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Aluminum, Stainless, and Carbon Steel Square Tubing Bending

Square Tube Bending Machine

To bend your square tubes as accurately as possible, please choose the right square tube roller with our guidelines.  BIT is proud to recommend the PBH Section Bending Machine for your square tube bending project.
Maybe you will like to check out our profile bending process page.

SHS Metal Square Tubing

Square Tube Bending
Square Tube Bending

Square hollow sections/SHS steel ( square tube/pipe ) are another popular type of structural steel tube. They are a kind of intermediate between RHS steel tubing and CHS beams in terms of appearance and structural behavior. Square section steel also has a flat surface and clean lines — which both make welding and joining very economical.

Square and rectangular tubing are always called out the same way. The first two numbers designate the size of the material (in inches). The last number (typically represented as a decimal) defines the thickness of the tubing. An example callout for standard rectangular tubing would be TS 8” x 6” x .375”. This tubing measures 8” long x 6” wide and has a wall thickness of 3/8”. You know this is rectangular tubing because the sides are not equal.
Carbon square and rectangular materials (mill produced) are classified as ASTM A500 resulting in a yield point (psi) of 39,000 minimum for Grade A and 46,000 minimum for Grade B.

Related Reading: Similarities Between Bending Round and Rectangular Tubing

square tube bending machine


Square and Rectangular materials can be used in virtually any application. Structural (roof trusses), ornamental (staircases), recreational (bike racks), manufacturing (various widgets), and artistic. Virtually, anything that needs to bend, can be and is designed out of square and rectangular materials (HSS materials).

Notes: Square section steel often provides the ideal balance between strength, aesthetic appearance, and functionality.
These three reasons are why square metal tubing is still so popular to this day. But like the RHS sections, steel tube squares are difficult to use. It is hard to bolt them to beams. Square steel tubing also comes in ‘hot’ and ‘cold’ forms. Another name for them is a “box section”.

Hot Bending And Cold Bending

Induction Bending Square Tubing

There are many types of bending square tubing, but the simplest classification method is to divide them into hot bending and cold bending.
There are pros and cons to both hot and cold bending, depending on the type of material you need to be bent and the angle of the bend required.
Cold bending methods often rely on sheer physical force to help bring the pipe to its final shape, it is more suitable for bending iron tubes, stainless steel tubes, aluminum tubes and copper tubes; while hot bending methods use careful heating to reduce the force required. Read More: Nine steps of the square tube induction bending process

Hot Bending VS Cold Bending: Compared with hot bending, the cold bending of automatic square & rectangular tube bender needs more bending power, and the spring back and residual stress increase obviously. The full-automatic square & rectangular bending machine cannot bend sharp bends with a small radius of curvature. Hot bending can form a small radius elbow on the pipe. For carbon steel pipe and most alloy steel pipe, the bending radius of hot bending is much smaller than that of cold bending by automatic pipe bender, and the bending radius can be as small as 0.7-1.5 times of the outer diameter of the pipe. However, hot bending still has the following disadvantages: complex equipment, high processing cost, low production efficiency, and poor surface finish.

Read More: 4 Key Points Cold Bending And Hot Bending In Pipe Bending

Four methods of bending square tube

Image Source: AIbina

BIT PBH/PBA series profile bending machine‘s ability to roll bending both round, square, and rectangular tubing. For rectangular tubing, it can bend both the easy way (against the weak axis) and the hard way (against the strong axis). It can even provide Multi-Plane bending where we are bending both the easy way and the hard way. Related Reading: Square and rectangular tubing is also known as HSS (hollow structural steel).

Square and rectangular tubing are also known as HSS (hollow structural steel), the name is always called out the same way( The first two numbers designate the size of the material in inches). it includes aluminum, stainless, carbon steel, copper, zirconium, and titanium tubing.

Cold roll bending square and rectangular tubing can be used with and without a mandrel. If the material with mandrels, the hollow material into a solid. This helps minimize distortion without increasing the thickness of the material.

Read More: Easy-Way vs. Hard-Way of Profile Bending

Three Notes For Bending Aluminum, Stainless/Carbon Steel Tubes

Bending Square Tube
bending square tube (square pipe)

However, there is some troubleshooting to do when performing steel tube bending.

  • Bends often require achieving a tight radius. Since the outer wall of the bend becomes thinner, the result may be a distorted bend. To prevent this, using a mandrel to give support is recommended. That is also why press or ram bending is not recommended in these situations. The most adequate bending method would be mandrel bending, which is the same as rotary draw bending but adds a mandrel to support the inside of the pipe.
  • Sometimes the radius we need to achieve makes the steel to exceed its elastic limits. It can result in deformation in the form of a hump or wrinkles. To prevent the formation of humps and wrinkles, it is recommended to use rotary draw bending or three-roll bending.
  • When bending stainless steel tubes and pipes, it is important to remember that some stainless steel requires around 50% more power for bending than carbon steel. Therefore, the machinery must be set accordingly.

Four Tips That Influence The Tubing Bending Process

Several tips can help to ease the bending of square or rectangular material and reduce the amount of distortion in bent tubes.

