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Aluminium Temper Designations
The temper designation system used for all forms of aluminium and its alloys is based on the sequence of basic treatments used to produce various tempers. The basic temper designation consists of a letter. Subdivisions of basic temper are indicated by one or more digits following the letter.
Basic temper designations
F – as manufacture
O –annealed, soft.
H – strain hardened, non heat-treated material.
W- solution heat-treated
W- thermally treated- to produce a stable temper other than those listed.
Subdivision of T temper
• T1- cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition.
• T2- cooled from an elevated temperature shaping process, cold worked, and naturally aged to a substantially stable condition.
• T3- solution heat-treated, cold worked, and naturally aged to a substantially stable condition.
• T4- solution heat-treated and naturally aged to a substantially stable condition.
• T5- cooled form an elevated temperature shaping process and then artificially aged.
• T6- solution heat treated and then artificially aged
• T7- solution heat treated and stabilised
• T8- solution heat treated, and then artificially aged.
• T9- solution heat-treated, artificially aged, and then cold worked.
• T10- cooled from an elevated temperature shaping process, cold worked and then artificially aged. Some additional digits have been assigned for specific conditions such as stress-relieved tempers, as follows.
• T51- stress relieved by controlling stretching. This applies to plate. For extrusions there are two subdivisions.
• T510- for products that receive no further straightening after stretching.
• T511- for products that may receive minor straightening after stretching, to comply with tolerances.
Among the commonly used T-51 conditions are:
• T351- solution heat treated, cold worked, controlled stretching and naturally aged.
• T651- solution heat treated, controlled stretched and artificially aged.
• T851- solution heat treated, cold worked, controlled stretched and artificially aged.
• T7351- solution heat treated, controlled stretched and artificially aged to provide optimum stress corrosion resistance but with 15-20% lower tensile properties than T6.
• T7651- solution heat treated, controlled stretched and artificially aged to achieve optimum exfoliation resistance corrosion resistance but with about 10% lower tensile properties than T6.
• T52- stress relieved by compressing.
• T54- stress relieved by combining stretching and compressing.
Specific digits are also assigned to indicate properties of materials supplied for heat treatment by the user:
• T42- solution heat treated from the O or F temper to demonstrate response to heat treatment, and naturally aged to a substantially stable condition.
• T62- solution heat treated from the O or F temper o demonstrate response to heat treatment, and then artificially aged.