Modelling viscoplastic behavior of solidifying shell under applied electromagnetic breaking during continuous casting

Abstract

Since several decades the continuous casting (CC) process became one of the dominant technologies for the metal production. The quality optimization and the production rate growth are the primary targets. Nowadays the numerical modelling is a valuable tool to assist in these aims. Moreover, it efficiently competes with the physical experiment and the industrial trials. One of the key issues with the high casting speeds especially for the thin slab products are the strong turbulent flow of the fresh melt being feed from the submerged entry nozzle (SEN) and the non-uniformity of the solidifying shell thickness. Thereby the electromagnetic braking (EMBr) is typically applied to damp the hot jets and to evenly redistribute the superheat. In the previous work it was shown by the authors that the presence of the highly conductive solid shell plays crucial role for the melt flow under the applied magnetic field. Excluding this interaction does not allow predicting the EMBr effects on the melt flow correctly during the solidification. Recently a viscoplastic deformation model was implemented to model a withdrawal of the solidified shell in a funnel type CC mold for a full 3D engineering geometry. An extended model was used to predict the macro-segregation during twin-roll casting of an Al-alloy using 2D assumption due to the large width / thickness ratio of the casted sheet. In the current study an effort is done to combine the viscoplastic deformation model of the solidified shell and the magnetohydrodynamics effects of the EMBr. The flow field alternation as well as the thickness of the solidified shell during CC are presented and analyzed with and without the magnetic field been applied.