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 and 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.
Volvo STD 1027,14
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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