Roll-Gap Deviation on Centerline Segregation Evolution in Continuous Casting Slab

Roll-gap deviation (RGD) is commonly observed in the slab continuous caster, which means the thicknesses of the right and left sides are different. The RGD amounts and positions on the solute redistribution are investigated. In the RGD zone, slab thickness decreases from the left to the right side. Dynamic grid technology is used to consider the mesh deformation in the model. When RGD is set before the solidification end of the slab middle part, the center segregation in the right-edge part decreases but that in the left-edge part increases. That is because the solute-enriched liquid moves from the right to the left side with solid compression. When RGD is set after the slab middle part is solidified, the center segregation in the right-edge part is deteriorated, while that in the left-edge part is reduced. This is because the slab right-edge part is fully solidified in the RGD zone, and the segregation cannot be reduced in the later stage. With the RGD position moving from 15.5 to 18.0 m from the meniscus, the center segregation in the right-edge part decreases first and then increases, while that in the left-edge part increases slightly and then declines.