- O: Annealed, soft
- T: Heat-treated
- H: Strain-hardened
- T1: Direct-formed
- T2: Annealed
- T3: Taken in solution and cold processed
- T4: Taken in solution and natural aged
- T5: Direct-formed and artificial aged
- T6: Solution heat-treated and then artificially aged
- T7: Solution heat-treated and overaged/stabilised
- T8: Solution heat treated, cold worked then artificially aged
- T9: Solution heat treated, artificially aged and cold worked
- T10: Cooled from an elevated temperature, artificially aged then cold worked
- T42: Fatigue and corrosion in mechanical properties after Ta and T6 heat
- T62: If there is a change in resistance
- T351: Additional controlled stretching before aging
- T651: Additional controlled stretching before aging
- T6511: Additional controlled stretching and extra unstressing before aging
- T851: Additional controlled stretching before aging
- H1: Strain hardened, not annealed after rolling
- H11: Strain-hardened, quarter hard
- H111: Low-stretching
- H112: Hardened with uncontrolled strecthing
- H12: Strain-hardened, quarter hard
- H14: Strain-hardened, half hard
- H16: Strain-hardened, three quarter hard
- H18: Strain-hardened, fully hard
- H19: Strain-hardened, extra hard
- H2: Strain hardened and partially annealed
- H21: Strain-hardened, partially annealed 1/8 hard
- H22: Strain-hardened, partially annealed quarter hard
- H24: Strain-hardened, partially annealed half hard
- H26: Strain-hardened, partially annealed three quarter hard
- H28: Strain-hardened, partially annealed fully hard
- H29: Strain-hardened, partially annealed extra hard
- H3: Strain-hardened and stabilized
- H32: Strain-hardened and stabilised, quarter hard
- H34: Strain-hardened and stabilised, half hard
- H36: Strain-hardened and stabilised, three quarter hard
- H38: Strain-hardened and stabilised, fully hard
- H39: Strain-hardened and stabilised, extra hard
- H4: Strain-hardened and stoved
- H42: Strain-hardened and stoved, quarter hard
- H44: Strain-hardened and stoved, half hard
- H46: Strain-hardened and stoved, three quarter hard
- H48: Strain-hardened and lacquered or painted, fully hard
- H49: Strain-hardened and lacquered or painted, extra hard