Pipe and tubing is also known as HSS (hollow structural steel), just like square and rectangular tubing, since it is hollow.
CHS Steel Pipe
CHS MEANING ‘CIRCLE HOLLOW SECTIONS’
Of all the steel hollow sections, the circular hollow section came first. The CHS section is a common feature in a wide variety of structural steel operations and has a lot of construction and mechanical uses. The consistent and clean lines of steel CHS make this circular tube a very aesthetic choice in many building designs.
CHS steel is popular for the construction of handrails, balustrades, and scaffolding. Other purposes include sign poles, columns, fences, and architectural features such as bending steel staircases. CHS can be fine-controlled and internally scarfed. This allows the tube to be suitable for mandrel bending.
Pipe and tubing is also known as HSS (hollow structural steel), just like square and rectangular tubing, since it is hollow.
Few examples of pipe bending
- Elbows for general industrial applications.
- Serpentine for heat exchanger. Flat, cylindrical, conic, bended tube bundles, …
- Elbow for pneumatique conveying
- Railings, handrails and tubular arched portal
- Tubular safety barriers
- Exhaust pipe elbow
- Tubular handrail and baserail for balanced staircase.
- Small thickness pipe elbow
- Industrial facilities (chemical, petrochemical, pharmaceutical, food, etc.)
- Agricultural machinery and equipment
- Railways, naval, military, nuclear and energy sectors
- Metallic construction
- Metallic parts furniture manufacturer
- Building ironwork
- Automotive equipment and construction machinery
- Manufacture of safety and protective equipment
- Boiler manufacturer, heat production, cold production
- Pneumatic conveying systems
Pipe bending video
Depending upon your unique project requirements, BIT pipe bending machine may be performed on a variety of materials, including carbon steel, stainless steel, aluminum, titanium, and copper.
Round tube lends itself well to bending because of the symmetry of the part and because, with the proper tubing, the part can be encapsulated well to avoid ovality or other distortion. Generally speaking, tighter bends are more difficult in round tube bending; similarly, the thinner the wall, the more difficult the bend. However, with the correct tooling, machinery, and procedures, excellent quality can be achieved even with tight-radius, thin-wall round tube bending.
Further reading: The difference between tube and pipe
Selection table of BIT angle bending machine for bending pipe
| Specification (mm) | Minimum Inside Diameter (mm) | |
| PBH-120 | 76 × 4 | 700 |
| PBH-140 | 102 × 4 | 1000 |
| PBH-200 | 140 × 4 | 1800 |
| PBH-300 | 170 × 6 | 2000 |
| PBH-360 | 219 × 6 | 2500 |
| PBH-450 | 245 × 6 | 3000 |
| PBH-500 | 325 × 6 | 4000 |
| PBH-550 | 400 × 6 | 8000 |
| PBH-600 | 452 × 6 | 8000 |
| PBH-700 | 510 × 20 | 10000 |
Bending Pipe & Round Tube Circular Hollow
BIT series profile bending machine can bend all types of pipe and tubing including aluminum, stainless and carbon steel. We even bend specialty materials such as copper, zirconium and titanium.
Pipe and tubing are specified in different ways. Pipe is NOT called out by the OD size of the material and is not called out with an easily identifiable thickness.
BIT provides detailed information on nominal pipe size and pipe schedules and sets out a complete table of schedule 40 and schedule 80 thicknesses & weights.
Like square and rectangular tubing, round tubing and pipe can be bent with virtually every bending process BIT series section bending machine have available in our shop. Processes include draw bending, roll bending, increment hot bending, increment cold bending and induction bending. The only exception is the plate roll.
PBH series section bending machine can bend all types of pipe and tubing including aluminum, stainless and carbon steel. We even bend specialty materials such as (zirconium and titanium). Carbon pipe (mill produced) is classified as ASTM A53 (most commonly) resulting in a yield point (psi) of 30,000 minimum for grade A and 35,000 for grade B. Carbon tubing (mill produced) are most commonly classified as ASTM A500B resulting in a yield point (psi) of 46,000 minimum for Grade B.
