Socket Weld Reducing Couplings

What is a Socket Weld Reducing Coupling?

A reducing coupling is a forged sleeve with a larger socket at one end and a smaller socket at the other. Each pipe is inserted and fillet welded, giving a compact size change on small-bore lines. ASME B16.11 tabulates full and half couplings of equal size; reducing couplings are made with socket dimensions and wall thicknesses to B16.11 for each end. Where a larger reduction is needed, a reducer insert (MSS SP-79) or a swage nipple may be used instead.

Key features

• Large and small sockets in one forged body
• Class 3000 and 6000
• Socket dimensions per ASME B16.11 for each end
• Shorter than a swage nipple for small reductions

Specification

Applications

• Size changes on instrument and sampling lines
• Small-bore process and utility piping
• Drain and vent connections
• Steam tracing

Reducing coupling vs reducer insert

A reducing coupling receives two pipes, one in each socket, and makes an in-line size change. A reducer insert to MSS SP-79 fits into the socket of a standard fitting such as a tee or elbow, and the smaller pipe then goes into the insert. Inserts let you use standard equal fittings with a smaller branch; reducing couplings are used for straight size changes between two pipes.