New insight into relationship between casting speed and inclusion removal in the tundish

The tundish is the last refractory metallurgical reactor during the continuous casting process, and the fluid flow in the tundish is one of the key factors to control inclusion collision-coalescence and its removal. Thus, numerical method is applied to obtain the flow field, the RTD curve and the inclusion field. Numerical results showed that the predicted RTD curve and the inclusion number density agree well with the experimental data. In the case of different fluid velocity at tundish inlet, the volume fraction of plug zone, dead zone and well-mixed zone keep unchanged, but the dimensionless tundish inclusion volume concentration, the dimensionless tundish inclusion radius and the inclusion removal ratio have the exponential relation to the fluid velocity at tundish inlet. Further, there is maximum inclusion removal rate for the specific tundish. Another interesting phenomenon is about the inclusion behavior and the characteristic time of the RTD curve. The inclusion removal ratio and the dimensionless tundish inclusion radius have the linear relation to the minimum residence time, the peak concentration time and the average residence time.