A.25號(hào)鋼 B.45號(hào)優(yōu)質(zhì)鋼 C.鑄鋼 D.鑄鐵
A.<1mm B.>1mm C.≤1mm D.≥1mm
A.0.05~0.1mm B.0.2~0.25mm C.0.25~0.4mm D.0.4~0.5mm