A.等于0.675% B.≤0.015% C.等于0.11% D.≤0.5%
A.普通鋼 B.優(yōu)質(zhì)鋼 C.高級優(yōu)質(zhì)鋼 D.特級質(zhì)量鋼
A.≤0.025% B.等于0.22% C.等于0.15% D.≤0.725%