EN ISO 9227:2022
(Main)Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2022)
Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2022)
This document specifies the apparatus, the reagents and the procedure to be used in conducting the neutral salt spray (NSS), acetic acid salt spray (AASS) and copper-accelerated acetic acid salt spray (CASS) tests for assessment of the corrosion resistance of metallic materials, with or without permanent or temporary corrosion protection.
It also describes the method employed to evaluate the corrosivity of the test cabinet environment.
It does not specify the dimensions or types of test specimens, the exposure period to be used for a particular product, or the interpretation of results. Such details are provided in the appropriate product specifications.
The salt spray tests are particularly useful for detecting discontinuities, such as pores and other defects, in certain metallic, organic, anodic oxide and conversion coatings.
The NSS test is particularly applicable to:
— metals and their alloys;
— metallic coatings (anodic and cathodic);
— conversion coatings;
— anodic oxide coatings;
— organic coatings on metallic materials.
The AASS test is especially useful for testing decorative coatings of copper + nickel + chromium, or nickel + chromium. It has also been found suitable for testing anodic and organic coatings on aluminium.
The CASS test is useful for testing decorative coatings of copper + nickel + chromium, or nickel + chromium. It has also been found suitable for testing anodic and organic coatings on aluminium.
The salt spray methods are all suitable for checking that the quality of a metallic material, with or without corrosion protection, is maintained. They are not intended to be used for comparative testing as a means of ranking different materials relative to each other with respect to corrosion resistance or as means of predicting long-term corrosion resistance of the tested material.
Korrosionsprüfungen in künstlichen Atmosphären - Salzsprühnebelprüfungen (ISO 9227:2022)
Dieses Dokument legt die Prüfeinrichtung, die Reagenzien und das anzuwendende Verfahren bei der Durchführung der Prüfungen mit neutralen Salzsprühnebel (NSS, en: neutral salt spray), Essigsäure-Salzsprühnebel (AASS, en: acetic acid salt spray) und kupferbeschleunigtem Essigsäure-Salzsprühnebel (CASS, en: copper-accelerated acetic acid salt spray) zum Beurteilen der Korrosionsbeständigkeit von metallischen Materialien mit oder ohne dauerhaftem oder temporärem Korrosionsschutz fest.
Dieses Dokument beschreibt auch das Verfahren, welches angewendet wird, um die Korrosivität in der Prüfkammer zu bewerten.
Dieses Dokument legt nicht die Maße oder Arten der Prüfproben, die für ein bestimmtes Produkt anzu-wendende Dauer der Beanspruchung oder die Auswertung der Ergebnisse fest. Solche Einzelheiten werden in den entsprechenden Produktspezifikationen angegeben.
Die Salzsprühnebelprüfungen sind besonders nützlich zum Nachweis von Schwachstellen, wie Poren und anderen Schäden, in bestimmten metallischen Überzügen und organischen Beschichtungen sowie anodischen Oxid¬schichten und Umwandlungsschichten.
Die NSS-Prüfung ist insbesondere anwendbar für:
Metalle und deren Legierungen;
(anodisch oder kathodisch wirksame) Beschichtungen;
Umwandlungsschichten;
anodische Oxidschichten;
organische Beschichtungen auf metallischen Materialien.
Die AASS-Prüfung ist besonders nützlich zum Prüfen dekorativer Überzüge aus Kupfer + Nickel + Chrom oder Nickel + Chrom. Sie wurde auch zum Prüfen anodischer und organischer Schichten auf Aluminium als geeignet befunden.
Die CASS-Prüfung ist besonders nützlich zum Prüfen dekorativer Überzüge aus Kupfer + Nickel + Chrom oder Nickel + Chrom. Sie eignet sich auch zum Prüfen anodischer und organischer Schichten auf Aluminium.
Die Salzsprühnebelverfahren sind alle geeignet zum Prüfen, ob die Qualität eines metallischen Materials, mit oder ohne Korrosionsschutz, erhalten bleibt. Sie sind nicht als Vergleichsprüfung gedacht, um unterschiedliche Materialien nach ihrer Korrosionsbeständigkeit einzustufen oder um die Langzeitkorrosionsbeständigkeit des geprüften Materials vorherzusagen.
