Numerical Simulation of the Dynamic Formation of Slag Skin and Heat Flow Distribution during the Electroslag Remelting Process

Abstract

A 2D axisymmetric model is established to investigate the dynamic formation of slag skin and heat flow distribution during the electroslag remelting process. The growth of ingots is addressed with the dynamic mesh technique, and the volume of fluid model is employed to trace the slag/metal interface. The results indicate that the slag skin thickness at the slag/mold interface increases with the distance from the free slag surface, with a maximum thickness of 4 mm at the slag/pool interface. With the growth of ingot, the slag skin at the slag/pool interface is partially remelted by the hotter metal and finally solidifies around the solidified ingot with a thickness of 1 mm. The calculated percentage of heat flow is in reasonable agreement with the measurement. The loss of heat flow to the mold accounts for 67% of the power input, and approximately 28% of that power is absorbed by droplets in a laboratory scale ESR unit. The heat loss to slag/mold interface first increases with increasing slag temperature and then slowly decreases with decreasing slag bath height. The heat of the ingot primarily escapes from the baseplate at the initial stage. However, as the ingot grows, the heat loss in the radial gradually becomes dominant.