Simulation of Solidification Structure During Vacuum Arc Remelting Using Cellular Automaton−Finite Element Method

A 3D vacuum arc remelting model coupling heat transfer, fluid flow, solidification, nucleation, and grain growth is established. The effect of melting rate and current intensity on the solidification structure, depth of the molten pool, and equiaxed crystal rate is investigated by the simulation. Near the baseplate of the mold, the direction of columnar dendrites is vertically upward. Near the mold lateral wall, the columnar dendrites grow aslant upward. From the initial time to the end of the remelting period, the depth of the molten pool increases continuously and reaches the maximum value of 105.5 mm at the end of the remelting period. In the end feeding period, the depth of the molten pool decreases gradually until the molten pool solidifies completely. With the melting rate increasing from 0.8 to 2.4 kg min −1 , the maximum depth of the molten pool increases from 84.6 to 130.3 mm and the equiaxed crystal rate is 42.5%, 57.2%, and 62.7%, respectively. With the current intensity increasing from 2 to 6 kA, the maximum depth of the molten pool increases from 63.1 to 92.9 mm and the equiaxed crystal rate decreases from 51.7% to 45.6%.