Numerical Simulation of Oscillation Mark Formation and Slag Consumption in Meniscus Region During a Mold Oscillation Cycle

During an oscillation cycle of the mold, the fluid flow, heat transfer, and solidification behavior within the meniscus region control the slag infiltration, lubrication, and formation of oscillation marks, which are of great significance to the smooth running of continuous casting and the surface quality of slab. A comprehensive two-dimensional (2D) transient thermal-fluid model has been developed to study the fluid flow, heat transfer, dynamic shape of steel/slag interface, as well as the growth of shell in the meniscus region during an oscillation cycle. In addition, calculations of slag consumption were performed, and the results were consistent with previous research, thereby the reliability of the model is validated. During an oscillation cycle, the upstroke and downstroke cause the meniscus profile to bulge and collapse, which dominates the increase and decrease of heat flux in the Eulerian reference frame reference frame. However, the variation of heat flux in the Lagrangian reference frame is determined by the instantaneous position. The freezing and overflow behaviors of the meniscus are the primary factors contributing to the formation of oscillation marks, and the final profile of oscillation marks is determined by the two freezing events of the meniscus within an oscillation cycle. The positive slag consumption primarily occurs during the negative strip time (NST), while there is also positive slag consumption during certain periods of positive strip time (PST), which is closer to the motion state of the mold. This research contributes to explaining and understanding the formation mechanism of surface defects and issues of continuous casting strands, aiming to facilitate the improvement of related problems.