A.1060及以級機(jī)械變 B.1070 C.1120 D.1150
A.鑄鐵 B.鑄鋼 C.輾鋼 D.輾鋼和鑄鋼
A.0.3%~0.5% B.0.3%~0.4% C.0.37%~0.55% D.0.4%~0.5%