Patent ID: 6192969
Filing Date: 2001-02-27
Classification: B22D

Abstract:
A method for making high purity copper castings from high purity copper which castings are substantially void free and inclusion free comprising the steps of:providing an open top container having a closed bottom and sidewalls for melting and holding copper therein;supplying high purity copper to the container;melting the copper in the container using a coil induction furnace wherein the coil forms a vertical opening therebetween in which the container is positioned and forming an annular space between the container sidewalls and the coil and wherein the copper in the container is melted by energizing the furnace with an electric current;providing insulation in the annular space;providing a cooler having cooled sidewalls and a vertical opening therebetween, the cooler being configured to accommodate and receive the container in the vertical opening in a heat transfer relationship so that heat is transferred from the container to the cooler;positioning the bottom of the container at the top of the cooler opening and passing the container downwardly through the cooler opening at a controlled downward rate and/or a controlled cooler sidewall cooling rate wherein both solidified copper and molten copper are present in the container at the same time with the copper solidifying from the bottom of the container upwards toward the top of the container and continuing to solidify on top of the solidified copper so that a layer of molten copper is maintained on top of the solidified and solidifying copper until the copper is solidified and a casting is formed.