Hardness is low, it extends guarantees the surface scratch with the production manner and this manner of the wire rod for cheap cold working which is produced the wire rod rolling the hot rolling material

摘要

PROBLEM TO BE SOLVED: To provide a method of inexpensively producing a soft wire rod of carbon steel for machine structural use, alloy steel for machine structural use and high carbon chromium bearing steel for cold working in which flaws are warranted over the whole length, and to provide a wire rod produced by the method.;SOLUTION: A hot rolling stock of steel for a wire rod is subjected to wire rod rolling into a bus having a dimensional tolerance of ±0.15 mm or lower and a diameter deviation difference of ≤70%. The bus is subjected to annealing treatment. The bus subjected to the annealing treatment is subjected to cold drawing at a drawing reduction of area of ≤5% with a working margin of ≥0.12 mm in a diameter in such a manner that the half angle θ of a die shown in the figure with a drawing die shape is controlled to 5 to 35°. Also, eddy current flaw detection is performed. Thus, the inexpensive wire rod for cold working having a low hardness, and in which surface flaws are warranted over the whole length is obtained.;COPYRIGHT: (C)2004,JPO