Weld-On Flanges | McMaster-Carr

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	Connection Style Connection Style

	Socket Connect Type Socket Connect Type

	Weld

	Pipe Size Pipe Size

1/8
1/4
3/8
1/2
3/4
1
1 1/4
1 1/2
2
2 1/2
3
4
5
6
8
10
12

	Type Type


Flange	Adapter

Reducing Adapter	Stub End

	Material Material

Aluminum

Stainless Steel

Steel

	Pressure Class Pressure Class

	For Pipe Material For Pipe Material

Stainless Steel

Steel

Aluminum

	Flanged Connection Surface Flanged Connection Surface


Raised	Flat

O-Ring Groove

	For Pipe Schedule For Pipe Schedule

Any

	Number of Bolt Holes Number of Bolt Holes

	System of Measurement System of Measurement

Inch

Metric

	Flange OD Flange OD

	For Use With For Use With

	Specifications Met Specifications Met

	Bolt Circle Diameter Bolt Circle Diameter

	Shape Shape

	Straight

	Connection Type Connection Type


Pipe	Tube

Press Fit

	Bolt Hole Diameter Bolt Hole Diameter

	Maximum Steam Pressure Maximum Steam Pressure

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	Tank Connection Type Tank Connection Type

	Weld

	Flange Mount Type Flange Mount Type

Weld On

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742 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 Stainless Steel Unthreaded Pipe Flanges

Bolt two same-size flanges together with a gasket to create an access point within a pipe line.

Standard-Wall Butt-Weld Stainless
Steel Unthreaded Pipe Fittings

Butt-weld fittings allow for a smooth, flush connection that provides maximum flow.

High-Pressure Stainless Steel Unthreaded Pipe Flanges

Use these heavy duty forged flanges for high-pressure applications.

High-Pressure Stainless Steel
Unthreaded SAE Pipe Flanges

Also known as Code 61 SAE hydraulic flanges.

Thin-Wall Butt-Weld Stainless
Steel Unthreaded Pipe Fittings

Also known as Schedule 10 fittings, these are thin, lightweight, and corrosion resistant.

Low-Pressure Stainless Steel Threaded Pipe Fittings

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

Low-Pressure Steel Unthreaded Pipe Flanges

Bolt two flanges of the same size together with a gasket to create an access point in a pipe line.

Standard-Wall Butt-Weld Steel Unthreaded Pipe Fittings

Butt-weld fittings allow for a smooth, flush connection that provides maximum flow.

High-Pressure Steel Unthreaded Pipe Flanges

Forged for extra strength, these heavy duty unthreaded flanges can withstand high-pressure applications.

High-Pressure Steel Unthreaded SAE Pipe Flanges

Also known as Code 61 SAE hydraulic flanges.

Extreme-Pressure Steel Unthreaded Pipe Flanges

For excellent strength in extreme-pressure applications, choose these heavy duty Pressure Class 1500 flanges.

Low-Pressure Iron and Steel Threaded Pipe Fittings

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

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.

Aluminum Unthreaded Pipe Flanges

Use these unthreaded flanges in low-pressure applications. Also known as Pressure Class 125 flanges.

Tube Fittings for Stainless Steel Tubing

Quick-Clamp High-Vacuum
Fittings for Stainless Steel Tubing

Also known as KF, QF, and NW fittings, these fittings are for high-vacuum applications, such as vacuum coating and heat treating, leak testing, and analyzing gases.

Ultra-High-Vacuum Flanges and
Fittings for Stainless Steel Tubing

Create access points in ultra-high-vacuum lines or chambers by bolting two same-size flanges together with a copper gasket between them. The flanges’ sharp edges dig into the copper gasket and form an extremely tight seal, which means they handle higher vacuum pressures than other high-vacuum fittings with rubber gaskets.

Bolt-Together High-Vacuum
Fittings for Stainless Steel Tubing

For high-vacuum systems with tube sizes too large for quick-clamp (KF) fittings, choose these bolt-together fittings.

Weld-On Duct Flanges

Weld flanges to equipment to start a run of duct.