A.硬質(zhì)合金鋼 B.高速鋼 C.優(yōu)質(zhì)碳素鋼 D.碳素工具鋼
A.齒數(shù) B.模數(shù) C.常數(shù) D.壓力角
A.25mm B.50mm C.60mm D.40mm