A.Q460 B.T7 C.T10A D.T8
A.碳素結(jié)構(gòu)鋼 B.低合金高強(qiáng)度結(jié)構(gòu)鋼 C.碳素鑄鋼 D.碳素工具鋼
A.3% B.4% C.5% D.6%