Class 300 Pipe Flanges | McMaster-Carr

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313 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.

Medium-Pressure Steel Threaded Pipe Flanges

With better strength than our low-pressure steel flanges, these are for use in medium-pressure applications.

Medium-Pressure Galvanized
Steel Threaded Pipe Flanges

Also known as Pressure Class 300 flanges, these medium-pressure flanges have a galvanized finish for fair corrosion resistance.

High-Pressure Steel Unthreaded Pipe Flanges

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

Thick-Wall Butt-Weld Steel Unthreaded Pipe Fittings

With thicker, stronger walls than our standard-wall butt-weld pipe fittings, these fittings stand up to your high strength applications.

Steel Bleed Rings

Access the inside of lines, so you can vent pressure, drain liquid, or take samples. Made of steel, these bleed rings should be used in dry environments to prevent rusting.

High-Pressure Stainless Steel
Unthreaded Pipe Flanges

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

Stainless Steel Bleed Rings

Create an access point in systems where corrosion is a concern. Made of stainless steel, these bleed rings resist rusting.

High-Pressure Stainless
Steel Threaded Pipe Flanges

Also known as ANSI flanges.

Flow-Control Flange Unions

Measure, throttle, and regulate the flow of liquids and gases in your line by adding an orifice plate to these unions.

Hex Head Screw and Nut Kits for Pipe Flanges

Stainless Steel Hex Screw
and Nut Kits for Pipe Flanges

Join standard-sized stainless steel and aluminum pipe flanges in corrosive conditions.

Stainless Steel Heavy Hex Screw
and Nut Kits for Pipe Flanges

Connect standard-size stainless steel pipe flanges with these kits—they come with screws and nuts in the right size and number to match the bolt holes. The screw heads are 10% wider than a standard hex head, so they spread force over a larger area, and you can tighten with more torque.

Steel Hex Screw and Nut Kits for Pipe Flanges

Connect standard-sized steel and cast iron pipe flanges. These kits come with the right size and number of screws and nuts for the bolt holes in each pipe size.

Steel Heavy Hex Screw and
Nut Kits for Pipe Flanges

Join standard-sized steel and cast iron pipe flanges—these kits come with the screws and nuts in the right size and number to match the bolt holes. The screw heads and nuts are 10% wider than standard hex fasteners, so they spread force over a larger area, and you can tighten with more torque.