Casting of stock
Aluminium alloys are increasingly being transported in the molten state, in special thermally insulated containers. However, for many applications alloys, which are obtained by smelting or remelting, have to be in a solid form before they can be processed, and casting processes are used for this purpose.
Casting alloys are usually supplied in solid form as remelting ingots, i.e. ingots that can be easily stacked in such a manner that they interlock and do not slip during transport.
In order to produce semi-finished products, wrought alloys are cast as rolling ingots or extrusion billets of the appropriate shape and size. Rolling ingots and extrusion billets can be produced using batch or continuous processes. In the batch ingot casting process, molten metal is poured into a stationary permanent mould, where it solidifies. The mould is subsequently stripped, i.e. the solidified metal is removed.
However, continuous-casting processes , which enable better results to be achieved, are now becoming increasingly more important.