Corrosion of metals and alloys - Removal of corrosion products from corrosion test specimens (ISO 8407:2021)

This document specifies procedures for the removal of corrosion products formed on metal and alloy corrosion test specimens during their exposure in corrosive environments. For the purpose of this document, the term “metals” refers to pure metals and alloys.
The specified procedures are designed to remove all corrosion products without significant removal of base metal. This allows an accurate determination of the mass loss of the metal, which occurred during exposure to the corrosive environment.
In some cases, these procedures are also applicable to metal coatings, providing the possible effects from the substrate are considered.

Korrosion von Metallen und Legierungen - Entfernen von Korrosionsprodukten von Korrosionsprobekörpern (ISO 8407:2021)

Dieses Dokument legt Verfahren für das Entfernen von Korrosionsprodukten fest, die sich während der Auslagerung von Korrosionsprüfkörpern aus Metallen und Legierungen in korrosiven Umgebungen gebildet haben. In diesem Dokument bezieht sich der Begriff „Metalle“ auf reine Metalle und Legierungen.
Die aufgeführten Verfahren wurden entwickelt, um alle Korrosionsprodukte zu entfernen, ohne das Grundmetall signifikant zu entfernen. Dadurch ist eine genaue Bestimmung des Massenverlustes des Metalls möglich, der während der Auslagerung in korrosiver Umgebung stattfindet.
Diese Verfahren sind in einigen Fällen auch bei metallenen Überzügen anwendbar, vorausgesetzt, dass die möglichen Wechselwirkungen mit dem Substrat berücksichtigt werden.
WARNUNG - Sicherheitsvorschriften für Personal: Die beim Entfernen von Korrosionsprodukten verwendeten Lösungen dürfen nur von erfahrenem Personal gehandhabt werden oder müssen unter deren Kontrolle verwendet werden. Die Geräte müssen von erfahrenem Personal verwendet und gewartet werden, nicht nur, damit die Reinigungsverfahren ordnungsgemäß durchgeführt werden können, sondern auch wegen der damit verbundenen Gefährdungen für Gesundheit und Sicherheit.

Corrosion des métaux et alliages - Élimination des produits de corrosion sur les éprouvettes d'essai de corrosion (ISO 8407:2021)

Le présent document spécifie des méthodes permettant d'éliminer les produits de corrosion qui se sont formés sur des éprouvettes en métal ou en alliage au cours de leur exposition en milieu corrosif. Pour les besoins du présent document, le terme «métaux» couvre à la fois les métaux purs et les alliages.
Les méthodes spécifiées sont conçues pour éliminer tous les produits de corrosion sans élimination significative de métal sous-jacent. Elles permettent une détermination précise de la perte de masse du métal qui se produit pendant son exposition en milieu corrosif.
Dans certains cas, ces méthodes sont également applicables aux revêtements métalliques, à condition de prendre en considération les effets possibles du substrat.

Korozija kovin in zlitin - Odstranjevanje produktov korozije s preskusnih vzorcev (ISO 8407:2021)

General Information

Status
Published
Public Enquiry End Date
19-Mar-2020
Publication Date
11-Feb-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Feb-2021
Due Date
10-Apr-2021
Completion Date
12-Feb-2021

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SLOVENSKI STANDARD
SIST EN ISO 8407:2021
01-marec-2021
Nadomešča:
SIST EN ISO 8407:2014
Korozija kovin in zlitin - Odstranjevanje produktov korozije s preskusnih vzorcev
(ISO 8407:2021)
Corrosion of metals and alloys - Removal of corrosion products from corrosion test
specimens (ISO 8407:2021)
Korrosion von Metallen und Legierungen - Entfernen von Korrosionsprodukten von
Korrosionsprobekörpern (ISO 8407:2021)
Corrosion des métaux et alliages - Élimination des produits de corrosion sur les
éprouvettes d'essai de corrosion (ISO 8407:2021)
Ta slovenski standard je istoveten z: EN ISO 8407:2021
ICS:
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 8407:2021 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 8407:2021

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SIST EN ISO 8407:2021


EN ISO 8407
EUROPEAN STANDARD

NORME EUROPÉENNE

January 2021
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 8407:2014
English Version

Corrosion of metals and alloys - Removal of corrosion
products from corrosion test specimens (ISO 8407:2021)
Corrosion des métaux et alliages - Élimination des Korrosion von Metallen und Legierungen - Entfernen
produits de corrosion sur les éprouvettes d'essai de von Korrosionsprodukten von
corrosion (ISO 8407:2021) Korrosionsprobekörpern (ISO 8407:2021)
This European Standard was approved by CEN on 19 December 2020.

