SIST ISO 11845:2021
(Main)Corrosion of metals and alloys -- General principles for corrosion testing
Corrosion of metals and alloys -- General principles for corrosion testing
This document specifies general principles for carrying out corrosion tests under conditions of constant immersion. Some of these general principles are applicable to other types of corrosion testing.
This document does not cover important procedures for stress corrosion testing, such as those given in ISO 7539 (all parts).
Corrosion des métaux et alliages -- Principes généraux des essais de corrosion
Korozija kovin in zlitin - Splošna načela preskušanja korozije
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SLOVENSKI STANDARD
SIST ISO 11845:2021
01-julij-2021
Nadomešča:
SIST ISO 11845:1999
Korozija kovin in zlitin - Splošna načela preskušanja korozije
Corrosion of metals and alloys -- General principles for corrosion testing
Corrosion des métaux et alliages -- Principes généraux des essais de corrosion
Ta slovenski standard je istoveten z: ISO 11845:2020
ICS:
77.060 Korozija kovin Corrosion of metals
SIST ISO 11845:2021 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 11845:2021
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SIST ISO 11845:2021
INTERNATIONAL ISO
STANDARD 11845
Second edition
2020-03
Corrosion of metals and alloys —
General principles for corrosion testing
Corrosion des métaux et alliages — Principes généraux des essais de
corrosion
Reference number
ISO 11845:2020(E)
©
ISO 2020
---------------------- Page: 3 ----------------------
SIST ISO 11845:2021
ISO 11845:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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 2020 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 11845:2021
ISO 11845:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General principles . 1
5 Materials . 2
6 Corrosive medium . 3
7 Test procedure . 3
8 Test report . 5
Annex A (informative) General requirements for corrosion tests under constant immersion
for a specific purpose . 7
Bibliography .10
© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 11845:2021
ISO 11845:2020(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.
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 156, Corrosion of metals and alloys.
This second edition cancels and replaces the first edition (ISO 11845:1995), which has been technically
revised. The main changes compared with the previous edition are as follows:
— the format has been changed;
— Annex A has been added with general requirements for corrosion tests under constant immersion.
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.
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 11845:2021
ISO 11845:2020(E)
Introduction
The existence of a wide range of corrosion tests, partly as a function of the various materials and
corrosive media in existence, calls for guidance in the general procedures that should be used. Corrosion
tests, if they are to evaluate and give comparable results, are carried out in accordance with established
conditions. Conditions deviating from these conditions are precisely quoted, taking into account all the
details given in this document. The most relevant results on corrosion behaviour of metals can normally
be obtained from long-term tests under conditions close to those obtained in practice.
© ISO 2020 – All rights reserved v
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SIST ISO 11845:2021
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SIST ISO 11845:2021
INTERNATIONAL STANDARD ISO 11845:2020(E)
Corrosion of metals and alloys — General principles for
corrosion testing
1 Scope
This document specifies general principles for carrying out corrosion tests under conditions of constant
immersion. Some of these general principles are applicable to other types of corrosion testing.
This document does not cover important procedures for stress corrosion testing, such as those given in
ISO 7539 (all parts).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 8044, Corrosion of metals and alloys — Vocabulary
ISO 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 General principles
4.1 Corrosion tests are generally carried out as comparative tests, i.e. a number of materials or corrosive
media are compared under the given test conditions. It is, however, also advisable to include reference
materials or reference solutions in which the behaviour under practical conditions of attack are known.
It is important to have a clear understanding of the objectives of any corrosion testing programme and to
make a judicious choice of the most practical methods in order to evaluate corrosion damage.
4.2 During the tests, the degree of attack as a function of time is observed and, as far as possible,
quantitatively recorded. The objective of most types of testing should be to determine the state of the
specimens on more than three separate occasions apart from the start of the test. The duration of tests
should be such that, on completion of the test, a clear result is obtained concerning the behaviour of
the material and, where applicable, the reference material under the given test conditions. If necessary,
additional tests extending beyond the time originally planned should be required.
4.3 Because results often exhibit considerable scatter, a single value provides little useful information.
For this reason, whenever possible, every test result should be verified by taking the mean of at least
three tests per measurement point. For this purpose, each specimen should be used only once.
© ISO 2020 – All rights reserved 1
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SIST ISO 11845:2021
ISO 11845:2020(E)
4.4 The test conditions should, as far as possible, be matched to the practical conditions under which
the material and the corrosive media will be used, except for short-duration tests as detailed in 4.5. This
applies:
a) to the material, in relation to its shape, surface condition, grain structure, etc., for details see
Clause 5;
b) to the corrosive medium, in relation to concentration, temperatures, etc., for details see Clause 7.
