Patent ID: 7819170
Filing Date: 2010-10-26
Classification: B22D,Y10T

Abstract:
1. A method of casting a composite metal ingot comprising at least two layers formed of one or more alloy compositions, which method comprises providing an open ended annular mould having a feed end and an exit end wherein molten metal is added at the feed end and a solidified ingot is extracted from the exit end, and divider walls for dividing the feed end into at least two separate feed chambers, the divider walls terminating at lower ends thereof positioned above the exit end of said mould, with each feed chamber adjacent at least one other feed chamber, wherein for each pair of the adjacent feed chambers a first stream of a first alloy is fed to one of the pair of feed chambers to form a pool of metal in the first chamber and a second stream of a second alloy is fed through the second of the pair of feed chambers to form a pool of metal in the second chamber, the pools of metal each having an upper surface, contacting the first alloy pool with the divider wall between the pair of chambers to thereby cool the first alloy pool to form a self-supporting surface adjacent to the divider wall, wherein part of said self-supporting surface below said divider wall is at a temperature between the solidus and liquidus temperatures of the first alloy, and allowing the second alloy pool to contact the first alloy pool such that the upper surface of the second alloy pool contacts the divider wall at a position no more than 3 mm above the lower end of the divider wall or contacts the self-supporting surface of the first alloy pool at a position where the temperature of the self-supporting surface is between the solidus and liquidus temperatures of the first alloy, whereby the two alloy pools are joined as two layers, and cooling the joined alloy layers to form a composite ingot.