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 CEN-CENELEC Management Centre 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 under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8407:2021 E
worldwide for CEN national Members.

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SIST EN ISO 8407:2021
EN ISO 8407:2021 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST EN ISO 8407:2021
EN ISO 8407:2021 (E)
European foreword
This document (EN ISO 8407:2021) has been prepared by Technical Committee ISO/TC 156 "Corrosion
of metals and alloys" in collaboration with Technical Committee CEN/TC 262 “Metallic and other
inorganic coatings, including for corrosion protection and corrosion testing of metals and alloys” the
secretariat of which is held by BSI.
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 July 2021, and conflicting national standards shall be
withdrawn at the latest by July 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8407:2014.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8407:2021 has been approved by CEN as EN ISO 8407:2021 without any modification.

3

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SIST EN ISO 8407:2021

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SIST EN ISO 8407:2021
INTERNATIONAL ISO
STANDARD 8407
Third edition
2021-01
Corrosion of metals and alloys —
Removal of corrosion products from
corrosion test specimens
Corrosion des métaux et alliages — Élimination des produits de
corrosion sur les éprouvettes d'essai de corrosion
Reference number
ISO 8407:2021(E)
©
ISO 2021

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SIST EN ISO 8407:2021
ISO 8407:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 8407:2021
ISO 8407:2021(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Procedures . 1
4.1 General . 1
4.2 Chemical procedures . 3
4.3 Electrolytic procedures . 3
4.4 Mechanical procedures . 3
5 Test report . 4
Annex A (informative) Chemical and electrolytic cleaning procedures for removal of
corrosion products . 5
Bibliography .11
© ISO 2021 – All rights reserved iii

---------------------- Page: 9 ----------------------
SIST EN ISO 8407:2021
ISO 8407:2021(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, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
TC 262, Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of
metals and alloys, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 8407:2009), which has been technically
revised. The main changes compared with the previous edition are as follows:
— Table A.1 has been revised to include current chemical cleaning procedures for the removal of
corrosion products.
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 2021 – All rights reserved

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SIST EN ISO 8407:2021
INTERNATIONAL STANDARD ISO 8407:2021(E)
Corrosion of metals and alloys — Removal of corrosion
products from corrosion test specimens
WARNING — Safety rules for personnel: handling of the solutions used for the removal of
corrosion products shall be left to skilled personnel or conducted under their control. The
equipment shall be used and maintained by skilled personnel, not only so that the procedures
can be performed correctly, but also because of the hazards to health and safety that are
involved.
1 Scope
This document specifies procedures for the removal of corrosion products formed on metal and alloy
corrosion test specimens during their exposure in corrosive environments. For the purpose of this
document, the term “metals” refers to pure metals and alloys.
The specified procedures are designed to remove all corrosion products without significant removal of
base metal. This allows an accurate determination of the mass loss of the metal, which occurred during
exposure to the corrosive environment.
In some cases, these procedures are also applicable to metal coatings, providing the possible effects
from the substrate are considered.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
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 Procedures
4.1 General
4.1.1 A light mechanical cleaning treatment by brushing, e.g. a soft bristle brush under running water,
should first be applied to remove lightly adherent or bulky corrosion products.
4.1.2 If the treatment described in 4.1.1 does not remove all corrosion products, it will be necessary to
use other procedures. These are of three types:
a) chemical;
b) electrolytic;
c) more vigorous mechanical treatments.
NOTE These treatments will also remove some base metal.
© ISO 2021 – All rights reserved 1

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SIST EN ISO 8407:2021
ISO 8407:2021(E)

