Comparative Characteristics
& Applications
What is an Aluminum Alloy?
An aluminum alloy is a chemical composition where other elements are added to pure aluminum in order to enhance its properties, primarily to increase its strength. These other elements include iron, silicon, copper, magnesium, manganese and zinc at levels that combined may make up as much as 15% of the alloy by weight. Alloys are assigned a four-digit number, in which the first digit identifies a general class, or series, characterized by its main alloying elements.
| Alloy | Characteristics | Available Forms | Applications |
|---|---|---|---|
| 1350 | Commercially pure, very ductile in extruded condition. Excellent resistance to corrosion. Excellent electrical conductivity. | Simple shapes | Mouldings, lightly stressed and decorative assemblies in architecture and transport, chemical, food and brewing equipment, heat exchangers. |
| 6060 | Suitable for intricate sections of light and medium strength. Forms well in T4 temper. High corrosion resistance, good surface finish, anodises well. | All shapes. tubing, rod. | Architectural extrusions such as glazing bars, window frames and general purpose extrusions. |
| 6106 | Light structural alloy. Designed to provide an optimum combination of mechanical properties, complexity of shape, minimum section thickness and good surface finish. Good corrosion resistance, weldability and formability. | Thinner structural shapes, rod, bar and tubing. | Light structural applications, lwhere surface finish is important. Marine, Transport applications. |
| 6005A | Medium structural alloy. Good extrusion characteristics with good surface finish. | Structural shapes of all types, rod, bar and tube, offered in the T5 temper. | Medium structural applications where surface finish is important. Marine, Transport applications. |
| 6261 | Special purpose structural alloy. Good surface finish and corrosion resistance. Good formability in T4 temper. Good weldability. | Structural shapes of all types, rod, bar and tube, offered in the T6 temper. | Structural applications where surface finish is important . Marine, Transport applications. |
| 6082 | Recommended alloy for structural purposes. Good strength and general corrosion resistance. Good weldability. | Structural shapes of all types, rod, bar and tube, offered in the T6 temper. | Vehicles, bridges, roof trusses and general structural applications. |
| 7075 | Very high strength material used for highly stressed structural parts. The T7351 temper offers improved stress-corrosion cracking resistance. | Simple shapes. | Aircraft fittings, gears and shafts, fuse parts, meter shafts and gears, missile parts, regulating valve parts, worm gears, keys, aircraft, aerospace and defense applications; bike frames, all terrain vehicle (ATV) sprockets. |
| 2011 | Free machining alloy of medium strength giving fragmented chips. Not suitable for anodising or welding. | Rod. | Automatic lathe products, suitable for high speed repetitive machining. |
Heat Treatment Temper Designations
The physical properties exhibited by aluminum alloys are significantly influenced by the treatment of the sample. A standardized system has been developed to designate these treatments.
| Letter | Code | Explanation |
|---|---|---|
| F | As Fabricated | No special control has been performed to the heat treatment or strain hardening after the shaping process such as casting, hot working, or cold working. |
| O | Annealed | This is the lowest strength, highest ductility temper. |
| H | Strain Hardened | (applied to wrought products only) Used for products that have been strengthened by strain hardening, with or without subsequent heat treatment. |
| W | Solution Heat Treated | This is seldom encountered because it is an unstable temper that applies only to alloys that spontaneously age at ambient temperature after heat treatment. |
| T | Solution Heat Treated | Used for products that have been strengthened by heat treatment, with or without subsequent strain hardening. The designation is followed by one or more numbers. |
T-Codes
Solution Heat Treated products are designated the letter 'T', followed by a number per the table below.
| T Code | Description |
|---|---|
| T1 | Cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition. |
| T2 | Cooled from an elevated temperature shaping process, cold worked, and naturally aged to a substantially stable condition. |
| T3 | Solution heat treated, cold worked, and naturally aged to a substantially stable condition. |
| T4 | Solution heat treated, and naturally aged to a substantially stable condition. |
| T5 | Cooled from an elevated temperature shaping process then artificially aged. |
| T6 | Solution heat treated then artificially aged. |
| T7 | Solution heat treated then overaged/stabilized. |
| T8 | Solution heat treated, cold worked, then artificially aged. |
| T9 | Solution heat treated, artificially aged, then cold worked. |
| T10 | Cooled from an elevated temperature shaping process, cold worked, then artificially aged. |