In connection with extruded products the most frequently used tempers are O,
F, T4, T5 and T6.
If the extrusion process is performed efficiently (i.e. the run out temperature of the profile is over
the solution temperature for Mg2Si and the cooling rate of the extrusion is
fast enough) the 6000-group attain the same specified mechanical properties
whether furnace solution heat-treated or cooled from the extrusion temperature.
For such alloys the T3, T4, T6, T7 and T9 tempers are correspondent with
either process, because the extrusion temperature is above the solution
heat-treatment temperature and the cooling from the extrusion temperature is fast enough to
keep the hardening elements in solid solution.
(EXAMPLE: The artificially aged temper T5 equals T6 if the run out temperature
of the alloy is over the solution temperature for the hardening elements Mg2Si
and the cooling rate after the pressing is fast enough to keep the elements in
solution).
Additional Information (Topic: 10028)