Hardness coding

Quality Description
F As fabricated (no mechanical property limits specified).
O Annealed – products that achieved the required annealed properties after hot forming processes may be designated as O temper.
O1 Thermally treated at approximately the same time and temperature required for solution treatment and slow cooled to room temperature (formerly designated as T41).
O2 Thermo-mechanically processed to enhance formability, such as required for super-plastic forming (SPF).
O3 Homogenized.
H12 Strain-hardened – 1/4 hard.
H14 Strain-hardened – 1/2 hard.
H16 Strain-hardened – 3/4 hard.
H18 Strain-hardened – 4/4 hard (fully hardened).
H19 Strain-hardened – extra hard.
Hxx4 Applies to embossed or patterned sheet or strip, fabricated from the corresponding Hxx temper.
Hxx5 Strain-hardened – applies to welded tubes.
H111 Annealed and slightly strain-hardened (less than H11) during subsequent operations such as stretching or levelling.
H112 Slightly strain-hardened from working at an elevated temperature from a limited amount of cold work (mechanical property limits specified).
H116 Applies to aluminium-magnesium alloys with a magnesium content of 4% or more and for which mechanical property limits and exfoliation corrosion resistance are specified.
H22 Strain-hardened and partially annealed – 1/4 hard.
H24 Strain-hardened and partially annealed – 1/2 hard.
H26 Strain-hardened and partially annealed – 3/4 hard.
H28 Strain-hardened and partially annealed – 4/4 hard (fully hardened).
H32 Strain-hardened and stabilized – 1/4 hard.
H34 Strain-hardened and stabilized – 1/2 hard.
H36 Strain-hardened and stabilized – 3/4 hard.
H38 Strain-hardened and stabilized – 4/4 hard (fully hardened).
H42 Strain-hardened and painted or lacquered – 1/4 hard.
H44 Strain-hardened and painted or lacquered – 1/2 hard.
H46 Strain-hardened and painted or lacquered – 3/4 hard.
H48 Strain-hardened and painted or lacquered – 4/4 hard (fully hardened).
W Solution heat-treated (unstable temper). The period of natural ageing (W2h..) may also be specified.
W51 Solution heat-treated (unstable temper) and stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for hand or ring forging and rolled ring). The products receive no further straightening after stretching.
W510 Solution heat-treated (unstable temper) and stress-relieved by controlled stretching (permanent set 1% to 3% for extruted rod, bar, shapes and tube, 0.5% to 3% for drawn tube). The products receive no further straightening after stretching.
W511 Same as W510 except minor straightening is allowed after stretching to comply with standard tolerances.
W52 Solution heat-treated (unstable temper) and stress-relieved by compressing to produce a permanent set of 1- 5%.
W54 Solution heat-treated (unstable temper) and stress-relieved by restriking cold in the finish die (die forging).
T1 Cooled from an elevated temperature shaping process and naturally aged.
T2 Cooled from an elevated temperature shaping process, cold worked and naturally aged.
T3 Solution heat-treated, cold worked and naturally aged.
T31 Solution heat-treated, cold worked approximately 1% and naturally aged.
T351 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and naturally aged. The products receive no further straightening after.
T3510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, shapes and tube, 0.5% to 3% for drawn tube) and naturally aged. The products receive no further straightening after stretching.
T3511 Same as T3510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T354 Solution heat-treated stress-relieved by restriking cold in the finish die and naturally aged.
T36 Solution heat-treated, cold worked approximately 6% and naturally aged.
T37 Solution heat-treated, cold worked approximately 7% and naturally aged.
T39 Solution heat-treated and cold worked to an appropriate degree to achieve the specified mechanical properties. Cold work may be carried out before or after natural ageing.
T4 Solution heat-treated and naturally aged.
T42 Solution heat-treated and naturally aged. Applies to test material heat-treated from annealed or F temper or to products heat-treated from any temper by the user.
T451 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and naturally aged. The products receive no further straightening after stretching.
T4510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar shapes and tube, 0.5% to 3% for drawn tube) and naturally aged. The products receive no further straightening after stretching.
T4511 Same as T4510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T452 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and naturally aged.
T454 Solution heat-treated, stress-relieved by restriking cold in the finish die and naturally aged.
T5 Cooled from an elavated temperature shaping process and then artificially aged.
T51 Cooled from an elavated temperature shaping process and then artificially aged in underageing conditions to improve formability.
T56 Cooled from an elevated temperature shaping process and then artificially aged – mechanical property level higher than T5 achieved through special control of the process (6000 series alloys).
T6 Solution heat-treated and then artificially aged.
T61 Solution heat-treated and then artificially aged in underageing conditions to improve formability.
T6151 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate) and then artificially aged in underageing conditions to improve formability. The products receive no further straightening after stretching.
T62 Solution heat-treated and then artificially aged. Applies to test material heat-treated from annealed or F temper or to products heat-treated from any temper by the user.
