Before decarbonizing refining IF steel by a 300 t RH unit

it is required to control converter end [C

]

≤ 0. 06%

end [O

]

0. 05% ~ 0. 08% and taping temperature 1 680 〜1 700 ℃; at argon injection station the (FeO) and (CaO)/(Al

2

O

3

) of ladle slag are modified and decreased respectively from original 12. 2% and 6. 7 to 5. 0% and 1. 7 to increase its ability to adsorb inclusions. Based on production data

an auto-calculation model for RH decarburizing operation is established effectively to improve the percentage of hits of each technical index during RH refining

and the average [O

]

and [C

]

decrease respectively from 0. 046% and 0. 031 % at the beginning of RH decarburizing to 0. 035 0% and 0. 001 3% at end of RH decarburizing.