Zhang Guolei,Guo Yunfei,Qiu Mian,et al.Effect of Refining Slag Basicity on the Molten Steel Cleanliness of GCr15SiMn Bearing Steel[J].Special Steel,2025,46(05):32-38.
This article studies the effect of different refining slag basicity on the cleanliness of GCr15SiMn bearing steel by combining laboratory slag-steel equilibrium experiments and theoretical calculations. Slag-steel equilibrium experiments were conducted with three different refining slag basicity ratios (6.32,5.28 and 4.27 respectively) and steel samples with the identical chemical composition.The experimental results show that the experimental steel group with a basicity of 4.27 had the lowest oxygen and magnesium contents (0.000 6% and 0.000 9%, respectively), and the smallest number density of inclusions (0.31 per mm²), demonstrating excellent performance in controlling molten steel cleanliness. Additionally, the changes in SiO
2
and FeO in the corresponding slag for this experimental group were also the smallest, indicating that reducing the initial refining slag basicity helps to quickly achieve equilibrium in the slag-steel metallurgical reaction and reduce the formation of inclusions in the steel. Further calculations using the slag-steel equilibrium thermodynamic model confirmed that reducing the refining slag basicity can increase the logarithmic ratio of SiO
2
to Al
2
O
3
, inhibit the reaction between Al and SiO
2
in the slag, and reduce the transfer of oxygen from SiO
2
to the molten steel. Finally, the experim
ental results were applied to factory practice. The results showed that appropriately reducing the refining slag basicity can significantly improve the cleanliness of the GCr15SiMn molten steel. This research provides strong theoretical support and guidance for the industrial practice of smelting high-cleanliness bearing steel.
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references
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