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Bending steel and aluminum U/C channel steel: the same has the flanges out, with the flanges in, and the hard way of the web.



Bending aluminum C channel


Similar to wide flange and I-beam, the channel can be bent with a number of different bending processes. The most common bending method is a roll bend or pyramid bends method. Straight material is inserted into the rolls; the rolls are then moved horizontally to put the desired radius into the material. The material can also be bent incrementally hot or incrementally cold. This is where small sections of material are bent at one time. When finished the section has a smooth curve to the bent section. Finally, the channel can also be bent in a plate roll which is typically done when bending stair stringers.

Just like wide flange and I-beam, to successfully bend channel the hard way one must use a web stretcher and/or mandrels. These tools are critical to use when bending the hard way as they keep the critical web from buckling or distorting.


Channels can be rolled the Hard Way, Flanges In, or Flanges Out. Because channels are asymmetrical, they can present a challenge when rolling. Care must be taken to support the inside flange of a channel rolled the Hard Way, as the inside flange will typically want to tip in as the rolling process continues.  Channels rolled Flanges In or Flanges Out can typically be rolled to much tighter radii than channels rolled the Hard Way.

The easiest channel bending process is “flanges out.” “Flanges in” channel bending can be difficult if the flanges are relatively tall. The most difficult channel bending process is “the hard way”—indeed, all else being equal, the hard way is one of the most difficult structural shapes to bend without distortion. In checking the quality of the “hard-way” bent steel channel, it is critical to check that the flanges are square, that there has been no buckling of the web, and that the radius is true.

Cold bending process ability to bend both standard channels (designated as C channel) as well as miscellaneous channels (designated as MC channel), from the very small sizes to the very large sizes. In fact, a profile bending machine can bend all of the mills supplied sizes of all types of channels.

Section bending machine can ability to bend channels the easy way (against the weak axis) and the hard way (against the strong axis). It can bend all types of channels including aluminum, stainless, and carbon steel.

Standard channels and miscellaneous channels are specified in similar fashions. An example callout for a standard channel would be C12x20.7#. The C indicates the standard channel. The 12 (in inches) indicates the depth of the channel. The 20.7# indicates the pounds per foot for the channel.


The U channel is placed inside of an induction coil, which, when turned on, heats localized sections of the U channel to temperatures ranging between 1750° F to 1850° F. The exact sections depend on the part design and the exact temperature depends on the base material. As each section reaches the correct bending temperature, the machine slowly moves the U channel through the induction coil as a fixed radius arm mechanism applies the necessary force to bend the U channel at the heated area. When the U channel exits the induction coil, it is immediately quenched with water to minimize thermal expansion.

induction bending h beam
induction bending H beam

This process can take up to an hour since it must occur gradually to avoid snapping or deforming the structure.


Compared to other methods, induction bending offers a number of advantages, including:

  • Smaller tooling requirements: does not need dies or mandrels to produce bends.
  • Lower material costs: machines allow manufacturers to create standard bent shapes from straight materials as required, which enables them to take advantage of the lower material cost. Additionally, they can save on storage costs since they no longer need to keep standard bends in stock.
  • Cleaner operations: do not require the use of lubrication. Additionally, the water used for quenching operations can be recycled.
  • Stronger parts: eliminates the need for welds at critical structural points, which improves an assembly’s ability to withstand pressure and stress.

Bending channel

Depending upon your unique project requirements, Profile Bending angle bending may be performed on a variety of materials, including carbon steelstainless steelaluminumtitanium, and copper.

Important things about steel channels

Here are some important things about structural steel channels that you should keep in mind when looking at them:

  • The ‘depth’ of the channel (how tall it is)
  • Leg height
  • The thickness of the leg
  • The thickness of the web
  • The fillet of the C-channel. The fillet is the angle where the leg meets with the web. This radius is not always provided

PBH Series U channel bending machine parameter

:: Read More: The Awesome 4 Roll Profile Bending Machine For Bending Steel U Channel

The horizontal bending of the steel channel (Hardway) is a hard way, and the bending method is as difficult as the H-beam. It requires a special BIT section bending machine with a ninth hydraulic component.

An important tip for choosing a U channel bending machine

PBH Series section bending machine can bend U channel steel of stainless steel, carbon steel, aluminum, and other materials.

But when you need to bend aluminum U/C-channel steel for decoration or automobile and train use, we recommend that you choose our B- CNC aluminum profile bending machine. Because the bending accuracy of our CNC-controlled aluminum profile bending machine is as high as 0.01mm.

ModelToes OutToes In
Inside Diameter(mm)
Inside Diameter(mm)
PBH 120120600120500
PBH 140140600140600
PBH 20020010002001000
PBH 30030012003001000
PBH 3603602000360900
PBH 45045025004502000
PBH 50050030005001000
PBH 55055040005501200
PBH 60060050006001600
PBH 70070060007002000


In the field of aluminum extrusion bending few things can be as difficult as bending an aluminum U channel.

