A.低碳鋼 B.中碳鋼 C.高碳鋼 D.普通鋼
A.普通鋼 B.優(yōu)質(zhì)碳素合金鋼 C.優(yōu)質(zhì)碳素結(jié)構(gòu)鋼 D.優(yōu)質(zhì)碳素工具鋼
A.0.30% B.0.25% C.0.030 D.0.045%