Effect of strip feeding on melt flow and equiaxed crystal formation in a mold

Feeding a strip into the mold has a positive effect on improving the homogeneity of a large continuous casting bloom. A visualized solidification experimental system was established to investigate the solidification and flow behavior in the mushy zone and melt under conditions without strip and strip feeding. Results show that the rejection and flow of the lighter water-rich solutions form channels in the mushy zone and cause stratification in the melt. The crystal agglomeration of equiaxed crystals produced by dendrite remelting is observed at the top corner of the mold. After strip feeding, the dendrites on the surface and inside the cold strip are remelted into free-moving equiaxed crystals. The counterclockwise flow is changed into a smaller flow and a clockwise axe-shaped flow, and the maximum velocity increases from 1.38 mm/s without strip to 5.25 mm/s after strip feeding. The equiaxed crystals are transported by both the counterclockwise flow and the axe-shaped flow before settling to the mold bottom. The volume fractions of equiaxed crystals in the solidification structure are 19% and 31% under the conditions without strip and strip feeding. The mathematical relationships between the volume fraction of solidification structure and time are established.