SIST EN ISO 7539-7:1999
(Main)Corrosion of metals and alloys - Stress corrosion testing - Part 7: Slow strain rate testing (ISO 7539-7:1989)
Corrosion of metals and alloys - Stress corrosion testing - Part 7: Slow strain rate testing (ISO 7539-7:1989)
Korrosion der Metalle und Legierungen - Prüfung der Spannungsrißkorrosion - Teil 7: Prüfung mit langsamer Dehnrate (ISO 7539-7:1989)
Der vorliegende Teil von ISO 7539 behandelt Verfahren für die Durchführung von Prüfungen mit langsamer Dehnrate zur Untersuchung der Anfälligkeit eines Metalls gegenüber Spannungsrißkorrosion einschließlich der Wasserstoffinduzierten Schädigung. In diesem Teil der ISO 7539 werden mit dem Begriff "Metall" auch Legierungen erfaßt.
Corrosion des métaux et alliages - Essais de corrosion sous contrainte - Partie 7: Essais a faible vitesse de déformation (ISO 7539-7:1989)
Korozija kovin in zlitin - Ugotavljanje pokanja zaradi napetostne korozije - 7. del: Preskušanje s počasno deformacijo (raztezanjem) (SSRT) (ISO 7539-7:1989)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 7539-7:1999
01-oktober-1999
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3UHVNXãDQMHVSRþDVQRGHIRUPDFLMR UD]WH]DQMHP 6657 ,62
Corrosion of metals and alloys - Stress corrosion testing - Part 7: Slow strain rate testing
(ISO 7539-7:1989)
Korrosion der Metalle und Legierungen - Prüfung der Spannungsrißkorrosion - Teil 7:
Prüfung mit langsamer Dehnrate (ISO 7539-7:1989)
Corrosion des métaux et alliages - Essais de corrosion sous contrainte - Partie 7: Essais
a faible vitesse de déformation (ISO 7539-7:1989)
Ta slovenski standard je istoveten z: EN ISO 7539-7:1995
ICS:
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 7539-7:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 7539-7:1999
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SIST EN ISO 7539-7:1999
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SIST EN ISO 7539-7:1999
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SIST EN ISO 7539-7:1999
ISO
INTERNATIONAL
7539-7
STANDARD
First edition
1989-12-01
Corrosion of metals and alloys - Stress
corrosion testing -
Part 7:
Slow strain rate testing
Corrosion des mhtaux et alliages - Essais de corrosion sous contrainte -
Partie 7: Essais 2 faible vitesse de dhformation
Reference number
ISO 7539-7 : 1989 (El
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SIST EN ISO 7539-7:1999
ISO 7539-7 : 1989 (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. Esch 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, govern-
mental 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.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council. They are approved in accordance with ISO procedures requiring at
least 75 % approval by the member bodies voting.
International Standard ISO 7539-7 was prepared by Technical Committee ISO/TC 156,
Corrosion of metals and alloys.
ISO 7539 consists of the following Parts, under the general title Corrosion of metals
and alloys - S tress corrosion tes ting :
-
Part 7: General guidance on testing procedures
-
Part 2: Preparation and use of ben t-beam specimens
-
Part 3: Preparation and use of U-bend specimens
-
Part 4: Preparation and use of uniaxially loaded tension specimens
- Part 5: Preparation and use of C-ring specimens
-
Part 6: Preparation and use of pre-cracked specimens
-
Part 7: Slow strain rate testing
-
Part 8: Preparation and use of welded specimens
Annex A of this patt of ISO 7539 is for information only.
0 ISO 1989
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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SIST EN ISO 7539-7:1999
ISO 7539-7 : 1989 (El
Introduction
This part of ISO 7539 is one of a series giving procedures for designing, preparing and
using various forms of test specimen to carry out tests to establish a metals resistance
to stress corrosion.
Esch of the Standards in the series needs to be read in association with ISO 7539-1.
This helps in the choice of an appropriate test procedure to suit particular
circumstances as well as giving guidance towards assessing the significance of the
results of the tests.
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SIST EN ISO 7539-7:1999
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SIST EN ISO 7539-7:1999
ISO 7539-7 : 1989 (E)
INTERNATIONAL STANDARD
- Stress corrosion
Corrosion of metals and alloys
testing -
Part 7:
Slow strain rate testing
3 Definitions
1 scope
For the purposes of this part of ISO 7539, the following
1 .l This patt of ISO 7539 covers procedures for conducting
definitions and those given in ISO 7539-1 apply.
slow strain rate tests for investigating susceptibility of a metal
to stress corrosion cracking, including hydrogen-induced
31 creep : Time-dependent mechanical deformation of a
failure.
specimen after application of the initial load.
