Forged weld neck flanges designed for direct butt-welding to the pipe, providing a robust flanged connection for demanding pressure, temperature and process applications. Available in carbon steel, low-temperature carbon steel and stainless steel according to applicable standards and project requirements.
A weld neck flange is a forged flange with an integral tapered hub designed to be butt-welded directly to the pipe. The long tapered neck provides a gradual transition from the flange to the pipe.
Weld neck flanges are commonly selected for applications involving higher pressures, elevated temperatures, cyclic loading or demanding process conditions where a robust flange-to-pipe connection is required.
Rhevon can source weld neck flanges in different nominal sizes, pressure classes, facing configurations, bore requirements and material grades according to project specifications.
Supplied according to required NPS, pressure class, facing, bore/schedule, material and applicable standard.
Weld neck flange selection is based on nominal size, pressure class, facing, bore or pipe schedule and material.
The extended tapered hub provides the transition from the flange body to the pipe and is butt-welded directly to the pipe. The bore is selected to correspond with the connected pipe requirements.
The flange bore is matched to the connected pipe outside diameter and wall thickness or schedule. Correct bore selection is important for proper alignment and welding.
Weld neck flanges are available with different pressure classes and facing configurations. The selected class and facing must correspond with the piping class, gasket and mating flange.
Flange material should be selected according to operating temperature, pressure, process media, corrosion requirements and the applicable piping specification.
| Material | Typical Specification | Typical Application |
|---|---|---|
| Carbon Steel | ASTM A105 | General Process · Oil & Gas |
| Low-Temperature Carbon Steel | ASTM A350 LF2 | Low-Temperature Service |
| Stainless Steel 304 | ASTM A182 F304 | Corrosive / Process Service |
| Stainless Steel 316 | ASTM A182 F316 | Corrosive / Process Service |
Class 150 and Class 300 raised-face weld neck flange dimensions, hubs and drilling.
Swipe horizontally to view every column.
| NPS | O(mm) | CRFmin(mm) | P(mm) | n × h(mm) | dbolt(mm) | GRF(mm) | W(mm) | KWN(mm) | Y1WN(mm) |
|---|---|---|---|---|---|---|---|---|---|
| ½ | 88.90 | 9.65 | 60.45 | 4 × 15.75 | 12.70 | 35.05 | 30.23 | 21.34 | 45.97 |
| ¾ | 98.55 | 11.18 | 69.85 | 4 × 15.75 | 12.70 | 42.93 | 38.10 | 26.67 | 50.80 |
| 1 | 107.95 | 12.70 | 79.25 | 4 × 15.75 | 12.70 | 50.80 | 49.28 | 33.53 | 53.85 |
| 1 ¼ | 117.35 | 14.22 | 88.90 | 4 × 15.75 | 12.70 | 63.50 | 58.67 | 42.16 | 55.63 |
| 1 ½ | 127.00 | 15.75 | 98.55 | 4 × 15.75 | 12.70 | 73.15 | 65.02 | 48.26 | 60.45 |
| 2 | 152.40 | 17.53 | 120.65 | 4 × 19.05 | 15.88 | 91.95 | 77.72 | 60.45 | 61.98 |
| 2 ½ | 177.80 | 20.57 | 139.70 | 4 × 19.05 | 15.88 | 104.65 | 90.42 | 73.15 | 68.33 |
| 3 | 190.50 | 22.35 | 152.40 | 4 × 19.05 | 15.88 | 127.00 | 107.95 | 88.90 | 68.33 |
| 3 ½ | 215.90 | 22.35 | 177.80 | 8 × 19.05 | 15.88 | 139.70 | 122.17 | 101.60 | 69.85 |
| 4 | 228.60 | 22.35 | 190.50 | 8 × 19.05 | 15.88 | 157.23 | 134.87 | 114.30 | 74.68 |
| 5 | 254.00 | 22.35 | 215.90 | 8 × 22.35 | 19.05 | 185.67 | 163.58 | 141.22 | 87.38 |
| 6 | 279.40 | 23.88 | 241.30 | 8 × 22.35 | 19.05 | 215.90 | 192.02 | 168.40 | 87.38 |
| 8 | 342.90 | 26.92 | 298.45 | 8 × 22.35 | 19.05 | 269.75 | 246.13 | 219.20 | 100.08 |
Swipe horizontally to view every column.
