INTERN TMS 4520 PDF

This specification covers the general coating requirements, coating performance and fastener torquetension requirements, quality, KCC, source approval and quality control, packing, shipping, and identification requirements, and designation on drawings.

APPLICATION

This specification covers the requirements for a black, corrosion resistant, non-electrolytically applied, water-based coating for steel substrates. The coating is heat-converted from an aqueous dispersion of zinc and aluminum flakes, and contains a PTFE lubricant dispersed throughout the topcoat. This coating system is free of both hexavalent and trivalent chromium, and is suitable for high hardness parts since hydrogen embrittlement is not induced by the process. This type of coating is intended for fasteners size M6 and larger, for exterior applications, as well as small steel clips, brackets, etc., requiring good corrosion resistance. It is not intended for use on internal recessed drive fasteners. This coating should not be used on parts which will come in contact with uncoated copper, magnesium, or stainless steel, but will provide good bi-metallic corrosion resistance when in contact with aluminum. Coating should not be used on materials which might be adversely affected by a cure temperature range of 288-315°C (550-600°F). The maximum continuous service temperature is 180°C (350°F).

Restricted Chemical Substances

Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the CEMS B-50 Specification.