SIST EN ISO 6252:2000
(Main)Plastics - Determination of environmental stress cracking (ESC) - Constant-tensile-stress method (ISO 6252:1992)
Plastics - Determination of environmental stress cracking (ESC) - Constant-tensile-stress method (ISO 6252:1992)
Kunststoffe - Bestimmung der umgebungsbedingten Spannungsrißbildung (ESC) - Zeitstandzugversuch (ISO 6252:1992)
Diese Internationale Norm legt Verfahren fest zum Bestimmen der medienunterstützten Spannungsrißbildung (ESC) von Kunststoffen, indem diese einem Zeitstandzugversuch in Gegenwart von Medien unterworfen werden. Probekörper können durch Formgebung sowie durch mechanisches Bearbeiten hergestellt werden.
Plastiques - Détermination de la fissuration sous contrainte dans un environnement donné (ESC) - Méthode sous contrainte de traction constante (ISO 6252:1992)
Polimerni materiali - Ugotavljanje napetostne korozije (ESC) - Metoda konstantne natezne obremenitve (ISO 6252:1992)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 6252:2000
01-maj-2000
Polimerni materiali - Ugotavljanje napetostne korozije (ESC) - Metoda konstantne
natezne obremenitve (ISO 6252:1992)
Plastics - Determination of environmental stress cracking (ESC) - Constant-tensile-stress
method (ISO 6252:1992)
Kunststoffe - Bestimmung der umgebungsbedingten Spannungsrißbildung (ESC) -
Zeitstandzugversuch (ISO 6252:1992)
Plastiques - Détermination de la fissuration sous contrainte dans un environnement
donné (ESC) - Méthode sous contrainte de traction constante (ISO 6252:1992)
Ta slovenski standard je istoveten z: EN ISO 6252:1997
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 6252:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
INTERNATIONAL
STANDARD
Second edition
1992-08-l 5
Plastics - Determination of environmental
stress cracking (ESC) - Constant-tensile-stress
method
Plastiques
- D&termination de la fissuration sous contrainte dans un
environnement don& (ESC) - MHhode sow contrainte de traction
constanie
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~- --
-- --
Reference number
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- - ------.---__
_ - _. ~_ _ _ _ fS0 6252: 1992(E)
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SIST EN ISO 6252:2000
IS0 6252:1992(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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, govern-
mental and non-governmental, in liaison with ISO, also take part in the
work. IS0 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 voting. Publication as an Inter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard IS0 6252 was prepared by Technical Committee
ISO/TC 61, Plastics, Sub-Committee SC 6, Ageing, chemical and en-
vironmental resistance.
This second edition cancels and replaces the first edition
(IS0 6252:1981), which has been revised to include a third method
(method C).
Annex A of this International Standard is for information only.
0 IS0 1992
All rights reserved. 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 the publisher.
International Organization for Standardization
Case Postale 56 l Cl-l-121 1 Geneve 20 l Switzerland
Yinted in Switzerland
i
ii
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SIST EN ISO 6252:2000
IS0 6252:1992(E)
Introduction
Environmental stress cracking is exhibited by many materials, including
plastics. When a plastic material is stressed or strained in air below its
yield point, stress cracking can occur after a period of time, which may
be very long. These stresses may be internal or external, or a combi-
nation of both. Exposure to a chemical environment simultaneously with
the same stress or strain may result in a dramatic shortening of the time
to failure. This phenomenon is referred to as environmental stress
cracking (ESC). The permissible long-term stress or strain may be re-
duced considerably by this phenomenon.
The cracks produced may penetrate completely through the thickness
of the material, separating it into two or more pieces, or they may be
arrested on reaching regions of lower stress or different material
morphology.
The determination of ESC is complex because it is influenced by many
parameters, including:
- test specimen dimensions;
-
test specimen state (orientation, structure, internal stresses);
-
stress and strain;
- temperature of test;
- duration of test;
-
chemical environment:
- test method;
- failure criterion.
By keeping all but one parameter constant, the influence of the variable
parameter on ESC can be assessed. The main objective of ESC
measurements is to determine the effect of chemical media (environ-
ment) on plastics (test specimens and articles). The measurements may
also be used to evaluate the influence of the moulding conditions upon
the quality of an article when the failure mode corresponds to that ob-
tained in actual service. It may not be possible, however, to establish
any direct correlation between the results of short-duration ESC
measurements on test specimens and the actual service behaviour of
articles, because the behaviour of the latter is likely to be more complex
than that of test specimens.
. . .
Ill
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SIST EN ISO 6252:2000
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SIST EN ISO 6252:2000
IS0 6252:1992(E)
INTERNATIONAL STANDARD
Plastics - Determination of environmental stress cracking
- Constant-tensile-stress method
0
ISO/R 527: 1966, Plastics - Determination of tensile
1 Scope
properties.
