Effect of casting speed on floating grains and macrosegregation of direct-chill cast 2024 alloy with intensive melt shearing

Abstract

The ingot was prepared by direct-chill (DC) casting technology with different casting speeds under the influence of intensive melt shearing to explore the effect of casting speed and intensive melt shearing on the floating grains and negative centerline segregation. The results indicate that the application of intensive melt shearing in DC casting process can distribute the floating grains uniformly, reduce the area fraction of the floating grains, alleviate the negative centerline segregation, and improve the uniformity of temperature field in the sump. It is also suggested that under the influence of intensive melt shearing, the casting speed plays a crucial role in the amounts and distribution of floating grains. At low casting speed, the intensive melt shearing can significantly reduce the area fraction of the floating grains and distribute them uniformly throughout the ingot. However, this effect gradually disappears with the increase of casting speed.