Essais de corrosion en atmosphères artificielles - Essais aux brouillards salins (ISO 9227:2022)
Le présent document spécifie l’appareillage, les réactifs et le mode opératoire à utiliser lors de la réalisation de l’essai au brouillard salin neutre (NSS), de l’essai au brouillard salin acétique (AASS) et de l’essai accéléré au brouillard salin cupro‑acétique (CASS) destinés à évaluer la résistance à la corrosion de matériaux métalliques, avec ou sans revêtement de protection contre la corrosion, temporaire ou permanent.
Il décrit également la méthode à appliquer pour évaluer la corrosivité du milieu de la chambre d’essai.
Il ne spécifie pas les dimensions ou types des éprouvettes d’essai, le temps durant lequel exposer un produit particulier ni l’interprétation des résultats. Ces détails sont fournis dans les spécifications des produits correspondantes.
Les essais au brouillard salin sont particulièrement utiles pour détecter les discontinuités du type pores ou autres défauts de certains revêtements métalliques, organiques, d’oxydes anodiques ou de couches de conversion.
L’essai NSS s’applique particulièrement:
— aux métaux et à leurs alliages;
— aux revêtements métalliques (anodiques et cathodiques);
— aux couches de conversion;
— aux revêtements d’oxydes anodiques;
— aux revêtements organiques sur matériaux métalliques.
L’essai AASS est particulièrement utile pour évaluer les revêtements décoratifs de cuivre + nickel + chrome ou de nickel + chrome. Il s’est également révélé utile pour évaluer des revêtements anodiques et organiques sur l’aluminium.
L’essai CASS est utile pour évaluer les revêtements décoratifs de cuivre + nickel + chrome ou de nickel + chrome. Il s’est également révélé utile pour évaluer des revêtements anodiques et organiques sur l’aluminium.
Les méthodes au brouillard salin conviennent toutes pour vérifier que la qualité d’un matériau métallique, avec ou sans revêtement protecteur contre la corrosion, est maintenue. Il n’est pas recommandé de les utiliser pour des essais comparatifs en vue de classer les différents matériaux les uns par rapport aux autres vis‑à‑vis de la résistance à la corrosion ou comme moyen de prédire la résistance à la corrosion à long terme du matériau soumis à essai.
Korozijski preskusi v umetnih atmosferah - Korozijski preskusi v slani komori (ISO 9227:2022)
Ta dokument določa naprave, reagente in postopek, namenjene za izvajanje preskusov z nevtralno slano meglico (NSS), slano meglico z ocetno kislino (AASS) in preskusov s slano meglico z ocetno kislino, pospešenih z bakrom (CASS) za oceno korozijske odpornosti kovinskih materialov s trajno ali začasno protikorozijsko zaščito ali brez nje. Opisuje tudi metodo za vrednotenje korozivnosti v okolju preskusne komore. Ne določa dimenzij ali vrst preskušancev, časa izpostavljenosti za določen proizvod ali razlage rezultatov. Te podrobnosti so navedene v ustreznih specifikacijah proizvodov. Preskusi s slano meglico so še posebej uporabni za zaznavanje nepravilnosti, kot so pore in druge napake v določenih kovinskih, organskih, anodno oksidnih in reakcijskih prevlekah. Preskus NSS se uporablja predvsem za: – kovine in njihove zlitine, – kovinske prevleke (anodne in katodne), – reakcijske prevleke, – anodno oksidne prevleke; – organske prevleke na kovinskih materialih. Preskus AASS je še posebej uporaben za preskušanje dekorativnih prevlek z bakrom + nikljem + kromom ali nikljem + kromom. Ugotovljeno je bilo tudi, da je primeren za preskušanje anodnih in organskih prevlek na aluminiju. Preskus CASS je uporaben za preskušanje dekorativnih prevlek z bakrom + nikljem + kromom ali nikljem + kromom. Ugotovljeno je bilo tudi, da je primeren za preskušanje anodnih in organskih prevlek na aluminiju. Vse metode s slano meglico so ustrezne za preverjanje vzdrževanja kakovosti kovinskih materialov s protikorozijsko zaščito ali brez nje. Niso namenjene za uporabo pri primerjalnih preskusih kot sredstvo za razvrščanje različnih materialov glede na odpornost proti koroziji ali kot sredstvo za predvidevanje dolgoročne odpornosti preskusnih materialov proti koroziji.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2023
Nadomešča:
SIST EN ISO 9227:2017
Korozijski preskusi v umetnih atmosferah - Korozijski preskusi v slani komori (ISO
9227:2022)
Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2022)
Korrosionsprüfungen in künstlichen Atmosphären - Salzsprühnebelprüfungen (ISO
9227:2022)
Essais de corrosion en atmosphères artificielles - Essais aux brouillards salins (ISO
9227:2022)
Ta slovenski standard je istoveten z: EN ISO 9227:2022
ICS:
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 9227
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2022
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 9227:2017
English Version
Corrosion tests in artificial atmospheres - Salt spray tests
(ISO 9227:2022)
Essais de corrosion en atmosphères artificielles - Korrosionsprüfungen in künstlichen Atmosphären -
Essais aux brouillards salins (ISO/FDIS 9227:2022) Salzsprühnebelprüfungen (ISO/FDIS 9227:2022)
This European Standard was approved by CEN on 12 November 2022.
