WIRE-SHAPED OR BAR-SHAPED STEEL EXCELLENT IN DEFORMABILITY AND MACHINE PART

摘要

PROBLEM TO BE SOLVED: To provide a wire-shaped or bar-shaped steel which is excellent in deformablity and has high strength as a steel material itself only by hot rolling even when spheroidizing annealing is omitted.;SOLUTION: The wire-shaped or bar-shaped steel substantially has a ferrite structure, and ferrite grain size number (A) in the ferrite structure within a range between a center and a diameter/4 of a rolled material is 7.0 to 10.0, ferrite grain size number (B) in the ferrite structure at an uppermost layer of the rolled material is 7.0 to 10.0. Further (A) and (B) satisfy a relation: 0≤(B)-(A)≤0.5.;COPYRIGHT: (C)2003,JPO