The Effect of the Rate of Filling Moulds on the Solidification of Titanium-Alloy Ingots

Abstract

In vacuum arc melting, as well as in continuous casting of ingots, two processes occur simultaneously: the filling of the mould with a melt, and crystallization of the metal. As the first process leads to an increase, and the second to a decrease in the mass of the melt in the mould, they may be regarded as being opposite. With the rate of filling the mould being constant, such a system should in the course of time tend toward a quasi-stationary equilibrium in which the mass velocities of filling the mould and of crystallization will prove to be equal, while the dimensions of the pool of the melt in the mould will tend toward a constant magnitude. The rate of crystallization depends on the intensity of heat transfer from the ingot to the mould and is at the same time a function of the rate of filling the mould with a melt. But the latter belongs to the independent variables. The rate of filling the mould, when shaping ingots of a given composition and diameter, is the most important parameter to be controlled within a wide range.