Full Description

This specification covers the basic requirements for electroplatedzinc applied to iron and steelsubstrates with provision for plating thickness, use or non-use ofsupplementary treatments andcorrosion resistance. Provision is also made to specify mechanicalplating.

Material Description. This coating system must be free of hexavalentchromium, per GMW3059requirements. The plating shall be shown on the part drawing as perthe example shown in Section 7.Table 1 lists the common types of finishes covered by thisspecification. However, it may benecessary to devise additional combinations of finishes as follows:(1) the first one or two digitsdepict the minimum plated metal thickness in micrometers; (2) thecharacter that follows indicatesthe use or non-use of supplementary (e.g. chromate) treatment; (3) theNeutral Salt Spray (NSS)hours to base metal/white corrosion are shown next; (4) the nextcharacter, when shown, indicatesthe use of a post-supplementary treatment (e.g. wax); (5) the finalcharacter, when shown,indicates the need to heat treat the finish prior to NSS testing; (6)the color may be indicated,if desired, in parentheses at the end of the suffix.

Cross-Reference of Replaced Specifications.

Typical Application. Zinc plating is typically applied on small tomedium-sized ferrous parts suchas castings, fasteners, stampings, and clips.

Zinc plated parts or their corrosion products must not come in contactwith stressed Polyamides 6or 66.

Zinc plating types without supplementary treatment are also used as abasecoat for an additionalpaint. This coating must be so applied that no negative influence inappearance and adhesionappears (e.g. blistering by effusion of hydrogen).