Method for casting composite ingot

摘要

A method for the casting of a composite metal ingot comprising at least two layers formed of one or more alloys compositions, which 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 above the exit end of the mould, with each feed chamber adjacent at least one other feed chamber, wherein for each pair of 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 for 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 chambers to thereby cool the first alloy pool to form a self-supporting surface adjacent the divider wall and allowing the second alloy pool to contact the first alloy pool such that the second alloy pool contacts the self-supporting surface of the first alloy pool at a point where the temperature of the self-supporting surface is below the solidus temperatures of the first alloy to for an interface between the first alloy and the second alloy, and reheating the interface to a temperature between the solidus and liquidus temperature 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.