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, Türkiye 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9227:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 9227:2022) 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 May 2023, and conflicting national standards shall be
withdrawn at the latest by May 2023.
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 9227:2017.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 9227:2022 has been approved by CEN as EN ISO 9227:2022 without any modification.
INTERNATIONAL ISO
STANDARD 9227
Fifth edition
2022-11
Corrosion tests in artificial
atmospheres — Salt spray tests
Essais de corrosion en atmosphères artificielles — Essais aux
brouillards salins
Reference number
ISO 9227:2022(E)
ISO 9227:2022(E)
© ISO 2022
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 9227:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Test solutions . 2
5.1 Preparation of the sodium chloride solution . 2
5.2 Preparation of each test solution with pH adjustment . 3
5.2.1 pH of the salt solution . 3
5.2.2 Neutral salt spray test . 3
5.2.3 Acetic acid salt spray test . 3
5.2.4 Copper-accelerated acetic acid salt spray test . 4
5.3 Filtration . 4
6 Apparatus . 4
6.1 Component protection . 4
6.2 Spray cabinet . 4
6.3 Heater and temperature control . . 4
6.4 Spraying device . 4
6.5 Collecting devices . 5
6.6 Re-use . 6
7 Method for evaluating cabinet corrosivity . 6
7.1 General . 6
7.2 Reference specimens . 6
7.3 Arrangement of the reference specimens . 7
7.4 Determination of mass loss (mass per area) . 7
7.5 Satisfactory performance of cabinet . 8
8 Test specimens . 8
9 Arrangement of the test specimens .8
10 Operating conditions . 9
11 Duration of tests . 9
12 Treatment of test specimens after test .10
12.1 General . 10
12.2 Non-organic coated test specimens: metallic and/or inorganic coated . 10
12.3 Organic coated test specimens . 10
12.3.1 Scribed organic coated test specimens . 10
12.3.2 Organic coated but not scribed test specimens . 10
13 Evaluation of results .11
14 Test report .11
Annex A (informative) Example schematic diagram of one possible design of spray cabinet
with means for optional treating fog exhaust and drain .13
Annex B (informative) Complementary method for evaluating cabinet corrosivity using
zinc reference specimens .15
Annex C (normative) Preparation of specimens with organic coatings for testing .17
Annex D (informative) Required supplementary information for testing test specimens
with organic coatings.18
iii
ISO 9227:2022(E)
Annex E (informative) Examples of arrangement of the collecting devices .19
Annex F (informative) Interlaboratory comparison for reference specimens .21
Bibliography .23
iv
ISO 9227:2022(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 fifth edition cancels and replaces the fourth edition (ISO 9227:2017), which has been technically
revised.
The main changes are as follows:
— the arrangement of test specimens has been added;
— the arrangement of collecting devices has been changed; examples of arrangement of collecting
devices have been added as Annex E;
— DC04, DC05 and UNS G10080 have been added for steel reference specimens as an alternative of CR4-
grade steel, and interlaboratory comparison for reference specimens has been added as Annex F;
— the diluted acetic acid for preparing the test solution of AASS and CASS has been added;
— the allowed limit of copper concentration when the cabinet once used for CASS is re-used for NSS or
AASS has been specified.
