SIST EN ISO 12737:2005
(Main)Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2005)
Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2005)
ISO 12737:2005 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 a slowly increasing crack displacement force.
Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand) (ISO 12737:2005)
Diese Internationale Norm legt das Verfahren zur Bestimmung der Bruchzähigkeit homogener metallischer Werkstoffe im Fall des ebenen Dehnungszustandes unter quasi-statischer Belastung fest. Dazu werden gekerbte und mit einem Ermüdungsanriss versehene Proben einer langsam anwachsenden Rissöffnungskraft ausgesetzt.
Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO 12737:2005)
L'ISO 12737:2005 spécifie la méthode ISO 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 12737:2005)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 12737:2005
01-november-2005
Kovinski materiali – Ugotavljanje lomne žilavosti pri ravninskem deformacijskem
stanju (ISO 12737:2005)
Metallic materials - Determination of plane-strain fracture toughness (ISO 12737:2005)
Metallische Werkstoffe - Bestimmung der Bruchzähigkeit (ebener Dehnungszustand)
(ISO 12737:2005)
Matériaux métalliques - Détermination du facteur d'intensité de contrainte critique (ISO
12737:2005)
Ta slovenski standard je istoveten z: EN ISO 12737:2005
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
SIST EN ISO 12737:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 12737:2005
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SIST EN ISO 12737:2005
EUROPEAN STANDARD
EN ISO 12737
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2005
ICS 77.040.10
English Version
Metallic materials - Determination of plane-strain fracture
toughness (ISO 12737:2005)
Matériaux métalliques - Détermination du facteur d'intensité Metallische Werkstoffe - Bestimmung der Bruchzähigkeit
de contrainte critique (ISO 12737:2005) (ebener Dehnungszustand) (ISO 12737:2005)
This European Standard was approved by CEN on 14 April 2005.
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 Central Secretariat 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
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versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
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© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12737:2005: E
worldwide for CEN national Members.
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SIST EN ISO 12737:2005
EN ISO 12737:2005 (E)
Foreword
This document (EN ISO 12737:2005) has been prepared by Technical Committee ISO/TC 164
"Mechanical testing of metals" in collaboration with 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 February 2006, and conflicting national
standards shall be withdrawn at the latest by February 2006.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 12737:2005 has been approved by CEN as EN ISO 12737:2005 without any
modifications.
2
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SIST EN ISO 12737:2005
INTERNATIONAL ISO
STANDARD 12737
Second edition
2005-08-01
Metallic materials — Determination of
plane-strain fracture toughness
Matériaux métalliques — Détermination du facteur d'intensité de
contrainte critique
Reference number
ISO 12737:2005(E)
©
ISO 2005
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SIST EN ISO 12737:2005
ISO 12737:2005(E)
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ii © ISO 2005 – All rights reserved
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SIST EN ISO 12737:2005
ISO 12737:2005(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. 4
7.1 Specimen size . 4
7.2 Recommended specimen proportions . 5
7.2.1 Recommended specimens . 5
7.2.2 Alternative proportions . 5
7.2.3 Alternative specimen configurations (for information only) . 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
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 2005 – All rights reserved iii
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SIST EN ISO 12737:2005
ISO 12737:2005(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 second edition cancels and replaces the first edition (ISO 12737:1996), which has been technically
revised. It includes the changes in Draft Amendement 1:2004, Recommendations relating to specimen test
temperature and crack-plane orientation.
iv © ISO 2005 – All rights reserved
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SIST EN ISO 12737:2005
INTERNATIONAL STANDARD ISO 12737:2005(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 7500-1:2004, 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
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.
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
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SIST EN ISO 12737:2005
ISO 12737:2005(E)
do not coincide with the product's characteristic directions, then two letters are used to denote the normal to the crack
plane and/or the expected direction of crack extension [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 International Standard, 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
1/2 a
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 Opening mode stress intensity factor (mode I)
I
1/2
K MPa·m Critical value of K (plane-strain fracture toughness)
Ic I
Ratio of minimum to maximum fatigue cracking force during any single cycle of
R —
fatigue operation
R MPa 0,2 % offset yield strength
p0,2
S mm Span between outer loading points
V mm Notch opening displacement
W mm Width for bend specimen or effective width for compact specimen
Difference between maximum and minimum values of K during any single cycle of
1/2
I
DK MPa·m
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
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
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SIST EN ISO 12737:2005
ISO 12737:2005(E)
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.
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.
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SIST EN ISO 12737:2005
ISO 12737:2005(E)
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 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 distribution is uniform across the specimen
thickness and symmetrical about the plane of the prospective crack.
6.3 Displacement gauge
The displacement-gauge electrical output shall represent the relative displacement (V) of two precisely located
gauge positions spanning th
...
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