Effect of Nozzle Geometry on Slag Entrapment During Thin Slab Continuous Casting Process

A process known as continuous casting, turns molten metal into a semi-finished billet, bloom, or slab that can then be rolled in finishing mills. It is the widely used method for casting billets, blooms or slabs of steel, aluminum, and copper alloys. Overcoming or minimizing the slag entrapment during the process is a major challenge for steelmakers. The slag entrapment is accentuated because of the mold level fluctuation coupled with the flow-induced effects of the molten steel coming out of the submerged entry nozzle. The volume of fluid (VOF) method is typically used for the multi-phase analysis of slag level fluctuations. In the present study, two different nozzle port geometries, one elliptical and the other with a rectangular-shaped cross-section are chosen with a bifurcated nozzle outlet. The casting speed has been varied while keeping the submerged length fixed. Comparative performance analysis of the nozzles is done with respect to slag level fluctuations during the process. Results indicate the presence of downward and upward recirculation zones.