HOT ROLLED STEEL WIRE ROD FOR COLD HEATING AND METHOD FOR PRODUCING COLD HEADING ARTICLE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a hot rolled steel wire rod for cold heading which exhibits excellent deformability even without performing softening annealing such as spheroidizing annealing in forming of a bolt, a nut or the other parts by cold heading, and a method for producing a cold headed article using the steel wire rod.;SOLUTION: The hot rolled steel wire rod having excellent deformability in cold heading is consisting of steel having a C content of 0.25 to 0.5% (by mass% in the case of a chemical component, and so forth), and has tensile strength of ≤650 MPa. The wire rod has a metallic structure of a dual-phase structure of ferrite + pearlite, the ferrite fraction in the dual-phase structure is ≥55%, and the pearlite grain size is ≤30 μm.;COPYRIGHT: (C)2002,JPO