Wire rod for high intensity steel wire, high intensity steel wire and these production mannered

摘要

PROBLEM TO BE SOLVED: To provide a steel wire which is producible even without performing patenting treatment in the process of a wire drawing stage, and is excellent in mechanical properties such as strength and tensile strength, to provide a wire rod for producing the same steel wire, and to provide their production methods.;SOLUTION: A hot rolled wire rod with a wire diameter of 4 to 7 mm consisting of steel having a composition comprising 0.2 to 0.55 C, 0.1 to 1.0% Si, 0.1 to 1.1% Mn and ≤0.01% (inclusive of 0%) Al, and, if required, further comprising at least one kind of metals selected from the group consisting of Cr, Ni, Co, V, Cu, Mo, W, Nb, Ti and B and having a structure in which the area ratio of ferrite is 20 to 50%, and the balance 90% pearlite is subjected to wire drawing without performing patenting treatment, so that the steel wire satisfying the tensile strength of ≥2,800 MPa and also free from the generation of longitudinal cracks (delamination) at the time of a torsion test is obtained.;COPYRIGHT: (C)2005,JPO&NCIPI