Steel Pipe Bend 3D 5D 8D
Steel Pipe Bend 3D 5D
In case bending radius in 1D or 1.5D, it is elbow. (short radius elbow 1D and long radius elbow 1.5D).
Pipe Bending Radius: 3D Bend, 5D Bend, 6D, 8D and customized
Bending Degrees: 15°, 22.5°, 30°, 45°, 60°, 90°, 180° and customized

1.3D Bend
2.5D Bend
5D bend means the bend radius is 5 times of pipe nominal diameter. It provides better smooth performance to change pipeline direction than 3D bend.
3.Large Diameter Pipe Bend / Bending Steel pipe bending usually required in large diameter in oil and gas pipelines, since it has better capacity to transport the material, and long pipelines will need different radius of pipe bends to be intalled in complex conditions.


Differences between Steel Pipe Bend VS Elbow
Pipe bend and elbow both for change the pipe direction, still there are a lot of differences in below aspects:
Bending Radius
Manufacturing Processes
Different cost
Application scope
Bending Radius of Bend 3D, 5D, 8D and Elbow 1D, 1.5D
As we talked above,
Steel pipe bend radius: Above 2 times of D, so there are 2D, 2.5D, 3D, 5D, 6D, 7D or 8D pipe bend.
Steel
pipe elbow radius: R=1D or R=1.5D or 2D. Below 1.5D is short radius
elbow, and more than 1.5D but not over 2D is long radius elbow.
R is radius of curvature; D is (elbow or bend) pipe diameter
Different of manufacturing processes
3D, 5D, 8D Bend: Could be bend directly from a finished pipe with cold bending processes, to different degrees.
1D, 1.5 D Elbow: Shall be made according by standard manufacture procedures, with hot finishing or hot bending, to a certain degree, 45°, 90° or 180°.
Cost different with elbow and 3D, 5D, 8D bend
So by the help of simple production process with standard 1.5D or 1D, steel pipe elbow cost is lower than bend. Pipe bend is mostly required with customized radius like 3D, 4D, 5D, 6D, 8D or degrees so the processes is more complicated than elbow and cost is higher.
Different applications scope
Bend: Compatible with slower liquid and lower pressure.
Elbow: Compatible with high pressure and rapid liquid.
Sometimes elbows must be used in narrow sections, because the radius of curvature of the elbow is small, generally 1.5D, but the pipe bend could be up to 40D.