Slag entraining vortexing funnel formation during ladle teeming: similarity criteria and scale-up relationships

Abstract

There are several motivations for minimising slag entrainment during the teeming of steelmaking ladles. Cleaner steel, improved yield, and higher productivity are all at stake. As one of several identifiable contributors to slag entrainment, vortexing has received considerable attention in the past decade and a half. What is commonly referred to as 'vortexing' in fact comprises two distinct phenomena, namely, vortexing funnels and non-vortexing funnels, each controlled by entirely different sets of variables. Dimensionless correlations describing the two phenomena were determined, and validated, using separate sets of dimensional analyses and appropriately designed scale model experiments. The importance of these findings to the teeming of steel is discussed. Performance results of a patented 'vortex buster' device, developed on the basis of the understanding gained from these studies, and validated in water models as well as in a 12 ton tundish, are also presented.