GMNA GM6046M PDF

This specification covers the basic requirements for fluorocarbon post treatments. It is supplied in black color unless otherwise specified.

Material Description. The coating system is free of hexavalent chromate, with no hexavalent chromate in final product per GMW3059 requirements. GMW3034 will be used as a referee test. The coating can be applied over any combination of zinc phosphate, zinc plate, iron phosphate or grit blast pretreatments. Substrate pretreatment requirements, where they exist, are to be shown separately on drawings or applicable documents.

Typical Application. The coating is suitable for simple formed metal parts, casting, fasteners, clips, and other ferrous parts which are not adversely affected by baking temperatures in the range of 150 to 190ºC. These coatings may also be used to reduce friction and wear on material surfaces or as an anti-scuff type finish. This specification covers 3 thickness of coatings.

Basic Considerations. This coating is not recommended for parts with recess drives. Fluorocarbon coatings are not recommended for screw and washer combinations due to washer sticking. Use of this finish on threaded surface and/or bearing surface of joints could affect the torque-tension relationship. It is recommended that a torque-tension study of the fastener joint be performed before releasing this finish of a new application. Black fluorocarbon coating should not be specified on zinc or aluminum threaded fasteners larger than 12 mm in diameter, due to objectionable appearances that may result.