A.35號(hào)鋼 B.45號(hào)鋼 C.65號(hào)鋼 D.40號(hào)鋼
A.0.20% B.0.45% C.0.35% D.0.65%
A.1.0%-1.4% B.1.4%-2.4% C.2.5%-4.0% D.4.0%以上