GB/T 10125-2021Corrosion tests in artificial atmospheres - Salt spray tests (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020

"Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents".

This document replaces GB/T 10125-2012 "Corrosion tests in artificial

atmospheres - Salt spray tests". Compared with GB/T 10125-2012, in addition

to structural adjustments and editorial changes, the main technical changes are

as follows.

- ADD the scope of application of the acetic acid salt spray test, copper

accelerated acetic acid salt spray test, as well as the unapplicable scope of

this method (see Chapter 1);

- MODIFY and ADD the normative references (see Chapter 2; Chapter 2 of

the 2012 edition);

- ADD Chapter 3 "Terms and definitions";

- ADD Chapter 4 "Principles";

- MODIFY the control requirements for the heavy metal impurity content of

sodium chloride, which is used in solution preparation (see 5.1; 3.1 of the

2012 edition);

- MODIFY the method of measuring the pH value of the collected spray

solution (see 5.2; 3.2 of the 2012 edition);

- ADD the requirements for specimen holders (see 6.1);

- DELETE the requirement that the volume of the salt spray chamber is not

less than 0.4 m3 (see 4.2 of the 2012 edition);

- ADD the new requirements for spraying in the salt spray chamber (see 6.2);

- MODIFY the requirements for the location of the temperature measurement

area (see 6.3; 4.3 of the 2012 edition);

- ADD the recommended value of spray pressure (see 6.4.2);

- MODIFY the requirements for compressed air humidification equipment

(see 6.4.3; 4.4 of the 2012 edition);

- ADD the guide value of the hot water temperature of the saturation tower,

at 160 MPa and 170 MPa spray pressure (see Table 1);

- ADD the operation method for obtaining stable, continuous, uniform spray

(see 6.4);

- ADD the precautions for cleaning after the salt spray chamber test (see 6.6);

- MODIFY the use quantity and treatment method of steel reference

specimens (see 7.2; 5.2.1, 5.3.1, 5.4.1 of the 2012 edition);

- MODIFY the number of steel reference specimens, which are placed in the

salt spray chamber, as well as the requirements for the verification method

of the salt spray chamber (see 7.3; 5.2.2, 5.3.2, 5.4.2 of the 2012 edition);

- DELETE the test time (see 5.2.2, 5.3.2, 5.4.2 of the 2012 edition);

- DELETE the method for removing steel corrosion products, which is

specified in ISO 8407 (see 5.2.3, 5.3.3, 5.4.3 of the 2012 edition);

- MODIFY the writing format of the performance evaluation method of salt

spray chamber for the neutral salt spray, acetic acid salt spray, copper

accelerated acetic acid salt spray test (see Chapter 7; Chapter 5 of the

2012 edition);

- ADD the parameter setting value requirements of the salt spray chamber

(see Table 3);

- ADD the precautions for the concentration and pH measurement of the salt

spray collection solution (see 10.2);

- ADD the recommended value for the test frequency of salt spray

sedimentation rate (see 10.3);

- ADD measures to prevent fluctuations in the concentration and pH of

sodium chloride solution (see 10.5);

- MODIFY the recommended value of the test period (see 11.1; 9.1 of the

2012 edition);

- ADD the requirement that the opening time of the salt spray chamber shall

not exceed 1 hour per day, during the test (see 11.2);

- ADD an overview of the test sample treatment method after the test (see

12.1);

- ADD the specific method for handling the test specimen of the organic

coating after the test (see 12.3);

- MODIFY the design diagram of the salt spray chamber (see Figure C.1,

Figure C.2; Figure A.1, Figure A.2 in Appendix A of the 2012 edition);

- MODIFY the number of zinc reference specimens, which are placed in the

salt spray chamber, as well as the requirements for the verification method

of the salt spray chamber (see D.1, D.2; B.1, B.2 of the 2012 edition);

- MODIFY the value of the distance between scratches on the organic

coating test specimens (see E.4; C.4 of the 2012 edition);

- MODIFY the Appendix G China's foreign standard year number (see

Appendix G; Appendix E of the 2012 edition);

- DELETE the "Appendix NA" (see Appendix NA of the 2012 edition).

This document uses the redrafting method, to modify and adopt ISO 9227.2017

"Corrosion tests in artificial atmospheres - Salt spray tests".

Compared with ISO 9227.2017, this document has more structural adjustments.

Appendix A lists the comparison of structural adjustment between this

document and ISO 9227.2017.