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.
v
ISO 9227:2022(E)
Introduction
There is seldom a direct relation between resistance to the action of salt spray and resistance to
corrosion in other media, because several factors influencing the progress of corrosion, such as the
formation of protective films, vary greatly with the conditions encountered. Therefore, the test results
should not be regarded as a direct guide to the corrosion resistance of the tested metallic materials
in all environments where these materials can be used. Also, the performance of different materials
during the test should not be taken as a direct guide to the corrosion resistance of these materials in
service.
Nevertheless, the method described gives a means of checking that the comparative quality of a metallic
material, with or without corrosion protection, is maintained.
Different metallic substrates (metals) cannot be tested in direct comparison in accordance to their
corrosion resistances in salt spray tests. Comparative testing is only applicable for the same kind of
substrate.
Salt spray tests are generally suitable as corrosion protection tests for rapid analysis for discontinuities,
pores and damage in organic and inorganic coatings. In addition, for quality control purposes,
comparison can be made between specimens coated with the same coating. As comparative tests,
however, salt spray tests are only suitable if the coatings are sufficiently similar in nature.
When interpreting test results (e.g. minimum time until appearance defects or protection defects) for
product quality control or acceptance specifications, it is important to recognize that the salt spray test
can have a low level of reproducibility, especially with production parts tested in different laboratories.
It is often not possible to use results gained from salt spray testing as a comparative guide to the
long-term behaviour of different coating systems, since the corrosion stress during these tests differs
significantly from the corrosion stresses encountered in practice.
vi
INTERNATIONAL STANDARD ISO 9227:2022(E)
Corrosion tests in artificial atmospheres — Salt spray tests
1 Scope
This document specifies the apparatus, the reagents and the procedure to be used in conducting the
neutral salt spray (NSS), acetic acid salt spray (AASS) and copper-accelerated acetic acid salt spray
(CASS) tests for assessment of the corrosion resistance of metallic materials, with or without permanent
or temporary corrosion protection.
It also describes the method employed to evaluate the corrosivity of the test cabinet environment.
It does not specify the dimensions or types of test specimens, the exposure period to be used for a
particular product, or the interpretation of results. Such details are provided in the appropriate product
specifications.
The salt spray tests are particularly useful for detecting discontinuities, such as pores and other defects,
in certain metallic, organic, anodic oxide and conversion coatings.
The NSS test is particularly applicable to:
— metals and their alloys;
— metallic coatings (anodic and cathodic);
— conversion coatings;
— anodic oxide coatings;
— organic coatings on metallic materials.
The AASS test is especially useful for testing decorative coatings of copper + nickel + chromium, or
nickel + chromium. It has also been found suitable for testing anodic and organic coatings on aluminium.
The CASS test is useful for testing decorative coatings of copper + nickel + chromium, or nickel +
chromium. It has also been found suitable for testing anodic and organic coatings on aluminium.
The salt spray methods are all suitable for checking that the quality of a metallic material, with or
without corrosion protection, is maintained. They are not intended to be used for comparative testing
as a means of ranking different materials relative to each other with respect to corrosion resistance or
as means of predicting long-term corrosion resistance of the tested material.
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 1514, Paints and varnishes — Standard panels for testing
ISO 2808, Paints and varnishes — Determination of film thickness
ISO 3574, Cold-reduced carbon steel sheet of commercial and drawing qualities
ISO 4623-2:2016, Paints and varnishes — Determination of resistance to filiform corrosion — Part 2:
Aluminium substrates
ISO 8044, Corrosion of metals and alloys — Vocabulary
ISO 9227:2022(E)
ISO 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens
ISO 17872, Paints and varnishes — Guidelines for the introduction of scribe marks through coatings on
metallic panels for corrosion testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
reference specimen
portion of the reference material that is to be exposed with the intention to check the reproducibility
and repeatability of the test results for the test cabinet in use
Note 1 to entry: The reference material is the material with known test performance.
3.2
test specimen
specific portion of the samples upon which the testing is to be performed
3.3
substitute specimen
inert materials (such as plastic or glass) used for the substitute of a test specimen (3.2)
4 Principle
WARNING — This document can involve hazardous materials, operations and equipment. This
document does not purport to address all of the safety concerns, if any, associated with its use.
