EN ISO 11463:2020
(Main)Corrosion of metals and alloys - Guidelines for the evaluation of pitting corrosion (ISO 11463:2020)
Corrosion of metals and alloys - Guidelines for the evaluation of pitting corrosion (ISO 11463:2020)
This document gives guidelines for the selection of procedures that can be used in the identification and examination of corrosion pits and in the evaluation of pitting corrosion and pit growth rate.
Korrosion von Metallen und Legierungen - Richtlinien für die Bewertung der Lochkorrosion (ISO 11463:2020)
Dieses Dokument liefert einen Leitfaden für die Auswahl von Verfahren, die zum Nachweis und zur Untersuchung von Lochkorrosion und zur Bewertung von Lochkorrosion und Lochwachstumsgeschwindigkeit angewendet werden können.
Corrosion des métaux et alliages - Lignes directrices pour l’évaluation de la corrosion par piqûres (ISO 11463:2020)
Le présent document fournit des lignes directrices concernant la sélection de modes opératoires pouvant être utilisés dans l'identification et l'examen de piqûres de corrosion ainsi que dans l'évaluation de la corrosion par piqûres et de la vitesse de propagation de piqûre.
Korozija kovin in zlitin - Smernice za vrednotenje jamičaste korozije (ISO 11463:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2020
Nadomešča:
SIST EN ISO 11463:2008
Korozija kovin in zlitin - Smernice za vrednotenje jamičaste korozije (ISO
11463:2020)
Corrosion of metals and alloys - Guidelines for the evaluation of pitting corrosion (ISO
11463:2020)
Korrosion von Metallen und Legierungen - Richtlinien für die Bewertung der
Lochkorrosion (ISO 11463:2020)
Corrosion des métaux et alliages - Lignes directrices pour l’évaluation de la corrosion par
piqûres (ISO 11463:2020)
Ta slovenski standard je istoveten z: EN ISO 11463:2020
ICS:
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 11463
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2020
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 11463:2008
English Version
Corrosion of metals and alloys - Guidelines for the
evaluation of pitting corrosion (ISO 11463:2020)
Corrosion des métaux et alliages - Lignes directrices Korrosion von Metallen und Legierungen - Richtlinien
pour l'évaluation de la corrosion par piqûres (ISO für die Bewertung der Lochkorrosion (ISO
11463:2020) 11463:2020)
This European Standard was approved by CEN on 9 August 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,
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United Kingdom.
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© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11463:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 11463:2020) 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 March 2021, and conflicting national standards shall
be withdrawn at the latest by March 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 11463:2008.
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 11463:2020 has been approved by CEN as EN ISO 11463:2020 without any modification.
INTERNATIONAL ISO
STANDARD 11463
Second edition
2020-08
Corrosion of metals and alloys —
Guidelines for the evaluation of pitting
corrosion
Corrosion des métaux et alliages — Lignes directrices pour
l’évaluation de la corrosion par piqûres
Reference number
ISO 11463:2020(E)
©
ISO 2020
ISO 11463:2020(E)
© 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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
ISO 11463:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Identification and examination of pits . 1
4.1 Preliminary low magnification visual inspection . 1
4.2 Optical microscopic examination of pit size and shape . 1
4.3 In situ non-destructive inspection . 3
4.3.1 General. 3
4.3.2 Radiographic . 3
4.3.3 Electromagnetic . 3
4.3.4 Ultrasonics. 3
4.3.5 Penetrants . . 3
4.3.6 Replication . 4
4.4 Ex situ examination techniques . 4
4.4.1 General. 4
4.4.2 Scanning electron microscopy . 4
4.4.3 X-ray computed tomography . 4
4.4.4 Image analysis . 4
4.4.5 Profilometry . 4
5 Extent of pitting . 5
5.1 Mass loss . 5
5.2 Pit depth measurement . 5
5.2.1 Metallography . 5
5.2.2 Machining . 5
5.2.3 Micrometer or depth gauge . 6
5.2.4 Microscopy . 6
6 Evaluation of pitting . 6
6.1 General . 6
6.2 Standard charts . 7
6.3 Metal penetration . 9
6.4 Statistical . 9
7 Test report .10
8 Additional information .11
Bibliography .12
ISO 11463:2020(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, 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 second edition cancels and replaces the first edition (ISO 11463:1995), which has been technically
revised. The main changes compared with the previous edition are as follows:
— modern surface analysis and characterization techniques for ex situ examination have been
included.
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
ISO 11463:2020(E)
Introduction
It is important to be able to determine the extent of pitting and its characteristics, either in a service
application, where it is necessary to estimate the remaining life in a metal structure, or in laboratory
test programmes that are used to select pitting-resistant materials for a particular service. Corrosion
pits can also act as the precursor to other damage modes such as stress corrosion cracking and
corrosion fatigue.
The application of the materials to be tested will determine the minimum pit size to be evaluated and
whether total area covered, average pit depth, maximum pit depth or another criterion is the most
important to measure.
INTERNATIONAL STANDARD ISO 11463:2020(E)
Corrosion of metals and alloys — Guidelines for the
evaluation of pitting corrosion
1 Scope
This document gives guidelines for the selection of procedures that can be used in the identification
and examination of corrosion pits and in the evaluation of pitting corrosion and pit growth rate.
