Earlier in these articles we explored welded vs seamless tubing. With Aluminum tubing this is not even a discussion as nearly all aluminum tube material is extruded (seamless). Raw and recycled aluminum come to an extruder in billets. Billets are pre-heated before they reach the extrusion station and are then heated to a specific temperature according to the requirements of the standard extrusion die that will be used.
With over 15,000 tons of force, the aluminum materials are pushed through a forming die to create hollow aluminum tubes. The extruded tubes are then cooled down on tables, stretched and cut according to the order. The aluminum is also hardened with heat to help bring out the inherent qualities of the metal, such as strength, durability and natural corrosion resistance.
Aluminum is widely used all around the world today because it is very cost-effective and has a natural protection from corrosion through a transparent layer ceramic layer of aluminum oxide. This layer can be enhanced through chemical and electrochemical means (anodizing) to provide even greater protection. Aluminum is also the most recycled metal in the world. It doesn’t lose any of its properties during recycling and can be recycled an unlimited number of times.
Hollow aluminum tubes made with standard aluminum extrusions are both strong and lightweight, making them a great choice for products that benefit from low-weight materials. Like other metals, aluminum that is pushed through a standard extrusion die can also be brazed, glued, joined, soldered and welded according to a user's specific needs. Aluminum also has excellent heat conductivity and is the top choice for heat-dissipating devices and for use in heat shields.
Another tremendous feature of many aluminum alloys is the ability to increase the strength through heat treatment. Also known as precipitation hardening, aluminum alloys can be heated and cooled under precise control to achieve "tempers" of varying strength and brittleness. The most widely used specification for tubing alloys is AMS2770 (Heat Treatment of Wrought Aluminum Alloy Parts). the spec details heat-treatment processes such as aging, annealing and solution heat treating in addition to defining parameters such as times, temperatures and quench procedures.
Two of the most popular aluminum alloys used in extruded tube manufacturing are 6061 and 6063. Very similar in terms of strength/weight ratio. They both include magnesium content to provide strength and silicon to reduce the melting temperature. 6061 has a bit more strength and better for cutting, welding and machining than 6063, making it a more versatile alloy, albeit more expensive. 6063 has a smaller grain which allows it to be easily formed into complex shapes, and better for finishing and has a better corrosion resistance. Both alloys are heat-treatable.
We prefer 6061 in at Burns Stainless and offer it in straights, 45°, 90°, and U-bends. All of our bends are initially annealed to the "O" condition, which is necessary for bending. During the bending process, some work hardening in the bend area occurs, and the finished bends are classed as condition "F." Straight material is normally sold in the T6 condition for good strength. Note that in order to maintain the T6 strength, aluminum fabricated assembled must be heat-treated since welding will affect the heat treatment. Aluminum can be polished, but due to the softness of the aluminum, care should be taken not to remove too much material, particularly with bends since they are in the soft, annealed condition.. Click here to see our variety of aluminum tubing.
Aluminum tubing is perfect for cold air intake, intercooler plumbing, and other lightweight, yet strong stable tube requirements. For more on aluminum as an alloy choice for racers visit this article.