デンドライト–液相混相領域における模擬介在物の移動挙動

抄録

Clarification of nonmetallic inclusions behavior in molten steel is a critical challenge for achieving high-quality steel materials. In particular, the inclusion behavior in dendritic regions during solidification plays a significant role in inclusion retention, yet its physical understanding remains insufficient. In this study, a low-temperature model experimental system was developed to investigate the inclusion behavior in the dendritic region. Simulated dendrites with horizontal direction were aligned in a transparent viscous liquid, and the motion of a spherical simulated inclusion with relatively high density was directly observed using a high-speed camera. The particle Reynolds number in this experimental system was 0.0178. This corresponds to an alumina inclusion with a diameter of 37.7 µm in molten steel. Furthermore, numerical calculations were introduced to predict the inclusion behavior. The main results obtained in this research are as follows. When the simulated inclusion fell through inter-dendritic spaces, its velocity decreased to approximately 0.851 of the falling velocity in the liquid while it was about 0.597 when the simulated inclusion fell above the simulated dendrite. The velocity of the simulated inclusion was slower when passing beside the simulated dendrite than moving between the vertically aligned simulated dendrites. The velocity decrease of the simulated inclusion was intensified as decrease of the horizontal distance to the simulated dendrite. Furthermore, the rotation of the simulated inclusion affects its trajectory and velocity.