Flow Field and Inclusions Movement in the Cold Hearth for the Ti-0.3Mo-0.8Ni Alloy

To investigate the melt flow field and inclusions movement in the cold hearth for the Ti-0.3Mo-0.8Ni alloy during electron-beam cold-hearth melting, a three-dimensional numerical model was established. By using solidification and discrete phase models, the information on the melt flow field and inclusions movement in the cold hearth were obtained. As the casting velocity increased, the melt flow velocity increased, the solid–liquid interface moved down. Inclusions with a density of 4.5 g/cm³ were the most difficult to remove. When the density of the inclusions was 3.5 g/cm³, the number of inclusions that escaped decreased with an increase in the inclusion diameter; these inclusions easily floated on the pool surface and remained in the cold hearth. Inclusions with a density of 5.5 g/cm³ have a similar escaping trend to the inclusions with a density of 3.5 g/cm³; as the diameter of these inclusions increased, gravity on these inclusions had a larger effect and caused them to sink more easily. Generally, for high and low density inclusions with a large diameter, the effect of density can be eliminated; the most effective method to remove inclusions in the metallurgical industry is to promote the polymerization and growth of the inclusions.