Dynamics of mold flux composition in high-titanium steel continuous casting: modeling and prediction

Continuous casting of high-titanium steels face significant challenges due to steel-flux reactions, which will cause rapid compositional deviations and impair operational stability. A kinetic model to predict real-time mold flux composition evolution by integrating multicomponent mixed-transport-control theory with thermodynamics computing platform was developed in the current study. The model employed a cyclic time-step algorithm to compute thermodynamic equilibrium in reaction layer, mass transfer flux between reaction and bulk layers, and composition updates in reaction and bulk layers. The accuracy of the model was validated by plant trial data. The effect of casting parameters and initial compositions on the evolution of mold flux composition were investigated. The TiO₂ accumulation and SiO₂ consumption in mold flux under varying casting parameters was predicted. It was found that higher casting speeds accelerated compositional equilibrium, while the increase of mold flux consumption rates reduced TiO₂ accumulation. The increase of pool depth resulted in slower consumption and accumulation rates of components like SiO₂ and TiO₂, prolonging the time to reach equilibrium. Additionally, the CaO-Al₂O₃-based flux suppressed the Ti-SiO₂ reaction for the high-titanium steel continuous casting. However, the CaO-Al₂O₃-based flux should limited contents of Na₂O, MnO, and FeO to prevent additional TiO₂ accumulation due to Ti-Na₂O, Ti-MnO, and Ti-FeO reactions. The model provided a reliable tool for understanding and optimizing the continuous casting process of high-titanium steels.