Related Reading：Similarities Between Bending Round and Rectangular Tubing
Tubing and pipe can be used in virtually any application but are most commonly used as railings, recreational products (play grounds, bike racks, goal posts), industrial products (boiler tubes, heat exchangers, piping systems) and curved members of canopies and awnings.
Related Reading： Square and rectangular tubing is also known as HSS (hollow structural steel).
Photo of profile pipe bending machine
Why are there rippling on the surface when bending pipes
Rippling on the surface of a pipe is a somewhat common problem that occurs during bending operations.
Ripples are caused by high levels of compressive force on the inside of a pipe or tube with thin wall thickness. Thicker pipe walls can withstand higher compressive forces on the inside of a bend without distorting or wrinkling. With custom rolled pipe, material on the outside of the bend stretches – this causes wall thinning. The material resists this thinning and as a result the outside surface of the bend wants to cave in.
For precision work, material cannot have ovality or distortion because there may be a need to splice a bent pipe to a straight pipe. If the profiles of these two mating parts are different, there may be an issue fitting them up to each other.
To avoid distortion when bending pipe, it starts with evaluating the material itself. Pipe comes in many sizes with varying wall thicknesses. It is important to keep in mind that the wall thickness can have nominal variations.
Some pipe sizes perform better in minimum wall thicknesses and above. With cold rolling specifically, a large diameter pipe with a thin wall does not bend well and can even be difficult to bend to large radiuses with a slight curvature. This is because the ratio of diameter to wall thickness of the material is too large and translates to an unstable profile shape.
How to avoid corrugation on the surface of the bent pipe
Pipe bending techniques include, first, looking at the inside and outside bend radii of the task – this will help identify the best machine and tooling to successfully bend pipe. If the pipe requires a tight bend radius, usually with a radius from 1 to 8 times the diameter of the pipe, then a heat induction, rotary draw or push bending operation with a die matching the shape and size of the pipe should be used. These methods offer the most support.
Bending pipe to any radius 8 or more times larger than the pipe diameter in inches should be able to withstand bending on a section rolling machine with a thick enough wall for stability under opposing compressive and tensile forces.
When bending pipe, springback can occur leading to radial growth. To account for this, pipes are usually slightly over bent or bent to a slightly smaller radius than the print or design requires depending on how small the radius is and what material is being used. Steel members with abnormally high tensile and yield strengths require rolling to a much tighter radius than the design requires to achieve the true design radius. This is because you must strain the material more to force it to hold a shape. Typical pipe steel grades and pipe sizes don’t require severe over-bending in most cases to achieve the desired results.
Works Cited: How to Avoid Rippling when Pipe Bending – CMRP Pipe Bending Techniques to Avoid Rippling – CMRP
PBH & MS Series cold Pipe bending Machine
Can bend square pipe/tube into circle or arc.
Focus on pipe diameters for bending up to 20 inches, with cross-section bending combination mold can bend various profiles, multi-purpose section bending machine.
- Pipe. Dia (mm): Ø25-510
- Max.Wall thickness (mm): 1.5-20
- Bending. DIA(mm): Φ400-10000
Note: A larger size cold pipe roll bending machine can be customized.
PBT-25 CNC cold tube bending machine
High-performance cold pipe bending machine, CNC control, multiple programs, multiple angle settings, simpler operation, and program settings.
It is widely used and can be used in mass-produced or standardized products, such as exhaust pipes, seats, bumpers, and all steel furniture.
- Pipe. Dia (mm): Ø18-219
- Wall thickness (mm): 2-16
- Min Bending Dia:1.5D
- Maximum bending angle (°) :0-200
- Core length (mm) :1800-5000
CNC aluminum cold pipe rolling machine
Can be bent in various shapes (3-D graphics, C-shaped, U-shaped, full circle, ellipse, multiple radii combination shapes, etc.). Suitable for bending aluminum profiles for automobiles, doors, and windows
- Pipe. Dia (mm): Ø50-300
- Y-axis thrust (ton):10-70
induction bending machine
It is used for all kinds of round or square steel pipes, stainless steel pipes, I-beam, H-beam, U-channel hot bending, suitable for petroleum, chemical industry, metallurgy, steel structure, boilers, and other projects.