A.28%~48% B.30%~68% C.48%~78% D.78%~95%
A.調(diào)整鋼液溫度和防止?fàn)t渣結(jié)殼 B.均勻鋼水溫度和成份,促進(jìn)夾雜上浮 C.防止鋼液二次氧化
A.先開氣后點(diǎn)火 B.先點(diǎn)火后開氣 C.邊開氣邊點(diǎn)火