FORMATION OF LUBRICATING FILM SUITABLE FOR COLD FORGING OF METAL MATERIALS

摘要

PURPOSE: An excellent method for formation of lubricating film,which does not produce any sludge and results in the high productivity. and a lubricating film therefrom, which is suitable for cold forging of metal, are provided. CONSTITUTION: The lubricating film is prepared by: (i) forming 6-20 gram/square meter of phosphate substrate on the metal by electrolyzing an electrolyte containing 20-50 gram/liter of zinc ion, 20-70 gram/liter of phosphate ion and 30-80 gram/liter of nitrate ion with 20-100 ampere/square meter using metal as cathode; and (ii) covering the substrate with water type or oil type lubricant after de-scaling the metal with either using acid or mechanical de-scaling accompanied by using acid.