Anodizing of aluminium and its alloys - Measurement of abrasion resistance of anodic oxidation coatings (ISO 8251:2018)

This document specifies the following tests:
a) abrasive-wheel-wear test, determining the abrasion resistance of anodic oxidation coatings with
abrasive wheel on flat specimens of aluminium and its alloys;
b) abrasive jet test, determining the comparative abrasion resistance of anodic oxidation coatings
with jet of abrasive particles on anodic oxidation coatings of aluminium and its alloys;
c) falling sand abrasion test, determining the abrasion resistance of anodic oxidation coatings with
falling sand on thin anodic oxidation coatings of aluminium and its alloys.
The use of abrasive-wheel-wear test and abrasive jet test for coatings produced by hard anodizing is
described in ISO 10074.

Anodisieren von Aluminium und Aluminiumlegierungen - Messung der Abriebfestigkeit von anodisch erzeugten Oxidschichten (ISO 8251:2018)

Anodisation de l'aluminium et de ses alliages - Détermination de la résistance à l'abrasion des couches d'oxyde anodiques (ISO 8251:2018)

Le présent document spécifie les essais suivants:
a) essai d'usure à la roue abrasive, qui détermine la résistance à l'abrasion de couches d'oxyde anodiques par une roue abrasive sur des éprouvettes plates d'aluminium et de ses alliages;
b) essai au jet abrasif, qui détermine la résistance comparée à l'abrasion de couches d'oxyde anodiques par un jet de particules abrasives sur des couches d'oxyde anodiques en aluminium ou ses alliages;
c) essai d'abrasion par chute de sable, qui détermine la résistance à l'abrasion de couches d'oxyde anodiques par chute de sable sur des couches d'oxyde anodiques minces en aluminium ou ses alliages.
L'application de l'essai d'usure à la roue abrasive et de l'essai au jet abrasif à des couches produites par anodisation dure est décrite dans l'ISO 10074.

Anodizacija aluminija in aluminijevih zlitin - Meritve obrabne obstojnosti anodno oksidiranih prevlek (ISO 8251:2018)

Ta dokument določa naslednje preskuse:
a) preskus obrabe z brusilnim kolutom, ki določa obrabno odpornost anodno oksidiranih prevlek z uporabo brusilnega koluta na ploščatih vzorcih aluminija in aluminijevih zlitin;
b) preskus obrabe z brusilnim curkom, ki določa primerjalno obrabno odpornost anodno oksidiranih prevlek z uporabo curka brusilnih delcev na anodno oksidiranih prevlekah aluminija in aluminijevih zlitin;
c) brusilni preskus s padajočim peskom, ki določa obrabno odpornost anodno oksidiranih prevlek z uporabo padajočega peska na tankih anodno oksidiranih prevlekah aluminija in aluminijevih zlitin.
Uporaba preskusa obrabe z brusilnim kolutom in preskusa obrabe z brusilnim curkom pri prevlekah, izdelanih s trdno anodizacijo, je opisana v standardu ISO 10074.

General Information

Status
Published
Public Enquiry End Date
14-Nov-2017
Publication Date
11-Nov-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
19-Oct-2018
Due Date
24-Dec-2018
Completion Date
12-Nov-2018

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SLOVENSKI STANDARD
SIST EN ISO 8251:2018
01-december-2018
1DGRPHãþD
SIST EN ISO 8251:2012

Anodizacija aluminija in aluminijevih zlitin - Meritve obrabne obstojnosti anodno

oksidiranih prevlek (ISO 8251:2018)

Anodizing of aluminium and its alloys - Measurement of abrasion resistance of anodic

oxidation coatings (ISO 8251:2018)

