Aluminium Foil

Flat rolled aluminium is produced by casting aluminium through the melting of aluminium ingots / t-bars. The cast coils are then rolled down to the desired thickness in cold rolling mills. Aluminium foil is produced by rolling mill-finished coils in foil rolling mills down to thicknesses of 0.2 mm or thinner gauges. Aside from foil rolling, the foil production process may also include the annealing, separating, slitting and packaging processes. 

The foil production process begins with the re-melting of unwrought aluminum, aluminum scrap and alloying elements in the melting furnaces to produce a given alloy chemical composition and casting of coils on twin roll continuous casting lines.

Cast coils are reduced in thickness in successive stages on cold rolling mills to the desired thickness and heat-treated in annealing furnaces as required by the metallurgical process to produce foil stock.

Foil stock coils are reduced in thickness in successive stages on foil rolling mills and after the rolling, the coils are slit to the final width. For thinner gauge foil, the last rolling pass is done on two layers of foil at once, and the doubled layers are separated at the slitting step. Such products have one bright and one matte surface, whereas singly rolled products have two bright surfaces. The coils are annealed after slitting to achieve the desired temper and to remove rolling oil. For products that are lubricated, the order of slitting and annealing operations is reversed, and lubrication is applied during slitting. For a very small portion of products intermediate annealing in between rolling passes is required.

 Finishing operations are performed on slitting, separating, and packaging lines as needed. Slitting lines are used to reduce the coil width or to slit it into strips. Separator lines are used to separate the layers and slitting at the same time.