SIST EN ISO 8994:2019
(Main)Anodizing of aluminium and its alloys - Rating system for the evaluation of pitting corrosion - Grid method (ISO 8994:2018)
Anodizing of aluminium and its alloys - Rating system for the evaluation of pitting corrosion - Grid method (ISO 8994:2018)
This document specifies a grid rating system that provides a means of defining levels of performance of anodic oxidation coatings on aluminium and its alloys that have been subjected to corrosion tests.
This rating system is applicable to pitting corrosion resulting from
— accelerated tests,
— exposure to corrosive environments, and
— practical service tests.
This document takes into account only pitting corrosion of the basis metal resulting from penetration of the protective anodic oxidation coating.
NOTE 1 ISO 8993[1] describes a similar rating system based on defined chart scales.
NOTE 2 The grid rating system is frequently used for rating the results of short-term corrosion tests for relatively thin anodic oxidation coating, such as those used in the automotive industry.
Anodisieren von Aluminium und Aluminiumlegierungen - Bewertungssystem für Lochkorrosion - Rasterzählmethode (ISO 8994:2018)
Anodisation de l'aluminium et de ses alliages - Système de cotation de la corrosion par piqûres - Méthode par quadrillage (ISO 8994:2018)
Le présent document spécifie un système de cotation par quadrillage qui permet de définir des niveaux de performance des couches anodiques déposées sur l'aluminium et ses alliages, soumises à des essais de corrosion.
Ce système de cotation s'applique à la corrosion par piqûres résultant
— d'essais accélérés,
— de l'exposition à des milieux corrosifs, et
— d'essais en service.
Le présent document ne tient compte que de la corrosion par piqûres du métal de base résultant de la pénétration de la couche anodique de protection.
NOTE 1 L'ISO 8993[1] décrit un système de cotation similaire fondé sur la méthode des échelles graduées (images types).
NOTE 2 Le système de cotation par quadrillage est souvent utilisé pour la classification des résultats d'essais de corrosion de courte durée pour des couches anodiques relativement fines, telles que celles utilisées dans l'industrie automobile.
Anodizacija aluminija in njegovih zlitin - Ocenjevalni sistem za vrednotenje jamičaste korozije - Rastrska metoda (ISO 8994:2018)
Ta dokument določa rastrski ocenjevalni sistem, ki omogoča opredelitev ravni učinkovitosti anodno oksidiranih prevlek na aluminiju in aluminijevih zlitinah, ki so bile preskušene glede odpornosti proti koroziji.
Ta ocenjevalni sistem se uporablja za jamičasto korozijo, ki nastane kot posledica
– pospešenih preskusov,
– izpostavljenosti v korozivnem okolju in
– praktičnih delovnih preskusov.
Ta dokument obravnava samo jamičasto korozijo osnovne kovine, ki je posledica prodiranja zaščitne anodno oksidirane prevleke.
OPOMBA 1: Standard ISO 8993[1] opisuje podoben ocenjevalni sistem, ki temelji na grafičnih lestvicah.
OPOMBA 2: Rastrski ocenjevalni sistem se pogosto uporablja za ocenjevanje rezultatov kratkoročnih preskusov korozije za relativno tanke anodizirane plasti, kot so tiste, ki se uporabljajo v avtomobilski industriji.
General Information
Relations
Overview
SIST EN ISO 8994:2019 is a key international standard specifying a grid rating system for evaluating pitting corrosion on anodic oxidation coatings of aluminium and its alloys. This standard applies to coatings subjected to various corrosion tests including accelerated, environmental, and practical service exposure. It provides a systematic method to assess the degree of corrosion damage specifically from pitting, which results from the penetration of the protective anodized layer.
This standard is widely recognized and adopted across Europe by CEN members, ensuring consistent and reliable assessment of aluminium anodizing performance. It is vital for industries relying on aluminium components with protective anodic coatings, particularly where corrosion resistance is critical.
Key Topics
Scope of Evaluation
Focuses exclusively on pitting corrosion caused by breaches in the anodic oxidation coating. This excludes surface discoloration and other defects that do not penetrate the coating.Grid Methodology
The evaluation divides a significant test surface into a grid of 5 mm × 5 mm squares over an area exceeding 5,000 mm². Corrosion pits within these squares are counted to determine the extent of damage.Grid Rating Number Calculation
Results are quantified as a percentage of defective squares-those containing one or more corrosion pits-and translated into a grid rating number using defined tables. This simplifies comparing corrosion resistance levels across products and tests.Specimen Preparation
Detailed procedures including mechanical cleaning, chemical treatment with nitric acid, phosphoric acid/chromic acid mixtures, or hydrochloric acid ensure corrosion pits are clearly visible and measurable.Reporting Requirements
Test reports must document tested product details, sample preparation, rating results (percentage defective squares and/or grid rating number), and any observations relevant to corrosion assessment.
Applications
Quality Assurance in Aluminium Anodizing
Manufacturers and testing labs use SIST EN ISO 8994:2019 to verify performance of anodic coatings in various environments, ensuring products meet specified corrosion resistance levels.Automotive Industry
Particularly relevant for thin anodic coatings common in automotive aluminium parts subjected to short-term corrosion testing.Corrosion Testing and Product Development
Enables robust and comparable evaluation across accelerated corrosion tests, field exposure, or practical service tests, promoting improvements in anodizing processes and coating durability.Surface Treatment Specification
Provides suppliers and end-users with a standardized rating system to define acceptable performance criteria for anodized aluminium components.
