What aluminum alloy is best for bending?
Numerous metal alloying agents can be combined with aluminum to produce different aluminum alloys. The system for naming them uses four digits, with the first digit representing their chemical composition.
Generally speaking, aluminum alloys from the 1XXX, 3XXX, and 5XXX series demonstrate better bendability than other aluminum alloys. Some 6XXX series alloys are fairly bendable as well.
However, the different properties offered by each may make some more desirable than others. For example, 1XXX series aluminum generally has poor mechanical properties and is not suited to structural applications.
The best series for forming – and thus for bending – are the alloy series 3xxx, 5xxx and in some cases 6xxx. Aluminium alloy 6063 is a good choice, for example, while 6082 is more difficult. I would avoid using alloys in the 2xxx and 7xxx families because they are so strong and therefore difficult to form. However, in the right temper, the bending of those alloys is also possible.
Aluminium alloy 3003
In most cases, this is probably the best alloy for bending. You get average strength, very good cold workability and high elongation. It also offers one of the biggest differences between yield and tensile strength.
This alloy is primarily alloyed with manganese and is one of the most commonly used aluminum alloys for bending applications. It has excellent formability properties and does not require heat to be bent or molded.
Companies often make gutters, roofing, siding, chemical equipment, and storage tanks from 3003 aluminum.
Aluminium alloy 5052
This alloy comes right behind. You get high elongation (not as high as 3003, however) and a solid difference between yield and tensile strength. You also get high strength when compared with other non-heat-treatable grades and outstanding corrosion behavior. When annealed, it beats the 3003 alloy in formability.
With magnesium as the primary alloying element, AA5052 demonstrates moderate-to-high strength characteristics. At the same time, it retains good bendability, and designers can use it for more intensive applications than AA3003. The corrosion resistance of this alloy is also excellent against seawater, meaning it is excellent for applications in marine equipment.
Manufacturers often produce hydraulic tubes, traffic and hardware signs, medical equipment, marine equipment, and electronics (chassis and enclosures).
Aluminium alloy 5083
Not far behind 5052 comes this one, its big brother, and a classic alloy for marine applications with good corrosion resistance and weldability. There is some variation with regard to temper, but if you chose H111, H112 or O temper you will be fine.
Aluminium alloys 6061 and 6082
These are versatile heat-treatable alloys that, when annealed, offer a satisfactory difference between yield and tensile strength, and good elongation. Their bending ability will decrease, however, when you move to T4 and T6 tempers. My recommendation therefore is to bend in T4 condition and then heat treat to T6 if this is possible.
Don’t forget that the grain structure of the material will also impact bending capabilities, although grain structure affects several processes, not only bending.
Alloy 6061 is widely referred to as “structural aluminum” because it is so commonly used in structural (construction) applications. Nevertheless, due to its outstanding properties, it is also used in food and beverage containers, ladders, aircraft and automotive parts, scuba tanks, bicycle frames, and more.
Why Are These 4 Alloys Important?
Despite their different properties, these alloys are excellent examples of bendability in aluminum alloys. They demonstrate that even though some aluminum alloys feature better formability and percent elongation for a given bend radius and thickness, they each serve a unique purpose and a wide variety of applications.
Even with slightly lower bendability, the strength of alloy 6061 makes it one of the most widely used aluminum alloys. In the same way, alloy 3003 has multiple uses in applications that require superior bendability. Meanwhile, alloy 5052 is commonly used thanks to its balance in terms of bendability and strength.