Study on thermodynamics and dynamics of top slag modification in O5 automobile sheets

Abstract

Abstract This article presents a new Ruhrstahl–Heraeus top slag modifier with an enhanced modification effect at an enterprise producing O5 automobile sheets. To compare the modification effect of the original and new modifiers, the thermodynamic and dynamic conditions of the top slag modification were studied by thermodynamic calculations and dynamic analysis. The results showed that the utilization of both modifiers reduced the total iron (TFe) content in the top slag. The new modifier controlled the CaO/Al2O3 (C/A) and TFe content of the top slag to approximately 1.22–1.30 and 6.07–7.97%, respectively. The adsorption capacity of top slag for inclusions was stronger than that of the top slag modified with the original modifier. The concentrations of Al2O3-type inclusions, Ti x O·Al2O3 composite inclusions, and oxide inclusions were reduced by 13.4, 21.2, and 3.4 per cm2 with the new modifier compared with the original modifier. The total oxygen content in molten steel was 2.8 ppm lower than that of the original when the new modifier was used. Moreover, the new modifier exhibited a better dynamic condition on the surface of top slag, as determined by R-G-B numerical analysis. Overall, the new modifier improved the dynamic conditions of top slag modification, reduced top slag oxidation, and effectively improved the cleanliness of the molten steel.