Steel (Class 300) Pipe Flanges

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	Pipe Size Pipe Size

1/2

3/4

1 1/4

1 1/2

2 1/2

	Connection Style Connection Style

	Type Type


Flange	Adapter

Cap

	Maximum Pressure Maximum Pressure

300 psi @ 72° F

740 psi @ 72° F

Not Rated

	Flanged Connection Surface Flanged Connection Surface


Raised	Flat

	Flange OD Flange OD

	For Use With For Use With

	Number of Bolt Holes Number of Bolt Holes

	Bolt Circle Diameter Bolt Circle Diameter

	Specifications Met Specifications Met

ANSI/ASME

ASTM

	Maximum Steam Pressure Maximum Steam Pressure

300 psi @ 300° F

Not Rated

	Finish Finish

Black Coated

Galvanized

	For Bolt Diameter For Bolt Diameter

	Shape Shape

	Straight
	Cap/Plug

	Bolt Hole Diameter Bolt Hole Diameter

	Dash Size Dash Size

	Socket Depth Socket Depth

	Wall Thickness Wall Thickness

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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.

High-Pressure Steel Unthreaded Pipe Flanges

Forged for extra strength, these heavy duty flanges can withstand high-pressure applications. Bolt two flat-surface flanges or two raised-surface flanges of the same size together with a gasket (sold separately) to create an access point in a pipe line.

Butt-weld flanges are also known as weld-neck flanges; the flange neck has a beveled end that, when flush to pipe, creates a trough for a strong weld.

Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.

Socket-connect flanges have an internal stop that supports the pipe when welding and prevents the pipe from sliding all the way through.

Stub-end flanges are also known as lap-joint flanges; use them with a stub-end straight adapter (not included). The stub-end straight adapter slides into the flange and welds to pipe (not the flange). Since the flange isn’t welded to the pipe, it can be disconnected easily for frequent cleaning and inspecting.

Cap flanges are also known as blind flanges.

For technical drawings and 3-D models, click on a part number.

Butt-Weld Flanges

Front

Raised Surface on Back

For Use With: Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: ASTM A105, ANSI/ASME B16.5
Certification: Material Certificate with Traceable Lot Number and Test Report
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 3000 and Schedule 80 steel

					Bolt Hole
Pipe Size	Dash Size	Wall Thick.	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
300 Class
1/2	08	0.147"	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
3/4	12	0.154"	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1	16	0.179"	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/4	20	0.191"	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/2	24	0.2"	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2	32	0.218"	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2 1/2	40	0.276"	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
3	48	0.3"	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
4	64	0.337"	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
5	__	0.375"	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
6	96	0.432"	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
8	__	0.5"	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
10	__	0.594"	17 1/2"	1.12"	1.12"	16	15 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
12	__	0.688"	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000

Slip-On Weld Flanges

Front

Raised Surface on Back

For Use With: Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: ASTM A105, ANSI/ASME B16.5
Certification: Material Certificate with Traceable Lot Number and Test Report
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 3000 and Schedule 80 steel

				Bolt Hole
Pipe Size	Dash Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
300 Class
1/2	08	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
3/4	12	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1	16	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/4	20	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/2	24	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2	32	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2 1/2	40	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
3	48	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
4	64	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
5	__	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
6	96	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
8	__	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
10	__	17 1/2"	1.12"	1.12"	16	15 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
12	__	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000

Socket-Connect Flanges

Front

Raised Surface on Back

For Use With: Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: See table
Certification: Material Certificate with Traceable Lot Number and Test Report
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 3000 and Schedule 80 steel

				Bolt Hole
Pipe Size	Dash Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material	Specifications Met		Each
300 Class
1/2	08	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	000000
3/4	12	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
1	16	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
1 1/4	20	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
1 1/2	24	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
2	32	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
2 1/2	40	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
3	48	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
4	64	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	00000
5	__	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	000000
6	96	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	000000
8	__	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	ANSI/ASME B16.5, ASTM A105	00000000	000000
10	__	17 1/2"	1.12"	1.12"	16	15 1/4"	Not Rated	Not Rated	Black-Coated Steel	ASTM A105	00000000	000000
12	__	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	Not Rated	Not Rated	Black-Coated Steel	ASTM A105	00000000	000000

