There are 4 basic temper groupings for aluminium products:
- as fabricated
Shaped by cold working, hot working or casting processes in which no special
control over thermal processes or strain hardening is employed.
- Dead soft (i.e. fully annealed)
Applies to wrought products that are annealed to obtain the lowest strength
temper and to cast products tha t are annealed to improve ductility and
dimensional stability. The "O" may be followed by a digit other
than zero. Click for details
about "O" condition
"T" - Heat treated (i.e. for age hardening
Applies to products that are thermally
treatable (2000, 6000 and 7000 series), with or without supplementary
strain-hardening, to produce stable tempers. The "T" is always
followed by one or more digits. Click for details about "T1",
"T7" or "T8"
"H" - Strain hardened (i.e. for non
age hardening alloys, wrought products only)
This temper applies to products that have their strength increased by
hardening, with or without supplementary thermal treatment to produce
some reduction in strength. The "H" is always followed by two
or more digits:
The first digit following the H indicates the specific
combination of basic operations and is comprised between 1 and 4:
- H1x: cold worked only.
Applies to products that are strain-hardened to obtain the desired strength
without supplementary thermal treatment.
- H2x: cold worked and partially annealed.
Applies to products that are strain-hardened and then reduced in strength
to the desired level by partial annealing.
- H3x: cold worked and stabilized.
Applies to products that are strain-hardened and whose mechanical properties
are stabilized, either by a low temperature thermal treatment or as
a result of heat introduced during fabrication. Stabilization usually
- H4x: cold worked and lacquered or painted.
Applies to products which are strain-hardened and which are subjected
to some thermal operation during the subsequent painting or lacquering
The second digit following the H indicates the degree
of strain hardening (or cold work) as identified by the minimum value
of the ultimate tensile strength and is comprised 1 and 9. The minimum
tensile strength of tempers Hx8 is calculated from a table and is based
on the minimum tensile strength of the alloy in the annealed temper (for
more info please refer to European standard EN 515:1993).
Click for details about "Hx2",
"Hx8" or "Hx9"