Anodisieren von Aluminium und Aluminiumlegierungen - Messung der Abriebfestigkeit

von anodisch erzeugten Oxidschichten (ISO 8251:2018)
Anodisation de l'aluminium et de ses alliages - Détermination de la résistance à
l'abrasion des couches d'oxyde anodiques (ISO 8251:2018)
Ta slovenski standard je istoveten z: EN ISO 8251:2018
ICS:
25.220.20 Površinska obdelava Surface treatment
77.120.10 Aluminij in aluminijeve zlitine Aluminium and aluminium
alloys
SIST EN ISO 8251:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8251:2018
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SIST EN ISO 8251:2018
EN ISO 8251
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2018
EUROPÄISCHE NORM
ICS 25.220.20 Supersedes EN ISO 8251:2011
English Version
Anodizing of aluminium and its alloys - Measurement of
abrasion resistance of anodic oxidation coatings (ISO
8251:2018)
Anodisation de l'aluminium et de ses alliages - Anodisieren von Aluminium und

Détermination de la résistance à l'abrasion des couches Aluminiumlegierungen - Messung der Abriebfestigkeit

d'oxyde anodiques (ISO 8251:2018) von anodisch erzeugten Oxidschichten (ISO
8251:2018)
This European Standard was approved by CEN on 19 August 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 8251:2018 E

worldwide for CEN national Members.
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SIST EN ISO 8251:2018
EN ISO 8251:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 8251:2018
EN ISO 8251:2018 (E)
European foreword

This document (EN ISO 8251:2018) 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 March 2019, and conflicting national standards shall

be withdrawn at the latest by March 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 8251:2011.

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 8251:2018 has been approved by CEN as EN ISO 8251:2018 without any modification.

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SIST EN ISO 8251:2018
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SIST EN ISO 8251:2018
INTERNATIONAL ISO
STANDARD 8251
Third edition
2018-08
Anodizing of aluminium and its
alloys — Measurement of abrasion
resistance of anodic oxidation
coatings
Anodisation de l'aluminium et de ses alliages — Détermination de la
résistance à l'abrasion des couches d'oxyde anodiques
Reference number
ISO 8251:2018(E)
ISO 2018
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SIST EN ISO 8251:2018
ISO 8251:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© 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
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SIST EN ISO 8251:2018
ISO 8251:2018(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Characteristics of abrasion tests .......................................................................................................................................................... 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Abrasive-wheel-wear test .............................................................................................................................................................. 2

4.3 Abrasive jet test ...................................................................................................................................................................................... 2

4.4 Falling sand abrasion test .............................................................................................................................................................. 2

5 Abrasive-wheel-wear test ............................................................................................................................................................................ 2

5.1 Principle ........................................................................................................................................................................................................ 2

5.2 Apparatus .................................................................................................................................................................................................... 3

5.2.1 Abrasive-wheel-wear test apparatus ............................................................................................................. 3

5.2.2 Abrasive strip ...................................................................................................................................................................... 3

5.2.3 Eddy-current meter ....................................................................................................................................................... 3

5.2.4 Balance ..................................................................................................................................................................................... 3

5.3 Procedure .................................................................................................................................................................................................... 3

5.3.1 Standard specimen......................................................................................................................................................... 3

5.3.2 Test specimen ..................................................................................................................................................................... 4

5.3.3 Test procedure ................................................................................................................................................................... 4

5.4 Expression of results .......................................................................................................................................................................... 5

5.4.1 General...................................................................................................................................................................................... 5

5.4.2 Wear resistance ................................................................................................................................................................. 5

5.4.3 Mass wear resistance ................................................................................................................................................... 5

5.4.4 Wear index ............................................................................................................................................................................ 5

5.4.5 Mass wear index ............................................................................................................................................................... 6

6 Abrasive jet test ..................................................................................................................................................................................................... 6

6.1 Principle ........................................................................................................................................................................................................ 6

6.2 Apparatus .................................................................................................................................................................................................... 6

6.2.1 Abrasive jet test apparatus ...................................................................................................................................... 6

6.2.2 Abrading medium ........................................................................................................................................................... 7

6.2.3 Eddy-current meter ....................................................................................................................................................... 7

6.2.4 Balance ..................................................................................................................................................................................... 7

6.3 Procedure .................................................................................................................................................................................................... 7

6.3.1 Standard specimen......................................................................................................................................................... 7

6.3.2 Test specimen ..................................................................................................................................................................... 7

6.3.3 Calibration of apparatus ............................................................................................................................................ 8

6.3.4 Calibration of jet nozzle ............................................................................................................................................. 8

