A.25號(hào)鋼 B.20號(hào)鋼 C.35號(hào)鋼 D.70號(hào)鋼
A.0.20% B.0.45% C.0.35% D.0.65%
A.HT200 B.QT42-10 C.KTH300-06 D.ZG