6xxxSerie

The 6xxx serie refers to a family of aluminum alloys whose main alloying elements are magnesium and silicon. The combination forms magnesium silicide and yields a group that is both heat-treatable and versatile. The 6xxx alloys are known for a good balance of strength, formability, corrosion resistance, and weldability, making them suitable for a wide range of structural and architectural applications.

Composition and common grades

- Primary elements: magnesium (Mg) and silicon (Si). Small additions of other elements such as copper or chromium may be used to modify properties.

- Notable alloys include 6061 (general-purpose structural alloy), 6063 (premium extrusions and architectural profiles), and 6082 (high-strength extrusions). Other popular grades are 6005, 6005A, and 6013, used in various fabrication contexts. EN equivalents and regional designations exist alongside the ASTM naming.

Properties

- Strength: can be increased by heat treatment (age hardening) but remains lower than some other families (e.g., 2xxx or 7xxx series).

- Formability and machinability: good, especially in the annealed or moderately tempered conditions.

- Weldability: generally excellent compared with many other heat-treatable alloys.

- Corrosion resistance: good, though performance depends on temper and environmental exposure.

Tempering and heat treatment

- Common tempers include O (annealed), T4 (solution heat treated and naturally aged), and T6 (solution heat treated and artificially aged). These tempers allow a range of strength and formability to suit specific parts and processes.

Applications

- Widely used in extrusions for architectural profiles, automotive components, bicycle frames, machinery housings, and various structural components. The 6xxx series is favored where a combination of lightweight, corrosion resistance, and formability is important.

See also: aluminum alloy series, 6061, 6063.