<blockquote><font size=1>In reply to:</font><hr>
Heating Al alloys above this temperature causes a granular rearrangement of the metallurgical structure resulting in a significant change of bulk properties. The tensile strength of the metal is dramatically lowered, much like a stress relief anneal on a
steel piece would do. The resultant metal is not as strong, nor will
pressure vessels made of such treated aluminum (e.g., scuba tanks) hold near
the pressure that they were originally rated for. Since wheels are essentially load-bearing structures, they should never be heated like this unless the alloy is known to tolerate it well.