Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2012)

MINOR REVISION

Korrosionsprüfungen in künstlichen Atmosphären - Salzsprühnebelprüfungen (ISO 9227:2012)

Diese Internationale Norm legt das Gerät, die Reagenzien und das anzuwendende Verfahren bei der Durchführung der neutralen Salzsprühnebelprüfung (NSS, neutral salt spray), der Essigsäure-Salzsprüh-nebelprüfung (AASS, acetic acid salt spray) und der kupferbeschleunigten Essigsäure-Salzsprühnebelprüfung (CASS, copper-accelerated acid salt spray) zum Beurteilen der Korrosionsbeständigkeit von metallischen Werkstoffen mit oder ohne ständigen Korrosionsschutz oder mit temporärem Korrosionsschutz fest.
Die Norm beschreibt auch das Verfahren, mit dem die Korrosivität in der Prüfkammer bewertet werden kann.
Die Norm legt nicht die Maße der Proben, die für ein bestimmtes Produkt anzuwendende Dauer der Beanspruchung oder die Interpretation 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 Oxidschichten und Umwandlungsschichten.
Die neutrale Salzsprühnebelprüfung ist das Prüfverfahren, bei dem eine 5%ige Natriumchlorid-Lösung mit einem pH Wert von 6,5 bis 7,2 unter festgelegten Bedingungen versprüht wird. Sie gilt insbesondere für:
-   Metalle und deren Legierungen,
-   (anodisch oder kathodisch wirksame) Metallüberzüge,
-   Umwandlungsschichten,
-   anodische Oxidschichten und
-   organische Beschichtungen auf metallischen Werkstoffen.
Die Essigsäure-Salzsprühnebelprüfung ist das Prüfverfahren, bei dem eine 5%ige Natriumchlorid-Lösung, der Eisessig zugesetzt wurde, mit einem pH Wert von 3,1 bis 3,3 unter festgelegten Bedingungen versprüht wird. Sie ist besonders nützlich zum Prüfen dekorativer Überzüge aus Kupfer + Nickel + Chrom oder Nickel + Chrom. Sie ist auch zum Prüfen anodischer Schichten auf Aluminium geeignet.
Die kupferbeschleunigte Essigsäure-Salzsprühnebelprüfung ist das Prüfverfahren, bei dem eine 5%ige Natriumchlorid-Lösung, der Kupferchlorid und Eisessig zugesetzt wurde, mit einem pH Wert von 3,1 bis 3,3 unter festgelegten Bedingungen versprüht wird. Sie ist nützlich zum Prüfen dekorativer Überzüge aus Kupfer + Nickel + Chrom oder Nickel + Chrom. Sie ist auch zum Prüfen anodischer Überzüge auf Aluminium geeignet.
Alle Salzsprühnebelverfahren sind geeignet zum vergleichenden Prüfen, ob die Qualität eines metallischen Werkstoffes, mit oder ohne Korrosionsschutz, beibehalten wird. Sie ist nicht als Vergleichsprüfung gedacht, um unterschiedliche Werkstoffe nach ihrer Korrosionsbeständigkeit einzustufen.

Essais de corrosion en atmosphères artificielles - Essais aux brouillards salins (ISO 9227:2012)

Korozijsko preskušanje v umetnih atmosferah - Korozijski preskusi v slani komori (ISO 9227:2012)

