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Bending Aluminum Flat Bar

flat bar rolling machine

BIT hydraulic flat bar bender has super-strong ability to bend flat bar and high precision. Therefore, flat bar rolling machine is often used to bend bar steel and make flanges in practical applications, At the same time, BIT B-CNC series aluminum bending machine can perfectly bending aluminum flat bar.
Therefore, we also call the profile bending machine the flange forming machine.

Flat bars are solid, which means that they can be easily bent into the shapes required by a project. 

Flat bar roller is used for the bending of flat bar (flange forming)
Hard way to bent flat bar

how to bend aluminum flat bar

Bending Aluminum Flat Bar

BIT series aluminum bending machine can bend aluminum bars, aluminum structural shapes, aluminum pipe, and aluminum tubing to match your exact specifications.

PBT aluminum bending machine

Aluminum can be tricky to bend, especially to tight radii, but we has the skills and experience to deliver precision bent aluminum profiles of all shapes and sizes.

Video of Bending Aluminum Flat Bar

how to bend aluminum flat bar?

6061-T6 aluminum is tempered and notorious for not bending easily. From a bending perspective, it’s always best to bend these parts in an annealed state and then temper them to the correct condition. That’s the ideal, anyway, but the reality is that many parts arrive at the press brake in a less than ideal state.

T6 aluminum is precipitation-hardened, which is a form of artificial aging that causes particles within the metal to be spread evenly throughout the grain structure of the metal. Once the particles become dispersed, they hinder any further dislocation of the grain, thereby strengthening the metal.

To create these precipitates, the aluminum is heated using a solution treatment at high temperatures and at a prescribed time, then quenched for rapid cooling. This type of hardening typically is performed in an inert-atmosphere vacuum at temperatures between 900 and 1,150 degrees F. The process can take up to four hours to complete, depending on the characteristics of the material.


Bending T6 aluminum square tube

Is there any better way to bend T6 aluminum profile?

For the bending of T6 U profiles, 3 methods can be used to form them.

Sand filling, wax filling, mandrel (here we use flat strips suitable for the shape of the profile).

Sand filling: If the plane of the U-shaped aluminum profile is an inner arc surface, the plane needs to be slightly concave.

Wax filling: The wax filling process is more troublesome. The heated wax solution is poured into the aluminum profile, and the aluminum profile can be bent after cooling, and then baked and then flowed out.

Mandrel: This is a better choice for bending long aluminum profiles. For example, in the bending of a 6-meter-long T6 aluminum profile, a mandrel can be used at both ends, and a spring steel plate can be used in the middle.

General Advice on Aluminum

When bending aluminum, know that the smaller your inside bend radius, the larger the chance that cracking will occur in the part. Also know that, for the best results and fewer cracks on the outside of the bend, the bend line should go across or diagonal to the material grain when and where possible.

Ideally, part designers should know that when it comes to aluminum grades, 3003 and 5052 will bend, 6061 will not. This is generalizing, of course, as there are ways to form 6061. 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. If you’re not careful, you can completely fracture the bend line.
ModelHard Way X-X AxisEasy Way Y-Y Axis
Specification (mm)Minimum Inside Diameter (mm)Specification (mm)Minimum Inside Diameter (mm)
PBH-12080× 10800180× 20500
PBH-140100× 25700200× 35600
PBH-200120× 251000250× 301000
PBH-300150× 301500250× 401000
PBH-360175× 401500350× 50900
PBH-450200× 502500400× 602000
PBH-500250× 703500450× 701000
PBH-550250× 703500500× 801200
PBH-600300× 704000500× 1001600
PBH-700300× 805000650× 1002000

Hydraulic bar bending machine

Flat bar bender

How to bend a radius in flat bar

Bent flat bars are frequently used in tank stiffeners, matching flanges, curved lintels, hand rails, curved stringers, pipe clamps and kick rails on circular platforms.

2 processes flow of roll bending flat bar

Bars can be bent with virtually every bending process.

For very tight radius bending you can utilize a draw bending process where you must be pull the material (draw the material) around a bend die matching the desired bend radius.

But for larger or sweeping radii must be utilize a roll bending process (section bending). At this time, need to use flat bar bending machine.

Flat bars are solid, which means that they can be easily bent into the shapes required by a project. There are two ways to bend non-circular or non-square bars:

Easy way to roll bending flat bar

Easy Way

The Easy Way: This involves bending a bar along the wider axis of the bar. This means an easier bend, reducing the problem of rippling on the inside of the curve. Bars bent the easy way resemble a belt when completed.

Hard way to roll bend flat bar

Hard Way

The Hard Way: Bars bent in this manner are bent along the thicker axis. This also presents more difficulty during the bending process, as rippling and compression can occur on the inside of the bends. When bent the hard way, bars resemble a metal washer.


Minimum Bending Radius When Bending Bars

There is not a mathematical formula for determining the minimum bending radius of steel sections.

To better explain this, lets look at bar bending. Steel is curved using a cold-roll bending process.

