Motion Behavior of Ce-Containing Inclusions in 8Cr4Mo4V-Bearing Steel during Vacuum Arc Remelting

Herein, the Ce-containing inclusions in8Cr4Mo4V-bearing steel are taken as the research objective to develop anumerical model of inclusions motions behavior. The model is validated bycomparing it with experimental data. During the vacuum arc remelting process, inclusions move along the molten pool's surface toward the edge under theaction of resultant force, and finally become trapped within the mushy zone. Notably, the majority of inclusions are concentrated near the ingot's edge, andtheir numbers decrease as the radial distance decreases. Furthermore, thenumber of Ce-Mg-O-S inclusions exceeds that of Ce-O-S inclusions near the ingot's center. This discrepancy arises due to lower density of Ce-Mg-O-Sinclusions, which exhibits a stronger tendency to migrate toward the moltenpool's center. Additionally, as the inclusion diameter increases, buoyancy forceacting on the inclusions increases, resulting in a higher number of inclusionsnear the ingot's center. When considering the effect of gas cooling, theinclusion distribution becomes more pronounced at the ingot's edge. This isattributed to the enhanced cooling capacity of the mold resulting in the decreasing of molten pool depth and consequently a stronger ability of themushy zone to trap inclusions. The motion behavior of Ce-containing inclusions in vacuum arcremelting is closely related to the inclusion characteristics. The decrease in density and increase in diameter of inclusions make the net effect of buoyancy and gravity increase, and the inclusions are more likely to escape from mushy zone and exhibit a stronger tendency to migrate toward the molten pool's center.image (c) 2024 WILEY-VCH GmbH