Whichever method is used, it might be necessary to repeat the cleaning treatment to ensure complete
removal of the corrosion products. Removal shall be confirmed by visual examination. The use of a low-
power microscope (i.e. × 7 to × 30) is particularly helpful with a pitted surface since corrosion products
can accumulate in pits.
4.1.3 An ideal procedure should remove corrosion products and not result in the removal of any
base metal. Two procedures can be used to confirm this point. One procedure uses a control specimen
(see 4.1.4) and the other requires a certain number of cleaning cycles on the corroded specimen (see
4.1.5). The procedures shall be maintained while the rust removal performance of the solutions listed in
Tables A.1 and A.2 is not impaired.
NOTE 1 Indications that the solution needs to be discarded can be discoloration or the presence of a significant
amount of corrosion products in the solution.
NOTE 2 Some solutions might need some aging before working without etching the substrate.
4.1.4 Uncorroded control specimens, which should be similar chemically, metallurgically and
geometrically to the test specimens, should be cleaned by the same procedure as used for the test
specimen. By weighing the control specimen before and after cleaning (weighing to the fifth significant
figure is suggested, e.g. a 70 g specimen should be weighed to three decimal places), the metal loss
resulting from cleaning may be determined. The mass loss of the control specimen will reflect the mass
loss of test specimens resulting from the cleaning procedure.
4.1.5 The cleaning of each corroded test specimen should be repeated several times after the removal
of the corrosion products is completed. The mass shall be plotted as a function of the periods of
cleaning cycles with the same interval time or time units (see Figure 1). Point A represents the mass of
corroded specimens before the start of the cleaning. In many cases, two straight lines, AB and BC, will
be obtained. Line AB characterizes the removal of corrosion products and may not always be visible.
Line BC characterizes the removal of the substrate after the corrosion products are completely removed.
Point D, which characterizes the mass of the pure metal at zero number of cleaning cycles, is obtained by
extrapolation of line BC to the ordinate axis. In some cases, the relationship may not be linear, and the
most appropriate extrapolation shall then be made. If the relationship of B and C is not linear, a linear
regression method, e.g. by applying the least squares from later points of cleaning cycles, can be used for
estimation of the point for the D value.
If the durations of each cleaning step are not equal, the x-axis should be expressed in units of cumulative
exposure time in the cleaning solution, rather than the number of cleaning steps used up to that point.
Key
X numbers of cleaning cycles or time units
Y mass
Figure 1 — Mass of corroded specimens after repetitive cleaning cycles
2 © ISO 2021 – All rights reserved

---------------------- Page: 12 ----------------------
SIST EN ISO 8407:2021
ISO 8407:2021(E)

NOTE The number of points needed to establish the line BC is sometimes less than indicated in the figure for
the specific case, especially if there is significant experience for the pickled material and solution.
4.1.6 The true mass of the specimen, after removal of the corrosion products, will be a value between
the masses represented by the points B and D, depending on the degree of protection provided by the
corrosion products during the cleaning procedure.
4.1.7 The preferred cleaning method will be one that:
a) provides efficient removal of corrosion products;
b) provides low or zero mass loss when applied to new uncorroded specimens (see 4.1.4);
c) provides a curve of mass as a function of the number of cleaning cycles or time of pickling, which is
close to horizontal when the latter is plotted as the abscissa (see 4.1.5).
4.1.8 When chemical or electrolytic procedures are used, solutions freshly prepared with distilled or
deionized water and reagent grade chemicals shall be used.
4.1.9 After cleaning, the specimen should be thoroughly rinsed with tap water. A light brushing during
this procedure will help to remove any remaining surface products resulting from the cleaning process.
Finally, the specimens shall be rinsed with distilled or deionized water. The specimen shall then be rinsed
thoroughly in ethanol and dried in air. Drying in an air stream is strongly recommended, or optionally a
hot air blower or an oven may be used. After drying, the specimens shall be allowed to cool in a dessicator
to the balance room temperature before weighing.
4.2 Chemical procedures
4.2.1 Chemical procedures involve the immersion of the corroded test specimen in a chemical solution
that is specifically designed to remove the corrosion products with minimal dissolution of any base
metal. Several procedures are listed in Annex A (see Table A.1). To facilitate the cleaning, an ultrasonic
bath treatment should be used.
4.2.2 Chemical cleaning is often preceded by a light brushing of the test specimen to remove lightly
adherent, bulky corrosion products.
4.2.3 Before the chemical treatment, clean the specimens as described in 4.1.1. In connection with
the intermittent removal of specimens for weighing, brush the specimens, if necessary, to facilitate the
removal of tightly adherent corrosion products.
4.3 Electrolytic procedures
Electrolytic cleaning can also be used to remove corrosion products. Several methods of electrolytic
cleaning of corrosion test specimens are given in Annex A (see Table A.2). To facilitate the cleaning, an
ultrasonic bath treatment should be used.
Brushing should follow electrolytic cleaning to remove any loose deposits. This will help to minimize
any redeposition of metal from reducible corrosion products in solution that would reduce the
measured mass loss.
4.4 Mechanical procedures
Mechanical procedures
...

