1.  F (As Fabricated):

• • This temper designation indicates that the aluminium alloy has undergone little to no thermal treatment after being fabricated into its final shape. It retains the mechanical properties imparted by the fabrication process, such as rolling or extrusion.
  • The F temper is characterized by relatively low strength and hardness but high ductility.

2.  O (Annealed):

• • The O temper represents fully annealed aluminium alloys. The material is heated to a specific temperature and then slowly cooled to relieve internal stresses and improve ductility.
  • Annealed aluminium alloys are soft and have low strength, making them highly formable and suitable for cold working processes such as bending and deep drawing.

3.  H (Strain Hardened):

• • The H temper designation is followed by one or more digits that indicate the degree of strain hardening or work hardening applied to the material.
  • H1 to H3: Low-strain hardening, typically achieved through cold working processes such as rolling or stretching, resulting in increased strength and hardness.
  • H4 to H18: Medium to high-strain hardening, achieved through more extensive cold working processes or a combination of cold working and thermal treatment (aging).
  • Higher numbers indicate higher levels of strain hardening and increased strength.

4.  T (Thermal Treatment):

• • The T temper designation is followed by one or more digits that indicate the specific thermal treatment applied to the material.
  • T1 to T5: Solution heat-treated, followed by artificial aging to achieve various combinations of strength and ductility.
  • T6: Solution heat-treated and artificially aged to achieve the highest combination of strength and toughness.
  • T7: Solution heat-treated and overaged to optimize resistance to stress corrosion cracking.
  • T8: Solution heat-treated, cold worked, and artificially aged to achieve high strength.

5.  W (Solution Heat-Treated Only):

• • The W temper designation indicates that the aluminium alloy has undergone only solution heat treatment without subsequent aging.
  • This temper is typically followed by a digit (e.g., W1) to indicate the specific solution heat treatment process used.

6.  H1X, H2X, H3X (Strain Hardened and Partially Annealed):

• • These temper designations indicate alloys that have been strain hardened and then subjected to partial annealing to reduce hardness and improve formability.
  • The digits following “H” denote the degree of strain hardening, similar to the H temper, while “X” indicates the extent of partial annealing. i