HOMOGENIZATION AND HEAT-TREATMENT OF CAST ALUMINIUM ALLOY

摘要

A method is provided of continuously or semi-continuously direct chill casting an ingot made of a castable metal, comprising the steps of: (a) providing a direct chill casting mold having one or more mold inlets and one or more mold outlets; (b) supplying molten metal to at least one inlet of the casting mold; (c) cooling the mold to solidify a peripheral portion of the metal, thereby forming an embryonic ingot having an external solid shell and an internal molten core; (d) continuously advancing the embryonic ingot beyond at least one outlet of the mold, thereby extending the molten core contained within the solid shell beyond said at least one outlet of the mold; (e) cooling the embryonic ingot emerging from the mold to continue the solidification thereof by directing a supply of coolant liquid onto an outer surface of the embryonic ingot; (f) causing said coolant liquid to be removed from the surface of the embryonic ingot at a position where the ingot has not yet been transformed into a fully solid ingot such that internal heat from the molten core reheats the solid shell adjacent to the core, thereby causing temperatures of said core and said shell to equilibrate at a convergence temperature, said coolant liquid being removed from said surface at a distance from said at least one mold outlet that causes said convergence temperature to become 425°C or higher; and (g) varying said position in step (f) in different phases of said casting of said ingot to minimize differences of said convergence temperature below said wiper during said different phases of casting.