTERNATIONAL STANDARD ISO/FDIS12737Metallic materials — Determination of plane-strain fracture toughness Matériaux métalliques — Détermination du facteur d'intensité de contrainte critique
kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(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.
Copyright notice This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted under the applicable laws of the user's country, neither this ISO draft nor any extract from it may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, photocopying, recording or otherwise, without prior written permission being secured. Requests for permission to reproduce should be addressed to 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.
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ii © ISO 2010 – All rights reserved
kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) © ISO 2010 – All rights reserved iii ISO/CEN PARALLEL PROCESSING This Minor Revision has been developed within the International Organization for Standardization (ISO), and processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement. This final draft is hereby submitted to a parallel two-month approval vote in ISO and three-month UAP vote in CEN. Positive votes shall not be accompanied by comments. Negative votes shall be accompanied by the relevant technical reasons.
kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) iv © ISO 2010 – All rights reserved Contents Page Foreword.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.1 4 Symbols and designations.2 5 Principle.2 6 Apparatus.4 6.1 Testing machine and force measurement.4 6.2 Fatigue cracking machine.4 6.3 Displacement gauge.4 6.4 Testing fixtures.4 7 Test specimen size, configuration and preparation.5 7.1 Specimen size.5 7.2 Recommended specimen proportions.5 7.2.1 Recommended specimens.5 7.2.2 Alternative proportions.5 7.2.3 Alternative specimen configurations.5 7.2.4 Fatigue-crack starter notch.5 7.3 Specimen preparation and fatigue precracking.5 7.3.1 Material condition.5 7.3.2 Crack-plane orientation.7 7.3.3 Machining.7 7.3.4 Fatigue precracking.7 8 Procedure.8 8.1 Specimen measurement.8 8.2 Specimen test temperature.8 8.3 Fixture measurements for bend specimen.8 9 Test procedure.8 10 Calculation and interpretation of results.9 10.1 General.9 10.2 Residual stresses.9 11 Test report.9 Annex A (normative)
Fatigue precracking of KIc fracture toughness specimens.11 Annex B (normative)
Bend specimen.12 Annex C (normative)
Compact specimen.14 Annex D (informative)
Test fixtures.16 Bibliography.18
kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) © ISO 2010 – All rights reserved v 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 12737 was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 4, Toughness testing — Fracture (F), Pendulum (P), Tear (T). This third edition cancels and replaces the second edition (ISO 12737:2005), which has been technically revised.
kSIST FprEN ISO 12737:2010
kSIST FprEN ISO 12737:2010
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 12737:2010(E) © ISO 2010 – All rights reserved 1 Metallic materials — Determination of plane-strain fracture toughness 1 Scope This International Standard specifies the ISO method for determining the plane-strain fracture toughness of homogeneous metallic materials using a specimen that is notched and precracked by fatigue, and subjected to slowly increasing crack displacement force. 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 7500-1:2004, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Verification and calibration of the force-measuring system ISO 9513:1999, Metallic materials — Calibration of extensometers used in uniaxial testing ASTM E399-09, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIc of Metallic Materials 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 plane-strain stress intensity factor KI magnitude of the elastic stress field at the tip of a crack subjected to opening mode displacement (mode I) NOTE It is a function of applied force and test specimen size, geometry, and crack length, and has the dimensions of force times length-3/2. 3.2 plane-strain fracture toughness KIc measure, by the operational procedure of this method, of a material's resistance to crack extension when the state of stress near the crack tip is predominantly plane strain and plastic deformation is limited NOTE It is the critical value of KI at which significant crack extension occurs on increasing load with high constraint to plastic deformation. kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) 2 © ISO 2010 – All rights reserved 3.3 crack-plane orientation method for relating the plane and direction of crack extension to the characteristic directions of the product NOTE A hyphenated code is used wherein the letter(s) preceding the hyphen represent(s) the direction normal to the crack plane, and the letter(s) following the hyphen represent(s) the anticipated direction of crack extension (see Figure 1). For wrought metals, the letter X always denotes the direction of principal deformation (maximum grain flow in the product), the letter Y the direction of least deformation, and the letter Z the direction normal to the X-Y plane. If specimen directions do not coincide with the product's characteristic directions, then two letters are used to denote the normal to the crack plane or the expected direction of crack extension, or both [see Figure 1 b)]. If there is no grain flow direction (as in a casting), reference axes may be arbitrarily assigned but must be clearly identified. 3.4 notch opening displacement V displacement measured at or near the notch mouth 4 Symbols and designations For the purposes of this document, the following symbols apply (see also Figures 1, 2 and 4). Symbol Unit Designation a mm Crack length B mm Specimen thickness E MPa Young's modulus F kN Applied force FQ kN Particular value of F (see Figure 4) F5 kN Particular value of F (see Figure 4) Kf MPa·m 1/2a Maximum stress intensity factor during the final stage of fatigue cracking KQ MPa·m 1/2 Provisional value of KIc KI MPa·m 1/2 Opening mode stress intensity factor (mode I) KIc MPa·m 1/2 Critical value of KI (plane-strain fracture toughness) R — Ratio of minimum to maximum fatigue cracking force during any single cycle of fatigue operation Rp0,2 MPa 0,2 % offset yield strength S mm Span between outer loading points V mm Notch opening displacement W mm Width for bend specimen or effective width for compact specimen DKI MPa·m 1/2 Difference between maximum and minimum values of KI during any single cycle of fatigue operation a 0,031 6 MPa·m1/2 = 1 N·mm-3/2 = 0,031 6 MN·m-3/2. 5 Principle This method covers the determination of the plane-strain fracture toughness (KIc) of metallic materials by increasing-force tests of fatigue-precracked test specimens. Details of the test specimens and experimental procedures are given in Annexes B and C. Force versus notch opening displacement is recorded autographically, or converted to digital form for accumulation in a computer information storage facility and kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) © ISO 2010 – All rights reserved 3 subsequent processing. The force corresponding to 2 % apparent crack extension is established by a specified deviation from the linear portion of the test record. If certain validity requirements are satisfied, the value of KIc is calculated from this force.
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Basic identification b)
Non-basic identification
c)
Radial grain flow, axial working direction d)
Axial grain flow, radial working direction a Grain flow. Figure 1 — Crack-plane identification The property KIc characterizes the resistance of a material to fracture in the presence of a sharp crack under severe tensile constraint, such that a) the state of stress near the crack front approaches plane strain, and b) the crack-tip plastic zone is small compared to the crack size, specimen thickness, and ligament ahead of the crack. KIc is believed to represent a lower limiting value of fracture toughness in the environment and at the temperature of test. kSIST FprEN ISO 12737:2010
ISO/FDIS 12737:2010(E) 4 © ISO 2010 – All rights reserved Cyclic or sustained loads can cause crack extension at KI values less than KIc. Crack extension under cyclic or sustained loads can be influenced by temperature and environment. Therefore, when KIc is applied to the design of service components, differences between laboratory test and field conditions should be considered. With plane-strain fracture toughness testing, there can be no advance assurance that a valid KIc will be determined in a particular test. 6 Apparatus 6.1 Testing machine and force measurement The testing machine shall be calibrated in accordance with ISO 7500-1 and shall be of at least grade 1. The testing machine shall have provisions for the autographic recording of the force applied to the specimen; alternatively, a computer data acquisition system may be used to record force and displacement for subsequent analysis. The combination of force-sensing device and recording s
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