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

General Information

Status
Published
Publication Date
08-Jun-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
02-Jun-2021
Due Date
07-Aug-2021
Completion Date
09-Jun-2021

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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.

---------------------- Page: 1 ----------------------
SIST ISO 11845:2021
---------------------- Page: 2 ----------------------
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
---------------------- Page: 7 ----------------------
SIST ISO 11845:2021
---------------------- Page: 8 ----------------------
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
---------------------- Page: 9 ----------------------
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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