Related Standards
ISO 8993 - Chart Method for Pitting Corrosion
An alternative rating system that uses defined chart scales for evaluating corrosion, complementing the grid method defined in ISO 8994.ISO 7583 - Terms and Definitions for Anodizing
Offers essential terminology for aluminium anodizing and anodic oxidation coatings to ensure clarity and uniformity in communication.ISO 2106 - Gravimetric Method for Coating Mass Determination
Supports corrosion evaluation by detailing methods to measure anodic coating thickness and mass, important for interpreting corrosion resistance.
Keywords
Anodizing, aluminium alloys, anodic oxidation coating, pitting corrosion, grid rating system, corrosion testing, accelerated corrosion tests, aluminium surface treatment, corrosion evaluation, automotive anodic coatings, ISO 8994, SIST EN ISO 8994:2019, CEN, corrosion pits, quality assurance in anodizing.
Standards Content (Sample)
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Anodizing of aluminium and its alloys - Rating system for the evaluation of pitting
corrosion - Grid method (ISO 8994:2018)
Anodisieren von Aluminium und Aluminiumlegierungen - Bewertungssystem für
Lochkorrosion - Rasterzählmethode (ISO 8994:2018)
Anodisation de l'aluminium et de ses alliages - Système de cotation de la corrosion par
piqûres - Méthode par quadrillage (ISO 8994:2018)
Ta slovenski standard je istoveten z: EN ISO 8994:2018
ICS:
25.220.20 Površinska obdelava Surface treatment
77.120.10 Aluminij in aluminijeve zlitine Aluminium and aluminium
alloys
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 8994
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 25.220.20; 77.060 Supersedes EN ISO 8994:2011
English Version
Anodizing of aluminium and its alloys - Rating system for
the evaluation of pitting corrosion - Grid method (ISO
8994:2018)
Anodisation de l'aluminium et de ses alliages - Système Anodisieren von Aluminium und
de cotation de la corrosion par piqûres - Méthode par Aluminiumlegierungen - Bewertungs-system für
quadrillage (ISO 8994:2018) Lochkorrosion - Rasterzählmethode (ISO 8994:2018)
This European Standard was approved by CEN on 11 December 2018.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8994:2018 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 8994:2018) has been prepared by Technical Committee ISO/TC 79 "Light
metals and their alloys" in collaboration with Technical Committee CEN/TC 132 “Aluminium and
aluminium alloys” the secretariat of which is held by AFNOR.
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 June 2019, and conflicting national standards shall be
withdrawn at the latest by June 2019.
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 8994:2011.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 8994:2018 has been approved by CEN as EN ISO 8994:2018 without any modification.
INTERNATIONAL ISO
STANDARD 8994
Third edition
2018-11
Anodizing of aluminium and its
alloys — Rating system for the
evaluation of pitting corrosion —
Grid method
Anodisation de l'aluminium et de ses alliages — Système de cotation
de la corrosion par piqûres — Méthode par quadrillage
Reference number
ISO 8994:2018(E)
©
ISO 2018
ISO 8994:2018(E)
© ISO 2018
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 2018 – All rights reserved
ISO 8994:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Procedure for rating . 2
4.1 Preparation of test specimen . 2
4.2 Determination of grid rating number . 2
5 Expression of results . 3
6 Test report . 3
Bibliography . 4
ISO 8994:2018(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
...
Frequently Asked Questions
SIST EN ISO 8994:2019 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Anodizing of aluminium and its alloys - Rating system for the evaluation of pitting corrosion - Grid method (ISO 8994:2018)". This standard covers: This document specifies a grid rating system that provides a means of defining levels of performance of anodic oxidation coatings on aluminium and its alloys that have been subjected to corrosion tests. This rating system is applicable to pitting corrosion resulting from — accelerated tests, — exposure to corrosive environments, and — practical service tests. This document takes into account only pitting corrosion of the basis metal resulting from penetration of the protective anodic oxidation coating. NOTE 1 ISO 8993[1] describes a similar rating system based on defined chart scales. NOTE 2 The grid rating system is frequently used for rating the results of short-term corrosion tests for relatively thin anodic oxidation coating, such as those used in the automotive industry.
This document specifies a grid rating system that provides a means of defining levels of performance of anodic oxidation coatings on aluminium and its alloys that have been subjected to corrosion tests. This rating system is applicable to pitting corrosion resulting from — accelerated tests, — exposure to corrosive environments, and — practical service tests. This document takes into account only pitting corrosion of the basis metal resulting from penetration of the protective anodic oxidation coating. NOTE 1 ISO 8993[1] describes a similar rating system based on defined chart scales. NOTE 2 The grid rating system is frequently used for rating the results of short-term corrosion tests for relatively thin anodic oxidation coating, such as those used in the automotive industry.
SIST EN ISO 8994:2019 is classified under the following ICS (International Classification for Standards) categories: 25.220.20 - Surface treatment; 77.120.10 - Aluminium and aluminium alloys. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN ISO 8994:2019 has the following relationships with other standards: It is inter standard links to SIST EN ISO 8994:2012. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase SIST EN ISO 8994:2019 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of SIST standards.
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