Aging (precipitation hardening)
After stretching, extrusions are cut into manageable lengths (normally 4–6 metres) and are then aged.
This is done by heating the material to 175ºC–185ºC for 5 to 8 hours. During this process, the grain boundaries of the constituent alloys are bound together and the material gets its final mechanical characteristics.
The graph below show the stretch limit variations for material 6060 at different aging temperatures and aging times.