  • Factors 1#: Wall Thickness. Bending round, square, or rectangular material involves stretching the outside diameter (OD) of the bend and compressing its ID. Consequently, a heavier wall thickness allows for a tighter bend radius and more material stretchability with less distortion.
    Method of Bending. This is a key factor in controlling distortion. A correctly chosen procedure can help to produce consistent tolerances and accurate parts. Generally, smaller material requires rotary draw bending or compression bending, which can incorporate wiper dies and mandrels. Induction and increment bending should be used with larger material bent to a larger radius. Design distortion and material size are important factors for determining the bending method.
    In many cases, there is no better factor than experience. Many trained bending artisans know what is required to produce an acceptable product.
  • Factors 2#: Size of Material. Larger material bent to a smaller radius has a greater chance to distort than smaller material bent to a larger radius. Design and planning are necessary to help solve bending problems before they arise.
  • Factors 3#: Tooling. After the parts have been designed, the method of bending has been chosen, and procedures to bend to proper tolerances are established, the machine must be set up with the proper tooling. Based on design conditions, tooling that can be used includes a bend die, clamp block, follower block, mandrel, and wiper die. All or some of this tooling may be required.
  • Factors 4#: Internal and External Lubricant. Lubricants decrease the friction between the tooling and the material to be bent. When friction is reduced, material flows smoothly through the bending equipment, allowing the machinery to perform its designed operation efficiently.

:: Reference: Bending square and rectangular tubing

Six Parameters Of Bending Tubing

The basics of bending are the same for all materials in that certain information is required to produce an accurate part of a square pipe:

Diagram of Tubing Bending Parameters
Diagram of Tubing Bending Parameters
  • Degree of bend
  • The radius of the bent section
  • Chord of the bent section
  • Arc length
  • The slope of the bent section
  • Tangent lengths

It isn’t necessary to know all six parameters. However, at least three must be known to produce a bent section.

Read More: How Does Bending The Stainless Steel Tubing

Top 5 Types of Square Aluminum, Stainless/Carbon Steel Tube Bending Machines

3D Freeform Square Tube Bending Machine

CNC 3D Freeform Square Tube Bending Machine

Experience the future of tube bending with BIT’s 3D Freeform Square Tube Bending Machine. Empowered by advanced CNC and servo technologies, it crafts intricate, custom components with unmatched precision. Versatile and efficient, it excels in tight radius, multi-radius, and symmetrical bending, ensuring high-quality parts with tight tolerances. From prototypes to large volumes, it offers flexibility and consistency while minimizing waste. Ideal for automotive, aerospace, architecture, and industrial design, it revolutionizes tube bending with unparalleled flexibility and precision.

Square Tube Stretch Bending Machine

CNC Square Tube Stretch Forming Machine

Equipped with hydraulic control and rebound control technology, it ensures precise stretch forming with an accuracy of over 0.01mm. Delivering high-quality bends without surface damage, it accommodates profiles with complex cross-sections, eliminating wrinkles and distortion. Cold-formed sections up to 500 mm x 350 mm can be effortlessly shaped, with a maximum bending arc length of 12 meters. With a maximum tensile force of 300 tons, it offers unmatched bending ability for projects requiring superior precision and efficiency. Experience unparalleled stretch forming quality with the PBF CNC Square Tube Stretch Forming Machine.

PBH Square Tube Rolling Machine

PBH Square Tube Rolling Machine

Driven by 3-roller rotation, PBH series section bending machines offer unparalleled bending capability. The hydraulic bottom two rollers move independently, enabling symmetric and asymmetric bending with minimal material slippage. Equipped with versatile tooling and accessories, including combination molds for various profiles, it enhances productivity and quality. Boasting a robust full-frame design, PBH machines ensure reliability and precision. With efficient hydraulic 3D guide rolls, they offer optimal control for planarity and diameter calibration. Experience unmatched performance and versatility with the PBH Square Tube Rolling Machine.

PBA Square Tube Rolling Machine

PBA CNC Square Tube Rolling Machine

With CAD design, workpieces are replicable anytime. Versatile and reliable, it excels in complex variable-curvature arc aluminum bending. Featuring up to 9 controllable servo axes for precision ≤0.01mm. User-friendly CNC control system with drawing upload. Craft shapes like C, U, S, and ellipse effortlessly. Benefit from consistent repeatability, precise ‘Z’-axis control, and adaptable variable centers. Software supports 2D/3D import/export, 3-axis linear interpolation, and self-diagnosis. With a robust memory capacity, it ensures seamless operation and efficient production.

PBT CNC Square Tube Bending Machine

PBT CNC Square Tube Bending Machine

Our product range includes pipe bending machines, tube end forming, deburring, chamfering, and notching machines, all supported by leading CNC and Hydraulic software. With over 30 years of experience, we offer high-quality molds, spare parts, and efficient software for ease of use. Choose from various working lengths and CNC/NC options to suit your needs. Experience long-lasting performance and minimal service requirements with our tube processing solutions. For unparalleled quality and service in the pipe and tube processing industry, BIT Machine is your ideal partner.