Assessment of Critical Vortexing Height to Prevent Slag Entrapment During Tundish Teeming

With globalization and increased competitiveness in the steel market, industries are required to produce quality steel at a reasonable cost. This necessitates the introduction of either new manufacturing techniques, or to improve quality and yield with the existing processes. It is well established that slags entrapped by the vortexing phenomenon during steelmaking processes are responsible for causing quality issues and lowering the yield of steel produced. Measures are taken to end teeming from tundish before initiation of vortexing to prevent slag entrainment. This premature end of teeming is an inevitable yield loss that needs to be minimized. The present work aims to increase the efficiency of the steelmaking process by control techniques for minimizing tundish slag entrainment during tundish teeming. Experimental and mathematical simulations with different tundish configurations have been carried out to analyze the initiation of slag vortexing. The mathematical simulation uses multiphase models with a steel–slag–air system while the physical simulation uses a water–paraffin oil system to replicate the steel–slag system. It has been observed that the presence of higher turbulence and a thicker slag layer over liquid steel increases vortex initiation height (Hcr). An empirical correlation between these parameters with Hcr has been developed to optimize the end of teeming and increase process yield.