METHOD FOR DRAWING OR STRAIGHTENING METAL

摘要

PROBLEM TO BE SOLVED: To greatly prolong the life of a die and to obtain a product which is free of speckles and stains on the surface and has beautiful metallic gloss by applying working oil uniformly dispersed with a fluorine resin on the working surface of the metal to be worked and subjecting the metal to be worked to drawing or shape straightening. SOLUTION: The metal to be worked is nonferrous metal and more preferably a copper alloy. The fluorine resin is polytetrafluoroethylene(PTFE) and the working oil is polybutene. The viscosity at 40 deg.C of the working oil is preferably 150 to 20000 mm2/sec. The material of the die is preferably superhard steel or superhard alloy. More preferably, a blank is coated with the fluorine resin and the film thickness of the coating is specified to 0.5 to 2μm in drawing of the product below 0.3 mm. Also, the grain size of the PTFE is 0.3 to 0.7μm and the fluorine resin is mixed at 1 to 10 in wt.% in the working oil.