TENNALUMŽ Aluminum Alloys, Tempers and Terminology

Temper Designation System

The temper designation system is used for all forms of wrought and cast aluminum and aluminum alloys except ingot. It is based on the sequence of basic treatments used to produce various tempers. The temper designation follows the alloy designation with the two separated by a hyphen. Basic designations consist of a letter while subdivisions of those basic tempers, where required, are indicated by one or more digits following those letters. The system is designed to set down specific sequences of fabrication processes, but only those operations that are recognized as significantly influencing the characteristics of the product involved. Should some other variation of the same sequence of basic operations be applied to the same alloy, resulting in different characteristics, the additional digits will be added to the numerical designation.

Basic Temper Designations

F	as fabricated. Denotes metal that has been fabricated to ordered dimensions without any attempt on the part of the producer to control the results of either strain-hardening operations or thermal treatments. There are no mechanical property limits, and the strength levels may vary form lot to lot and from shipment to shipment.
O	annealed. Applies to wrought products that have undergone a thermal treatment to reduce their mechanical property levels to their minimums. Often described as "dead soft" metal.
W	solution heat-treated. An unstable temper applying to certain of the (7XXX) heat-treatable alloys that, after heat treatment, spontaneously age harden at room temperature. Only when the period of natural aging is indicated (W 1hr. for example) is this a specific and complete designation.
H	strain-hardened. Applies to those wrought products which have had an increase in strength by reduction through strain-hardening or cold working operations. The "H" is always followed by two or more digits.
T	thermally treated to produce tempers other than F, O or H. Applies to those products which have had an increase in strength due to thermal treatments, with or without supplementary strain-hardening operations. The "T" is always followed by one or more digits.

Subdivisions of "T" Temper-

Heat-Treatable Alloys

T1	cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition. Usually associated with extruded products and limited to the 6XXX series alloys.
T2	cooled from an elevated temperature shaping process, cold worked, and naturally aged to a substantially stable condition. Usually associated with cast products.
T3	solution heat-treated, cold worked, and naturally aged to a substantially stable condition. (T4+cold work)
T4	solution heat-treated, and naturally aged to a substantially stable condition.
T5	cooled from an elevated temperature shaping process and artificially aged. Usually associated with extruded products in the 6XXX series alloys. (T1+artificial age)
T6	solution heat-treated, and artificially aged. (T4+artificial age)
T7	solution heat-treated, and overaged/stabilized. Applies to alloy products which are thermally overaged after solution heat-treatment to carry them beyond the point of maximum strength to provide control of some special characteristic.
T8	solution heat-treated, cold worked, and artificially aged. (T3+artificial age)
T9	solution heat-treated, artificially aged and cold worked. (T6+artificial age)
T10	cooled from an elevated temperature shaping process, cold worked, and artificially aged. Usually associated with cast products.(T2+artificial age)

The following specific digits have been assigned for stress-relieved tempers of wrought products:

T_51	Applies to cold finished rod or bar when stress-relieved by stretching 1 to 3 % permanent set. Stretching is performed after solution heat treatment or after cooling from an elevated temperature shaping process. No straightening takes place after stretching.
T_510	Applies to extruded products and to drawn tube when stress-relieved by stretching 1 to 3 % permanent set. Stretching is performed after solution heat treatment or after cooling from an elevated temperature shaping process. No straightening takes place after stretching 1 to 3 % permanent set.
T_511	Applies to extruded products and to drawn tube when stress-relieved by stretching 1 to 3 % permanent set. Stretching is performed after solution heat treatment or after cooling from an elevated temperature shaping process. These products may receive minor straightening after stretching to comply with standard tolerances.

Subdivisions of "H" Temper-

Non-Heat-Treatable Alloys

H1	strain-hardened only. Applies to products which are strain-hardened or cold worked to obtain the desired strength level without supplementary thermal treatments. The number following this designation indicates the degree of strain-hardening.
H2	strain-hardened partially annealed. Applies to products strain-hardened or cold worked more than the desired level by partial annealing. The number following this designation indicates the degree of strain hardening remaining after the partial annealing process.
H3	strain-hardened and stabilized. Applies to products in the magnesium-aluminum class which will age-soften at room temperature after strain-hardening. These products are strain-hardened to the desired amount and then subjected to a low temperature thermal operation which results in a improved ductility. The number following this designation indicates the degree of strain-hardening remaining after the stabilization treatment.