It is the responsibility of the user of this document to establish appropriate safety and health
practices and determine the applicability of regulatory limitations prior to use.
The NSS test is the test method in which a neutral approximate 5 % sodium chloride solution is atomized
under a controlled environment.
The AASS test is the test method in which an approximate 5 % sodium chloride solution acidified by the
addition of acetic acid is atomized under a controlled environment.
The CASS test is the test method in which an approximate 5 % sodium chloride solution acidified by
the addition acetic acid and with the addition of copper(II) chloride is atomized under a controlled
environment.
5 Test solutions
5.1 Preparation of the sodium chloride solution
Dissolve a sufficient mass of sodium chloride in distilled or deionized water with a conductivity not
higher than 20 µS/cm at 25 °C to produce a concentration in a range between 45 g/l and 55 g/l. The
sodium chloride concentration of the sprayed solution collected shall be 50 g/l ± 5 g/l. The specific
gravity range for a 50 g/l ± 5 g/l solution is 1,029 to 1,036 at 25 °C.
ISO 9227:2022(E)
The sodium chloride shall not contain a mass fraction of the heavy metals copper (Cu), nickel (Ni) and
lead (Pb) in total more than 0,005 %. It shall not contain a mass fraction of sodium iodide more than
0,1 % and a mass fraction of total impurities more than 0,5 %, calculated for dry salt.
NOTE Anti-caking agents added to the sodium chloride can act as corrosion inhibitors or accelerators. A
useful sodium chloride salt grade is a grade named Ph. Eur/USP or JIS, ACS.
5.2 Preparation of each test solution with pH adjustment
5.2.1 pH of the salt solution
Adjust the pH of the salt solution to the desired value on the basis of the pH of the sprayed solution
collected.
5.2.2 Neutral salt spray test
Adjust the pH of the salt solution (see 5.1) so that the pH of the sprayed solution collected within the
test cabinet (6.2 and 6.5) is 6,5 to 7,2 at 25 °C ± 2 °C. Check the pH using electrometric measurement.
Measurements of pH shall be done using electrodes suitable for measuring in weakly buffered
sodium chloride solutions in distilled or deionized water. Make any necessary corrections by adding
hydrochloric acid, sodium hydroxide or sodium bicarbonate solution of analytical grade.
®1)
WARNING — Hydrochloric acid (CAS Registry Number 7647-01-0) solution is toxic, corrosive,
irritating and very toxic to aquatic life. Refer to the safety data sheet for details. Handling of
hydrochloric acid solution shall be restricted to skilled personnel or conducted under their
control. Care shall be taken in the disposal of this solution.
WARNING — Sodium hydroxide (CAS 1310-73-2) solution is toxic, corrosive and irritating. Refer
to the safety data sheet for details. Handling of sodium hydroxide solution shall be restricted to
skilled personnel or conducted under their control. Care shall be taken in the disposal of this
solution.
NOTE Possible changes in pH can result from loss of carbon dioxide in the solution when it is sprayed. Such
changes can be avoided by reducing the carbon dioxide content of the solution by, for example, heating it to a
temperature above 35 °C before it is placed in the apparatus, or by making the solution using freshly boiled water.
5.2.3 Acetic acid salt spray test
Add a sufficient amount of glacial acetic acid not less than 99,7 % of mass fraction or diluted acetic
acid more than 10 % of mass fraction to the salt solution (see 5.1) to ensure that the pH of samples of
sprayed solution collected in the test cabinet (6.2 and 6.5) is between 3,1 and 3,3 at 25 °C ± 2 °C. Take
the added volume of acetic acid into account when making up the initial sodium chloride solution. If the
pH of the solution initially prepared is 3,0 to 3,1, the pH of the sprayed solution is likely to be within the
specified limits. Check the pH using electrometric measurement. Measurements of pH shall be done
using electrodes suitable for measuring in weakly buffered sodium chloride solutions in distilled or
deionized water. Make any necessary corrections by adding acetic acid, sodium hydroxide, or sodium
bicarbonate of analytical grade.
WARNING — Glacial acetic acid (CAS 64-19-7) is a flammable liquid, toxic, corrosive and irritating.
