Abstract: Through analyzing the industrial data and discussing the factors affecting the slag composition, basicity，C_S and w(Ca)/w(Al), the corresponding optimization measures of the smelting process was proposed from two aspects of desulfurization thermodynamics and kinetics in order to further reduce the sulfur content in bearing steel. The results showed that controlling w(SiO₂)≤5 %, refining slag basicity R≥10, w(FeO+MnO)≤0.5 % and w(CaO)/w(Al2O3)=1.6－1.7, desulphurization effect was the best, desulphurization rate of bearing steel could be reached 94 %, the mass fraction of sulfur in steel was no more than 20×10^-6.

Key words: refining, deep desulphurization, refining slag