SLOVENSKI STANDARD
oSIST prEN ISO 8407:2020
01-marec-2020
Korozija kovin in zlitin - Odstranjevanje produktov korozije s preskusnih vzorcev
(ISO/DIS 8407:2020)
Corrosion of metals and alloys - Removal of corrosion products from corrosion test
specimens (ISO/DIS 8407:2020)
Korrosion von Metallen und Legierungen - Entfernen von Korrosionsprodukten von
Korrosionsprobekörpern (ISO/DIS 8407:2020)
Corrosion des métaux et alliages - Élimination des produits de corrosion sur les
éprouvettes d'essai de corrosion (ISO/DIS 8407:2020)
Ta slovenski standard je istoveten z: prEN ISO 8407
ICS:
77.060 Korozija kovin Corrosion of metals
oSIST prEN ISO 8407:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 8407:2020

---------------------- Page: 2 ----------------------
oSIST prEN ISO 8407:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8407
ISO/TC 156 Secretariat: SAC
Voting begins on: Voting terminates on:
2020-01-13 2020-04-06
Corrosion of metals and alloys — Removal of corrosion
products from corrosion test specimens
Corrosion des métaux et alliages — Élimination des produits de corrosion sur les éprouvettes d'essai de
corrosion
ICS: 77.060
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 8407:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020

---------------------- Page: 3 ----------------------
oSIST prEN ISO 8407:2020
ISO/DIS 8407:2020(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 ----------------------
oSIST prEN ISO 8407:2020
ISO/DIS 8407:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Procedures . 1
4.1 General . 1
4.2 Chemical procedures . 3
4.3 Electrolytic procedures . 4
4.4 Mechanical procedures . 4
5 Test report . 4
Annex A (informative) Chemical and electrolytic cleaning procedures for removal of
corrosion products . 5
© ISO 2020 – All rights reserved iii

---------------------- Page: 5 ----------------------
oSIST prEN ISO 8407:2020
ISO/DIS 8407:2020(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 on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys., WG 6,
General principles of testing and data interpretation.
This third edition cancels and replaces the second edition (ISO 8407:2009), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Annex A
A list of all parts in the ISO 8407:2009 series can be found on the ISO website.
iv © ISO 2020 – All rights reserved

---------------------- Page: 6 ----------------------
oSIST prEN ISO 8407:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 8407:2020(E)
Corrosion of metals and alloys — Removal of corrosion
products from corrosion test specimens
WARNING — Safety rules for personnel: handling of the solutions used for removal of corrosion
products must be left to skilled personnel or conducted under their control. The equipment must
be used and maintained by skilled personnel, not only so that the procedures can be performed
correctly, but also because of the hazards to health and safety that are involved.
1 Scope
This document specifies procedures for the removal of corrosion products formed on metal and alloy
corrosion test specimens during their exposure in corrosive environments. For the purpose of this
document, the term "metals" refers to pure metals and alloys.
The specified procedures are designed to remove all corrosion products without significant removal of
base metal. This allows an accurate determination of the mass loss of the metal, which occurred during
exposure to the corrosive environment.
These procedures may, in some cases, also be applied to metal coatings. However, possible effects from
the substrate must be considered.
NOTE If a significant portion of the substrate is visible after the pickling procedure is completed, the results
will be unreliable.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Procedures
4.1 General
4.1.1 A light mechanical cleaning treatment by brushing with a soft bristle brush under running water
should first be applied to remove lightly adherent or bulky corrosion products.
4.1.2 If the treatment described in 4.1.1 does not remove all corrosion products, it will be necessary to
use other procedures. These are of three types:
a) chemical;
b) electrolytic;
c) more vigorous mechanical treatments.
© ISO 2020 – All rights reserved 1

---------------------- Page: 7 ----------------------
oSIST prEN ISO 8407:2020
ISO/DIS 8407:2020(E)