Refer to the safety data sheet for details. Handling of glacial acetic acid shall be restricted to
skilled personnel or conducted under their control. Care shall be taken in the disposal of this
solution. ®
1) CAS Registry Number is a trademark of CAS corporation. This information is given for the convenience of users
of this document and does not constitute an endorsement by ISO of the product named. Equivalent products may be
used if they can be shown to lead to the same results.
ISO 9227:2022(E)
5.2.4 Copper-accelerated acetic acid salt spray test
Dissolve a sufficient mass of copper(II) chloride dihydrate (CuCl ⋅2H O) not less than 99,0 % of mass
2 2
fraction in the salt solution (5.1) to produce a concentration of 0,26 g/l ± 0,02 g/l [equivalent to
(0,205 ± 0,015) g of CuCl per litre].
WARNING — Copper(II) chloride dihydrate (CAS 10125-13-0) is toxic, corrosive, irritating and
very toxic to aquatic life. Refer to the safety data sheet for details. Handling of copper(II) chloride
dihydrate shall be restricted to skilled personnel or conducted under their control. Care shall be
taken in the disposal of this solution.
Adjust the pH using the procedures described in 5.2.3.
5.3 Filtration
If necessary, filter the solution before placing it in the reservoir of the apparatus, to remove any solid
matter which can block the apertures of the spraying device.
6 Apparatus
6.1 Component protection
All components in contact with the spray or the test solution shall be made of, or lined with, materials
resistant to corrosion by the sprayed solution and which do not influence the corrosivity of the sprayed
test solutions.
The supports for the test specimen shall be constructed such that different substrate types do not
influence each other. It shall also be constructed so that the supports themselves do not influence the
test specimens.
6.2 Spray cabinet
The cabinet shall be such that the conditions of homogeneity and distribution of the spray are met.
Due to the limited capacity of cabinets smaller than 0,4 m , the effect of the loading of the cabinet on
the distribution of the spray and temperature shall be carefully considered. The solution shall not be
sprayed directly onto test specimens but rather spread throughout the cabinet so that it falls naturally
down to them. The upper parts of the cabinet shall be designed so that drops of sprayed solution formed
on its surface do not fall on the test specimens.
The size and shape of the cabinet shall be such that the collection rate of solution in the cabinet is within
the limits specified in 10.3.
Preference shall be given to apparatus that has a means for properly dealing with fog after the test,
prior to releasing it from the building for environmental conservation, and for diluting salt solution
prior to discharging it to the drainage system.
NOTE A schematic diagram of one possible design of spray cabinet is shown in Annex A (see Figures A.1 and
A.2).
6.3 Heater and temperature control
The test cabinet shall be maintained at the specified temperature (see 10.1) in the zone where the test
specimens are placed by the appropriate system.
6.4 Spraying device
The device for spraying the salt solution comprises a supply of clean air, of controlled pressure and
humidity, a reservoir to contain the solution to be sprayed, and one or more atomizers.
ISO 9227:2022(E)
The compressed air supplied to the atomizers shall be passed through a filter before introduction into
the air humidifier to remove all traces of oil or solid matter, and the atomizing pressure shall be at an
overpressure of 70 kPa to 170 kPa. The pressure is typically 98 kPa ± 10 kPa but can vary depending on
the type of cabinet and atomizer used.
In order to prevent the evaporation of water from the sprayed droplets (aerosol), the air shall be
humidified before entering the atomizer by passing through a suitable humidifier. The humidified air
shall be saturated such that the concentration of the fallout solution falls within the specifications
of 5.1. The humidified air shall also be heated such that when mixed with the salt solution and after
the adiabatic expansion at the atomizer, there is no significant disturbance of the temperature in the
cabinet. The appropriate temperature depends on the pressure used and on the type of atomizer.
Temperature, pressure or humidification, or a combination thereof, shall be adjusted so that the rate
of collection of the spray in the cabinet and the concentration of the collected spray are kept within the
specified limits (see 10.3). A commonly used humidifier is the saturation tower where temperature and
pressure are controllable. Table 1 gives guiding values on temperature and pressure combinations for
the saturation tower.
