A.碳素鋼和合金鋼 B.中碳鋼和高碳鋼 C.普通和優(yōu)質(zhì)碳素鋼 D.結(jié)構(gòu)鋼和工具鋼
A.>1% B.>1.5% C.<1.5% D.<1%
A.Al B.A3 C.Acm D.Ac3