Novelis, Inc.

Jeff McDermott

Robert Bruce Wagstaff

Wayne J Fenton

Todd F Bischoff

Aaron David Sinden

Eric Ball

The invention relates to a method and apparatus for direct chill casting ingots with in-situ homogenization. Large particles of eutectic material may form in the solid ingot and the metal may exhibit macrosegregation of alloying components, especially when large ingots are cast in this way. This can be alleviated by applying a first liquid coolant to the ingot emerging from the mold, removing the first liquid coolant at a certain distance along the ingot by means of a wiper, and then applying a second liquid coolant to perform a quench at a greater distance along the ingot. The quench raises the level of the molten sump in the ingot, which helps to overcome the indicated problems, without affecting the desired temperature rebound of the ingot shell (usually at least 425&#xb0; C. (797&#xb0; F.)) for a time effective to cause in-situ homogenization.

In-situ homogenization of DC cast metals with additional quench

An exemplary embodiment of the invention provides a method of direct chill casting a composite metal ingot. The method involves sequentially casting two or more metal layers to form a composite ingot by supplying streams of molten metal to two or more casting chambers within a casting mold of a direct chill casting apparatus. Inlet temperatures of one or more of the streams of molten metal are monitored at a position adjacent to an inlet of a casting chamber fed with the stream, and the inlet temperatures are compared with a predetermined set temperature for the stream to determine if there is any difference. A casting variable that affects molten metal temperatures entering or within the casting chambers (e.g. casting speed) is then adjusted by an amount based on the difference of the compared temperatures to eliminate adverse casting effects caused by the difference of the inlet temperature and the set temperature. Preferably an adjustment is selected that causes the monitored temperature to approach the set temperature. Another exemplary embodiment provides equipment for operation of the method.

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Liberty Lake, WA, United States of America

Jeff McDermott