ABSTRACT
Virgin aluminium produced in the smelting process may be converted into a number of semi-fabricated forms. All sheet and coil material undergoes a series of passes through cold mills in which the metal thickness is progressively reduced. Aluminium foil is produced in a similar manner to sheet using specialized mills that enable the metal thickness to be reduced to the finest of webs. A particular characteristic of foil rolling is that of ‘double rolling’ where two layers of metal are rolled together with touching surfaces. The versatility of aluminium as a metal is complemented by the design scope offered by the extrusion process. Casting is one of the oldest processes for producing articles in metal. There are many excellent aluminium alloys that have been specially designed for casting using processes from sand casting to gravity die- and pressure die-casting. Metal moulds are generally fed by gravity but forced flow of the molten aluminium is sometimes achieved by low-pressure injection.
