Aluminium Alloy and Temper

This article mainly introduces the classification of aluminium alloy and temper. It will give you an outline of aluminium alloy family.

Wrought alloy with a 4-digit number was widely accepted by many countries, it works as follows: the first digit indicates the major alloying element or elements, as shown in the table:

Major Alloying Elements	Series
Pure Aluminium（not less 99.00%）	1×××
Copper	2×××
Manganese	3×××
Silicon	4×××
Magnesium	5×××
Magnesium, Silicon and Mg₂Si as strengthening	6×××
Zinc	7×××
Others (including Lithium)	8×××
Standby	9×××

The basic temper designations for aluminium and aluminium alloys are symbolized by a capital letter in English, and divided into five as following:

Code	Designation	Instructions & Applications
F	Fabricated	No mechanical properties specified. Apply to products that have no special requirements for work hardening and heat treatment.
O	Annealed	Apply to obtain lowest strength temper by full annealing, O may be followed by a digit to indicate an annealed condition with special characteristics.
H	Work-hardening or Strain-hardening	Apply to products with or without additional thermal treatment to reduce strength. H always is followed by two or more digits.
W	Solution heat-treatment	W is an unstable temper due to natural aging at room temperature after solution heat-treatment.
T	Thermal treatment	To produce stable tempers with or without additional strain-hardening, T is always followed by one or more digits.

Temper	Instructions & Applications
T0	After Solution heat-treatment, naturally aged and cold worked. Suitable for products after cold worked to improve strength.
T1	Cooled from an elevated temperature shaping process and naturally aged. Suitable for products after shaping process, no longer cold worked ( can be straightened, flattened, but does not affect the mechanical properties)
T2	Cooled from an elevated temperature shaping process, cold worked, and naturally aged. Suitable for products after cooled from an elevated temperature, cold worked or straightened, flattened to improve the strength.
T3	Solution heat treated, cold worked, and naturally aged. Suitable for products after Solution heat treated, cold worked or straightened, flattened to improve the strength.
T4	Solution heat treated and naturally aged. Suitable for products after Solution heat treated, no longer cold worked ( can be straightened, flattened, but does not affect the mechanical properties).
T5	Cooled from an elevated temperature shaping process and artificially aged. Suitable for products after shaping process, no longer cold worked but artificially aged ( can be straightened, flattened, but does not affect the mechanical properties).
T6	Solution heat treatment and artificially aged. Suitable for products after solution heat treatment, no longer cold worked ( can be straightened , flattened, but does not affect the mechanical properties).
T7	Solution heat treatment and artificially overaged. Suitable for products after solution heat treatment, to obtain some important features, strength on aged curve over the peak point in the artificially aged.
T8	Solution heat treated, cold worked, and artificially aged. Suitable for products after cold worked, straightened, flattened to improve the strength.
T9	Solution heat treated, artificially aged, and cold worked. Suitable for products after cold worked to improve the strength.
T10	Cooled from an elevated temperature shaping process, cold worked, and artificially aged. Suitable for products after cold worked, straightened, flattened to improve the strength.