Casting

Cast aluminum wheels are produced from molten metal

The most common alloy is A-356

A-356 is both strong, and offers an extremely bright surface

Cast aluminum wheels are produced from molten metal.  The most common alloy is A-356 which is a heat treatable magnesium silicon alloy.  98% of all OEM custom wheels are made from cast A-356 aluminum.  A-356 is both strong, and offers an extremely bright surface when CNC machined, or polished.