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Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.
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Aluminum Unthreaded Pipe Flanges
Also known as Pressure Class 125 flanges, these are for use in low-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. Flanges are aluminum, which is lightweight with good corrosion resistance. Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides. Reducing flanges let you 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.
Slip-On Weld Flanges
Front
Flat Surface on Back
- For Use With: Air, Oil, Water
- Pressure Class: 125
- Specifications Met: ASME B16.1
- Fittings: Use Schedule 40 aluminum
- Pipe: Use Schedule 40 aluminum
Bolt Hole | ||||||||
|---|---|---|---|---|---|---|---|---|
Pipe Size | Flange OD | For Bolt Dia. | Dia. | No. of | Bolt Circle Dia. | Max. Pressure | Each | |
| 1/2 | 3 1/2" | 1/2" | 5/8" | 4 | 2 3/8" | 150 psi @ 72° F | 00000000 | 000000 |
| 3/4 | 3 7/8" | 1/2" | 5/8" | 4 | 2 3/4" | 150 psi @ 72° F | 00000000 | 00000 |
| 1 | 4 1/4" | 1/2" | 5/8" | 4 | 3 1/8" | 150 psi @ 72° F | 000000000 | 00000 |
| 1 1/4 | 4 5/8" | 1/2" | 5/8" | 4 | 3 1/2" | 150 psi @ 72° F | 000000000 | 00000 |
| 1 1/2 | 5" | 1/2" | 5/8" | 4 | 3 7/8" | 150 psi @ 72° F | 000000000 | 00000 |
| 2 | 6" | 5/8" | 3/4" | 4 | 4 3/4" | 150 psi @ 72° F | 000000000 | 00000 |
| 2 1/2 | 7" | 5/8" | 3/4" | 4 | 5 1/2" | 150 psi @ 72° F | 000000000 | 00000 |
| 3 | 7 1/2" | 5/8" | 3/4" | 4 | 6" | 150 psi @ 72° F | 000000000 | 00000 |
| 4 | 9" | 5/8" | 3/4" | 8 | 7 1/2" | 150 psi @ 72° F | 000000000 | 000000 |
| 6 | 11" | 3/4" | 7/8" | 8 | 9 1/2" | 150 psi @ 72° F | 000000000 | 000000 |
| 8 | 13 1/2" | 3/4" | 7/8" | 8 | 11 3/4" | 150 psi @ 72° F | 000000000 | 000000 |
Slip-On Weld Reducing Flanges
Front
Flat Surface on Back
- For Use With: Air, Oil, Water
- Pressure Class: 125
- Specifications Met: ASME B16.1
- Fittings: Use Schedule 40 aluminum
- Pipe: Use Schedule 40 aluminum