Table 1 — Guiding values for the temperature of the hot water in the saturation tower
Guiding values for the temperature, in °C, of the hot water in the
Atomizing overpressure
saturation tower when performing the different salt spray test
kPa
NSS and AASS CASS
70 45 61
84 46 63
98 48 64
112 49 66
126 50 67
140 52 69
160 53 70
170 54 71
The atomizers shall be made of inert material. Baffles made of inert material may be used to prevent
direct impact of the spray on the test specimens, and the use of adjustable baffles is helpful in obtaining
uniform distribution of the spray within the cabinet. For this purpose, a dispersion tower equipped
with an atomizer may also be helpful.
The salt solution supplied to the atomizer shall be kept stable to ensure a continuous and uniform fall
out as described in 10.3. A stable level of spraying can be achieved by either controlling the level of salt
solution in the reservoir or restricting the flow of salt solution to the atomizer such that a continuous
spray is achieved.
Distilled or deionized water with a conductivity not higher than 20 µS/cm at 25 °C shall be used for
humidification of spray air.
6.5 Collecting devices
At least two collecting devices shall be used to check the homogeneity of the spraying of the cabinet.
Suitable funnels shall be made of chemically inert material, with the stems inserted into graduated
cylinders or other similar containers and have a diameter of 100 mm, which corresponds to a collecting
area of approximately 80 cm . The collecting devices shall be placed in the zone of the cabinet where the
test specimens are placed. They shall be placed so that only mist, and not liquid falling from specimens
or from parts of the cabinet, is collected.
The collecting devices shall be placed as follows.
a) During the test, two collecting devices should be placed at central points in the zone (see Annex E
for an example).
ISO 9227:2022(E)
b) For calibration purposes, the collection rate of the cabinet shall be verified with at least six collecting
devices, which are placed at the four corners and two central points of the zone (see Annex E for
an example). This verification is done without test specimens in the cabinet, but preferably with
substitute specimens (see also 10.2). It is recommended to perform it after installation, a move,
modifications, adjustments or repair of the cabinet, after detecting nonconformities of the spray
collection rate during running tests [see a)], and after idle periods longer than four weeks.
c) If the collecting devices cannot be placed at four corners and/or at the central two points in the
zone, they may be placed at another point by agreement between the interested parties. The
number of collecting devices placed may also be changed according to the size of the cabinet by the
agreement between the interested parties. In those cases, it shall be stated in the test report.
NOTE During permanent operation, a reasonable time period of the verification of the collection rate of the
cabinet is generally considered to be three months.
When nonconforming spray collection rates are found during verification [see b)], the cabinet shall be
adjusted or the test specimens shall not be placed in the nonconforming area.
6.6 Re-use
If the cabinet has been used once for an AASS or CASS test, or has been used for any other purpose
with a solution differing from that specified for the NSS test, it shall not be used for the NSS test until
a thorough cleaning procedure has been completed and the pH of collected solution has been verified
by the method in 5.2.2 and the corrosivity of the cabinet verified by the method in Clause 7 to not be
significantly affected by previous tests.
Additionally, it is recommended to check that the copper concentration in the collected solution is below
the allowed limit of 2,5 mg/l (see 5.1), better below 0,5 mg/l, when the cabinet was previously used for
CASS, but should now be used for AASS or NSS.
NOTE It is very difficult to clean a cabinet sufficiently that was once used for AASS or CASS testing so that it
can be used for an NSS test.
7 Method for evaluating cabinet corrosivity
7.1 General
To determine the corrosivity of the cabinet, reference specimens made of steel shall be used. It is
necessary to verify the cabinet at regular intervals as described in 7.2 to 7.4.
NOTE 1 During permanent operation, a reasonable time period between two checks of the corrosivity of the
cabinet is generally considered to be three months.
As a complement to the reference specimens made of steel, high-purity zinc reference specimens may
also be exposed in the tests in order to determine the corrosivity against this metal as described in
Annex B.
NOTE 2 The corrosivity of the cabinet verified with steel or high-purity zinc reference specimens via their
mass loss does not guarantee reproducible times to the occurrence of certain corrosion products on coated
specimens from industrial production.
7.2 Reference specimens
To verify the apparatus, use at least four reference specimens of 1,0 mm ± 0,2 mm thickness and
150 mm × 70 mm of CR4-grade steel in accordance with ISO 3574 with an essentially faultless surface
and a matt finish (arithmetical mean deviation of the profile Ra = 0,8 µm ± 0,3 µm). Cut these reference
specimens from cold-rolled plates or strips. Alternatively to CR4-grade steel, the following steel grades
ISO 9227:2022(E)
can be used, DC04 and DC05 according to EN 10130 and UNS G10080 according to SAE HS-1086 with
reference to the results of the interlaboratory comparison (see Annex F).
