A pipe union is a three-part fitting that joins two pipes while allowing the connection to be assembled and separated quickly. It consists of a male end, a female end, and a central nut that draws the two ends together. Unlike a coupling, which must be unthreaded from one pipe to disconnect, a union lets you break the line without moving either pipe — a huge advantage for equipment that needs regular servicing.
At SS Flow Control, we manufacture pipe unions in stainless steel 304, 316, and 316L, so they hold up in demanding environments — oil and gas, chemical processing, water treatment, power plants, and food/beverage lines. Stainless steel resists rust and corrosion and keeps its strength at high temperatures, making it the preferred material for critical piping.
Key facts
- Three-piece design: male end, female end, and central nut
- Allows disconnection without disturbing the pipe run
- Available in ground joint, screwed, and socket weld types
- Standard sizes 1/8" to 4" (DN6 to DN100), custom sizes on request
- Every union is checked for thread fit and pressure rating before it ships
Pipe Union vs. Coupling — What's the Difference?
A coupling is a permanent or semi-permanent connection — you must unscrew it from one pipe to break the line. A union is designed for repeated disconnection. It uses a central nut that can be loosened by hand or with a wrench, allowing the two pipe ends to separate without moving either pipe. If you need to clean, inspect, or replace equipment regularly, a union is the fitting you want.
Tell us your pipe size, working pressure, temperature, and the fluid running through the line, and our team will help you select the right union — whether you need a single piece for a repair or a bulk order for a new installation.