GMNA - GM4435M
Protective Finishes - Phosphate Type
|Publication Date:||1 September 2010|
This standard covers corrosion protective finishes for iron and steel whose basic characteristic is zinc phosphate treatment and a subsequent protective compound. A grade with zinc phosphate only may be designated. A suffix code system is provided for designating certain limitations on compounds.
Parts coated with this coating are typically used internally for engines and transmissions or in areas where minimum corrosion protection is required.
Parts coated to this shall be free of hexavalent chromate per GMW3059 requirements. GMW3034 will be used as a referee test.
Documents that specify GM4435M, Code C shall meet the requirements of GM4435M, Code A.
Use of this finish on threaded surfaces and/or bearing surfaces 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 on a new application.
Coefficient of friction/torque tension values in this specification are also determined at ambient temperatures. New applications for this finish should be tested to confirm performance under application specific, operating conditions.
Finishes conforming to the requirements of this specification can be used in the application range of -50 to 120°C. For applications outside of this temperature range consult your local Material Engineering.
Finishes with oil coatings are not recommended for use against plastic surface.
This specification is not to be used on new designs. It is recommended to use GMW3179 on similar applications on new designs.