Abstract：Compared with reductive slag，free cutting steel LF refining slag possesses the unique metallurgical function of control of free oxygen content in molten steel , low rate of desulphurization and dephosphorization. With low basicity and proper quantity，the slag should contain proper ratio of FeO and MnO, and absorb A12O3 and silicate adequately. The proper refining slag contains 30-40%CaO,10-25%A12O3,2-6%FeO,10-25%MnO,10-20%SiO2,4-8%MgO.With this slag, the average desulphurization rate is 11.7%,( %p)/[%P] is 0.56，inclusion B ranges from 0 to 1, inclusion C is 0 to 1.5.
2010, Vol. 45 
