Simulation of coagulation of non-metallic inclusions in tundish and their trapping into solidified shell in continuous casting mould

A mathematical model simulating the coagulation and flotation of non-metallic inclusions in the tundish and continuous casting mould was developed based on turbulence coagulation and Stokes coagulation. From the simulation in the tundish, it was found that Stokes coagulation is dominant in the tundish. In the mould, the simulation result was that argon bubbles become the desirable sites where alumina inclusions are gathered and form large alumina clusters. The influence of the liquid steel flow in the mould applied by an in-mould electromagnetic stirring technique on the trapping rate of non-metallic inclusions into the solidified shell was examined. The horizontal flow in front of the shell was found to be effective for disturbing the trapping and decreasing the population of large non-metallic inclusions in the shallow surface layer of cast slabs. This effect was interpreted by the lift force applied to non-metallic inclusions in the velocity boundary layer formulated.