Method of producing steel wires each having very small diameter, high strength and excellent ductility

Abstract

The present invention is concerned with a method of producing steel wires each having a very small diameter of 0.4 mm or less and a tensile strength of 360 kgf/mm.sup.2 or more wherein a steel material having a composition comprising C: 0.90 to 1.10% by weight, Si: 0.4% or less by weight, Mn: 0.5% or less by weight, Cr: 0:10 to 0.30% by weight and a balance of iron an unavoidable impurities is subjected to diffusion treatment as desired, thereafter, the steel material is subjected to hot rolling, the hot-rolled steel wire is subjected to drawing, subsequently, the resultant steel rod having a smaller diameter is subjected to a final patenting treatment to give said rod a strength of 140 to 160 kgf/mm.sup.2, and thereafter, it is subjected to drawing with a true strain of 3.50 or more using a die having a die approach angle of 8 to 12 degrees.

Dependencies are inferred from the claim text.