| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a special steel wire whose tensile strength as a component is ≥1,200 MPa and <1,500 MPa, capable of acquiring a machine part excellent in hydrogen embrittlement resistance characteristic, and to provide a steel wire, and the machine part and a method for manufacturing the same. <P>SOLUTION: This special steel wire contains following steel material chemical components in terms of mass%, namely, 0.35-0.85% C, 0.05-2.0% Si, 0.20-1.0% Mn, ≤0.030% P, ≤0.030% S and 0.005-0.05% Al, and the balance Fe with inevitable impurities, wherein the grain size number of austenite crystal grains before transformation after hot rolling is ≥8, and a pearlite structure after transformation is contained as much as 64×(C%)+52% or more in terms of the volume ratio, and a residual structure comprises a pro-eutectoid ferrite structure or one or two kinds of bainite structures. A special steel wire manufactured from the wire, and the machine part manufactured from the steel wire, whose tensile strength is ≥1,200 MPa and <1,500 MPa, and which is excellent in hydrogen embrittlement resistance characteristic are also provided. <P>COPYRIGHT: (C)2012,JPO&INPIT |
