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Low-Pressure Stainless Steel Threaded Pipe Flanges
Also known as Pressure Class 150 flanges, these are designed for low-pressure pipe 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 within a line.
304 stainless steel flanges have very good corrosion resistance. 316 stainless steel flanges have excellent corrosion resistance. Alloy 20 stainless steel flanges have the best corrosion resistance of all the stainless steel flanges we offer. Alloy 20 stainless steel is also known as Carpenter 20 and resists cracking from stress and corrosion.
Forged flanges have better strength than cast flanges. They are also called ANSI flanges. Cast flanges are also called MSS flanges.
Reducing flanges allow you to transition your system to a smaller pipe size; attach to a flange with a larger pipe size but with the same flange dimensions.
For technical drawings and 3-D models, click on a part number.
- For Use With: Air, Natural Gas, Oil, Steam, Water
- Pressure Class: 150
- Specifications Met:
Alloy 20 flanges: ASME B16.5
All other flanges: ASME B16.5, ASTM A182 - Fittings: Use Class 150 stainless steel
- Pipe Nipples and Pipe: Use Schedule 40 stainless steel
Bolt Hole | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Pipe Size | Flange OD | For Bolt Dia. | Dia. | No. of | Bolt Circle Dia. | Max. Pressure | Max. Steam Pressure | Each | |
304/304L Stainless Steel | |||||||||
NPT | |||||||||
| 1/2 | 3 1/2" | 1/2" | 0.625" | 4 | 2 3/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 3/4 | 3 7/8" | 1/2" | 0.625" | 4 | 2 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 1/4 | 4 5/8" | 1/2" | 0.625" | 4 | 3 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 2 1/2 | 7" | 5/8" | 0.75" | 4 | 5 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 4 | 9" | 5/8" | 0.75" | 8 | 7 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 6 | 11" | 3/4" | 0.875" | 8 | 9 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
316/316L Stainless Steel | |||||||||
NPT | |||||||||
| 1/2 | 3 1/2" | 1/2" | 0.625" | 4 | 2 3/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 3/4 | 3 7/8" | 1/2" | 0.625" | 4 | 2 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 1/4 | 4 5/8" | 1/2" | 0.625" | 4 | 3 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 00000 |
| 2 1/2 | 7" | 5/8" | 0.75" | 4 | 5 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 4 | 9" | 5/8" | 0.75" | 8 | 7 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
| 6 | 11" | 3/4" | 0.875" | 8 | 9 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 00000000 | 000000 |
Alloy 20 Stainless Steel | |||||||||
NPT | |||||||||
| 1/2 | 3 1/2" | 1/2" | 0.62" | 4 | 2 3/8" | 290 psi @ 72° F | 200 psi @ 360° F | 0000000 | 000000 |
| 3/4 | 3 7/8" | 1/2" | 0.62" | 4 | 2 3/4" | 290 psi @ 72° F | 200 psi @ 360° F | 0000000 | 000000 |
| 1 | 4 1/4" | 1/2" | 0.62" | 4 | 3 1/8" | 290 psi @ 72° F | 200 psi @ 360° F | 0000000 | 000000 |
| 1 1/2 | 5" | 1/2" | 0.62" | 4 | 3 7/8" | 290 psi @ 72° F | 200 psi @ 360° F | 0000000 | 000000 |
| 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 290 psi @ 72° F | 200 psi @ 360° F | 0000000 | 000000 |
- For Use With: Air, Natural Gas, Oil, Steam, Water
- Pressure Class: 150
- Specifications Met: ASTM A182, ASME B16.5
- Pipe Nipples and Pipe: Use Schedule 40 stainless steel
- Fittings: Use Class 150 stainless steel
Bolt Hole | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | For Flange Pipe Size | Flange OD | For Bolt Dia. | Dia. | No. of | Bolt Circle Dia. | Max. Pressure | Max. Steam Pressure | Each | |
304/304L Stainless Steel | ||||||||||
NPT | ||||||||||
| 1/2 | 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 0000000 |
| 3/4 | 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 1 | 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 1 | 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 2 | 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
316/316L Stainless Steel | ||||||||||
NPT | ||||||||||
| 1/2 | 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 3/4 | 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 1 | 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 1 | 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 2 | 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
