Steel Group No. uniform digital code number Chemical composition (mass fraction) (%) C Si Mn Cr Mo Ni B V Other siMn 8 A1O272 27siMn O. 24～O. 32 1.10～1.40 1.10～1.40 Steel Group No. Brand Sample Blank Size/mm Heat Treatment Mechanical Properties Steel Annealing or High Temperature Tempering Supply State Brinell Hardness HBSl00/3000 ≤ Quenching and Tempering Tensile Strength ób/MPa Yield Point ós/MPa After Break Elongation δ5(%) Reduction in area ¢(%) Impact absorption power Aku2/J Heating temperature/°C Coolant heating temperature/°C Coolant first quenching Second quenching ≥ SiMn 27SiMn 25 920 Water 450 Water Oil 980 835 12 40 39 217