Cold model study of the effects of density difference and blockage factor on mold powder entrainment

Abstract

Cold model experiments were carried out to understand the effects of the density difference between mold powder and molten steel and of the blockage factor for the immersion nozzle on the mold powder entrapment in the continuous casting mold. Water, salt water, fluorinert, and mercury were used as the working fluids. A seesaw type vessel was used as a model for the mold and it was inclined for generating an uneven flow approaching the immersion nozzle of poor wettability. The meniscus descended along the outer surface of the immersion nozzle due to a pressure difference induced along the immersion nozzle. The pressure difference was caused through an effect of abrupt arrival of the uneven flow. The penetration depth of the meniscus is closely associated with the mold powder entrapment at the nozzle ports. An empirical equation was proposed for the penetration depth. An increase in the blockage factor promoted the penetration of the meniscus. © 2005 ISIJ.