Study on the behavior of bubbles escaping from low basicity mold flux for high-Mn high-Al steels using 3D X-Ray microscope

Different types of gases need to escape through the top of the mold during the continuous casting process of high-Mn high-Al steels. The behavior of bubbles passing through the liquid slag is the restrictive link, which is related to the viscosity. Compared with two-dimensional surface observation, three-dimensional analysis is more intuitive, accurate and comprehensive. The spatial distribution and three-dimensional morphological of residual bubbles in mold flux under different basicity, different temperature and different holding time were obtained by three-dimensional X-ray microscope in this paper. The results indicate that when the basicity increases from 0.52 to 1.03, the temperature increases from 1423 K to 1573 K, the holding time increases from 10 s to 30 s, the mean feret diameter of the bubbles solidified in the mold flux gradually decreases. Increasing the basicity and temperature will decrease the viscosity of the mold flux and increase the bubble floating rate, increasing the holding time will increase the bubble floating distance, both leading to an increase in the removal rate of bubbles especially for the large. The findings of bubbles escape behavior provide guidance for the research of functions of low basicity mold flux for high-Mn and high-Al steel.