There are technical differences between this document and ISO 9227.2017.

The terms of these differences have been marked by a vertical single line (|),

on the outer margin of the document. Appendix B gives a list of the

corresponding technical differences and their reasons.

2012 This is the second revision.

1 Scope

This document specifies the equipment, reagents, methods for neutral salt

spray (NSS), acetic acid salt spray (AASS), copper accelerated acetic acid salt

spray (CASS) tests. This document also specifies methods for evaluating the

corrosiveness of the test chamber atmosphere.

2 Normative references

The following documents are essential to the application of this document. For

the dated documents, only the versions with the dates indicated are applicable

to this document; for the undated documents, only the latest version (including

all the amendments) is applicable to this standard.

GB/T 6461 Methods for corrosion testing of metallic and other inorganic

coatings on metallic substrates - Rating of test specimens and manufactured

articles subjected to corrosion tests (GB/T 6461-2002, ISO 10289.1999, IDT)

GB/T 9271 Paints and varnishes standard panels for testing (GB/T 9271-

2008, ISO 1514.2004, MOD)

GB/T 10123 Corrosion of metals and alloys - Basic terms and definitions

(GB/T 10123-2001, eqv ISO 8044-1999)

GB/T 13452.2 Paints and varnishes - Determination of film thickness (GB/T

13452.2-2008, ISO 2808.2007, IDT)

GB/T 16545 Corrosion of metals and alloys - Removal of corrosion products

from corrosion test specimens (GB/T 16545-2015, ISO 8407.2009, IDT)

GB/T 30786 Paints and varnishes - Guidelines for the introduction of scribe

marks through coatings on metallic panels for corrosion testing (GB/T

30786-2014, ISO 17872-2007, IDT)

3 Terms and definitions

The terms and definitions, as defined in GB/T 10123, as well as the following

terms and definitions, apply to this document.

3.1

Reference material

Materials with known test performance.

3.2

Reference specimen

Part of the reference material (3.1), which is to check the reproducibility

and repeatability of the test results of the test chamber used.

4 Principle

The neutral salt spray test (NSS) is a test method, for atomizing a 5%

sodium chloride neutral solution, in a controlled environment.

The acetic acid salt spray test (AASS) is a test method, in which a 5%

sodium chloride acid solution, added with glacial acetic acid, is atomized, in a

controlled environment.

5 Test solution

At a temperature of 25 °C +/- 2 °C, dissolve sodium chloride in distilled

water or deionized water, which has a conductivity of not higher than 20 µS/cm,

to prepare a solution, which has a concentration of 50 g/L +/- 5 g/L.

6 Test equipment

All components, which are in contact with salt spray or test solution, shall

be made of corrosion-resistant materials, which do not affect the corrosiveness

of the solution.

The spray in the chamber shall be evenly distributed. For the chambers,

which have a capacity of less than 0.4 m3, due to the capacity restriction, it shall

carefully consider the effect of the loading of the chamber on the spray

distribution and temperature.

7 Methods of evaluating the performance of salt spray chamber

A steel reference specimen shall be used, to determine the corrosivity of the test.

As a supplement to the steel reference specimen, the high-purity zinc

reference specimen can be tested; the corrosion performance can be

determined, with reference to the provisions of Appendix D.

8 Test specimen

The type, quantity, shape, size of the test specimen shall be selected,

according to the relevant specifications of the tested material or product.

If the test specimen is cut from a workpiece, which has a covering layer, it

shall not damage the covering layer near the cutting area.

9 Placement of test specimens

The test specimen shall not be placed, where the salt mist is directly sprayed.

The test specimen holder shall be made of inert non-metallic materials.

10 Test conditions

Due to the different performance of the empty and fully loaded test

chambers, check the salt spray sedimentation rate and other test conditions of

the test chamber, with a similar loading volume, during the test.

11 Test period

The test period shall be selected, according to the relevant standards of

the tested material or product. If there is no standard, it can be negotiated and

agreed by related parties. The recommended test cycle is 2 h, 6 h, 24 h, 48 h,

96 h, 168 h, 240 h, 480 h, 720 h, 1008 h.

12 Handling of test specimens after the test

How to handle the test specimen, after the test, shall be included in the test

specification or material specification, which is provided by the customer.

13 Evaluation of test results

The appropriate evaluation standard for the tested coating or product shall be

determined in good engineering practice.

14 Test report

The test report shall state the test results, in accordance with the result

evaluation criteria.

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