| 摘要 |
PURPOSE:To obtain steel bar wire rod generating only slight strain aging during processing even if a member having high forming rate is cold forged by hot- rolling C-Si-Mn steel material of a specified compsn. and then subjecting it to aging under specified conditions. CONSTITUTION:Steel bar rod wire consisting by wt% of <=0.45 C, <=0.35 Si, 0.20-2.00 Mn, <=0.040 P, <=0.025 S, 0.030-0.090 sol. Al and <=60ppm N, with >=15 sol. Al/N, and residual wt% Fe, is hot-rolled. Then, the steel bar rod wire is aged at 200-500 deg.C during cooling or after cooled. so as to obtain <=5 age hardening rate defined by the formula (wherein T.S' is tensile strength when it is aged after drawing, and T.S is tensile strength of the drawn wire as it is). |