Steel sections are put into a flat bar bending machine (also called “section bending machine” or “angle roll”) with a three or four roll configuration. Rollers put force against the feed path to force the metal stock into a predetermined curved path. There is force applied by the rolling machine (stress) which in turn changes the structural steel into a curved shape (strain).

3D guide rolls

How to bend metal bar use PBH flat bar bender

The flat bending of flat steel bar and the bending of square steel bar can choose any combination of angle rolls molds.

The steel bar’s section rolling process uses an asymmetrical bending, put the 3D guide rolls are raised slowly in the roll bending process, otherwise the material would be distorted.

Before the roll bending procces, must be adjust the guide roller to the same distance, and the steel bar has the correct angle relative to the roller axis, which is suitable for bending small workpieces with small bending stress, which will cause slippage during the bending process. Mainly due to the low friction during feeding, increasing the roller clamping force can eliminate slippage.

The steel bar can be bent into a circular workpiece with a diameter slightly larger than the die diameter, and the friction clutch should be adjusted tighter.

Elastic state

If you look at the diagram left, steel is very ductile, and after a very brief elastic state the material goes into plastic deformation. The goal is to reach the desired radius without reaching the necking or ultimately the fracture point

Looking back at the diagram left, the goal is to maximize the elongation limit in the bar bending process which is done by going with steel that is more ductile.

Three minutes to read


  • Metal flat bars or ‘Flat Sections’
  • Steel flat bars are one of the most basic of building materials.
  • Flat metal bars are practical anywhere a connection between two beams is required.

flat bar bneding

Appliction of flat bars

  • Base plates
  • End plates
  • Stiffeners (secondary plates)
  • Tabs
  • Gussets
  • Splice plates

When a flat section is cut into smaller pieces it is called a flat steel plate. Flat sections are often used to strengthen other beams and are sometimes used to reinforce timber joists. That is why it is so typical to see a flat steel bar with holes in it, ready to be bolted in place.

Flange bending machine

What is “Roll Forming?”

The term “roll forming” lends itself to great ambiguity.

roll forming

Since steel mills producing “long sections” of structural steel–including angles, bars, beams, channels, and tees–manufacture their products through a rolling process, these sections are often referred to as, for example, “rolled beams.” (In part to distinguish them from built-up girders, i.e. beams made by welding three pieces together.)

angle ring rolling machine

roll bending

And these straight sections are often curved to a given radius, in a prescribed orientation, through a given number of degrees or a given arc length to be used in a variety of applications. Since the most common way of curving structural steel involves three-roll benders (also called “angle rolls,” “section benders,” and “pyramid rolls”) bending with these machines could also be called “roll forming.”

In construction, curved steel beams, for example, are often used as roof supports, canopies, and bridges; in manufacturing, curved steel sections are used in tractors, antennas, rail cars, and tanks–to name just a few applications.

angle ring roller

But perhaps the most common use of the term “roll forming” refers to a process whereby a strip of sheet metal or relatively light plate is fed off a coil into a series of rollers which progressively form the desired shape. The method has been used to form residential gutters whose length is limited only by the length of the metal in the steel or aluminum coil. The gutters can be formed to length in a truck at the job site. This type of roll forming is most commonly used to produce many feet of a formed product whether that be angles, channels, tees, etc.

Four basic knowledge of flat steel

flat bar bender machine

Flat bar sizes

Flat bar sizes are generally available and extruded shapes of the most common sizes of angles, tees and I-Beams can be found. In the world of specialty alloys, however, the demand for such products is so small that structural shapes are rarely produced for standard inventory.

Flat bar formed by cutting

Limited quantities of flat or square bar are produced in several alloys where they are in demand for aerospace applications or where cutting from plate is prohibited. This includes titanium alloys and PH 15-5.

However, for most other stainless and nickel alloy grades, flat bar is produced only when there is a significant quantity to justify a mill production run.

This usually means a minimum of 2500# per size.

Fortunately, most flat bar needs can be accommodated by cutting flat bar from plate.

Metallurgically speaking, this poses no problem because stainless and nickel alloy plate properties are nearly isotopic. Transverse mechanical properties can be slightly below those in the longitudinal direction, but the minimum tensile properties established for each plate material are tested in the transverse direction anyway.

Dimensional tolerance

The primary difference between true flat bar and flat bar cut from plate is dimensional tolerance. In true flat bar, tolerances for width and thickness are restrictive and more or less mirror those established for round bar.

In cutting bar from plate, the width tolerance will be more generous and in line with the cutting method. Typically the permitted range of variation on width is 1/8”.

The thickness of the flat bar cut from plate will be same as that of the plate. Plate thickness tolerances are skewed to the heavy side. The minimum under tolerance for plate thickness is 0.010”, while the over tolerance is either unrestricted or is at least 0.090” and increases with thickness.

Edge and corner conditions

Finally, edge and corner conditions will likely be different. For true bar, the surface finish on all four sides will be more or less the same. Corners will be full and nearly sharp with only a slight break. They will be nearly free of twist and camber. On flat bar cut from plate, the surface finish on the sides that were cut will differ from the top and bottom, which are the original plate surfaces. If the bars are merely stripped from plate, they may show some twist or camber. This can vary greatly with the cutting method.