- For Use With: Natural Gas, Steam, Oil, Water, Air
- Pressure Class: 150
- Specifications Met: MSS SP-51, ASTM A351, MSS SP-42
- Pipe Nipples and Pipe: Use Schedule 40 stainless steel
- Fittings: Use Class 150 stainless steel
Bolt Hole | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | Flange OD | For Bolt Dia. | Dia. | No. of | Bolt Circle Dia. | Max. Pressure | Max. Steam Pressure | Each | |
304 Stainless Steel | |||||||||
NPT | |||||||||
| 1/2 | 3 1/2" | 1/2" | 0.625" | 4 | 2 3/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 3/4 | 3 7/8" | 1/2" | 0.625" | 4 | 2 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 1/4 | 4 5/8" | 1/2" | 0.625" | 4 | 3 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 2 1/2 | 7" | 5/8" | 0.75" | 4 | 5 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 4 | 9" | 5/8" | 0.75" | 8 | 7 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
316 Stainless Steel | |||||||||
NPT | |||||||||
| 1/2 | 3 1/2" | 1/2" | 0.625" | 4 | 2 3/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 3/4 | 3 7/8" | 1/2" | 0.625" | 4 | 2 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 | 4 1/4" | 1/2" | 0.625" | 4 | 3 1/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 1/4 | 4 5/8" | 1/2" | 0.625" | 4 | 3 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 00000 |
| 1 1/2 | 5" | 1/2" | 0.625" | 4 | 3 7/8" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 2 | 6" | 5/8" | 0.75" | 4 | 4 3/4" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 2 1/2 | 7" | 5/8" | 0.75" | 4 | 5 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 3 | 7 1/2" | 5/8" | 0.75" | 4 | 6" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
| 4 | 9" | 5/8" | 0.75" | 8 | 7 1/2" | 230 psi @ 72° F | 150 psi @ 360° F | 000000000 | 000000 |
Low-Pressure Stainless Steel Unthreaded Pipe Flanges
Bolt two flat-surface flanges or two raised-surface flanges of the same size together with a
Long-neck weld flanges have a square-cut end for welding directly to a pressure vessel or tank. With a longer neck than butt-weld flanges, they stick out farther from your tank wall for easier access to bolts. These flanges eliminate the need to weld a flange to a length of pipe.
Forged flanges have better strength than cast flanges. 304 stainless steel flanges offer very good corrosion resistance, and 316 stainless steel flanges have excellent corrosion resistance.
For technical drawings and 3-D models, click on a part number.
- For Use With: Air, Natural Gas, Oil, Steam, Water
- Specifications Met: ASME B16.5, ASTM A182
- Certification: Material Certificate with Traceable Lot Number and Test Report
Bolt Hole | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | Construction | Flange OD | Overall Lg. | For Bolt Dia. | Dia. | No. of | Bolt Circle Dia. | Max. Pressure | Max. Steam Pressure | Each | |
304/304L Stainless Steel | |||||||||||
| 1 | Seamless | 4 1/4" | 9" | 1/2" | 0.62" | 4 | 3 1/8" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 0000000 |
| 1 1/2 | Seamless | 5" | 9" | 1/2" | 0.62" | 4 | 3 7/8" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 2 | Seamless | 6" | 9" | 5/8" | 3/4" | 4 | 4 3/4" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 3 | Seamless | 7 1/2" | 12" | 5/8" | 3/4" | 4 | 6" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 4 | Seamless | 9" | 12" | 5/8" | 3/4" | 8 | 7 1/2" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 00000000 |
| 6 | Seamless | 11" | 12" | 3/4" | 0.88" | 8 | 9 1/2" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 00000000 |
316/316L Stainless Steel | |||||||||||
| 1 | Seamless | 4 1/4" | 9" | 1/2" | 0.62" | 4 | 3 1/8" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 1 1/2 | Seamless | 5" | 9" | 1/2" | 0.62" | 4 | 3 7/8" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 2 | Seamless | 6" | 9" | 5/8" | 3/4" | 4 | 4 3/4" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 3 | Seamless | 7 1/2" | 12" | 5/8" | 3/4" | 4 | 6" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 000000 |
| 4 | Seamless | 9" | 12" | 5/8" | 3/4" | 8 | 7 1/2" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 00000000 |
| 6 | Seamless | 11" | 12" | 3/4" | 0.88" | 8 | 9 1/2" | 230 psi @ 72° F | 175 psi @ 300° F | 000000000 | 00000000 |