| 摘要 |
PURPOSE:To improve a cold forgeability and productivity by executing a copper plating in the specified amt. in a copper sulfate after descaling a wire rod, then, preheating the wire rod at the specific temp. and performing the lubricating ground treatment by phosphate solution of the specified temp. as well. CONSTITUTION:A hot rolled steel wire rod is descaled by a shot blast, etc., and thereafter, passed through a copper sulfate solution and a copper plating layer 2 is formed on the surface of the wire rod at the rate of >=0.2g/m<2>. In succession, in a preheating stage the copper plating wire rod is preheated by a hot blast, etc., to >=80 deg.C surface temp. A lubrication ground treatment is thereafter performed in the phosphate treating liq. heat-insulated at 70-90 deg.C and after forming a phosphate film 3 a dry powder lubrication film 4 is formed. The cold forgeability of the wire drawing material is improved with the formation of the copper plating layer 2 and the adhesion of the phosphate film 3 is improved as well, so a line speed can be increased. Consequently a productivity is improved as well.
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