Effect of temperature-dependent viscosity on molten steel behavior in ladle stirring: A numerical simulation and industrial practice

Ladle stirring plays a crucial role in improving the homogeneity of alloying elements and temperature distribution in molten steel. Due to the high-temperature nature of the process, numerical simulations have been widely used in the study of ladle stirring. However, previous numerical simulations have generally assumed viscosity as a constant parameter. In this study, viscosity is considered as a temperature-dependent variable, and its impact on temperature distribution, fluid flow, alloy melting, and alloying element diffusion is analyzed. The results show that in industrial practice, the average temperature decrease rate in molten steel is 1.31 K·min−1. When viscosity is assumed constant, the numerical simulation predicts a temperature decrease rate of 1.12 K·min−1, while when viscosity varies with temperature, the predicted temperature decrease rate is 1.312 K·min−1. The industrial alloy homogenization time is 140 s, and when the viscosity of molten steel changes, the numerical simulation predicts an alloy homogenization time of 138.6 s, which is more consistent with the industrial experimental results. The findings demonstrate the significance of incorporating temperature-dependent viscosity in simulations, as opposed to assuming viscosity as a constant parameter.