成份百分比（wt%）C0.19~0.25B0.0008~0.005Mn1.10~1.4Cr0.15~0.35Al0.02~0.06Ti0.02~0.05Si≤0.40P≤0.025S≤0.015性能：淬火前屈服强度≥300MPa,抗拉强度≥600MPa；淬火后屈服强度≥1200MPa,抗拉强度≥1500MPa；)