Union Joints | McMaster-Carr

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648 Products

About Pipe and Fittings

Measure your pipe and fittings to identify their pipe size, thread size, schedule, and thread type. Then, find compatible components.

Stainless Steel Pipe and Pipe Fittings

Low-Pressure Stainless Steel Threaded Pipe Fittings

Use these corrosion-resistant fittings in a low-pressure pipe line.

Precision Extreme-Pressure Stainless
Steel Threaded Pipe Fittings

These fittings are made to tighter tolerances than other stainless steel pipe fittings. They are also known as instrumentation fittings.

Medium-Pressure Stainless
Steel Threaded Pipe Fittings

Choose these fittings when you want the same high-quality found in our low-pressure pipe fittings, but need more strength to handle higher pressures.

High-Pressure Stainless
Steel Threaded Pipe Fittings

Use these heavy duty, corrosion-resistant fittings in high-pressure flow applications.

Low-Pressure Socket-Connect Stainless
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. Slip the pipe into the socket and weld.

Low-Pressure Press-Connect Stainless
Steel Unthreaded Pipe Fittings

Press these fittings onto stainless steel pipe using a crimping tool for a permanent, leak-tight connection that's faster than threading or welding and doesn't require heat.

High-Pressure Socket-Connect
Stainless 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. Slip the pipe into the socket and weld.

Iron and Steel 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.

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 Pipe Fittings
for Joining Dissimilar Metals

Use these unions to connect different metals in a piping or plumbing system. They have a gasket with a plastic sleeve that inhibits destructive corrosion.

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.

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.

High-Pressure Iron and Steel Threaded Pipe Fittings

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

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.

Brass and Bronze Pipe and Pipe Fittings

High-Pressure Brass Threaded Pipe Fittings

These brass fittings have the strength to handle high-pressure applications.

High-Pressure Brass Threaded
Pipe Fittings for Drinking Water

Use these heavy-duty brass fittings for high-pressure drinking water applications.

Medium-Pressure Brass and
Bronze Threaded Pipe Fittings

Choose these fittings when you need better strength than our low-pressure brass and bronze pipe fittings.

Low-Pressure Brass and
Bronze Threaded Pipe Fittings

Use these fittings in low-pressure flow applications. They have good corrosion resistance.

Low-Pressure Plated Brass Threaded Pipe Fittings

Used in low-pressure pipe lines, these brass fittings have a plating that makes them shiny and improves corrosion resistance.

Bronze Unthreaded Pipe Fittings

Also known as Silbraze fittings.

Aluminum Threaded Pipe and Pipe Fittings

High-Pressure Aluminum Threaded Pipe Fittings

Also known as Pressure Class 3000 fittings, these have the highest pressure rating of all the aluminum pipe fittings we offer.

Low-Pressure Aluminum Threaded Pipe Fittings

In addition to being lightweight, these aluminum fittings offer good corrosion resistance. Use them in low-pressure flow applications.

Plastic Pipe and Pipe Fittings

Standard-Wall Plastic Pipe Fittings for Water

Connect these fittings to Schedule 40 plastic pipe—they are the industry standard for residential and commercial low-pressure plumbing and water supply applications. They are plastic for good corrosion resistance.

Thick-Wall Plastic Pipe Fittings for Water

Connect these fittings to Schedule 80 pipe. With thicker, stronger walls than standard-wall fittings, they can handle heavy duty supply applications, such as water processing, wastewater treatment, and irrigation.

CPVC Pipe Fittings for Hot Water

Connect to CPVC pipe for use in high-temperature plumbing and water supply applications.

Aboveground Standard-Wall PVC Pipe
Fittings for Drain, Waste, and Vent

These Schedule 40 fittings are the industry standard for gravity-flow drain, waste, and vent (DWV) applications.

High-Purity Polypropylene Pipe
Fittings for Corrosive Chemicals

The inside of these fittings won’t leach contaminants into your line or accumulate particles—they’re polished to an ultra-smooth 12 Ra finish, which also makes it easy to clean. Made of polypropylene, they resist organic solvents, acids, and alkalis better than CPVC fittings.

High-Purity PVDF Pipe Fittings
for Corrosive Chemicals

Made of PVDF that’s finished to a 12 Ra smoothness, these fittings handle some of the harshest chemicals without leaching contaminants into your line. Comparable to Kynar, they handle most organic solvents that would dissolve CPVC, and chlorine or nitric acid that would weaken polypropylene.

Flame-Retardant PVDF Pipe Fittings for Chemicals

These PVDF fittings meet UL 94 V-0 for flame retardance, so they delay the spread of flames to valuable equipment. PVDF is comparable to Kynar, and has the chemical resistance to stand up to solvents and other harsh substances.

Drain, Waste, and Vent ABS
Pipe Fittings for Chemicals

These fittings are an economical option for chemical waste systems. Fittings are ABS plastic, which has excellent strength and impact resistance and good chemical resistance.

Gravity-Flow Polypropylene Pipe
Fittings for Corrosive Chemical Waste

Made of polypropylene, these gravity-flow fittings withstand organic solvents, such as acetone, that would dissolve CPVC pipe. They also stand up to highly corrosive acids, such as hydrochloric acid, and alkalies.

Expansion Joints with Threaded Ends

Connect male threaded pipe to these expansion joints to add a point of flexibility in your line that reduces stress, vibration, and noise.