The asymmetrical shape leads to a very high tendency for the section to warp or deform, usually resulting in the channel collapsing.

This is often unacceptable as the channel usually serves a purpose, either as a track, holding space or feature.

CNC aluminum profile bending machine bending the aluminum u channel with the hard way

This means that finding a way to curve U channel sections successfully is crucial.

The picture below is the C-channel profile bent by our CNC series aluminum profile bending machine, curved after powder coating, with no damage to the finish no warping or collapse. While the section might appear simple enough, it is easy to underestimate the difficulty in curving such a thin-walled U Channel consistently.

:: Read More: These Benefits Make a BIT CNC Aluminium Profile Bending a Great Machine Machine

2 key points of aluminum channel bending


Asymmetry is the enemy of easy bending, which is why aluminum channel sections can be so difficult to form. Please refer to the picture below:

Asymmetry of aluminum channel bending

Their severely asymmetric shape undergoes a large twisting force during bending, and the legs try to move toward the central axis. Altering the design—to one with a base that’s equal to or a little wider than the legs—will help to bend specialists control the twisting a little better.


Aluminum channel sections often serve a purpose, like being part of a track or transport system. Most bending specialists should be able to form them correctly, as long as tolerances are specified in a few key areas.
If a fabricator is subcontracting the work, it should send parts or fittings to the bending specialist to ensure everything fits as it should.

Any order for an aluminum forming specialist should state the requirements that would allow the section to fit into or freely move within the assembly as designed.

Tolerances of aluminum channel bending

The order also should specify the gap tolerance (Number 1 in the picture above) for the trolley or slide, as well as a twist tolerance (Number 2 in the picture above) that will ensure the trolley will not hit the profile.

C channels

C channels are manufactured using aluminum or other metals. Although the basic shape is the same for every C channel, there are a variety of types that can be created. An “Architectural Channel” has a very basic form with perfectly squared corners. Structural C channels come in several types, including what are known as Aluminum Association, American Standard, and Canadian.

Aluminum Association C channels are thicker with rounded corners on the inside of the channel, and they are very similar to Canadian-style channels. An American Standard C Channel, on the other hand, has rounded corners and the sides gradually become thinner moving up to the top. Each type has its own advantages and drawbacks, so they are all used for different purposes. Some are utilized in molding and trim around doors and windows, while others are used for structural and joining purposes.

Two-minute review


The U-profile is a simple semi-finished product. It is characterized by its open design and high transverse stability. This gives this long material a particularly wide range of uses.

Properties of the U-profile

The U-profile is one of the standard profiles. It offers higher transverse stability than the L- or the flat profile. This makes it suitable for high-strength welded constructions with demanding statics. Once firmly integrated into construction, U-profiles can be loaded from practically all sides. Its semi-open design is particularly interesting. This makes it suitable for use as a channel or as an easily accessible channel for cables, hoses, and pipes. It does not offer the protection of a completely closed pipe. However, it can easily be extended with a cover so that the elements inserted or liquids passed through are fully protected.

Materials for the U-profile

The versatility of the U-profile continues in its unpretentiousness when it comes to its materials. Unlike window profiles, for example, the choice of materials for U profiles is not limited.

Common materials for this long material are as follows:

  • Plastic
  • Sheet steel
  • Aluminum
  • Composite materials such as GRP or CFRP are also processed into U-profiles. Even ceramic materials or artificial stones such as concrete or brick are available in short profiles in U-shapes.

Manufacture of the U-profile

profile bending machine
PBH profile bending machine

U-profiles made of plastic or aluminum are extruded. For this purpose, a pre-material – for example plastic granulate or aluminum blocks – is heated and pressed through a die. The profile is cooled down behind the die. This creates an endless strand that is simply cut off at the desired length. Steel profiles in U-shape are edged from thin sheets or continuously cast. The continuous casting variant is considerably thicker-walled, heavier, and more stable.


Be used for bends over 180 degrees, can bend channels into circles or arcs, and is often chosen to create circular pieces.

BIT series steel channel bending machine can bend higher strength stainless steel channels of the same size.

  • Max.Section(mm): 80-700
  • Min.bending DIA(mm): Φ600-6000

Note: A larger size steel channel bending machine can be customized

More detailed parameters


Can be bent aluminum channel into various shapes (3D graphics, Is round, oval, a combination of multiple radii, etc.), is a curved arc of professional manufacturers of the ideal matching products, suitable for bending of aluminum profiles for automobiles, doors, and windows.

  • Spindle speed: 1-15r/min
  • Max.Section(mm): 50-300
  • Y-axis thrust (ton):10-70
  • CNC control. Accuracy is as high as ≤0.01mm. 

More detailed parameters