A.普通鋼 B.考登鋼 C.優(yōu)質(zhì)鋼 D.合金鋼
A.0.10~0.15 B.0.20~0.25 C.0.01~0.05 D.0.06~0.08
A.3~4 B.5~8 C.10~15 D.15~20