Tube Fittings for Copper and Brass Tubing

Solder-Connect Fittings for Copper Tubing

Solder these fittings to tubing for a permanent, leak-tight connection. They are also known as sweat fittings.

Cleaned and Bagged Solder-Connect
Fittings for Copper Tubing

When cleanliness is crucial to your application, choose these fittings that are individually cleaned and bagged to prevent contamination.

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.

Stainless Steel Pipe and Pipe Fittings

Low-Pressure Stainless Steel Threaded Pipe Fittings

Precision Extreme-Pressure StainlessSteel Threaded Pipe Fittings

Medium-Pressure StainlessSteel Threaded Pipe Fittings

High-Pressure StainlessSteel Threaded Pipe Fittings

Low-Pressure Socket-Connect StainlessSteel Unthreaded Pipe Fittings

Low-Pressure Press-Connect StainlessSteel Unthreaded Pipe Fittings

High-Pressure Socket-ConnectStainless Steel Unthreaded Pipe Fittings

Iron and Steel Pipe and Pipe Fittings

Low-Pressure Iron and Steel Threaded Pipe Fittings

Low-Pressure Galvanized Ironand Steel Threaded Pipe Fittings

Medium-Pressure Iron andSteel Threaded Pipe Fittings

Medium-Pressure Pipe Fittingsfor Joining Dissimilar Metals

Medium-Pressure Galvanized Ironand Steel Threaded Pipe Fittings

High-Pressure GalvanizedSteel Threaded Pipe Fittings

High-Pressure Iron and Steel Threaded Pipe Fittings

Extreme-Pressure Steel Threaded Pipe Fittings

Low-Pressure Press-ConnectSteel Unthreaded Pipe Fittings

High-Pressure Socket-ConnectSteel Unthreaded Pipe Fittings

Extreme-Pressure Socket-ConnectSteel Unthreaded Pipe Fittings

Brass and Bronze Pipe and Pipe Fittings

High-Pressure Brass Threaded Pipe Fittings

High-Pressure Brass ThreadedPipe Fittings for Drinking Water

Medium-Pressure Brass andBronze Threaded Pipe Fittings

Low-Pressure Brass andBronze Threaded Pipe Fittings

Low-Pressure Plated Brass Threaded Pipe Fittings

Bronze Unthreaded Pipe Fittings

Aluminum Threaded Pipe and Pipe Fittings

High-Pressure Aluminum Threaded Pipe Fittings

Low-Pressure Aluminum Threaded Pipe Fittings

Plastic Pipe and Pipe Fittings

Standard-Wall Plastic Pipe Fittings for Water

Thick-Wall Plastic Pipe Fittings for Water

CPVC Pipe Fittings for Hot Water

Aboveground Standard-Wall PVC PipeFittings for Drain, Waste, and Vent

High-Purity Polypropylene PipeFittings for Corrosive Chemicals

High-Purity PVDF Pipe Fittingsfor Corrosive Chemicals

Flame-Retardant PVDF Pipe Fittings for Chemicals

Drain, Waste, and Vent ABSPipe Fittings for Chemicals

Gravity-Flow Polypropylene PipeFittings for Corrosive Chemical Waste

Expansion Joints with Threaded Ends

Expansion Joints with Threaded Ends

Tube Fittings for Copper and Brass Tubing

Solder-Connect Fittings for Copper Tubing

Cleaned and Bagged Solder-ConnectFittings for Copper Tubing

Press-Connect Fittings for Copper Tubing

Precision Extreme-Pressure Stainless
Steel Threaded Pipe Fittings

Medium-Pressure Stainless
Steel Threaded Pipe Fittings

High-Pressure Stainless
Steel Threaded Pipe Fittings

Low-Pressure Socket-Connect Stainless
Steel Unthreaded Pipe Fittings

Low-Pressure Press-Connect Stainless
Steel Unthreaded Pipe Fittings

High-Pressure Socket-Connect
Stainless Steel Unthreaded Pipe Fittings

Low-Pressure Galvanized Iron
and Steel Threaded Pipe Fittings

Medium-Pressure Iron and
Steel Threaded Pipe Fittings

Medium-Pressure Pipe Fittings
for Joining Dissimilar Metals

Medium-Pressure Galvanized Iron
and Steel Threaded Pipe Fittings

High-Pressure Galvanized
Steel Threaded Pipe Fittings

Low-Pressure Press-Connect
Steel Unthreaded Pipe Fittings

High-Pressure Socket-Connect
Steel Unthreaded Pipe Fittings

Extreme-Pressure Socket-Connect
Steel Unthreaded Pipe Fittings

High-Pressure Brass Threaded
Pipe Fittings for Drinking Water

Medium-Pressure Brass and
Bronze Threaded Pipe Fittings

Low-Pressure Brass and
Bronze Threaded Pipe Fittings

Aboveground Standard-Wall PVC Pipe
Fittings for Drain, Waste, and Vent

High-Purity Polypropylene Pipe
Fittings for Corrosive Chemicals

High-Purity PVDF Pipe Fittings
for Corrosive Chemicals

Drain, Waste, and Vent ABS
Pipe Fittings for Chemicals

Gravity-Flow Polypropylene Pipe
Fittings for Corrosive Chemical Waste

Cleaned and Bagged Solder-Connect
Fittings for Copper Tubing