ASTM B537

ASTM B537 – Standard Practice for Rating of Electroplated Panels Subjected to Atmospheric Exposure

Description:

Abstract

This practice covers the recommended method for rating the condition of electroplated test panels subjected to corrosive environments for test purposes. This method is used with standard-sized panels exposed on standard ASTM racks at outdoor test sites in both natural atmospheres and accelerated test conditions. This practice refers only to decorative-protective coatings that are cathodic to the substrate such as nickel/chromium or copper/nickel/chromium on steel or zinc die castings, and is not intended for use with anodic sacrificial coatings such as zinc and cadmium on steel. Any modifications needed to adapt the method to rating actual production parts are not considered here. Panels shall be assigned separate rating numbers based on the ability of the coating to protect the substrate from corrosion (protection rating), and the overall appearance of panels as affected by deterioration of the coating itself (appearance rating). Accordingly, rating numbers shall be derived from the type of defect that exists, that is: (1) protection defects, which include crater rusting, pinhole rusting, rust stains, blisters, and other defects that involve basis metal corrosion; and (2) appearance defects, which include surface pits, “crow’s feet,” crack patterns, surface stains, tarnishes, and other defects that detract from commercial acceptability as to appearance. Inspection should be made in the as-is condition, and defects to be taken into account are only those that can be seen with the unaided eye at normal reading distance.

Scope

1.1 This practice covers a preferred method for evaluating the condition of electroplated test panels that have been exposed to corrosive environments for test purposes. It is based on experience in use of the method with standard 10- by 15-cm (4- by 6-in.) panels exposed on standard ASTM racks at outdoor test sites in natural atmospheres. It has been used also for rating similar panels that have been subjected to accelerated tests such as those covered by Practice B117, Method B287, Test Method B368, and Test Method B380. Any modifications needed to adapt the method to rating actual production parts are not considered in this practice.

1.2 This practice refers only to decorative-protective coatings that are cathodic to the substrate, typified by nickel/chromium or copper/nickel/chromium on steel or zinc die castings. It is not intended for use with anodic sacrificial coatings such as zinc and cadmium on steel.