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QUICK FACT GUIDES FOR MACHINISTS
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GUIDES |
TEMPER DESIGNATIONS OF ALUMINUM The temper designation system adopted by the Aluminum Association and used in industry pertains to all forms of wrought and cast aluminum and aluminum alloys except ingot. It is based on the sequences of basic treatments used to produce the various tempers. Basic temper designations consist of letters. subdivisions of the basic tempers, where required, are indicated by one or more digits following the letter. These designate specific sequences of basic treatments, but only operations recognized as significantly influencing the characteristics of the product are indicated. Should some other variation of the same sequence of basic operations be applied to the same alloy, resulting in different characteristics, then additional digits are added. The basic temper designations and subdivisions are as follows: -F as fabricated: applies to products which acquire some temper from shaping process not having special control over the amount of strain-hardening or thermal treatment. For wrought products, there are no mechanical property limits. -O annealed, recrystallized (wrought products only): Applies to the softest temper or wrought products. -H strain-hardened (wrought products only): applies to products which have their strength increased by strain-hardening with or without supplementary thermal treatments to produce partial softening. The -H is always followed by two or more digits. The first digit indicates the specific combination of basic operations, as follows: -H1 stain-hardened only: Applies to products which are strain-hardened to obtain the desired mechanical properties without supplemental thermal treatment. -H2 strain-hardened and then partial annealed: Applies to products which are strain-hardened more than the desired final amount and then reduced in strength to the desired level by partial annealing. for alloys that age-soften at room temperature, the -H2 tempers have approximately the same ultimate strength as the corresponding -H3 tempers. tempers. For other alloys, the -H2 tempers have the approximately the same ultimate strengths as the corresponding -H1 tempers and slightly higher elongations. -H3 strain-hardened and then stabilized: Applies to products which are strain=hardened and then stabilized by a low temperature heating to slightly lower their strength and increased ductility. This designation applies only to the magnesium-containing alloys which, unless stabilized, gradually age-soften at room temperature. -T thermally treated to produce stable tempers other than-F, -O, or -H: Applies to products which are thermally treated, with or without supplementary strain-hardening, to produce stable tempers.The -T is always followed by one or more digits. Numerals 2 through 10 have been assigned to indicate specific sequences of basic treatment as follows: -T2 annealed (cast products only): designates a type of annealing treatment used to improve ductility and increase dimensional stability of castings. -T3 solution heat-treated and then cold worked: Applies to products which are cold worked to improve strength, or in which the effect of cold work in flattening or straightening is recognized in applicable specifications. -T4 solution heat-treated and naturally aged to a substantially stable condition: Applies to products which are not cold worked after solution heat-treatment, or in which the effect of cold work in flattening or straightening may not be recognized in applicable specifications. -T5 artificially aged only: Applies to products which are artificially aged after an elevated-temperature rapid-cool fabrication process, such as casting or extrusion, to improve mechanical properties and/or dimensional stability. -T6 solution heat-treated and then artificially aged: Applies to products which are not cold worked after solution heat-treatment, or in which the effect of cold work in flattening or straightening may not be recognized in applicable specifications. -T7 solution heat-treated and then stabilized: Applies to products which are stabilized to carry them beyond the point of maximum hardness, providing control of growth and/or residual stress. -T8 solution heat-treated, cold worked, and then artificially aged: Applies to products which are cold worked to improve strength, or in which the effect of cold work in flattening or straightening is recognized in applicable specifications. -T9 solution heat-treated, artificially aged, and then cold worked: Applies to products which are cold worked to improve strength. -T10 artificially aged and then cold worked: Applies to products which are artificially aged after an elevated-temperature rapid-cool fabrication process, such as casting or extrusion, and then cold worked to improve strength. |
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