The test standard summaries are for general guidance only. Though believed to be accurate at the time of writing, this may change over time. So this information should not be used as a substitute for referring to a complete test standard, at an appropriate revision level.
Note: the terms salt spray, salt mist & salt fog are all in wide spread use within corrosion test standards. In this context they can be considered to be equivalent and interchangeable terms.
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 7 day main test cycle is composed of two twelve-hour sub-cycles, one with controlled humidity cycling, the other including salt solution application.
Sub cycle 1 requires four hours of constant conditions at 35°C & 95% RH, 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 four hours, followed by a 2 hour period of transition to 35°C & 95% RH
Sub cycle 2 requires spraying with salt solution for 15 mins then subjecting the samples to 35°C for one hour forty five minutes whilst maintaining a relative humidity of 95% – 99% RH to ensure the test samples remain wet. These steps are repeated to give a total period of 6 hours. This is followed by drying at 45°C & 50% RH for a two hour period followed by a further 2 hours of 35°C whilst maintaining 95% RH.
This test is also referred to as a Cyclic Corrosion Test, often abbreviated to CCT, and is based on Volvo 423-0014.