Reducing flanges are designed for when there is a change in the pipe size. The predominate flange (dimensions) matching the larger pipe size (NPT) but having a smaller bore matching the smaller pipe size (NPT). These flanges normally come in blind, slip-on, threaded and weld neck flanges. They are available in all pressure classes and provide a good alternative to connecting two different sizes of pipe. This type of flange should not be used if an abrupt transition would create unwanted turbulence, such as at a pump.

A reducing flange consists of a flange with one specified diameter having a bore of a different and smaller, diameter. Except for the bore and hub dimensions, the flange will have dimensions of the larger pipe size.

Material of Reducing Flange:

Cabon steel: A105, A350 LF2

Stainless steel: A182 F304/F304L/F316/F316L/F321

Alloy steel: F11, F12