ASTM D1654 test method is used for evaluation and comparison of basic corrosion performance of a painted substrate, coating system or pretreatment, or a combination of both after exposure to corrosive environments. Painted or coated samples are tested under accelerated and atmospheric exposure conditions.
Procedure A (Evaluation of rust creepage for scribed samples): Each sample is rinsed after completion of the exposure period using water at a temperature up to 45 °C. Then, the coating is removed along with scribe with one of the following methods (scraping, knife, paint stripper, air blow-off, power washer) in such a way that corrosion of the substrate can be observed. The maximum and minimum creepage is noted from the scribe.
Procedure B (Evaluation of unscribed areas): The photographic blister standards are used as stated by ASTM D714 to determine the results of the blister exposure test. Exposure with respect to rusting is specified by ASTM D610 guidelines.
Procedure C is used to evaluate unprotected edges and Procedure D is used to evaluate dimples, bends or other formed areas in a painted or coated sample.
The samples are prepared utilizing normal production processes. The standard sample dimensions are 36 inches but this can vary upon mutual agreement between user and producer.
The rust creepage is determined by the use of an arithmetic mean. The creep values are given millimeters, inches, or rating numbers as specified by the ASTM D1654 guidelines.
wc= mean overall width of the corrosion zone
w= width of the original scribe