T64 Solution heat-treated and then artificially aged in underageing conditions (between T6 and T61) to improve formability.
T651 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and then artificially aged. The products receive no further straightening after stretching.
T6510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, shapes and tube, 0.5% to 3% for drawn tube) and then artificially aged. The products receive no further straightening after stretching.
T6511 Same as T6510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T652 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and then artificially aged.
T654 Solution heat-treated, stress-relieved by restriking cold in the finish die and then artificially aged.
T66 Solution heat-treated and then artificially aged. Mechanical property level higher than T6 achieved through special control of the process (6000 series alloys).
T7 Solution heat-treated and then artificially overaged.
T73 Solution heat-treated and then artificially overaged in order to achieve the best stress corrosion resistance.
T732 Solution heat-treated and then artificially overaged in order to achieve the best stress corrosion resistance. Applies to test material heat-treated from annealed or F temper or to products heat-treated from any temper by the user.
T7351 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and then artificially overaged in order to achieve the best stress corrosion resistance. The products receive no further straightening after stretching.
T73510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, shapes and tube, 0.5% to 3% for drawn tube) and then artificially overaged in order to achieve the best stress corrosion resistance. The products receive no further straightening after stretching.
T73511 Same as T73510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T7352 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and then artificially overaged in order to achieve the best stress corrosion resistance.
T7354 Solution heat-treated, stress-relieved by restriking cold in the finish die and then artificially overaged in order to achieve the best stress corrosion resistance.
T74 Solution heat-treated and then artificially overaged (between T73 and T76).
T7451 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and then artificially overaged (between T73 and T76). The products receive no further straightening after stretching.
T74510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar shapes and tube 0.5% to 3% for drawn tube) and then artificially overaged (between T73 and T76). The pro-ducts receive no further straightening after stretching.
T74511 Same as T74510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T7452 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and then artificially overaged (between T73 and T76).
T7454 Solution heat-treated, stress-relieved by restriking cold in the finish die and then artificially overaged.
T76 Solution heat-treated and then artificially overaged in order to achieve a good exfoliation corrosion resistance.
T761 Solution heat-treated and then artificially overaged in order to achieve a good exfoliation corrosion resistance (applies to 7475 sheet and strip).
T762 Solution heat-treated and then artificially overaged in order to achieve a good exfoliation corrosion resistance. Applies to test material heat-treated from annealed or F temper or to products heat-treated from any temper by the user.
T7651 Solution heat-treated, stress-relieved by controlled stretching (permanent set 0.5% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and then artificially overaged in order to achieve a good exfoliation corrosion resistance. The products receive no further straightening after.
T76510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, shapes and tube, 0.5% to 3% for drawn tube) and then artificially overaged in order to achieve a good exfoliation corrosion resistance. The products receive no further straightening after stretching.
T76511 Same as T76510 except that minor straightening is allowed after stretching to comply with standard tolerances.
T7452 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and then artificially overaged in order to achieve a good exfoliation corrosion resistance.
T7454 Solution heat-treated, stress-relieved by restriking in the finish die and then artificially overaged in order to achieve a good exfoliation corrosion resistance.
T79 Solution heat-treated and then artificially overaged (very limited overageing).
T79510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, shapes and tube, 0.5% to 3% for drawn tube) and then artificially overaged (very limited overageing). The products receive no further straightening after stretching.
T8 Solution heat-treated, cold worked and then artificially aged.
T82 Solution heat-treated by the user, controlled stretched with a minimum permanent set of 2% and then artificially aged (alloy 8090).
T832 Solution heat-treated, cold worked a controlled specific amount and then artificially aged (applies to 6063 drawn tube).
T841 Solution heat-treated, cold worked and then artificially underaged (sheet and strip in alloys 2091 and 8090).
T851 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for sheet, 1.5% to 3% for plate, 1% to 3% for rolled or cold-finished rod and bar, 1% to 5% for hand or ring forging and rolled ring) and then artificially aged. The products receive no further straightening after stretching.
T8510 Solution heat-treated, stress-relieved by controlled stretching (permanent set 1% to 3% for extruded rod, bar, profiles and tube, 0.5% to 3% for drawn tube) and then artificially aged. The products receive no further straightening after stretching.
T8511 Same as T8510 except for minor straightening is allowed after stretching to comply with standard tolerances.
T852 Solution heat-treated, stress-relieved by compressing to produce a permanent set of 1% to 5% and then artificially aged.
T854 Solution heat-treated, stress-relieved by restriking cold in the finish die and then artificially aged.
T86 Solution heat-treated, cold worked approximately 6% and then artificially aged.
T87 Solution heat-treated, cold worked approximately 7% and then artificially aged.
T89 Solution heat-treated, cold worked to an appropriate degree to achieve the specified mechanical properties and then artificially aged.
T9 Solution heat-treated, artificially aged and then cold worked.