Test Standard Type: Cyclic Corrosion Test (CCT) Standards

Volvo Laboratory Accelerated Cyclic Corrosion Test

Volvo also Refer to this test as ACT -2.

This test procedure serves as a general purpose atmospheric corrosion test and can be applied to a wide variety of materials, coatings and interactions of materials. It has been developed to allow the evaluation of the corrosion resistance of metals in environments where there is a significant influence of chloride ions, mainly as sodium chloride from a marine source or by winter road de-icing salt. This test 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. The first 5 days comprise of the following 3 part repeating cycle. 6.0 hours exposure to a ‘wet’ climate of no less than 95% RH, at +25°C, with intermittent exposure to salt solution. This is followed by 2.5 hours climate controlled transition to 50°C & 70% RH. This is followed by 15.5 hours exposure to a constant climate of 50°C & 70% RH. The final 2 days comprise of 48.0 hours exposure to a constant climate of 50°C & 70% RH. This completes the total 7 day test cycle. The number of cycle repeats and therefore the test duration is variable.

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

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Accelerated atmospheric corrosion testing – Indoor Corrosion Test

This standard concerns determination of atmospheric corrosion resistance at an accelerated test. The test method has been developed to simulate the corrosion processes that take place on vehicles in a road environment where sodium chloride constitutes a dominating corrosive component.

For test objects exposed to special environmental conditions such as significant temperature changes in the engine compartment, or for materials like sealants and adhesives, an additional stage of exposure to wet conditions/low temperature/high temperature shall be included in the test procedure.

The test objects are placed in a test chamber permitting cycling of the relative humidity between two defined levels. The temperature is maintained at a constant level during the humidity cycling or, as an alternative, raised when changing to the lower humidity level. The controlled exposure to humidity is discontinued twice weekly by a wet exposure of the test objects using leaching acidified salt solution.

This solution is applied by means of spraying equipment or, as an alternative, by manual immersion so that, in addition to renewed salt exposure also leaching of corrosive products takes place on the test objects. This step is followed by a period of keeping the test objects wet and a subsequent period of forced drying (only when using automated precipitation) after which cycling of the humidity level is resumed.

In an alternative to the basic test method, the repeated exposure to leaching salt solution is replaced with an application of artificial dirt containing salt on the test objects. This procedure is applied before testing and is renewed every third week of testing.

This test is also referred to as a Volvo Indoor Corrosion Test, often abbreviated to VICT.

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Accelerated Atmospheric Corrosion Test (Volvo)

This test procedure defines an accelerated corrosion test method, to be used in assessing the corrosion resistance of metallic materials, with or without corrosion protection, where there is a significant influence of chloride ions (e.g.; sodium chloride) from a marine source or road de-icing salt. This test 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 a 1 week duration main test cycle, which is composed of 2 x 12 hour sub-cycles, one with controlled humidity cycling (sub-cycle 1) and the other including salt application (sub-cycle 2). Details as follows:

Sub-cycle 1

Step 1; 4.0 hours exposure to a constant climate of 95%RH at +35C. Step 2; exposure to a changing climate during which the humidity is reduced to 50%RH and the temperature increased to +45C, linearly, over a period of 2.0 hours. Step 3; 4.0 hours exposure to a constant climate of 50%RH at +45C. Step 4; exposure to a changing climate during which the humidity is increased to 95%RH and the temperature reduced to +35C, linearly, over a period of 2.0 hours.

Sub-cycle 2

On Mondays & Fridays sub-cycle 1 is replaced by the following;

Step 1; Spray with salt solution (from above) for 15 minutes. Step 2; 1 hour & 45 minutes exposure to a constant climate of 95-99%RH at +35C (test specimens to remain wet throughout). Steps 1 & 2 are then repeated in sequence twice to give a total period of 6.0 hours. Step 3; drying in a changing climate during which the humidity is reduced to 50%RH and the temperature increased to +45C, linearly, over a period of 2.0 hours. Step 4; 2.0 hours exposure to a constant climate of 50%RH at +45C. Step 5; exposure to a changing climate during which the humidity is increased to 95%RH and the temperature reduced to +35C, linearly, over a period of 2.0 hours.

Alternative sub-cycle 2

As an alternative to sub-cycle 2, samples may be completely immersed in salt solution instead of sprayed with salt solution, in which case step 1 of the above sub-cycle 2 is replaced with the following step;

Step 1; Immerse samples in salt solution for 15 minutes.

STD1027, 14 is a Volvo test standard.

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Scania Accelerated atmospheric corrosion testing – Indoor Corrosion Test

This Scania test is also known as the Volvo Indoor Corrosion Test STD 1027,1375. Click here for view details of the STD 1027,1375 standard test.

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Accelerated corrosion test

This standard defines an accelerated corrosion test method to be used in assessing the corrosion resistance of metals in environments where there is a significant influence of chloride ions, mainly as sodium chloride from a marine source or by winter road de-icing salt. It specifies a test procedure to be used in conducting the accelerated corrosion test to simulate atmospheric corrosion conditions in a controlled way.

The one-week main test cycle is composed of two twelve-hour sub-cycles, one with controlled humidity cycling; sub-cycle 1, the other including salt solution application, sub-cycle 2.

Sub cycle 1 requires constant conditions at 35°C & 95% RH for 4 h, followed by an increase of temperature to 45°C whilst reducing the humidity to 50% over a 2 hour period. This is followed by constant conditions of 45°C & 50% RH for 4 h, together with a 2 hour period of 35°C & 95% RH. Step 1:4) Temperature decrease from 45°C to 35°C

Sub cycle 2 requires spraying with salt solution for 15 mins then keeping the samples at 35°C for 1 h 45 min whilst maintaining a set point of 95% – 99% RH in such a way that the test objects remain wet. These steps are repeated in sequence to give a total period of 6 hours. Drying at 45°C & 50% RH for a 2hour period followed by a further 2 hour period of 35°C whilst maintaining 95% RH.

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

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