"Alloy 61S," which is now called 6061 aluminum, was only the second aluminum-magnesium-silicon alloy ever developed for commercial use. The first was 51S in 1921. After adding a little copper and chromium for strengthening and recrystalization control respectively, 6061 was introduced in 1935 to fill the need for medium-strength heat-treatable aluminum that was tough but could be easily welded and joined or anodized.
Unlike harder alloys of aluminum and copper, 6061 can be easily extruded, rolled and forged, making it a satisfactory substitute for mild steel products. It has a high resistance to corrosion from environmental conditions, making it popular for railroad applications and marine projects. It is the most versatile and least expensive of the heat-treatable aluminum alloys and is used where appearance and moderate strength are needed.
Tempering has a major effect on heat-treatable alloys like 6061. Many alloys gain strength from solution heat-treating (or thermal treatment) and aging. 6061 aluminum is available in pre-tempered grades such as 6061-O (annealed) and in tempered grades such as 6061-T6 (solution heat-treated then artificially aged), 6061-T4 (solution heat-treated then naturally aged), and 6061-T651 (solution heat-treated, stress-relieved by stretching, then artificially aged).
One of the most extensively used aluminum alloys for general purpose use, 6061 aluminum is available in a wide range of structural shapes and is favored by many for its solid mechanical capabilities and superior weldability. After welding, the product will have less strength than before welding, but the material can be heat-treated and artificially aged again to restore its strength. As an alternative to fusion welding, Sapa offers friction stir welding which provides a stronger weld with minimal deformation.
There are a wide variety of applications for which 6061 aluminum is well-suited, including yacht construction, railroad cars, truck bodies, automotive parts (such as wheel spacers), aftermarket motorcycle parts, aluminum beverage cans, tank fittings and screw machine parts. Aluminum-magnesium-silicon alloys are also used in wide-span roof structures for arenas and for bridge decks. Bicycles benefit from the use of 6061 aluminum alloy because it can be easily welded and is rigidly strong when compared to its overall weight.
Sapa Extrusion produces 6061 aluminum for use in standard and custom solid and hollow shapes, rod and bar products and seamless and structural pipe and tube, with a wide selection of tempers to meet an extensive list of applications. Sapa Extrusion's 6061 formulation conforms to industry specifications and provides improved machinability.