4.5 In the case of short-duration corrosion tests, the object is to achieve usable results in the shortest
possible time by intensifying the attack conditions. However, intensification of the attack conditions, e.g.
by increasing the temperature or concentration of the corrosive medium, often gives results that do not
correspond to behaviour under practical conditions. Care shall therefore be exercised when applying
such results in practice.
4.6 Particular care is necessary when applying the results of accelerated corrosion tests to practical
conditions since, with this type of corrosion test, corrosion media differing from those occurring in
practice are often used.
4.7 For the specific purpose, the material, the corrosive medium, the ratio of solution volume to surface
area, the surface area, the temperature, the agitation, the test duration, the evaluation, and the corrosion
form should be in accordance with the International Standards given in Annex A.
5 Materials
5.1 Test specimens shall be clearly identified. The following information should be given, when
applicable:
a) chemical composition of the material and the appropriate designation, according to the relevant
international, regional or national standards;
b) condition of the material and fabrication details (e.g. presence of welds, sand cast, gravity die
cast, pressure die cast, hot rolled, cold rolled, forged, heat-treatment, whether naturally or
artificially aged);
c) form of material (sheet, wire, tube, solid bars or similar);
d) position and orientation of the specimens in the original material (with a sketch if necessary);
e) dimensions (exact size, shape, area) and mass of specimens;
f) condition of the surface of the material (with or without rolling skin, thickness of rolling skin,
pickled, ground, polished, or other pretreatment);
g) mechanical properties of the material;
h) structure of the material, including any chemical or mechanical pretreatment;
i) protective layers and coatings (type, composition and thickness).
5.2 The method of producing the specimens from the test piece should be documented. Specimens
should preferably be taken from the test piece in such a manner as to exclude the effect of any significant
additional mechanical cold working and any substantial temperature rise at the cut edges during
machining. Any burr at the cut edges produced when the specimen is obtained should be removed. In
general, it is necessary to protect the edges where it is likely that unwanted effects on the corrosion
behaviour of the material being tested should originate at the edges (e.g. in the case of coated specimens).
2 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 11845:2021
ISO 11845:2020(E)
5.3 In the case of corrosion tests under conditions close to those obtained in practice, the surface
condition of the specimens should be the same as that found in practical application.
5.4 In general, specimens should be cleaned and degreased. The choice of suitable cleaning or
degreasing agents depends on the material being tested. Only products that do not alter the surface of
the part being tested should be used. In most cases, organic solvents are used. The cleaning agent used
should be reported.
5.5 If the specimen surface has to be mechanically pretreated, this should preferably be done by
grinding, with each step removing damage from the previous step. The grade of the final abrasive used
should be reported. Machining is preferable to grinding for soft metals.
5.6 Specimens should be clearly marked, for example by stamping with numbers or letters. Since the
mechanical stress resulting from stamping with numbers or
...
INTERNATIONAL ISO
STANDARD 11845
Second edition
2020-03
Corrosion of metals and alloys —
General principles for corrosion testing
Corrosion des métaux et alliages — Principes généraux des essais de
corrosion
Reference number
ISO 11845:2020(E)
©
ISO 2020
---------------------- Page: 1 ----------------------
ISO 11845:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 11845:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General principles . 1
5 Materials . 2
6 Corrosive medium . 3
7 Test procedure . 3
8 Test report . 5
Annex A (informative) General requirements for corrosion tests under constant immersion
for a specific purpose . 7
Bibliography .10
© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 11845:2020(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.
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 156, Corrosion of metals and alloys.
This second edition cancels and replaces the first edition (ISO 11845:1995), which has been technically
revised. The main changes compared with the previous edition are as follows:
— the format has been changed;
— Annex A has been added with general requirements for corrosion tests under constant immersion.
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.
iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 11845:2020(E)
Introduction
The existence of a wide range of corrosion tests, partly as a function of the various materials and
corrosive media in existence, calls for guidance in the general procedures that should be used. Corrosion
tests, if they are to evaluate and give comparable results, are carried out in accordance with established
conditions. Conditions deviating from these conditions are precisely quoted, taking into account all the
details given in this document. The most relevant results on corrosion behaviour of metals can normally
be obtained from long-term tests under conditions close to those obtained in practice.
© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 11845:2020(E)
Corrosion of metals and alloys — General principles for
corrosion testing
1 Scope
This document specifies general principles for carrying out corrosion tests under conditions of constant
immersion. Some of these general principles are applicable to other types of corrosion testing.
