Fabrication Design of Reducers

The simplest method of fabricating a pipe elbow is by the "cut-and-shut" method. It is only practicable in larger diameters of pipe, and the pressure drop of the assembly is rather more than would be the case for a "swept bend". As follows:

• A pair of saw cuts are sent through the pipe at opposing angles almost through to the other side, so that a small amount of sidewall remains and a V-shaped collar of pipe can be removed and discarded. The two faces remaining are brought together by bending the pipe and then they are welded together. Repeat as required to produce the desired angle of the bend.

A bit messy, though it works, and is a good way of getting a lot of change of direction in a relatively small space.

One can also produce a "cut elbow" as follows:

• Cut through the pipe at 45deg to the axis. Take one piece and rotate 180deg about the axis, then turn it 90deg so that the two cut edges are parallel. Bring the pieces together and weld them together.

One couldn't do this with some pipe materials as some cannot be welded, like malleable iron or concrete- or rubber-lined, for example. For these and even in smaller sizes of weldables it would be more appropriate either to use fittings or to bend the pipe itself in some form of jig, according to preference and local standard practices.

Oh yes. One more thing. Remember that the flange bolting has to be considered carefully in the context of the orientation of any cuts, so that the finished bend will attach to the neighbouring pipe flanges correctly.

It depends on the size and the material.

Some are made by forging.
Some are made by forging and machining.
Some are made by fabrication.

• Miter Bends : fabricated from pipe segments by fusion welding.

• Standard Bends (ready made) : Hot Formed, Cold Formed, Forged, and Fusion Welding. See specifications for wrought carbon steel & alloy steel ASTM A234.