Physical modeling of asymmetrical flow in slab continuous casting mold due to submerged entry nozzle clogging with the effect of electromagnetic stirring

Abstract

Submerged Entry Nozzle (SEN) clogging is a serious problem for continuous casting process and slab quality. In order to investigate the impact of the SEN clogging rate on the flow field and the optimization effect of electromagnetic stirring (EMS) on the asymmetrical flow due to the SEN clogging, a 1:5 scaled mercury model, with various SEN clogging rates and different electromagnetic stirring currents was established and the flow velocity was measured by means of Ultrasonic Doppler Velocimetry (UDV). S index is introduced to judge quantitatively whether the horizontal flow pattern is symmetrical or not. The results show that the symmetry of the flow pattern in the mold becomes broken with the increase of the SEN clogging rate. In this study, EMS is an effective method to increase S index and active the free surface flow when the SEN clogging rate is under 50%. However, the stirring current of EMS should be controlled to avoid the adverse surface flow which may induce slag entrapment.