1000’s – Aluminum 99% min. – excellent corrosion resistance, high thermal and electrical conductivity, low mechanical properties

2000’s – Copper – high mechanical properties, increased yield strength, best known and most widely used aircraft alloy

3000’s – Manganese – good workability and weldability, high corrosion resistance, moderate strength

4000’s – Silicon – low melting point, widely used in welding wire and as a brazing alloy

5000’s – Magnesium – moderate to high strength, good welding characteristics, good resistance to corrosion, especially in marine environments

6000’s – Magnesium/Silicon – good formability and corrosion resistance, moderate strength

7000’s – Zinc – highest strength alloy available, used in air-frame structures and for highly stressed parts 8000’s – Other element

1st digit – Identifies alloy types.

2nd digit – Identifies alloy modifications. Digit replaces letters formerly used.

3rd and 4th digits – Identifies the aluminum purity of the specific aluminum alloy.

The digits are the same as the numbers in the old designations for alloys in use prior to the adoption of the four-digit system.

H1 – strain-hardened only.

H2 – strain-hardened and partially annealed.

H3 – strain-hardened and stabilized by low-temperature thermal treatment.

The digit following H1, H2, or H3 indicates the temper:

2 –1/4Hard

4 – 1/2 Hard

6 – 3/4 Hard

8 – Full Hard

9 – Extra Hard

T1 – cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition

T2 – annealed (cast products only)

T3 – solution heat-treated and then cold worked

T4 – solution heat-treated and naturally aged to a substantially stable condition

T5 – cooled from an elevated temperature shaping process and then artificially aged

T6 – solution heat-treated and then artificially aged

T7 – solution heat-treated and then stabilized

T8 – solution heat-treated, cold worked, and then artificially aged

T9 – solution heat-treated, artificially aged, and then cold worked

T10 – cooled from an elevated temperature shaping process, artificially aged and then cold worked

Additional digits for T tempers include the following:

T51- stress relieved by stretching

T510- receives no further straightening after stretching

T511- receives minor straightening after stretching to comply with standard tolerances

T52 – stress relieved by compressing

T54 – stress relieved by combined stretching and compressing

Applications

Reflectors, cooking utensils and kitchenware, decorative parts, giftware, dials, name-plates, tank cars, storage tanks, chemical equipment, sheet metal work, heat exchangers, and etc.

Applications

Drawn and spun parts, ductwork, general sheet metal work, cooking utensils, awnings and sidings, decorative trim, garage doors, chemical equipment, pressure vessels, heat exchangers, and etc.

Applications

Sheet metal parts, aircraft components and tubes, small boats, tankage, bus and truck bodies, kitchen cabinets, cookware, appliances, fencing, fan blades, food-processing equipment, and etc.

Applications

Bare

Aircraft parts, caul plates, scientific instruments, truck wheels, fastening devices, and etc.

Alcad

Aircraft frames, fittings, and structural components, truck bodies and parts, railroad car roofs and sides, caul plates, and etc.

Applications

Marine equipment, boats, truck and bus bodies, tankage and-tank fittings, structural com­ponents, screw machine parts, high pressure applications, mine skips, transmission towers, moldings, pipes, and etc.

Applications

7075 finds greatest utilization where extreme high strength is required, especially in the aircraft industry.

Applications

2024 – The most common heat treatable aluminum is 2024. It is utilized where high strength and no welding is involved. Aircraft fittings, structures, and hardware are some of the major applications.

5052 – One of the strongest non-heat treatable aluminum alloys is 5052. Possessing excellent resistance to corrosion, good workability and high fatigue strength, it is used primarily for oxygen, fuel and oil lines.

6061 – The most common and least expensive of the heat treatable aluminum alloys is 6061. Used where good corrosion resistance and strength are needed, it can be found applied in areas for welded assemblies, heat exchangers and aircraft components.

Applications

Both 6061 -arid 6063 are used where the major requirements are good corrosion resistance, a high strength-to-weight ratio, and fairly good workability. 6063, because of its excellent finishing properties, finds popular use in architectural, furniture, and decorative applications.