Stub-End Flanges

Stub-End Flange (Front)

Flat Surface on Back

For Use With: Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: ASTM A105, ANSI/ASME B16.5
Certification: Material Certificate with Traceable Lot Number and Test Report
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 3000 and Schedule 80 steel

				Bolt Hole
Pipe Size	Dash Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
300 Class
1/2	08	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
3/4	12	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1	16	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/4	20	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/2	24	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2	32	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2 1/2	40	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
3	48	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
4	64	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
5	__	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
6	96	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
8	__	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
10	__	17 1/2"	1.12"	1.12"	16	15 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
12	__	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000

Caps

Front

Raised Surface on Back

For Use With: Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: ASTM A105, ANSI/ASME B16.5
Certification: Material Certificate with Traceable Lot Number and Test Report
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 3000 and Schedule 80 steel

				Bolt Hole
Pipe Size	Dash Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
300 Class
1/2	08	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
3/4	12	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1	16	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/4	20	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/2	24	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2	32	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2 1/2	40	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
3	48	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
4	64	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
5	__	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
6	96	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
8	__	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
10	__	17 1/2"	1.12"	1.12"	16	15 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
12	__	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000

Medium-Pressure Steel Threaded Pipe Flanges

Front

Raised Surface on Back

For Use With: Air, Natural Gas, Oil, Steam, Water
Class: See table
Specifications Met: ASTM A105, ANSI/ASME B16.5
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 300 or Schedule 80 iron and steel

With better strength than our low-pressure steel flanges, these are for use in medium-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. Flanges are also known as Class 300 or Class 600 flanges. Use in noncorrosive environments.

For technical drawings and 3-D models, click on a part number.

			Bolt Hole
Pipe Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
NPT
300 Class
1/2	3 3/4"	1/2"	5/8"	4	2 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
3/4	4 5/8"	5/8"	3/4"	4	3 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1	4 7/8"	5/8"	3/4"	4	3 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/4	5 1/4"	5/8"	3/4"	4	3 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
1 1/2	6 1/8"	3/4"	7/8"	4	4 1/2"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2	6 1/2"	5/8"	3/4"	8	5"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
2 1/2	7 1/2"	3/4"	7/8"	8	5 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
3	8 1/4"	3/4"	7/8"	8	6 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
4	10"	3/4"	7/8"	8	7 7/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	00000
5	11"	3/4"	7/8"	8	9 1/4"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
6	12 1/2"	3/4"	7/8"	12	10 5/8"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000
8	15"	7/8"	1"	12	13"	300 psi @ 72° F	300 psi @ 300° F	Black-Coated Steel	00000000	000000

Medium-Pressure Galvanized Steel Threaded Pipe Flanges

Front

Raised Surface on Back

For Use With: Air, Natural Gas, Steam, Water
Class: 300
Specifications Met: ASTM A123, ASTM A105, ANSI/ASME B16.5
Pipe Nipples and Pipe: Use Schedule 80 steel
Fittings: Use Class 300 iron or steel

A galvanized finish gives these flanges fair corrosion resistance. Also known as Class 300 flanges, they can withstand medium-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line.

For technical drawings and 3-D models, click on a part number.

			Bolt Hole
Pipe Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure		Each
NPT
1/2	3 3/4"	5/8"	0.62"	4	2 5/8"	740 psi @ 72° F	0000000	000000
3/4	4 5/8"	3/4"	3/4"	4	3 1/4"	740 psi @ 72° F	0000000	000000
1	4 7/8"	3/4"	3/4"	4	3 1/2"	740 psi @ 72° F	0000000	00000
1 1/4	5 1/4"	3/4"	3/4"	4	3 7/8"	740 psi @ 72° F	0000000	000000
1 1/2	6 1/8"	7/8"	0.88"	4	4 1/2"	740 psi @ 72° F	0000000	00000
2	6 1/2"	3/4"	3/4"	8	5"	740 psi @ 72° F	0000000	00000
3	8 1/4"	7/8"	0.88"	8	6 5/8"	740 psi @ 72° F	0000000	000000
4	10"	7/8"	0.88"	8	7 7/8"	740 psi @ 72° F	0000000	000000

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