B400NQ化学成分:
C≤0.12 Si0.10~0.40 Mn0.20~0.50 P≤0.10 S≤0.020 Cu0.25~0.45 Cr0.30~0.65 Ni≤0.50 Ti-
B400NQ 屈服强度MPa不小于260 抗拉强度mPa不小于400 断后伸长率(L0=50mm,b=25mm)%不小于27 180°弯曲试验(b≥20mm)c弯心直径1a