This International Standard specifies methods for
IS0 899:1981, Plastics - Determination of tensile
the determination of environmental stress cracking
creep.
(ESC) of plastics when they are subjected to a con-
stant tensile force in the presence of chemical
IS0 2557-1:1989, Plastics - Amorphous thermoplas-
agents.
tics - Preparation of test specimens with a specified
maximum reversion - Part I: Bars.
It is applicable to test specimens prepared by
moulding and/or machining and can be used both
IS0 2818: 1980, Plastics - Preparation of test speci-
for the assessment of ESC of plastics materials ex-
mens by machining.
posed to different environments, and for the deter-
mination of ESC of different plastics materials
IS0 3167:1983, Plastics - Preparation and use of
exposed to a specific environment.
multipurpose test specimens.
NOTE 1 Methods for the determination of en-
vironmental stress cracking by means of a constant-strain
IS0 4599: 1986, Plastics - Detern7ination of resist-
test are specified in IS0 4599 and IS0 4600.
ance to environmental stress cracking (ESC) - Bent
strip method.
IS0 4600: 1992, Plastics - Determination of en-
2 Normative references
vironmental stress cracking (ESC) - Ball or pin im-
pression method.
The following standards contain provisions which,
through reference in this text, constitute provisions
of this International Standard. At the time of publi-
3 Principle
cation, the editions indicated were valid. All stan-
dards are subject to (revision, and parties to
A test specimen is subjected to a constant tensile
agrleements based on this International Standard
force, corresponding to a stress lower than that at
are encouraged to investigate the possibility of ap-
yield, while immersed in a specified environment at
plying the most recent editions of the standards in-
the temperature selected for testing. The time
dicated below. Members of IEC and IS0 maintain
and/or stress at which the specimen breaks is re-
registers of currently valid International Standards.
corded.
The environmental stress cracking of the test speci-
IS0 150:1980, Raw, refined and boiled linseed oil for
paints and varnishes - Specifications and methods mens is determined by one of the following methods
of test. (A, B or C), depending upon the time to rupture:
IS0 291: 1977, Plastics -- Standard atmospheres for - Method A: Determination of the tensile stress
conditioning and testing. leading to rupture at 100 h. This stress is ob-
tained by interpolation of the graph of time to
- Compression moulding test rupture versus applied tensile stress.
IS0 293: 1986, Plastics
specimens of thermoplastic materials.
- Method B: Determination of the time to rupture
under a specified tensile stress. This method is
IS0 294:1975, Plastics - Injection moulding test
used when the time to rupture exceeds 100 h.
specimens of thermoplastic materials.
1
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SIST EN ISO 6252:2000
IS0 6252:1992(E)
- Method C: Determination of the tensile stress
either the agent which will be in contact with the
versus time to rupture curve up to an agreed material in the expected application or a reference
time. product agreed upon between the interested parties.
NOTE 2 If creep measurements are desired, the method NOTE 3 Examples of reference products are:
outlined in IS0 899 is followed.
a) 95 O/o ( r/l v) ethanol - pharmaceutical quality;
4 Apparatus
b) a 1 % (m/m) solution of nonylphenoxy-poly(ethylene-
oxy)ethanoll) in distilled water;
4.1 Testing, device, allowing test specimens to be
submitted simultaneously to a tensile stress and to
c) refined linseed oil (see IS0 150).
the chemical environment.
6 Conditioning and test conditions
If the chemical is a liquid at the test temperature, the
test specimen shall be completely immersed in it. If
it is highly viscous at the test temperature, the
6.1 Conditioning
specimens may be covered with a coating of the
agent at least 2 mm thick (see clause 5).
Unless otherwise agreed between the interested
parties, the test specimens shall be conditioned be-
The parts of the device that come into contact with
fore testing for at least 24 h at (23 + 2) “C and
the chemical shall be made of an inert material, for
.
(50 + 5) O/o relative humidity (see IS0 291).
example stainless steel.
6.2 Test temperature
The constant tensile stress may be applied with
weights (figures 1 and 2 are schematic diagrams of
The preferred test temperatures are (23 + 1) “C and
suitable apparatus). The force shall be accurate to
(55 + 0,5) “C. If required, other temper%ures may
+ 1 O/o. Care shall be taken to ensure that there is
be used, preferably selected from the following:
no loss of stress in the system, for example by fric-
tion.
(40 + 0,5) “C
If the testing device has several test stations, means
shall be provided to prevent the vibration occurring
(70 + 0,5) “C
through failure at one station from being transmitted
to the whole system.
(85 + 0,s) “C
Care shall be taken that the specimens are sub-
(100 + 0,5) “C
-
jected only to forces parallel to their longitudinal
axis, and not to bending or twisting forces.
or as agreed upon by the interested parties.
4.2 Temperature-controlled bath or room, allowing
7 Test stress
the test system to be maintained at (23 + 1) “C or
at a higher test temperature up to 105 “Cto within
...
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