Steel Unions | McMaster-Carr

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162 Products

How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

Low-Pressure Iron and Steel Threaded Pipe Fittings

Use these fittings for low-pressure applications in noncorrosive environments.

Low-Pressure Galvanized Iron
and Steel Threaded Pipe Fittings

The galvanized finish on these fittings provides fair corrosion resistance. Fittings are for use in low-pressure applications.

High-Pressure Iron and Steel Threaded Pipe Fittings

These fittings can stand up to high-pressure applications. Use them in noncorrosive environments.

High-Pressure Galvanized
Steel Threaded Pipe Fittings

A galvanized finish gives these fittings better corrosion resistance than our plain steel high-pressure fittings. Also known as Pressure Class 3000 fittings.

Medium-Pressure Iron and
Steel Threaded Pipe Fittings

For use in noncorrosive environments, these fittings have better strength than our low-pressure iron and steel pipe fittings.

Medium-Pressure Galvanized Iron
and Steel Threaded Pipe Fittings

A galvanized finish gives these fittings fair corrosion resistance. They have the strength to handle medium-pressure applications.

Extreme-Pressure Steel Threaded Pipe Fittings

The strongest steel fittings we offer, these can withstand extreme-pressure applications.

Low-Pressure Press-Connect
Steel Unthreaded Pipe Fittings

Crimp these fittings onto steel pipe to form a tightly sealed connection that’s faster than threading or welding and doesn’t require heat.

High-Pressure Socket-Connect
Steel Unthreaded Pipe Fittings

Socket-connect fittings are easier to weld than butt-weld fittings because the fitting doesn't need to align perfectly to the pipe. Slide the pipe into the socket and weld.

Extreme-Pressure Socket-Connect
Steel Unthreaded Pipe Fittings

Also known as Pressure Class 6000 fittings, these heavy duty forged fittings are the strongest steel fittings we offer.

Press-Connect Fittings for Copper Tubing

Crimp these fittings to copper tubing with a crimping tool for a leak-tight connection that doesn’t require heat or soldering. They are comparable to Viega ProPress fittings.

Hose Unions for Chemicals and Petroleum

Access your line without twisting the hose—these unions separate into three pieces.