A.[150/(2×29.5)]×1.5 B.[(150×29.5)]×1.5 C.150/(2×29.5)×1.5
A.讓鋼液通過 B.使鋼水形成一定厚度的坯殼 C.便于保護(hù)渣形成渣膜 D.都不是
A.5∶10 B.10∶15 C.15∶20