C碳: 0.32~0.40 Si硅: 0.2~0.40 Mn锰: 0.40~0.70 S硫: ≤0.035 P磷: ≤0.035 Cr铬: 0.80~1.10 Ni镍: ≤0.30 Cu铜: ≤0.25 Mo钼: 0.15~0.25