Introduces 3 commonly used bending processes of aluminum tubes and 3 optimal bending methods to avoid cracking, and the top 7 crucial basic knowledge.
3 Ways to Bend Aluminum Pipe and Tubes Without Cracking
When bending aluminum pipe and tube, know that the smaller your inside bend radius, the larger the chance that cracking will occur in the part.
The 3003 and 5052 pipes and tubes will bend, but the 6061 pipes and tubes will not. The aluminum series’ ability to bend tends to decrease as you move down the list of tempers, from annealed to T4 and T6. Bending these tempered alloys is not impossible, but it is very difficult and will most likely require large bend radii to avoid cracking on the outside of the bend.
Bend Ways 1#: Heating Aluminum
Heat the 6061-T6 (or other “T”) into a T-0 material. This makes the aluminum about as bendable as it can get.
- The aluminum does not change color when heated, so getting burned becomes a real concern.
- Aluminum oxide melts at a higher temperature than the encased aluminum, as the aluminum will melt from the inside out.
- If heating aluminum pipes and tubes enough to bend them, we can change the temper of the base material, in which case will need to retemper it.
Bend Ways 2#: Fill with sand
If wrinkles and/or flattening still appear with these bend aluminum tubes and pipes, sand-packing techniques may be used. Fill the tubes and pipes with sand or any other non-compressible material and cap the ends before performing the bend.
- Step 1#: Fill the pipe with sand or other material, and secure three layers of window screening, with double hose clamps on the ends.
- Step 2#: Bend the pipe slowly so that can watch to make sure it bends evenly and doesn’t collapse or deform, and watch for cracks that may occur if the pipe is bent too sharply.
Bend Ways 3#: Mandrel Bending
Mandrel bending is a method where a steel rod is inserted into the tubing as it is bent. This technique perfects the tube bend without wrinkling or breaking it at the bending point. Mandrel bending is performed by a machine such as a CNC pipe and tube bending machine.
Mandrel bending works much like a flexible straw. When the straw is bent, a flexible section of the straw expands to maintain the round opening no matter how much of an angle the straw is bent at. When an exhaust or downpipe is manufactured with mandrel bends, the aluminum is allowed to stretch on the outside of the bend and compress on the inside of the bend, maintaining the nominal pipe diameter.
The mandrel bends have been specifically designed to avoid the issue of wrinkling along the inside of pipes and tubing, during their manufacturing process. The mandrel stays in a fixed position as the outer radius of the tube experiences pressure, causing the pipe to stretch into the desired bend.
The 3 best methods to bend aluminum pipe and tubing
Bending aluminum tubes can be done in different ways (though most of them shouldn’t be used). Here are a few of those:
It is possible to bend very thin aluminum tubes without using an external tool. However, it requires a lot of physical force, and the bend angle will often turn out to be different than what you require. It also has a high chance of injury and the bend will not go beyond a certain angle.
Heating a metal such as aluminum makes it malleable and easy to bend. Therefore, you can use a blow torch to heat the tube at the location where you want to create the bend and then bend it with a wrench.
Again, this method also has a high risk of physical injury. Additionally, the bend angles are not perfect and the pipe can also be ruined due to the high heating.
Aluminum pipe and tube bending machine
A tube bending machine (also called a pipe bending machine) is the right tooling for bending aluminum tubing. It can perfectly create even bends exactly as required and save time while doing it. It also involves high safety and there is no risk of injury to the operator.
When it comes to which method to choose, the answer is a no-brainer. A pipe and tube bending machine is the only tool you should use for bending tubes and pipes, whether it is aluminum tubing or any other metal.
ALUMINUM PIPE AND TUBE 101: 7 important basic knowledge
Aluminum products are now very diverse and in demand, showing that this material is effective and indispensable in many areas of life.
Aluminum pipe and tube
Aluminum tubing ODs typically range from 0.062 in. to 3.00 in. with wall thicknesses from 0.010 in. to 0.250 in. It is a durable and solid product that can be used in many different sectors, which is very popular in various sectors, helping to create a solid product that the sectors need. Aluminum pipes are lightweight and non-corrosive, so most industrial projects use them where the application fits.
Aluminum tubing can be used in a variety of applications from aerospace, marine, healthcare, and other commercial applications where weight, strength, and corrosion resistance are required.
Basic knowledge 1#: 5 kinds of commonly used aluminum alloys
The most common aluminum alloys used for tubing and pipe are 2024, 3003, 5052, 6061, and 7075. Their primary alloying elements of copper, manganese, magnesium, silicon, and zinc lend each alloy slightly different physical and mechanical attributes.
Alloys: 2024, 3003, 5052, 6061, 7075
The alloys 2024, 6061, and 7075 for aircraft structures because of their high strength-to-weight ratios and good fatigue resistance. Untreated 2024 and 7075 are prone to corrosion, while 6061 is innately corrosion-resistant and easier to weld. 7075 provides higher strength with less weight.
Alloy 3003 is good for applications that need corrosion resistance and high strength with less of an emphasis on ductility. And for applications that rely on many joints, might choose the highly weldable 5052.
Temper: 0, T3, T4, T6, H14. The exact properties of a given aluminum alloy also depend on its temper or heat-treatment history.
H – Strain Hardened 0 – Annealed T – thermally treated.
The exact properties of a given aluminum alloy also depend on its temper or heat-treatment history. Temper O indicates the alloy is used as annealed, at its highest ductility and lowest strength. Tempers beginning with “T,” like T3, T4, and T6, involve heat treatments. Cold working or aging steps often follow to strengthen the metal by toughening it on the grain or molecular level.
