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.
JASO M 609
Corrosion test method for Automotive Materials
This standard specifies a test method to determine the corrosion resistance of steel sheets for automotive use. 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 salt spray at +35C according JIS Z 2371. This is followed by 4.0 hours of air drying in a climate of 20 to 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.
Please see elsewhere in this document for details of JIS Z 2371.
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.