Simulation of gas gap formation between substrate surface and molten steel during initial solidification

Synopsis : In order to evaluate the motion of molten steel just before its solidification, contact conditions between the molten steel and the mold surface at a time when the molten steel contacts the mold surface were analyzed. Conditions of gas-gap formation on the interface between the molten steel and the mold were simulated by preparing a simplified dynamic model in which physical-property values, such as, depths of unevenness of the mold surface, gas absorptions into the molten steel, heat flux, and various other conditions were systematically varied. The time needed for the molten steel to penetrate to the bottom of a depression 100 ,∑m deep in the mold surface was estimated to be 0.03 s. It was also estimated that the molten-steel penetration time is significantly influenced by the depth of depressions in the mold surface, gas absorptions into the molten steel, and heat fluxes, whereas the effects of viscosity and surface tension of the molten steel are insignificant.