Ta mednarodni standard določa naprave, reagente in postopek za izvajanje korozijskih preskusov v nevtralni slani komori (NSS), slani komori z ocetno kislino (AASS) in slani komori z ocetno kislino, pospešeno 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 preskušancev, časa izpostavljenosti za določen izdelek ali razlage rezultatov. Te podrobnosti so navedene v ustreznih specifikacijah izdelkov. Korozijski preskusi v slani komori so še posebej uporabni za zaznavanje nepravilnosti, kot so pore in druge napake v določenih kovinskih, organskih, anodno oksidnih in reakcijskih prevlekah. Preskus v nevtralni slani komori je preskusna metoda, pri kateri se v nadzorovanem okolju razprši 5-odstotno raztopino natrijevega klorida, ki ima pH vrednost med 6,5 in 7,2. Uporablja se zlasti za: – kovine in njihove zlitine, – kovinske prevleke (anodne in katodne), – reakcijske prevleke, – anodno oksidne prevleke in – organske prevleke na kovinskih materialih. Preskus v slani komori z ocetno kislino je preskusna metoda, pri kateri se v nadzorovanem okolju razprši 5-odstotno raztopino natrijevega klorida z dodano ledocetno kislino, ki ima pH vrednost med 3,1 in 3,3. Posebno uporabna je za preskušanje dekorativnih prevlek z bakrom–nikljem–kromom ali kromnikljem. Ugotovljeno je bilo tudi, da je primerna za preskušanje anodnih prevlek na aluminiju. Preskus v slani komori z ocetno kislino, pospešeno z bakrom, je preskusna metoda, pri kateri se v nadzorovanem okolju razprši 5-odstotno raztopino natrijevega klorida z dodanim bakrovim kloridom in ledocetno kislino, ki ima pH vrednost med 3,1 in 3,3. Uporabna je za preskušanje dekorativnih prevlek z bakrom–nikljem–kromom ali kromnikljem. Ugotovljeno je bilo tudi, da je primerna za preskušanje anodnih prevlek na aluminiju. Vse metode preskušanja v slani komori so ustrezne za preverjanje vzdrževanja primerjalne kakovosti kovinskih materialov s protikorozijsko zaščito ali brez. Niso namenjene za uporabo pri primerjalnih preskusih kot sredstvo za razvrščanje različnih materialov glede na odpornost proti koroziji.

General Information

Status
Withdrawn
Publication Date
30-May-2012
Withdrawal Date
15-May-2017
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
10-May-2017
Due Date
02-Jun-2017
Completion Date
16-May-2017

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SLOVENSKI STANDARD
SIST EN ISO 9227:2012
01-julij-2012
1DGRPHãþD
SIST EN ISO 9227:2006
SIST EN ISO 9227:2006
Korozijsko preskušanje v umetnih atmosferah - Korozijski preskusi v slani komori
(ISO 9227:2012)
Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2012)
Korrosionsprüfungen in künstlichen Atmosphären - Salzsprühnebelprüfungen (ISO
9227:2012)

Essais de corrosion en atmosphères artificielles - Essais aux brouillards salins (ISO

9227:2012)
Ta slovenski standard je istoveten z: EN ISO 9227:2012
ICS:
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 9227:2012 en,fr

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

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SIST EN ISO 9227:2012
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SIST EN ISO 9227:2012
EUROPEAN STANDARD
EN ISO 9227
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2012
ICS 77.060 Supersedes EN ISO 9227:2006
English Version
Corrosion tests in artificial atmospheres - Salt spray tests (ISO
9227:2012)

Essais de corrosion en atmosphères artificielles - Essais Korrosionsprüfungen in künstlichen Atmosphären -

aux brouillards salins (ISO 9227:2012) Salzsprühnebelprüfungen (ISO 9227:2012)
This European Standard was approved by CEN on 14 May 2012.

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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9227:2012: E

worldwide for CEN national Members.
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SIST EN ISO 9227:2012
EN ISO 9227:2012 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST EN ISO 9227:2012
EN ISO 9227:2012 (E)
Foreword

This document (EN ISO 9227:2012) has been prepared by Technical Committee ISO/TC 156 "Corrosion of

metals and alloys" in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the

secretariat of which is held by DIN.

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 November 2012, and conflicting national standards shall be withdrawn

at the latest by November 2012.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 9227:2006.

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, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice

The text of ISO 9227:2012 has been approved by CEN as a EN ISO 9227:2012 without any modification.

