Effect of the asymmetric flow behaviour of molten steel on solidified shell in slab continuous casting mould

Abstract

The flow behaviour of molten steel in the mould has an important influence on the solidification quality of the slab. A three-dimensional transient mould model has been developed to describe the effect of the asymmetric flow behaviour of molten steel on solidified shells in the mould. The causes of the asymmetric behaviour of molten steel in the mould were discussed, and the interaction between deviation flow and solidified shell was analysed. The results show that the asymmetric distribution of the flow field is caused by the difference in flow rate at the outlets on both sides of the nozzle and the irregular interaction between the molten steel and the complex nozzle geometry. The level fluctuation is correlated with the deviation flow of the molten steel on the opposite side. The velocity variation trend of the two models is similar, but the fluctuation amplitude of the velocity on both sides of the nozzle in the non-solidification model is more drastic. The conversion period of the deviation flow in the solidification model is longer than that in the non-solidification model. Moreover, the velocity and angle of incident and return flow on both sides are different due to the deviation flow, which mainly affects the solidification of the shell at and below the impact point of the molten steel. The deviation flow will strengthen the impact of the main stream on the shell, resulting in a significant decrease in the thickness at the impact point, while the thickness of the shell below the impact point fluctuates greatly.