Temperature control of TiAl melt during induction skull melting

Abstract

The properties of intermetallic compounds are sensitive to alloy composition and interstitial element content determined by the melting process. Induction skull melting is one of the best methods for melting reactive alloys. For induction heating under vacuum, melt temperature control is problematic. A numerical model for simulating temperature field during induction skull melting has been developed using the direct finite difference method. Factors such as water cooling boundaries, electromagnetic stirring meniscus, and power distribution in the charge were analysed. The chargecrucible interface was taken as a radiation boundary before melting and as a combined radiation and conduction boundary after melting. The free surface was taken as a radiation boundary. The relationship between the height of electromagnetic stirring meniscus and charge weight and melting power was reduced based on the conservation of mass. Based on the conservation of energy, the distribution density of induction current was ascertained. With the program, the relationship between melting power, charge weight, and melt temperature was established. During induction skull melting of gamma-TiAl based alloys, the melt temperature was measured carefully. The theoretical and experimental results were found to be in agreement.