A.普通鋼 B.45號(hào)優(yōu)質(zhì)碳素鋼 C.60號(hào)優(yōu)質(zhì)碳素鋼
A.33.44mJ(8000千卡) B.29.26mJ(7000千卡) C.25.08mJ(6000千卡)
A.閉路 B.開(kāi)路 C.預(yù)篩開(kāi)路