Bendability often plays a significant role in determining which materials a product designer can use in their product. Although bending may seem like a simple processing step, not all materials bend easily.
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Bendability, which indicates how easily you can bend a material without breaking it, is commonly associated with aluminum. Purer aluminum alloys, such as those used for household aluminum foil, are highly flexible and exhibit excellent bendability. However, adding other alloying elements to improve strength or other properties can impact bendability.
Do you want to know more about aluminum bending? This article will explain what controls bendability and which alloys are best for bending. So let&#;s start!
What Factors Affect Bendability?Before discussing aluminum alloys, we should cover some background about the factors that affect their bendability. As you can imagine, products like aluminum foil, gutters, traffic signs, and automotive body parts, which are all made from aluminum alloys, have different bendability.
Three factors control the bendability of the various alloys in these products:
Let&#;s have a deeper look at these factors!
1st Factor &#; FormabilityFormability is the ability of a given material to experience permanent deformation without the forming process cracking or tearing it. Permanent deformation is also known as plastic deformation in the materials science world.
Generally speaking, formability is a relative term and not a specific value. For example, the applied force necessary to shape a product depends on more than just the strength and ductility of a material. It also depends on factors such as the shape of the part and the thickness of the starting material.
In other words, we can measure the forming force to produce a specific part from a particular starting material. However, changing the shape of the part or the physical properties of the starting material will change the amount of force that needs to be applied.
That said, there are standardized tests, such as the ASTM E: Standard Test Method for Determining Forming Limit Curves. We can use these tests to establish a formability &#;ranking&#; for different sheets of alloy. We can use them to learn which alloys have better baseline formability.
2nd Factor &#; Thickness and Bend RadiusIf you&#;ve handled regular aluminum foil, you&#;ll know that it is effortless to bend. However, if you had to bend a sheet of aluminum that was one-thousand times thicker than aluminum foil, it would be much harder! That is because the thicker a material is, the more difficult it is to bend.
You can also bend an aluminum gutter with your bare hands. But if you try to bend it to a tight angle without breaking it, you will have a hard time! Bending metal to a small bend radius has the potential to cause tearing or cracking.
The Fabricator offers certain key tables and general rules which are helpful for understanding the limits to bendability for specific aluminum alloys. You can use these to determine the minimum allowable bend radius for particular thicknesses of aluminum sheet.
3rd Factor &#; Percent ElongationPercent elongation represents the ability of the material to be plastically deformed under tension. It is also known as plastic strain or stain applied beyond the yield strength limit of a material.
The more ductile aluminum alloys can experience more significant plastic deformation with small increases in applied stress. This results in better overall aluminum bendability.
Like the other properties, the percent elongation varies for each alloy. Take a look at the stress-strain curve above. You&#;ll see that annealed aluminum alloy (shown as AA-O) has a very high percent elongation (strain %) of roughly 35%. It has very high bendability relative to other alloys.
3 of the Best Aluminum Alloys for BendingNumerous 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. We explain this in our article on aluminum alloy designations and tempers.
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.
Now let&#;s discuss which alloys offer the best bendability and when you should use them.
#1 &#; Aluminum AlloyThis 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 aluminum.
#2 &#; Aluminum AlloyWith magnesium as the primary alloying element, AA demonstrates moderate-to-high strength characteristics. At the same time, it retains good bendability, and designers can use it for more intensive applications than AA. 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).
If you want to learn more, please visit our website aluminum sheet bending machine.
#3 &#; Aluminum AlloyYou will find this is an extremely common alloy in your day-to-day life. Even though it is not as bendable or formable as the two alloys above, it is the strongest among all three. It has magnesium and silicon as alloying elements, and you can further enhance its strength with heat treatment.
Alloy 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 3 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 makes it one of the most widely used aluminum alloys. In the same way, alloy has multiple uses in applications that require superior bendability. Meanwhile, alloy is commonly used thanks to its balance in terms of bendability and strength.
If you want to keep learning more about the applications of aluminum, check out our service pages for aluminum extrusions and quality rolled aluminum.
&#;Which aluminum alloy bends the best?&#; is a a common question customers want the answer to. In this post, we&#;ll explain it to you.
In high purity forms, aluminum is soft and ductile. Bending is a delicate and demanding process most of the time and common fabricating processes require a degree of formability that make your choice of proper alloy critical.
Depending on designation, alloys go through different heat treatment procedures during production. Typically, pure aluminum is more easily worked than the alloys. Annealed and natural aged tempers are more easily worked than hard tempers and artificially aged ones.
Clinton Aluminum offers a variety of products, each covering a wide range of applications and processes. From non-heat treatable and to the heat treatable , and , you have many options from which to choose.
But the question remains the same &#; which alloy is the best product for bending? There are three factors that contribute to the the answer.
To understand this better, we need to talk about alloys, which is the first factor to consider upon selection. In aluminum, we have various designations that all have different chemical compositions, making them applicable in various fields of metal processing. The most important ones are:
Source: http://www.slideshare.net/corematerials/talat-lecture--properties-characteristics-and-alloys-of-aluminium/21
So, we see that specific alloys have a high degree of formability that provide the proper behaviour in processing and especially in bending.
Another factor to consider is that during the process of bending, the metal hardens and strengthens by reason of the working effect. Apart from alloy selection, thickness and bend radius are also critical factors that must be considered. The table below shows the permitted bend radii for 90o bending.
Source: https://www.aircraftspruce.com/pdf/Individual/Cat.pdf
A third factor to be considered is that formability of a specific alloy can be found in the percentage of elongation and the difference between yield strength and ultimate tensile strength.
This rule states that the higher the elongation value (the wider the range between yield and tensile strength), the better the forming ability of the alloy.
From the aforementioned descriptions of alloys and the data shown in table 3 (below), it is quite obvious that the best series for forming, and thus for bending, are series 3xxx, 5xxx, and in some cases 6xxx. Series 2xxx and 7xxx are not to be considered and thus should be avoided due to being extremely strong. They are difficult to form in any way.
Top 3 Aluminum Alloys For Bending
1. . This would be the best solution for most application. This alloy exhibits medium strength, the best cold workability together with high elongation such as 25% and one of the biggest differences between yield and tensile strength of 14 Ksi (Kilo-pound of force per square inch) at 0 temper &#; annealed, followed by the H14 temper which is partially annealed and strain hardened.
2. . is a close second. At the annealed temper, it has an elongation of 20% and the difference between yield and tensile strength of 21.5 Ksi. It is the highest strength alloy of the more common non-heat treatable grades. It has excellent corrosion behavior and in the annealed condition has better formability than or even alloys, with 21.5 Ksi of difference between yield and tensile strength and up to 20% of elongation.
3. . This is one of the most versatile of the heat treatable family of alloys. In the annealed condition, it can be used for bending since the difference between yield and tensile strength is 10 Ksi and elongation is up to 18%. When moving up to T4 and T6 tempers, however, bending ability tends to decrease. Bending these temered alloys is not impossible, but requires great caution and probably larger bending radii to avoid cracking.
and alloys are not recommended for bending, since they are both alloys with great strength and forming capabilities which are very limited even in annealed condition.
Aside from these, special products such as ATP-5, K100-S, Duramold-2, Duramold-CS and M-1 are not recommended for bending applications. Table_3 below shows characteristics of the alloys discussed previously.
Source: https://www.aircraftspruce.com/pdf/Individual/Cat.pdf
Appendix_A
Calculation of maximum bending force:
Where,
If you&#;d like to know more about bending specific alloys or which alloy is best for your application, please contact our sales department by calling 800-826-.
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