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 Identification and examination of pits
4.1 Preliminary low magnification visual inspection
4.1.1 A visual examination of the corroded metal surface with or without the use of a low-power
magnifying glass may be used to determine the extent of corrosion and the apparent location of pits. It
is often advisable to photograph the corroded surface so that it can be compared with the clean surface
after the removal of corrosion products or with a fresh unused piece of material.
4.1.2 If the metal specimen has been exposed to an unknown environment, the composition of the
corrosion products may be of value in determining the cause of corrosion. Recommended procedures for
the removal of particulate corrosion products should be followed and the material removed should be
preserved for future identification.
4.1.3 To expose the pits fully, it is recommended that cleaning procedures should be used to remove the
corrosion products. Rinsing with water followed by light mechanical cleaning can be sufficient for lightly
[1]
adhered corrosion products. Chemical cleaning is required for more adherent products. ISO 8407
provides a range of chemical cleaning processes. Preliminary testing should be undertaken to ensure
that attack of the base metal is avoided.
4.2 Optical microscopic examination of pit size and shape
4.2.1 Examine the cleaned metal surface to determine the approximate size and distribution of pits.
Follow this procedure by a more detailed examination through a microscope using a low magnification
(approximately × 20). Pits can have various sizes and shapes. A visual examination of the metal surface
can show a round, elongated or irregular opening, but it seldom provides an accurate indication of the
ISO 11463:2020(E)
extent of corrosion beneath the surface. Thus, it is often necessary to cross-section the pit to determine
its actual shape. Several common variations in the cross-sectioned shape of pits are shown in Figure 1.
Key
(a) narrow, deep (e) undercutting
(b) elliptical (f) microstructural orientation (horizontal)
(c) wide, shallow (g) microstructural orientation (vertical)
(d) sub-surface
Figure 1 — Variations in the cross-sectional shape of pits
4.2.2 It is difficult to determine pit density by counting pits through a microscope eyepiece, but the
task can be made easier by the use of a plastic grid. Place the grid, containing 3 mm to 6 mm squares,
on the metal surface. Count and record the number of pits in each square and move across the grid in a
systematic manner until all the surface has been covered. This approach minimizes eyestrain because the
eyes can be taken from the field of view without fear of losing the area of interest. Enlarged photographs
of the area of interest may also be used to reduce eyestrain. An alternative approach is to mount the
specimen on an x-y stage and measure both the number and spatial distribution of pits. When coupled
with optical depth measurement, where applicable, the number, depth and spatial distribution of pits
can be determined.
4.2.3 Advanced optical microscopy techniques, such as infinite focus microscopy and confocal laser
microscopy may be used to obtain three-dimensional images of the pit surface, within the constraints
of optical observations [most relevant to Figure 1 a) to c) but not applicable to undercut]. Such
measurements can be used to view the surface features and quantify surface roughness, pit depth,
surface profile, etc.
4.2.4 To carry out a metallographic examination, select and cut out a representative portion of the
metal surface containing the pits and prepare a metallographic specimen. If corrosion products are to
be examined in cross-section, it may be necessary to fix the surface in a mounting compound before
cutting. Examine microscopically to determine whether there is a relation between pits and inclusions
or microstructure, or whether the cavities are true pits or might have resulted from metal loss caused by
intergranular corrosion, dealloying, etc.
2 © ISO 2020 – All rights reserved
ISO 11463:2020(E)
4.3 In situ non-destructive inspection
4.3.1 General
Several techniques have been developed to assist in the detection of cracks or cavities in a metal surface
without destroying the material (see Reference [2]). These methods are less effective for locating and
defining the shape of pits than some of those described previously, but they merit consideration because
they are often used in situ, and thus they are more applicable to field applications.
4.3.2 Radiographic
Radiation, such as X-rays, passes through the object. The intensity of the emergent rays decreases
with increasing thickness of the material. Imperfections can be detected if they cause a change in the
absorption of X-rays. Detectors or films are used to provide an image of interior imperfections. The
metal thickness that can be inspected is dependent on the available energy output. Pits must be as
large as 0,5 % of the metal thickness to be detected and care should be taken to ensure that pits are not
confused with pre-existing pores.
4.3.3 Electromagnetic
4.3.3.1 Eddy currents may be used to detect defects or irregularities in the structure of electrically
conductive materials. When a specimen is exposed to a varying magnetic field, produced by connecting
an alternating current to a coil, eddy currents are induced in the specimen and they in turn produce a
magnetic field of their own. Materials with defects will produce a magnetic field that is different from
that of a reference material without defects, and an appropriate detection instrument is required to
determine these differences.
4.3.3.2 The induction of a magnetic field in ferromagnetic materials is another approach that is used.
Discontinuities that are transverse to the direction of the magnetic field cause a leakage field to form
above the surface of the part. Ferromagnetic particles are placed on the surface to detect the leakage
field and to outline the size and shape of the discontinuities. Rather small imperfections can be detected
by this method. However, the method is limited by the required directionality of defects to the magnetic
...
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