| 摘要 |
PURPOSE:To easily produce a steel wire for springs having excellent resistance to fatigue by subjecting a wire contg. a small amt. of Cr as a steel wire for springs to a hardening treatment, then softening the surface layer of the wire by quick heating. CONSTITUTION:The steel products contg., by wt%, 0.3-1.0% C, 0.15-2.5% Si, 0.3-2.0% Mn, and <3.0% Cr are drawn by hot rolling, etc., to a base material having >=2.0mm diameter. The wire is then subjected to hardening and tempering treatments, by which the hardness is adjusted to >=500 Hv; thereafter, the surface layer part is heated to 500-700 deg.C for the treatment time of <=200m sec per time by a laser heating method or high-frequency induction heating method of >=10MHz. The hardness in the range of 10mum from the surface is adjusted to <=450 Hv and the hardness in the deep part of >=100mum to >=500 Hv. The steel wire for springs having the excellent resistance to fatigue is produced without subjecting the wire to a surface treatment such as shot peening treatment and soft nitriding as in the conventional practice. |
