A billet of series 1000, 3000 or 6000 aluminum alloy is placed in the extrusion press and is heated to between 750 to 900 degrees F, making it malleable. It is then forced through a steel die using a hydraulic ram that applies upwards of 15,000 tons of pressure.
The cross section of the extrusion is determined by the shape of the die it is pushed through. Complex shapes up to 14” in diameter may emerge from the extrusion press as slowly as one foot per minute. Simpler shapes can emerge as quickly as 200 feet per minute.
As the extrusion leaves the extrusion die, quenching (or cooling) methods such as air, water sprays, water baths and mists are used to quickly cool it.
In conjunction with the quenching, pullers cut and move the extrusion to a cooling table or stretcher, where the extrusion is straightened and cut to the ordered length. These run out tables are often upward of 175 feet in length.