A.45°~52° B.65°~72° C.90° D.75°-85°
A.150g-550g B.250g-650g C.350g-750g D.450g-850g
A.硬質(zhì)合金 B.一般鋼鐵材料 C.碳素工具鋼及合金工具鋼 D.彈簧鋼