MODELING MACROSEGREGATION DURING VAR OF TI-10V-2FE- 3AL ALLOY: Macroscopic Approach

Vacuum arc remelting (VAR) is a secondary melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. One of the most important problems of Vacuum Arc Remelting (VAR) is the lack of chemical homogeneity in the produced ingots. Past numerical studies of VAR have demonstrated that the characteristics of the mushy zone, the fluid flow and their interaction are the key factors defining the severity and the character of macrosegregation in the produced ingots. Thus, a new numerical model of the complete VAR process, capable of representing two distinctive morphologies of mushy zone: rigid columnar structure and slurry of free floating equiaxed grains is introduced. The presented model accompanied by a simple criterion for the columnar- to-equiaxed transition allows the capture of segregation defects induced by motion and settling of equiaxed grains.