0. 06Als) is KR metal desulphurization pretreatment-300 t top and bottom combined blowing converter-ladle argon blowing- LF-RH-250 mm x 2 150 mm slab casting process. The main steelmaking and refining optimizing processes are controlling converter tapping slag amount ≤4 kg/t
using (%) 55 ~60CaO
7 ~ 12SiO3
25 - 30Al
2
O
3
refining slag series to control LF refining slag CaO/Al
2
O
3
= 1.7 ~ 1. 9
CaO/SiO
2
二 4. 5 ~ 6. 0 and ( FeO + MnO)≤ 1. 0%
pre-forming slag at ladle argon blowing station with top and bottom argon blowing
RH vacuum ≤66. 7 Pa and feeding 0. 8 kg/t calcium wire after RH treatment. Re
sults show that carbon-oxygen product-[C
]
[0
]
at converter endpoint decreases to 0. 002 44 from original 0. 002 84
after refining ( FeO + MnO) is 0. 913%
T [0
]
is 0. 001 3% and rating of inclusions in products is 1. 0.