Test Standard Type: Cyclic Corrosion Test (CCT) Standards

Corrosion of Metals & Alloys – accelerated testing involving cyclic exposure to salt mist, dry & wet conditions

This test method specifies the apparatus and procedure to be used in conducting accelerated corrosion tests for the comparative evaluation of metallic materials, with or without permanent/temporary corrosion protection, when exposed to a salt contaminated, simulated outdoor environment. It is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.

Test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following 3 part repeating cycle. 2.0 hours exposure to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +35C . This is followed by 4.0 hours of air drying in a climate of <30%RH at +60C. This is followed by 2.0 hours exposure to a condensing water climate (wetting) of 95 to 100%RH at +50C. The number of cycle repeats and therefore the test duration is variable.

The maximum transition times between each part of the test cycle are also specified as follows:

From salt spraying to air drying within 30 minutes.

From air drying to wetting within 15 minutes.

From wetting to salt spraying within 30 minutes.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

This test is also referred to as a Cyclic Corrosion Test, often abbreviated to CCT., and is the international version of JASO M609/M610/CCT-1

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.

Accelerated corrosion test involving exposure under controlled conditions of humidity and intermittent spraying of salt solution

Accelerated corrosion tests to simulate atmospheric corrosion in such environments include cyclic exposure to a wet phase, during which the test object is repeatedly subjected first to a spray of salt solution then to a wet stand-by period for several hours. This is followed by a phase of controlled cyclic humidity conditions, where the test object is subjected to an environment which alternates between high humidity and comparative dryness.

In the first (wet) phase of exposure, the test objects are sprayed for 15 min with a 1% (mass fraction) aqueous solution of sodium chloride acidified to pH 4.2, to simulate the rather acidic precipitation present in industrialized areas, followed by a 1 h 45 min period of wet stand-by. This sequence is repeated three times to give a total of 6 h exposure to wetness. The whole of this first phase of the test cycle is repeated twice a week.

The major part of the test cycle, however, consists of humidity cycling between the two levels of 95 % RH and 50 % RH at a constant temperature of 35°C.

This test is also referred to as a Cyclic Corrosion Test, often abbreviated to CCT.

Paints & varnishes – determination of resistance to cyclic corrosion conditions, Part 1: wet(salt fog)/dry/humidity

This test method has been found to be useful for comparing the relative resistance to corrosion of paints, varnishes and similar materials, when exposed to a simulated aggressive outdoor environment, such as a marine environment. It is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.

3 different test cycles are defined within this test method, which are referred to as Cycle A, Cycle B & Cycle C.

Cycle A is based upon test CCT-4. Please see elsewhere in this document for details of CCT-4. This test method has been shown to correlate well with natural exposure for thermosetting paints. The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Cycle B is based upon test VDA 621-415. Please see elsewhere in this document for details of VDA 621-415. This test method has been shown to correlate well with natural exposure for thermosetting paints in vehicle corrosion. The number of cycle repeats is to be sufficient for 840 hours total test time, unless otherwise agreed.

Cycle C has been developed in the UK for use with water soluble and latex paint systems, and has been shown to correlate well with natural exposure. Cycle C test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following repeating cycle. 210 minutes exposure hours exposure to a continuous indirect spray of salt water solution, which falls-out on to the specimens at a rate of 2.0 to 4.0ml/80cm²/hour, in a chamber temperature of +25C. This is followed by 210 minutes exposure to an air drying climate at +40C (humidity unspecified). This is followed by 1470 minutes exposure to a controlled humidity climate of 75%RH at +40C. This is followed by 102 minutes exposure to an air drying climate at +25C (humidity unspecified). This is followed by 210 minutes exposure to a salt fog climate at +25C. This is followed by 378 minutes exposure to a condensing water climate of 95 to 100%RH at +30C. This is followed by 180 minutes exposure to an air drying climate at +35C (humidity unspecified). This is followed by 120 minutes exposure to an air drying climate at +25C (humidity unspecified). The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

These tests are also referred to as a Cyclic Corrosion Tests, often abbreviated to CCT.

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.

Paints & varnishes – determination of resistance to cyclic corrosion conditions, Part 1: wet(salt fog)/dry/humidity

This test method has been found to be useful for comparing the relative resistance to corrosion of paints, varnishes and similar materials, when exposed to a simulated aggressive outdoor environment, such as a marine environment. It is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.

3 different test cycles are defined within this test method, which are referred to as Cycle A, Cycle B & Cycle C.

Cycle A is based upon test CCT-4. Please see elsewhere in this document for details of CCT-4. This test method has been shown to correlate well with natural exposure for thermosetting paints. The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Cycle B is based upon test VDA 621-415. Please see elsewhere in this document for details of VDA 621-415. This test method has been shown to correlate well with natural exposure for thermosetting paints in vehicle corrosion. The number of cycle repeats is to be sufficient for 840 hours total test time, unless otherwise agreed.

Cycle C has been developed in the UK for use with water soluble and latex paint systems, and has been shown to correlate well with natural exposure. Cycle C test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following repeating cycle. 210 minutes exposure hours exposure to a continuous indirect spray of salt water solution, which falls-out on to the specimens at a rate of 2.0 to 4.0ml/80cm²/hour, in a chamber temperature of +25C. This is followed by 210 minutes exposure to an air drying climate at +40C (humidity unspecified). This is followed by 1470 minutes exposure to a controlled humidity climate of 75%RH at +40C. This is followed by 102 minutes exposure to an air drying climate at +25C (humidity unspecified). This is followed by 210 minutes exposure to a salt fog climate at +25C. This is followed by 378 minutes exposure to a condensing water climate of 95 to 100%RH at +30C. This is followed by 180 minutes exposure to an air drying climate at +35C (humidity unspecified). This is followed by 120 minutes exposure to an air drying climate at +25C (humidity unspecified). The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

These tests are also referred to as a Cyclic Corrosion Tests, often abbreviated to CCT.

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.