A.0.06% B.0.6% C.6% D.2%
A.優(yōu)質(zhì)碳素結(jié)構(gòu)鋼 B.優(yōu)質(zhì)碳素工具鋼 C.優(yōu)質(zhì)低碳合金鋼 D.優(yōu)質(zhì)高碳合金鋼
A.0.50% B.0.60% C.0.70% D.0.80%