A.普通碳素鋼 B.優(yōu)質(zhì)碳素結(jié)構(gòu)鋼 C.合金工具鋼 D.碳素工具鋼
A.±20mm B.±5mm C.±0.50mm D.±0.05mm
A.0.40 B.4 C.40 D.400