A.小于0.25% B.小于0.15% C.小于0.20% D.0.25-0.60%
A.不大于2% B.不大于5% C.不大于3% D.不大于4%
A.建筑及工程用鋼 B.結(jié)構(gòu)鋼 C.工具鋼 D.電工用鋼