NOTE 1 “Essentially faultless” means free from pores, marks, scratches and any light colouration.
Clean the reference specimens carefully, immediately prior to testing. Besides the specifications
given in 8.2 and 8.3, cleaning shall eliminate all those traces (dirt, oil or other foreign matter) that can
influence the test results.
Thoroughly clean the reference specimens with an appropriate organic solvent (such as a hydrocarbon
with a boiling point between 60 °C and 120 °C) using a clean soft brush or a soft cloth, a non-woven
lint-free cloth, that does not leave any remains, or an ultrasonic cleaning device. Carry out the cleaning
in a vessel full of solvent. After cleaning, rinse the reference specimens with fresh solvent and then dry
them.
NOTE 2 Cleaning with isopropanol can lead to a film of residues on the specimen surface.
WARNING — Most organic solvents are flammable liquids, toxic and irritating. Refer to the
safety data sheet for details. Handling of organic solvents shall be restricted to skilled personnel
or conducted under their control. Care shall be taken in the disposal of these solvents.
Determine the mass of the reference specimens to ±1 mg. Protect one face of the reference specimens
with a removable coating, e.g. an adhesive plastic film. The edges of the reference specimens may be
protected by the adhesive tape as well.
7.3 Arrangement of the reference specimens
Position at least four steel reference specimens in four quadrants (if six specimens are available, place
them in six different positions including four quadrants) in the zone of the cabinet where the test
specimens are placed, with the unprotected face upwards, and at an angle of 20° ± 5° from the vertical.
The support for the reference specimens shall be made of, or coated with, inert materials such as
plastics. The top of the collecting device should be in level with lower edge of the reference specimens
or at the mean reference specimen exposure height.
The cabinet should be verified during the testing of test specimens. If this is the case, great care shall be
taken that the specimens do not affect each other. Otherwise, the cabinet shall be filled with substitute
specimens to maintain the homogeneity of the cabinet. The verification procedure shall be performed
using the same settings as for the test runs.
7.4 Determination of mass loss (mass per area)
At the end of the test with duration according to Table 2, immediately take the reference specimens out
of the test cabinet and remove the protective coating. Remove the corrosion products by mechanical
and chemical cleaning, as described in ISO 8407. As one possibility of chemical cleaning, use a solution
of diammonium hydrogen citrate [(NH ) HC H O ] (recognized analytical grade) in water with a
4 2 6 5 7
concentration of 200 g/l for 10 min at 23 °C.
After each stripping, thoroughly clean the reference specimens at ambient temperature with water,
then with ethanol, followed by drying.
Weigh the reference specimens to the nearest 1 mg. Divide the determined mass loss by the area of the
exposed surface area of the reference specimen in order to assess the metal mass loss per square metre
of the reference specimen.
It is recommended that freshly prepared solution be used during each procedure for the removal of
corrosion products.
ISO 9227:2022(E)
7.5 Satisfactory performance of cabinet
The cabinet has not performed satisfactorily if the mass loss of steel reference specimen is outside the
allowed ranges given in Table 2.
[14]
Table 2 — Allowed range of mass loss of the steel reference specimens during verification
of the corrosivity of the cabinet
Test method Test duration Allowed range of mass loss
h g/m
NSS 48 70 ± 20
AASS 24 40 ± 10
CASS 24 55 ± 15
NOTE See Annex B for the use of a zinc reference specimen.
8 Test specimens
8.1 The number and type of test specimens, their shape and their dimensions shall be selected in
accordance with the specification for the material or product being tested. When not specified, these
parameters shall be mutually agreed between the interested parties. Unless otherwise specified
or agreed, test specimens with an organic coating to be tested shall be made from burnished steel
conforming to ISO 1514, and of approximate dimensions 150 mm × 100 mm × 1 mm. Annex C describes
how test specimens with organic coatings shall be prepared for testing. Annex D gives supplementary
information needed for testing test specimens with organic coatings.
8.2 The test spec
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