NOTE These treatments will also remove some base metal.
Whichever method is used, it might be necessary to repeat the cleaning treatment to ensure complete
removal of the corrosion products. Removal shall be confirmed by visual examination. The use of a low-
power microscope (i.e. x7 to x30) is particularly helpful with a pitted surface since corrosion products
may accumulate in pits.
4.1.3 An ideal procedure should remove corrosion products and not result in removal of any base
metal. Two procedures can be used to confirm this point. One procedure uses a control specimen
(4.1.3.1) and the other requires a certain number of cleaning cycles on the corroded specimen (4.1.3.2).
The procedures shall be maintained during the entire service life of the cleaning solutions listed in Tables
A.1 and A.2.
NOTE 1 Indications that the solution needs to be discarded can be discoloration or significant amount of
corrosion products in the solution.
NOTE 2 Some solutions might need some “running in” before working without etching the substrate.
4.1.3.1 Uncorroded control specimens, which should be similar chemically, metallurgically, and
geometrically to the test specimens, should be cleaned by the same procedure as used for the test
specimen. By weighing the control specimen before and after cleaning (weighing to the fifth significant
figure is suggested, e.g. a 70 g specimen should be weighed to three decimal places), the metal loss
resulting from cleaning may be determined. The mass loss of the control specimen will reflect the mass
loss of test specimens resulting from the cleaning procedure.
4.1.3.2 The cleaning of each corroded test specimen should be repeated several times after the removal
of the corrosion products is completed. The mass shall be plotted as a function of the number of equal
cleaning cycles (see Figure 1). Point A represents the mass of corroded specimens before the start of the
cleaning. In many cases two straight lines, AB and BC, will be obtained. Line AB characterizes the removal
of corrosion products and may not always be visible. Line BC characterizes the removal of substrate after
the corrosion products are gone. Point D, which characterizes the mass of the pure metal at zero number
of cleaning cycles, is obtained by extrapolation of line BC to the ordinate axis. In some cases, the relation
may not be linear and the most appropriate extrapolation shall then be made.
If no intervals of equal cleaning cycles are used during one cleaning procedure, the x-axis should be
expressed in time units.
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ISO/DIS 8407:2020(E)

Key
X numbers of cleaning cycles or time units
Y mass
Figure 1 — Mass of corroded specimens after repetitive cleaning cycles
NOTE The number of points needed to establish the line BC can be less than indicated in the figure for the
specific case, especially if there is significant experience for the pickled material and solution.
4.1.3.3 The true mass of the specimen, after removal of the corrosion products, will be a value between
the masses represented by the points B and D, depending on the degree of protection furnished by the
corrosion products during the cleaning procedure. If the relation from B to C is not linear, the point D
should be obtained by a mathematical formula such as a least square method from reliable last points of
cleaning cycles
4.1.4 The preferred cleaning method will be that which
a) provides efficient removal of corrosion products,
b) provides low or zero mass loss when applied to new uncorroded specimens (see 4.1.3.1), and
c) provides a curve of mass as a function of the number of cleaning cycles or time of pickling, which is
close to horizontal when the latter is plotted as the abscissa (see 4.1.3.2).
4.1.5 When chemical or electrolytic procedures are used, solutions freshly prepared with distilled or
deionized water and reagent grade chemicals shall be used.
4.1.6 After cleaning, the specimen should be thoroughly rinsed with tap water, a light brushing during
this procedure will help to remove any remaining surface products resulting from the cleaning process.
Finally, the specimens shall be rinsed with distilled or deionized water. The specimen shall then be rinsed
thoroughly in ethanol and dried using a hot air blower or an oven. After that, the specimens shall be
allowed to cool in a dessicator to the balance room temperature before weighing.
4.2 Chemical procedures
4.2.1 Chemical procedures involve immersion of the corrosion test specimen in a chemical solution
which is specifically designed to remove the corrosion products with minimal dissolution of any base
metal. Several procedures are listed in Annex A (see Table A.1). To facilitate the cleaning, it is strongly
recommended to use an ultrasonic bath treatment.
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oSIST prEN ISO 8407:2020
ISO/DIS 8407:2020(E)

4.2.2 Chemical cleaning is often preceded by light brushing of the test specimen to remove lightly
adherent, bulky corrosion products.
4.2.3 Before the chemical treatment, clean the specimens as described in 4.1.1. In connection with
the intermittent removal of specimens for weighing, brush the specimens, if necessary, to facilitate the
removal of tightly adherent corrosion products.
4.3 Electrolytic procedures
Electrolytic cleaning can also be used to remove corrosion products. Several methods of electrolytic
cleaning of corrosion test specimens are given in Annex A (see Table A.2). To facilitate the cleaning, it is
strongly recommended to use an ultrasonic bath treatment.
Electrolytic cleaning should be preceded by light brushing of the test specimen to remove lightly
adherent, bulky corrosion products. Brushing should also follow electrolytic cleaning to remove any
loose slime or deposits. This will help to minimize
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