Influence of Mold Flux Infiltration and Level Fluctuation Under High Speed Casting with Dynamic Shell Bulging
摘要
The bulging occurs in secondary cooling zone has an important influence on the mold-level fluctuation during slab continuous casting. A two-dimensional (2D) coupling model of molten steel multiphase flow, heat transfer and shell solidification is developed with the consideration of mold oscillation, the interfacial tension between molten steel and slag, and mold flux infiltration by loading user defined function. In the model, the dynamic mesh technique is applied to simulate the shell bulging in secondary cooling zone. The results show that the maximum fluctuation amplitude Hn of the mold-level is 10.67 mm for the slab mold of 230 × 1650 mm cross-section with high casting speed of 1.8m/min without the influence of the bulging. While the height of the level and fluctuation in the mold are obviously increased, when the bulging is considered, especially exhibit at the meniscus and 0.4 m away from the submerged entry nozzle. At this time, the maximum fluctuation amplitude Hc1 of molten steel at the convex bulge time is 14.01 mm, while the maximum fluctuation amplitude Hc2 at the concave bulge time is 14.64 mm. When the periodic bulging occurs, the position of the slag rim will also fluctuate periodically, which will cause the unsteady narrow and expansion of the slag channel, which will affect the infiltration of the liquid slag, and further lead to the non-uniform growth of the solidified shell.