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SIST EN ISO 9227:2012
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SIST EN ISO 9227:2012
INTERNATIONAL ISO
STANDARD 9227
Third edition
2012-05-15
Corrosion tests in artificial
atmospheres — Salt spray tests
Essais de corrosion en atmosphères artificielles — Essais aux
brouillards salins
Reference number
ISO 9227:2012(E)
ISO 2012
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SIST EN ISO 9227:2012
ISO 9227:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s

member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 9227:2012
ISO 9227:2012(E)
Contents Page

Foreword ............................................................................................................................................................................iv

Introduction ........................................................................................................................................................................ v

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

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

3 Test solutions ....................................................................................................................................................... 2

3.1 Preparation of the sodium chloride solution ............................................................................................... 2

3.2 pH adjustment ...................................................................................................................................................... 2

3.3 Filtration ................................................................................................................................................................. 2

4 Apparatus .............................................................................................................................................................. 3

4.1 Component protection ....................................................................................................................................... 3

4.2 Spray cabinet ........................................................................................................................................................ 3

4.3 Heater and temperature control ...................................................................................................................... 3

4.4 Spraying device ................................................................................................................................................... 3

4.5 Collecting devices ............................................................................................................................................... 4

4.6 Re‑use ..................................................................................................................................................................... 4

5 Method for evaluating cabinet corrosivity .................................................................................................... 4

5.1 General ................................................................................................................................................................... 4

5.2 NSS test ................................................................................................................................................................. 5

5.3 AASS test ............................................................................................................................................................... 6

5.4 CASS test ............................................................................................................................................................... 7

6 Test specimens .................................................................................................................................................... 8

7 Arrangement of the test specimens ............................................................................................................... 8

8 Operating conditions .......................................................................................................................................... 9

9 Duration of tests .................................................................................................................................................. 9

10 Treatment of specimens after test ................................................................................................................10

11 Evaluation of results .........................................................................................................................................10

12 Test report ...........................................................................................................................................................10

Annex A (informative) Schematic diagram of one possible design of spray cabinet with means for

treating fog exhaust and drain .......................................................................................................................12

Annex B (informative) Complementary method for evaluating cabinet corrosivity using zinc

reference specimens ........................................................................................................................................14

Annex C (normative) Preparation of panels with organic coatings for testing ...............................................16

Annex D (normative) Required supplementary information for testing test panels with organic coatings ..17

Bibliography .....................................................................................................................................................................18

© ISO 2012 – All rights reserved iii
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SIST EN ISO 9227:2012
ISO 9227:2012(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 9227 was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.

This third edition cancels and replaces the second edition (ISO 9227:2006), of which it constitutes a minor revision.

iv © ISO 2012 – All rights reserved
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SIST EN ISO 9227:2012
ISO 9227:2012(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 might 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.

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.

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.
© ISO 2012 – All rights reserved v
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SIST EN ISO 9227:2012
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SIST EN ISO 9227:2012
INTERNATIONAL STANDARD ISO 9227:2012(E)
Corrosion tests in artificial atmospheres — Salt spray tests
1 Scope

This International Standard 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 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 neutral salt spray test is the test method in which a 5 % sodium chloride solution in the pH range from 6,5

to 7,2 is atomized under a controlled environment. It particularly applies to:
— metals and their alloys,
— metallic coatings (anodic and cathodic),
— conversion coatings,
— anodic oxide coatings, and
— organic coatings on metallic materials.

The acetic acid salt spray test is the test method in which a 5 % sodium chloride solution with the addition of

glacial acetic acid in the pH range from 3,1 to 3,3 is atomized under a controlled environment. It is especially

useful for testing decorative coatings of copper + nickel + chromium, or nickel + chromium. It has also been

found suitable for testing anodic coatings on aluminum.

The copper-accelerated acetic acid salt spray test is the test method in which a 5 % sodium chloride solution

with the addition of copper chloride and glacial acetic acid in the pH range from 3,1 to 3,3 is atomized under

a controlled environment. It is useful for testing decorative coatings of copper + nickel + chromium, or

nickel + chromium. It has also been found suitable for testing anodic coatings on aluminum.