Basic knowledge 2#: 6 common shapes of aluminum tubes
Metal tubing is highly rigid. This enables them to remain in shape. Most tubing utilized for smooth liquid flow comes with round cross-sections. However, there is also metal tubing with various shapes, like rectangular, oval, square, and circular. Some manufacturers also offer customized shapes. But they are more costly than regular metal tubing. Circular tubing is the most popular shape among these, as it provides constant distribution throughout the tubing.
- Aluminum Square Pipes can be utilized in slightly stronger applications and to withstand collapsing. Instead of the round piping, which is weaker on the bends, the square piping is stronger at the corners because of its geometry.
- The Aluminum Section Pipe can be utilized in bigger applications such as the fuselages of aircraft and fuel pipelines. Since aluminum is lightweight, it can be utilized in systems that need a lightweight option. Thus, the aluminum seamless piping can be utilized in applications that are lightweight and require high precision. The fitting of two pipes can be done using threaded joints.
- The Threaded Aluminum Pipes can be joined without welding. There are large diameter aluminum pipes and small diameter aluminum pipes. The large diameter piping must be supported by some lattice that supports the piping structure.
- Spiral-Welded Aluminum Piping is produced from spirally cut aluminum plates.
- Anodized Aluminum Pipes are electricity treated to make oxides for finishing with protective or decorative layers.
- The Jindal Black Anodized Aluminum Piping is anodized with a black decorative oxide color. The uses of all types of aluminum piping can be seen in applications that require corrosion-resistant, lightweight material safe for usage in water lines.
Basic knowledge 3#: Four important parameters
- Pressure Rating – this defines the maximum or minimum pressure the tubing can withstand. The tubing’s pressure rating is important when buying for liquid flow applications.
- Minimum Bend Radius Rating – this shows the suitable amount of deformation a tubing’s cross-sectional area can go through. The structural application considers the smallest bend radius to comprehend the tubing’s loading capacity.
- Maximum Vacuum – this is the peak pressure that can be created inside the tube.
- Temperature Range – this shows the complete range of ambient temperatures the tubing can support. It is vital in industries whereby the conveyed fluid is liable to extreme temperatures.
Basic knowledge 4#: Four characteristics need to have
- Finned or Fluted – metal tubing has fins or flutes which create space for dissipating heat. It is vital for metal tubing utilized in air conditioners, refrigeration, and heat exchanger uses.
- Serializability – metal tubes can be sterilized utilizing many techniques. Tubes chosen undergo many sterilization methods, like gamma irradiation, dry heat chemical, disinfection, and autoclaving.
- Coiled or Spiral – the tubing must be flexible enough for running in a wrapped reel spring or format.
- Multi-Layered – metal tubing must have many concentric layers. It makes the tubing more robust and durable.
Basic knowledge 5#: Four surface treatments
Metal tubing must be finished and coated both on the internal and external surfaces. However, it must have a definite type of finish.
- Galvanized – the tubing has a zinc layer for great corrosion resistance.
- Bright Finish – the minor polishing must make the tubing look shiny.
- Plated – the tubing will have a thin layer of another metal to improve its outer physical characteristics, such as corrosion resistance and conductivity.
- Painted – the tubing will have a powder-colored coat for corrosion resistance and identification.
Basic knowledge 6#: 3 types of properties(physical and mechanical) of aluminum pipe and tubes
Aluminum pipe and tube come in a variety of alloys and tempers, each with its own physical and mechanical properties. Each metal has general properties that are true for all its alloys.
- Mechanical Properties: The aluminum is focused on keeping components lightweight, and the aluminum part weighs one-third less than a stainless steel part of the exact dimensions.
- Corrosion Resistance: Aluminum offers corrosion protection and the amount will vary depending upon the alloy chosen. The passivating oxide films that form on the surfaces of aluminum metals help keep the metals from corroding. (The operation of anodization thickens the material’s naturally occurring oxide coating, enhancing its resistance to corrosion and also making the material more wear-resistant, enhancing surface emissivity, and offering a porous surface that can accept different colored dyes.)
- Heat Resistance: Aluminum in the moving electricity or heat is better in the application. Aluminum’s high conductivity, along with thermal conductivity three times greater than that of steel, has led to its use in power transmission lines.
Regardless of whether your tube is intentionally conducting heat, you’ll want to ensure it can handle the temperature of its operating environment. On the opposite end of the spectrum, aluminum’s tensile strength increases as temperature drops and stays tougher at cold temperatures than many steel metals.
Basic knowledge 7#: Top 5 basic bits of knowledge of pipe bending
- Yield strength. The machinery has to be capable of performing the bend. The required force depends largely on the type of steel and its yield strength.
- Wall thickness. When bending tubes and pipes, the thickness changes in the inner and outer walls of the bend. The inner wall becomes thicker while the outer wall becomes thinner. Some machines provide support to avoid problems with the cross-section, such as wrinkles in the inner wall. If support is not provided, care must be taken to prevent these changes in thickness to become a problem.
- Bend radius. Suppliers normally provide recommendations for the minimum achievable radius without compromising the integrity of the pipe. It depends on the type of material. Reaching this minimum requires attention and expertise.
- Bend radius vs wall thickness. There is a relation between the minimum bend radius that can be achieved and the thickness of the wall. This is important because the tubes and pipes can fail when the radius is too small compared to the wall thickness.
- Material elongation value. Elongation can be described as the difference between the yield strength and the ultimate tensile strength of the material. A big difference means a big elongation, which results in better formability properties.