The billets of aluminium may be primary or secondary. They can be in various wrought alloys (usually for extrusion), expressed with different standards: 6063, 6060, 6005, 6082, 107...

High Grade primary aluminium is quoted on London Metal Exchange (LME). Its contract specifies a minimun 99.7% purity, with maximum permissible iron content of 0.20% and maximum permissible silic...