Numerical simulation and experimental investigation of manufacturing route of directional casting super slab

We proposed a new technique route of directional solidification for the manufacture of super slab. A 7-t laboratory-scale thick slab was casted and characterised for trial. To further understand the process, the evolution of the multiple physical fields during the directional solidification was simulated and verified. Similar to the convectional ingot casting, a negative segregated cone of equiaxed grains was formed at the bottom, and a seriously positive segregated region was formed beneath the top surface of the slab. Specific measures on the lateral walls, base plate, and free surface were strongly recommended to ensure that the slab is relatively directionally casted. A water-cooling copper base plate accelerates the solidification rate and the columnar growth along the vertical direction. It inhibits the sedimentation of equiaxed grains and enlarges the columnar zone. Based on the simulation analysis, it can be concluded that the directional solidification technique route is promising to manufacture super slab with lower segregation level, and less porosities and inclusions.