6.3.5 Determination .................................................................................................................................................................... 9

6.3.6 Use of a reference specimen .................................................................................................................................. 9

6.4 Expression of results .......................................................................................................................................................................... 9

6.4.1 General...................................................................................................................................................................................... 9

6.4.2 Abrasive jet factor ........................................................................................................................................................... 9

6.4.3 Mean specific abrasion resistance .................................................................................................................... 9

6.4.4 Relative mean specific abrasion resistance ...........................................................................................10

7 Falling sand abrasion test ........................................................................................................................................................................10

7.1 Principle .....................................................................................................................................................................................................10

7.2 Apparatus .................................................................................................................................................................................................10

7.2.1 Falling sand abrasion test apparatus ...........................................................................................................10

7.2.2 Ohmmeter ...........................................................................................................................................................................11

7.2.3 Abrading medium ........................................................................................................................................................11

© ISO 2018 – All rights reserved iii
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SIST EN ISO 8251:2018
ISO 8251:2018(E)

7.3 Test specimen ........................................................................................................................................................................................11

7.3.1 Sampling...............................................................................................................................................................................11

7.3.2 Size ............................................................................................................................................................................................11

7.3.3 Treatment before testing .......................................................................................................................................11

7.4 Test environment ...............................................................................................................................................................................11

7.5 Test conditions .....................................................................................................................................................................................11

7.6 Test procedure ......................................................................................................................................................................................11

7.6.1 General...................................................................................................................................................................................11

7.6.2 Electrical conductivity method ........................................................................................................................11

7.6.3 Spot diameter method .............................................................................................................................................12

7.7 Expression of results .......................................................................................................................................................................12

7.7.1 Electrical conductivity method ........................................................................................................................12

7.7.2 Spot diameter method .............................................................................................................................................13

8 Test report ................................................................................................................................................................................................................13

Annex A (normative) Preparation of the standard specimen .................................................................................................14

Annex B (informative) Other expressions of results for the abrasive-wheel-wear test ...............................16

Annex C (informative) Depth survey of abrasion resistance ....................................................................................................19

Annex D (informative) Design of abrasive-wheel-wear test apparatus.........................................................................22

Annex E (informative) Design of abrasive jet test apparatus ...................................................................................................24

Annex F (informative) Design of falling sand abrasion test apparatus..........................................................................27

Bibliography .............................................................................................................................................................................................................................29

iv © ISO 2018 – All rights reserved
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SIST EN ISO 8251:2018
ISO 8251:2018(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 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 79, Light metals and their alloys,

Subcommittee SC 2, Organic and anodic oxidation coatings on aluminium.

This third edition cancels and replaces the second edition (ISO 8251:2011), which has been technically

revised. The main technical changes are as follows:
— preparation for test specimens has been added;
— for expression of results, loss of mass has been added;
— some expressions of results have been moved to Annex B;
— standard specimen made of PMMA sheet has been added.

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.
© ISO 2018 – All rights reserved v
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SIST EN ISO 8251:2018
ISO 8251:2018(E)
Introduction

The resistance of anodic oxidation coatings to abrasion is an important property. As it is dependent upon

the composition of the metal, the thickness of the coating and the conditions of anodizing and sealing,

it can give information about the quality of the coating, its potential resistance to erosion or wear and

its performance in service. For example, the effect of an abnormally high anodizing temperature, which

could cause potential deterioration in service by chalking of the surface layers, can be readily detected

by means of an abrasive wear resistance test.

The use of the term “abrasion resistance” is a convention of the industry. Strictly, the property should

be described as “wear resistance”. There are different types of wear including abrasive wear and

erosive wear.
vi © ISO 2018 – All rights reserved
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SIST EN ISO 8251:2018
INTERNATIONAL STANDARD ISO 8251:2018(E)
Anodizing of aluminium and its alloys — Measurement of
abrasion resistance of anodic oxidation coatings
1 Scope
This document specifies the following tests:

a) abrasive-wheel-wear test, determining the abrasion resistance of anodic oxidation coatings with

abrasive wheel on flat specimens of aluminium and its alloys;

b) abrasive jet test, determining the comparative abrasion resistance of anodic oxidation coatings

with jet of abrasive particles on anodic oxidation coatings of aluminium and its alloys;

c) falling sand abrasion test, determining the abrasion resistance of anodic oxidation coatings with

falling sand on thin anodic oxidation coatings of aluminium and its alloys.