| NPS | O(mm) | CRFmin(mm) | P(mm) | n × h(mm) | dbolt(mm) | GRF(mm) | W(mm) | KWN(mm) | Y1WN(mm) |
|---|---|---|---|---|---|---|---|---|---|
| ½ | 95.25 | 12.70 | 66.55 | 4 × 16.00 | 12.70 | 35.05 | 38.10 | 21.34 | 50.80 |
| ¾ | 117.35 | 14.22 | 82.55 | 4 × 19.05 | 15.88 | 42.93 | 47.75 | 26.67 | 55.63 |
| 1 | 123.95 | 15.75 | 88.90 | 4 × 19.05 | 15.88 | 50.80 | 53.85 | 33.53 | 60.45 |
| 1 ¼ | 133.35 | 17.53 | 98.55 | 4 × 19.05 | 15.88 | 63.50 | 63.50 | 42.16 | 63.50 |
| 1 ½ | 155.45 | 19.05 | 114.30 | 4 × 22.35 | 19.05 | 73.15 | 69.85 | 48.26 | 66.80 |
| 2 | 165.10 | 20.57 | 127.00 | 8 × 19.05 | 15.88 | 91.95 | 84.07 | 60.45 | 68.33 |
| 2 ½ | 190.50 | 23.88 | 149.35 | 8 × 22.35 | 19.05 | 104.65 | 100.08 | 73.15 | 74.68 |
| 3 | 209.55 | 26.92 | 168.15 | 8 × 22.35 | 19.05 | 127.00 | 117.35 | 88.90 | 77.72 |
| 3 ½ | 228.60 | 28.45 | 184.15 | 8 × 22.35 | 19.05 | 139.70 | 133.35 | 101.60 | 79.50 |
| 4 | 254.00 | 30.23 | 200.15 | 8 × 22.35 | 19.05 | 157.23 | 146.05 | 114.30 | 84.33 |
| 5 | 279.40 | 33.27 | 234.95 | 8 × 22.35 | 19.05 | 185.67 | 177.80 | 141.22 | 97.03 |
| 6 | 317.50 | 35.05 | 269.75 | 12 × 22.35 | 19.05 | 215.90 | 206.25 | 168.40 | 97.03 |
| 8 | 381.00 | 39.62 | 330.20 | 12 × 25.40 | 22.23 | 269.75 | 260.35 | 219.20 | 109.73 |
K is the outside diameter at the weld end, not the bore. State the required bore or pipe schedule.
Y1 excludes the approximately 1.6 mm raised face. Confirm hub pattern, bore, weld preparation and tolerances on the supplier drawing.
Flange requirements can be reviewed against the applicable material specification, dimensional standard, pressure class, facing, bore and purchase order requirements before supply.
Common questions about weld neck flange specifications, pressure classes, facing, bore and applications.
A weld neck flange is a forged flange with an integral tapered hub that is butt-welded directly to the pipe. Its design provides a gradual transition between the pipe and flange and is commonly used for demanding piping applications.
The butt-welded connection and tapered hub provide a robust transition between the pipe and flange. This makes weld neck flanges suitable for many high-pressure, high-temperature and cyclic-service applications when correctly selected for the service conditions.
The bore must be compatible with the connected pipe outside diameter and wall thickness or schedule. Correct bore selection helps achieve proper fit-up, alignment and welding at the pipe-to-flange joint.
Provide the NPS, pressure class, facing type, material grade, pipe schedule or bore requirement, quantity and applicable flange standard. Project specifications or drawings should also be provided where applicable.
Yes. Weld neck flanges can be included in a mixed piping requirement together with compatible gaskets, studs, nuts, washers and other piping components. This allows the complete flange-joint requirement to be sourced together.
Share the NPS, pressure class, facing, material, pipe schedule or bore, quantity and applicable specification. Mixed piping component requirements are also welcome.
