Influence of Casting Speed Change and Submerged Entry Nozzle Offset on Mold Flow Field in Unsteady-State Continuous Casting Process

For the unsteady-state continuous casting process, the influences of changing the casting speed and the submerged entry nozzle (SEN) offset on the mold flow field are investigated with the water model experiment. The process of changing casting speed under the unsteady-state condition was divided into three phases to study the variation of the flow field in the mold, namely, the phase at the beginning of increasing or decreasing the casting speed, the phase of continuous increasing or decreasing the casting speed and the phase at the end of increasing or decreasing the casting speed. From the view point of the volumetric flow rate of the molten steel and the number of bubbles, the mechanisms for the variation of the flow field in the mold are discussed. In the industrial continuous casting process, since changing the casting speed has the greatest influence on the surface velocity and level fluctuation at the larger casting speed (1.6 m/min), the change in the casting speed should be operated more slowly at the larger casting speed. In addition, the variation of the flow field in the mold is studied when the SEN is offset to front, back, left and right on the cross section, and the mechanisms for the variation of the flow field in the mold are discussed from the view point of the number of bubbles and the kinetic energy of the jet.