A.钢水中气体含量高 B.结晶器冷却不均匀 C.轧制操作不当 D.浇注温度过低
A、0.2,45.7 B、0.1,45.7 C、0.2,54.5 D.0.1,45.70
A.正火 B.回火 C.淬火 D.退火
A.20# B、30MnSi C、245R
A.工作辊 B.中间辊 C.支撑辊 D.凸度辊