Tube & Pipe Bending Information
Basic Facts and FAQs
Metal Pipe: Steel and Aluminum
- Commonly produced in greater quantities than tubing and in relatively few standard sizes.
- Generally made to less exacting specifications for dimensions, finish, chemical composition, and mechanical properties than tubing.
- Sizes and wall thicknesses of pipe were originally standardized to permit threading the end for joining lengths with couplings or other connectors.
- A large proportion of pipe is also used without screw threads (plain end), where lengths are joined together, or fittings attached, by welding or other means.
Metal Tubing: Steel, Stainless Steel, Brass, Copper and Aluminum
- Tubing is lighter than pipe and easier to work with.
- Tubing can be bent into shape without the need for elbows or other fittings.
- Tubing is also thinner than pipe, so it cannot be threaded;
- Fittings are used to connect tubing to pumps, valves, and other components.
Pipe & Tube Construction
Each of the two types of pipe and tube construction, comes with their own advantages and disadvantages.
- Welded (Seams) - Welded tube is produced from a strip that is roll formed and welded to produce a tube. With a seam on the outside and a weld bead on the inside, use this tubing when your application does not require a smooth interior. For some tubing, the weld bead is smoothed (also known as drawn), which reduces the chance of particle buildup and makes it an economical alternative to seamless tubing. Welded tube is considerably less expensive than seamless tube and is readily available in long continuous lengths.
- Extruded (Seamless) - Seamless tube is extruded and drawn from a billet and has no weld, so it is smooth on the inside to reduce the chance of particle buildup. The working pressure of a seamless tube is 20% greater than welded tubing, has greater corrosion resistance and can be flared without splitting along the seam.
Each tubing OD comes in a variety of wall-thickness choices. As the walls get thicker, the amount of pressure the tubing can withstand increases and the amount of flow decreases.
What you should know about Tube Bending
Center Line Radius (CLR)
- Typical CLR is 2-3X the diameter of the tube, depending on wall thickness.
- It is possible to bend on tighter radius (up to 1X the diameter of the tube) with some materials, but not without more complex tooling. The tighter the radius, the more tooling required and the more expensive the part.
- Use the same CLR for all bends unless prohibited by design restraints if you want to minimize tooling costs.
- Straight between bends. Allow 3X the diameter of the tube of straight for clamping between bends and from the edge of the tube. This reduces the overall cost of the part by reducing additional trim operations and increasing the bend rate.
- Clamping closer than 3X the diameter of the tube may require a more aggressive grip finish and/or compound tooling.
- The tighter the tolerance, the greater the cost. Don't pay for something you don't need.
- Where possible, open all tolerances and deviate from engineering block tolerances when appropriate.
To learn more about how we can assist you with your custom tube bending and tubular component manufacturing, contact us today.