This document does not cover important procedures for stress corrosion testing, such as those given in
ISO 7539 (all parts).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 8044, Corrosion of metals and alloys — Vocabulary
ISO 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 General principles
4.1 Corrosion tests are generally carried out as comparative tests, i.e. a number of materials or corrosive
media are compared under the given test conditions. It is, however, also advisable to include reference
materials or reference solutions in which the behaviour under practical conditions of attack are known.
It is important to have a clear understanding of the objectives of any corrosion testing programme and to
make a judicious choice of the most practical methods in order to evaluate corrosion damage.
4.2 During the tests, the degree of attack as a function of time is observed and, as far as possible,
quantitatively recorded. The objective of most types of testing should be to determine the state of the
specimens on more than three separate occasions apart from the start of the test. The duration of tests
should be such that, on completion of the test, a clear result is obtained concerning the behaviour of
the material and, where applicable, the reference material under the given test conditions. If necessary,
additional tests extending beyond the time originally planned should be required.
4.3 Because results often exhibit considerable scatter, a single value provides little useful information.
For this reason, whenever possible, every test result should be verified by taking the mean of at least
three tests per measurement point. For this purpose, each specimen should be used only once.
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 11845:2020(E)
4.4 The test conditions should, as far as possible, be matched to the practical conditions under which
the material and the corrosive media will be used, except for short-duration tests as detailed in 4.5. This
applies:
a) to the material, in relation to its shape, surface condition, grain structure, etc., for details see
Clause 5;
b) to the corrosive medium, in relation to concentration, temperatures, etc., for details see Clause 7.
4.5 In the case of short-duration corrosion tests, the object is to achieve usable results in the shortest
possible time by intensifying the attack conditions. However, intensification of the attack conditions, e.g.
by increasing the temperature or concentration of the corrosive medium, often gives results that do not
correspond to behaviour under practical conditions. Care shall therefore be exercised when applying
such results in practice.
4.6 Particular care is necessary when applying the results of accelerated corrosion tests to practical
conditions since, with this type of corrosion test, corrosion media differing from those occurring in
practice are often used.
4.7 For the specific purpose, the material, the corrosive medium, the ratio of solution volume to surface
area, the surface area, the temperature, the agitation, the test duration, the evaluation, and the corrosion
form should be in accordance with the International Standards given in Annex A.
5 Materials
5.1 Test specimens shall be clearly identified. The following information should be given, when
applicable:
a) chemical composition of the material and the appropriate designation, according to the relevant
international, regional or national standards;
b) condition of the material and fabrication details (e.g. presence of welds, sand cast, gravity die
cast, pressure die cast, hot rolled, cold rolled, forged, heat-treatment, whether naturally or
artificially aged);
c) form of material (sheet, wire, tube, solid bars or similar);
d) position and orientation of the specimens in the original material (with a sketch if necessary);
e) dimensions (exact size, shape, area) and mass of specimens;
f) condition of the surface of the material (with or without rolling skin, thickness of rolling skin,
pickled, ground, polished, or other pretreatment);
g) mechanical properties of the material;
h) structure of the material, including any chemical or mechanical pretreatment;
i) protective layers and coatings (type, composition and thickness).
5.2 The method of producing the specimens from the test piece should be documented. Specimens
should preferably be taken from the test piece in such a manner as to exclude the effect of any significant
additional mechanical cold working and any substantial temperature rise at the cut edges during
machining. Any burr at the cut edges produced when the specimen is obtained should be removed. In
general, it is necessary to protect the edges where it is likely that unwanted effects on the corrosion
behaviour of the material being tested should originate at the edges (e.g. in the case of coated specimens).
2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 11845:2020(E)
5.3 In the case of corrosion tests under conditions close to those obtained in practice, the surface
condition of the specimens should be the same as that found in practical application.
5.4 In general, specimens should be cleaned and degreased. The choice of suitable cleaning or
degreasing agents depends on the material being tested. Only products that do not alter the surface of
the part being tested should be used. In most cases, organic solvents are used. The cleaning agent used
should be reported.
5.5 If the specimen surface has to be mechanically pretreated, this should preferably be done by
grinding, with each step removing damage from the previous step. The grade of the final abrasive used
should be reported. Machining is preferable to grinding for soft metals.
5.6 Specimens should be clearly marked, for example by stamping with numbers or letters. Since the
mechanical stress resulting from stamping with numbers or letters can initiate local corrosion, in the
case of particularly sensitive materials, and under defined test conditions, it is desirable to use a method
of marking which does not involve any cold working, e.g. electro-mechanical marking or notching of
specimens. It should be necessary to carry out heat treatment of the specimen after marking.
6 Corrosive medium
6.1 The corrosive medium shall be clearly described. In particular, the origin, composit
...
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