The salt spray methods are all suitable for checking that the comparative 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.

2 Normative references

The following referenced documents are indispensable for the application 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 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens

© ISO 2012 – All rights reserved 1
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SIST EN ISO 9227:2012
ISO 9227:2012(E)

ISO 17872, Paints and varnishes — Guidelines for the introduction of scribe marks through coatings on metallic

panels for corrosion testing
3 Test solutions
3.1 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 ± 2 °C to produce a concentration of 50 g/l ± 5 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.

The sodium chloride shall contain less than 0,001 % mass fraction of copper and less than 0,001 % mass

fraction of nickel, as determined by atomic absorption spectrophotometry or another analytical method of

similar sensitivity. It shall not contain more than 0,1 % of a mass fraction of sodium iodide, or more than 0,5 %

of a mass fraction of total impurities calculated for dry salt.

NOTE If the pH of the prepared solution at 25 °C ± 2 °C is outside the range 6,0 to 7,0, investigate the presence of

undesirable impurities in the salt and/or the water.
3.2 pH adjustment
3.2.1 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.

3.2.2 NSS test

Adjust the pH of the salt solution (3.1) so that the pH of the sprayed solution collected within the test

cabinet (4.2) is 6,5 to 7,2 at 25 °C ± 2 °C. Check the pH using electrometric measurement or in routine checks,

with a short-range pH paper, which can be read in increments or 0,3 pH units or less. Make any necessary

corrections by adding hydrochloric acid, sodium hydroxide or sodium bicarbonate solution of analytical grade.

Possible changes in pH may result from loss of carbon dioxide from 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.

3.2.3 AASS test

Add a sufficient amount of glacial acetic acid to the salt solution (3.1) to ensure that the pH of samples of

sprayed solution collected in the test cabinet (4.2) is between 3,1 and 3,3. 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 at 25 °C ± 2 °C, or in routine checks, with a short-range pH paper which can

be read in increments of 0,1 pH units or less. Make any necessary corrections by adding glacial acetic acid or

sodium hydroxide of analytical grade.
3.2.4 CASS test

Dissolve a sufficient mass of copper(II) chloride dihydrate (CuCl⋅2H O) in the salt solution (3.1) to produce a

2 2

concentration of 0,26 g/l ± 0,02 g/l [equivalent to (0,205 ± 0,015) g of CuCl per litre].

Adjust the pH using the procedures described in 3.2.3.
3.3 Filtration

If necessary, filter the solution before placing it in the reservoir of the apparatus, to remove any solid matter

which might block the apertures of the spraying device.
2 © ISO 2012 – All rights reserved
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SIST EN ISO 9227:2012
ISO 9227:2012(E)
4 Apparatus
4.1 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.

4.2 Spray cabinet

The cabinet shall be such that the conditions of homogeneity and distribution of the spray are met. The upper

parts of the cabinet shall be designed so that drops of sprayed solution formed on its surface do not fall on the

specimens being tested.

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 Table 2, measured as specified in 8.3.

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 drawing water prior to discharging it to

the drainage system.

NOTE A schematic diagram of one possible design of spray cabinet is shown in Annex A.

4.3 Heater and temperature control

An appropriate system maintains the cabinet and its contents at the specified temperature (see Table 2). The

temperature shall be measured at least 100 mm from the walls.
4.4 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.

The compressed air supplied to the atomizers shall be passed through a filter 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 should

be 98 kPa ± 10 kPa.

NOTE Atomizing nozzles can have a “critical pressure” at which an abnormal increase in the corrosiveness of the salt

spray occurs. If the “critical pressure” of a nozzle has not been established with certainty, control of fluctuations in the air

pressure within ±0,7 kPa, by installation of a suitable pressure regulator valve, minimizes the possibility that the nozzle will

be operated at its “critical pressure”.

