A.機(jī)械性能的高低 B.磷、硫含量的多少 C.硅、錳含量的多少 D.碳含量多少
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