GMNA GM7113M PDF

This specification covers the basic requirements for a non-oily corrosion protective coating consisting of zinc plate and subsequent aluminum rich organic topcoat.

The coating is suitable for internally and externally threaded and nonthreaded ferrous parts where high levels of corrosion protection are required. When applied over steel that is to be coupled to aluminum, the coating provides exceptional galvanic protection.

This coating system shall be completely free of hexavalent chromate by July 2005. The final product shall conform to the requirements of GMW3059. All the approved sources listed in MATSPC database (section 6 Approved Sources) shall be hexavalent chromate free by July 2005. At present the MATSPC database lists both applicators with and without hexavalent chromate.

Typical Application. It is required that the internally threaded part (nut) be coated in a variable speed, canting centrifuge, which applies paint coating by a gravity flow-through system Parts without internal threads may be coated by other processes.

This specification is intended for use on carry over parts only. Contact Materials Engineering before using this specification on any new designs.

Use of this finish on threaded surface and/or bearing surface of joints could affect the torquetension relationship. It is recommended that a torque- tension study of the fastener joint be performed before releasing the finish on a new application.