To provide an inexpensive surface treatment method for the plastic working of a metallic material in the consideration of global environmental protection by which a film having high lubricity equal to that of the conventional chemical conversion-soap treatment film can be given.
In the surface treatment method for the plastic working of a metallic material, powder grains in the following (1), (2) or (3) are stuck to the surface of a metallic material to form a composite film with a coating weight of 0.02 to 50 g/m2 consisting of a carrier components and lubricating components on the surface: (1) inorganic compound powder grains and powder grains selected from soap, molybdenum disulfide, polytetrafluoroethylene, wax and resins; (2) powder grains obtained by using an inorganic polyvalent metal compound as a nucleus, and coating the surface with a film of the metallic soap of the polyvalent metal; or (3) the powder grains in (2), and powder grains of at least one kind selected from soap, wax and resins.
KOMIYAMA SHINOBU
