ASTM International Committee B08 on Metallic and Inorganic Coatings has recently approved a revision of one of its most important standards, B 633, Specification for Electrodeposited Coatings of Zinc on Iron and Steel. B 633 is under the jurisdiction of Task Group B08.08.04 on Soft Metals, which is part of Subcommittee B08.08 on Metallic Coatings.
Zinc coatings are used to provide a sacrificial metal that prevents corrosion, protecting the base metal. These coatings are used extensively for building hardware, highways, fasteners, appliances, transportation and industrial applications.
The primary changes to B 633 involve three areas: expanding the stress relief and hydrogen embrittlement treatments to be consistent with B 849, Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement, and B 850, Guide for Post-Coating Treatments of Steel for Reducing the Risk of Hydrogen Embrittlement; the addition of non-chromate coatings to comply with the European Union directive 2002/95/EC, Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment; and changes to the language to eliminate ambiguous use of may, can, should and shall statements to comply with federal guidelines for procurement.
B 633 was originally published in 1978 and incorporated a unified technology describing heat treatments for stress relief and hydrogen embrittlement and post treatments using chromates. Since the original standard was issued, several changes have occurred in the industry, including the advent of RoHS.
Technical Information: Phil Stapleton, Stapleton Company, Long Beach, Calif.
ASTM Staff: Diane Rehiel