The use of abrasive-wheel-wear test and abrasive jet test for coatings produced by hard anodizing is

described in ISO 10074.
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 6344-1, Coated abrasives — Grain size analysis — Part 1: Grain size distribution test

ISO 7583, Anodizing of aluminium and its alloys — Terms and definitions

ISO 7823-1, Plastics — Poly(methyl methacrylate) sheets — Types, dimensions and characteristics —

Part 1: Cast sheets

ISO 8486-1, Bonded abrasives — Determination and designation of grain size distribution — Part 1:

Macrogrits F4 to F220
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 7583 and the following 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/
3.1
standard specimen
specimen produced in accordance with specified conditions
Note 1 to entry: The conditions are specified in Annex A.
© ISO 2018 – All rights reserved 1
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SIST EN ISO 8251:2018
ISO 8251:2018(E)
4 Characteristics of abrasion tests
4.1 General

In the scope of this document, there are three kinds of abrasion tests: abrasive-wheel-wear test (4.2),

abrasive jet test (4.3) and falling sand abrasion test (4.4).
4.2 Abrasive-wheel-wear test

Determination of the abrasion resistance by movement of a test specimen relative to an abrasive paper

under a specified pressure. The wear resistance or the wear index of the layers of oxide near the surface,

or of the whole oxidation coating thickness, or of any selected intermediate zone may be determined by

the test described.
NOTE 1 Abrasive-wheel-wear test determines the resistance to abrasive wear.

This test is applicable to all anodic oxidation coatings of thickness more than 5 μm on flat aluminium or

its alloy specimens.

This test does not apply to concave or convex specimens; these may be examined using the abrasive jet

test which will give an average value for the abrasive resistance of the coating.

NOTE 2 Minimum test specimen dimensions of 50 mm × 50 mm are normally used.
4.3 Abrasive jet test

Determination of the comparative abrasion resistance by the impact of abrasive particles projected onto

a test specimen. The mean specific abrasion resistance of anodic oxidation coatings can be determined.

NOTE 1 Abrasive jet test determines the comparative resistance to erosive wear.

This test is applicable to all anodic oxidation coatings of thickness more than 5 μm on aluminium or its

alloys. It is primarily intended for surfaces which are not flat. If suitable flat test surfaces are available,

the abrasive-wheel-wear test is the preferred test. Production components may be tested without

cutting if the apparatus chamber can accommodate these.

NOTE 2 This test is particularly suitable for small test specimens because the individual test area required is

only about 2 mm in diameter.
4.4 Falling sand abrasion test

Determination of the abrasion resistance by the impact of freely falling abrasive particles onto anodic

oxidation coatings.

This test is suitable to thin anodic oxidation coatings, generally less than 15 µm.

NOTE Falling sand abrasion test determines the resistance to erosive wear.
5 Abrasive-wheel-wear test
5.1 Principle

The anodic oxidation coatings on a test specimen are abraded, under defined conditions, by reciprocal

motion against a strip of silicon carbide paper attached to the outer circumference of a wheel. After each

double stroke, the wheel turns through a small angle to bring an unused portion of the abrasive strip

into contact with the test area. The decrease in coating thickness or mass obtained is used to calculate

the wear resistance, mass wear resistance, wear index or mass wear index. This result is compared

with that obtained using a standard specimen or reference specimen.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 8251:2018
ISO 8251:2018(E)

The measuring method of coating thickness normally requires an eddy-current meter with a probe of

less than 12 mm diameter. If this is not available, the method of loss in mass should be used.

NOTE A complete presentation of the wear characteristics of the anodic oxidation coatings can be obtained

by progressively abrading the test area, until the substrate metal is revealed, and then constructing a graph to

show the relation between the coating thickness removed and the number of double strokes used. This is referred

to as a depth survey of the anodic oxidation coatings (see Annex C).
The testing environment should be at room temperature and the relative h
...

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