In order to prevent the evaporation of water from the sprayed droplets, the air shall be humidified before

entering the atomizer by passing through a saturation tower containing hot distilled water or deionized water at

a temperature 10 °C above that of the cabinet. The appropriate temperature depends on the pressure used and

on the type of atomizer nozzle and shall be adjusted so that the rate of collection of spray in the cabinet and the

concentration of the collected spray are kept within the specified limits (see 8.3). In Table 1, guiding values are

given for the hot-water temperature in the saturation tower at different pressures. The level of the water shall

be maintained automatically to ensure adequate humidification.
1) 1 kPa = 1 kN/m = 0,01 atm = 0,01 bar = 0,145 psi.
© ISO 2012 – All rights reserved 3
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SIST EN ISO 9227:2012
ISO 9227:2012(E)

Table 1 — Guiding values for the temperature of the hot water in the saturation tower

Atomizing Guiding values for the temperature, in °C, of the hot water in the
overpressure saturation tower when performing the different salt spray tests
Neutral salt spray (NSS) and Copper‑accelerated acetic acid
kPa
acetic acid salt spray (AASS) salt spray (CASS)
70 45 61
84 46 63
98 48 64
112 49 66
126 50 67
140 52 69

The atomizers shall be made of inert material. Baffles 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

level of the salt solution in the salt reservoir shall be maintained automatically to ensure uniform spray delivery

throughout the test.
4.5 Collecting devices

At least two suitable collecting devices shall be available, consisting of funnels made of chemically inert

material, with the stems inserted into graduated cylinders or other similar containers. Suitable funnels 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, one close to an inlet of spray

and one remote from an inlet. They shall be placed so that only mist, and not liquid falling from specimens or

from parts of the cabinet, is collected.
4.6 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.

It is nearly impossible to clean a cabinet that was once used for AASS or CASS testing so that it can be used

for an NSS test. However, in such circumstances, the equipment shall be thoroughly cleaned and checked

using the method described in Clause 5, ensuring in particular that the pH of the collected solution is correct

throughout the entire spraying period. After this procedure, the specimens to be tested are placed in the cabinet.

5 Method for evaluating cabinet corrosivity
5.1 General

To check the reproducibility and repeatability of the test results for one piece of apparatus, or for similar items

of apparatus in different laboratories, it is necessary to verify the apparatus at regular intervals as described

in 5.2 to 5.4.

NOTE During permanent operation, a reasonable time period between two checks of the corrosivity of the apparatus

is generally considered to be 3 months.

To determine the corrosivity of the tests, reference-metal specimens made of steel shall be used.

As a complement to the reference-metal specimens made of steel, high-purity zinc reference-metal specimens

may also be exposed in the tests in order to determine the corrosivity against this metal as described in Annex B.

4 © ISO 2012 – All rights reserved
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SIST EN ISO 9227:2012
ISO 9227:2012(E)
5.2 NSS test
5.2.1 Reference specimens

To verify the apparatus, use four or six reference specimens of 1 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.

Clean the reference specimens carefully, immediately prior to testing. Besides the specifications given in 6.2

and 6.3, cleaning shall eliminate all those traces (dirt, oil or other foreign matter) that could 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 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.

Determine the mass of the reference specimens to ±1 mg. Protect one face of the reference specimens with

a removable coating, for example an adhesive plastic film. The edges of the reference test specimens may be

protected by the adhesive tape as well.
5.2.2 Arrangement of the reference specimens

Position 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

lower edge of the reference specimens shall be level with the top of the salt spray collector. The test duration

shall be 48 h.

The test cabinet shall be filled with dummy specimens of inert materials, such as plastic or glass, during the

verification procedure.
5.2.3 Determination of mass loss (mass per area)

At the end of the test, 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.

For chemical cleaning, use a solution with a mass fraction of 20 % of diammonium citrate [(NH ) HC H O ]

4 2 6 5 7
(recognized analytical grade) in water 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 remov

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