Fluid Flow and Inclusion Motion in a Multi-Heat Teeming Tundish for Heavy Steel Ingot

Besides the function of molten steel supply in the casting process, tundish has a capability of decreasing the formation of macro-scale inclusions and promoting the flotation of the remaining inclusions. Both the round shape tundish and the elliptical shape tundish were studied for the multi-heat teeming ingot. The transportation of molten steel and the motion of inclusions were compared using numerical simulation and physical modeling. The results showed that the short molten steel residence time, the large dead volume, and the low efficiency in inclusion removal for the round shape tundish were obtained even when a flow control device was installed. After comparing the two kinds of tundishes with the same capacity, it indicated that in the elliptical shape tundish, the molten steel residence time was prolonged by 1.6 times and the mean residence time increased by 6%; the dead volume was decreased from 18% to 13%, the ratio of the plug volume to the dead volume increased by 68%, and the inclusion flotation efficiency increased by 17%. The trial results indicated that, after using the elliptical tundish, the equivalent diameter of single defect was decreased from 2.5 to 1.6 mm, and no intensity defect was observed. The total oxygen content was 21 × 10−6, which was decreased by 30%.