| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high strength PC steel wire having ≥2,000 MPa strength and especially excellent in a delayed crack resistance characteristic with respect to the PC steel wire to be used for a prestressed concrete or the like, and to provide a manufacturing method therefor. <P>SOLUTION: As for the high strength DC steel wire excellent in the delayed crack resistance characteristic and the manufacturing method therefor, the PC steel wire contains, by mass%, 0.9-1.2% C, 0.01-1.5% Si, 0.2-1.5% Mn, 0.001-0.05% Al, 0.0005-0.010% N and the balance Fe with inevitable impurities, is composed of ≥90% wire-drawing pearlite and ≤10% ferrite and bainite structures. and has ≥2,000 MPa tensile strength. When the wire diameter of the PC steel wire is defined as D, the ratio (Hv surface/Hv inner part)of the surface layer Hv hardness (Hv surface) of 0.1D range (surface layer part) from the surface of the PC steel wire to the inner part Hv hardness (Hv inner part) of the inside range (inner part) from the surface layer part, is ≤1.1. Further, it is possible to contain one or more kinds among Cr, Mo, V, Ni, Cu, B and/or one or more kinds among Ti, Nb, Zr. <P>COPYRIGHT: (C)2010,JPO&INPIT |
