Study on the Force and Distribution Patterns of Bubbles at the Solidification Front of the Wide Face in a Continuous Casting Mold for Slabs

Large velocity, temperature, and concentration gradients at the solidification front in the mold expose bubbles to pressure‐gradient and Marangoni forces in the solidification direction. Through numerical simulation of the mold during the continuous casting process of high‐sulfur steel, it was found that the concentration and temperature gradient of the molten steel at the solidification front at different positions of the wide face are not significantly different, but the velocity gradient varied greatly. Based on this, the center and the quarter position of the wide face are selected to calculate the three forces and their resultant forces acting on the bubble at different heights in the solidification direction at the solidification front. The results are as follows: At the center of the wide face, the velocity gradient is small and the bubbles are easily captured at the solidification front; at the quarter position, the velocity gradient is large in the impact zone, making it difficult for bubbles to be captured. Both the distribution of bubbles within the 11.0–15.0 mm depth beneath the slab and bubble defects in the hot‐rolled plates are consistent with these findings. This study provides a theoretical basis for predicting subsurface bubble distribution on the slab‐wide face.