Method of casting lithium containing aluminium alloys

A method of casting an ingot of an aluminium alloy comprising lithium, the ingot having a length L, width W, and thickness T, the method comprising the steps of:

• (a) preparing at least two molten aluminium based alloys in separate furnaces, a first alloy with a composition A which is free from lithium as purposive alloying element, and a second alloy with a composition B which comprises lithium as purposive alloying element;
• (b) transferring the first alloy via a metal conveying trough from a first of said furnaces to a casting station;
• (c) initiating the start of casting an ingot and casting the first alloy to a required length L1 of an ingot in the casting direction;
• (d) subsequently transferring the second alloy via a metal conveying trough from a second of said furnaces to the casting station while simultaneously stopping the transfer of the first alloy to said casting station;
• (e) casting the second alloy from an end surface of the cast first alloy at length L1 to an additional required length L2 in the casting direction;
• (f) cropping the cast ingot at a bottom thereof at a length that is greater than or equal to the cast length L1.