The term “metal” as used in this part of ISO 7539 includes
alloys.
3.2 elongation to fracture: The ratio, expressed as a
percentage, of the increase in length of the gauge length which
1.2 Slow strain rate tests are adaptable for testing a wide
has occurred during a test, to the original gauge length.
variety of product forms, including plate, rod, wire, sheet and
tubes, as well as composites of these and Parts joined by
33 maximum load: The maximum value of the load
welding. Notched or pre-cracked specimens may be used, as
achieved during a test taken to total failure or, in the case of
well as initially plain specimens.
composite materials, the load corresponding to failure of one
element.
1.3 The principal advantage of the test is the rapidity with
which susceptibility to stress corrosion cracking of a particular
34 nominal stress - elongation curves: A plot of the
metal/environment combination tan be assessed.
nominal stress calculated from the instantaneous applied load
and the original Cross-sectional area of a specimen, against the
elongation of the gauge length at the time of the load measure-
ment.
2 Normative references
The following Standards contain provisions which, through 35 reduction of area: The ratio, expressed as a percen-
reference in this text, constitute provisions of this part of tage, of the maximum decrease in Cross-sectional area which
ISO 7539. At the time of publication, the editions indicated has occurred during a test, to the original Cross-sectional area.
were valid. All Standards are subject to revision, and Parties to
agreements based on this patt of ISO 7539 are encouraged to
3.6 strain rate: The initial rate of increase of the gauge
investigate the possibility of applying the most recent editions
length of an initially plain tensile specimen.
of the Standards listed below. Members of IEC and ISO main-
tain registers of currently valid International Standards.
4 Principle
ISO 7539-1 : 1987, Corrosion of metals and alloys - Stress
corrosion testing - Part 7: General guidance on testing pro-
4.1 The test consists in subjecting a specimen to an increas-
cedures.
ing strain whilst exposed to a specified environment with a view
to determining stress corrosion susceptibility by reference to
ISO 7539-4 : 1989, Corrosion of metals and alloys - Stress
one or more of the Parameters enumerated in clause 7.
corrosion testing - Part 4: Preparation and use of uniaxially
loaded tension specimens.
4.2 Corrosive environments may Cause a deterioration of the
properties of stressed materials beyond those observed with
ISO 7539-6 : 1989, Corrosion of metal and alloys - Stress cor-
Part 6: Preparation and use of pre-cracked the same combination of environment and material when the
rosion testing -
latter is not subjected to slow dynamic strain. This enhanced
specimens.
1
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SIST EN ISO 7539-7:1999
ISO 7539-7 : 1989 (El
deterioration, usually due to the initiation and growth of Cracks, other strain rates, such as 10-5 s-1 and IO-7 s-1, should be
may be expressed in a number of different ways for the purpose conducted if the initial test produces no evidente of stress cor-
of assessing stress corrosion susceptibility. rosion cracking. If specimens are pre-loaded to reduce the total
test time during tests at very slow strain rates, the comments
made in 7.4.3 may be important.
4.3 Tests may be conducted in tension or in bending, on
initially plain, notched or pre-cracked specimens. The most
important characteristic of the test is the relatively slow strain
6.6 The establishment of cracking conditions in a given
rate generated at the region of Crack initiation or growth in the
metaI/environment combination may be time-dependent, if
metal, hence the preference for such tests being referred to as
they do not exist at the outset of the test. In such cir-
slow strain rate tests.
cumstances stress corrosion cracking may only be observed if
the strain rate is sufficiently slow to ensure that overload failure
does not occur before the necessary time has elapsed whereby
5 Spetimens
the necessary environmental conditions for cracking have been
established. These difficulties tan sometimes be avoided by
5.1 A variety of specimen shapes and sizes tan be used, but exposure of the specimens to the test environment for some
those most commonly employed are described in ISO 7539-4
time Prior to the initiation of dynamic strain.
and ISO 7539-6.
6.7 The environmental testing conditions selected depend
5.2 The remarks in the aforementioned documents on
upon the purpose of the test but, ideally, should be the same as
specimen design, preparation and gripping are equally
those prevailing for the intended use of the metal or compar-
applicable to specimens for slow strain rate tests.
able to the anticipated Service condition. In practice, a number
of Standard environments is used for ranking purposes, but
application of the results obtained for predicting Service
6 Procedure
behaviour depends on an understanding of the System or on
correlation with experience.
6.1 The equipment required for slow strain rate testing is a
device that permits a selection of deflection rates whilst being
6.8 lt is recommended that wherever possible the gripped
powerful enough to cope with the loads generated. Deflection
portions shoul
...
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