From The Science and Engineering of Materials by Donald R. Askeland
Aluminum alloys can be divided into two major groups: wrought and casting alloys. These groups can be divided into two sub-groups: heat-treatable and nonheat-treatable alloys.
The temper designation (T or H) refers to heat-Treated or strain-Hardened. Other designations include annealed (O), solution-treated (W), or as-fabricated (F). The numbers following the T or H refer to the type of heat treatment or amount of strain hardening.
F: AS-FABRICATED (hot-worked, forged, cast, etc.) O: ANNEALED (in the softest possible condition) H: COLD-WORKED
H1x--cold-worked only (x refers to the amount of cold work and strengthening.)
H12--cold work that gives a tensile strength midway between O and H14 tempers.
H14--cold work that gives a tensile strength midway between O and H18 tempers.
H16--cold work that gives a tensile strength midway between H14 and H18 tempers.
H18--cold work that gives about 75% reduction.
H19--cold work that gives a tensile strength greater than 2000 psi of that obtained by the H18 temper.
H2x--cold-worked and partially annealed.
H3x--cold-worked and stabilized at a low temperature to prevent age hardening of the structure. W: SOLUTION-TREATED T: AGE-HARDENED
T1--cooled from the fabrication temperature and naturally aged.
T2--cooled from the fabrication temperature, cold-worked, and naturally aged.
T3--solution-treated, cold-worked, and naturally aged.
T4--solution-treated and naturally aged.
T5--cooled from the fabrication temperature and artificially aged.
T6--solution-treated and artificially aged.
T7--solution-treated and stabilized by overaging.
T8--solution-treated, cold-worked, and artificially aged.
T9--solution-treated, artificially aged, and cold-worked.
T10--cooled from the fabrication temperature, cold-worked, and artificially aged.
