Forged Welding Neck Flange is designed for critical piping systems requiring high structural strength and long service life. The flange features a long tapered hub that allows smooth stress transition from flange to pipe, reducing fatigue risk under cyclic loading and thermal expansion conditions.
Welding neck flanges are widely used in high pressure and high temperature environments such as oil and gas transmission pipelines, refinery processing units, offshore platforms and power generation plants.
The butt welding connection provides superior sealing reliability and vibration resistance compared with slip on or plate flanges.
Controlled forging process ensures dense grain structure and enhanced pressure resistance.
The tapered hub design allows gradual stress flow from flange ring to pipe wall, reducing stress concentration at the weld zone.
Benefits include:
This structural feature makes welding neck flange the preferred choice for critical pipeline systems.
Correct welding ensures long term operational safety.
| NPS | Outside Diameter | Hub Height | Thickness | Bolt Circle | Bolt Hole |
|---|---|---|---|---|---|
| 1/2 | 90 mm | 38 mm | 11 mm | 60 mm | 4-16 |
| 3/4 | 100 mm | 38 mm | 13 mm | 70 mm | 4-16 |
| 1 | 110 mm | 41 mm | 14 mm | 80 mm | 4-16 |
| 1-1/2 | 125 mm | 52 mm | 16 mm | 98 mm | 4-19 |
| 2 | 150 mm | 64 mm | 19 mm | 120 mm | 4-19 |
| 3 | 190 mm | 76 mm | 24 mm | 152 mm | 4-22 |
Full tables available for Class 300 / 600 / 900 / 1500 / 2500.
| Feature | Welding Neck | Slip On | Plate |
|---|---|---|---|
| Pressure Rating | Very High | Medium | Low-Medium |
| Strength | Maximum | Medium | Medium |
| Cost | High | Medium | Low |
| Installation | Butt Weld | Fillet Weld | Fillet Weld |
| Application | Critical Systems | Process Lines | General Pipeline |
Welding neck flanges are preferred where safety and reliability are primary considerations.
Manufactured according to:
Pressure Class:
Size Range:
ASTM A105
A350 LF2
A694 F52 / F60
F304 / 304L
F316 / 316L
F321
F904L
F11
F22
F91
S31803
S32205
S32750
Inconel 625
Inconel 825
Monel 400
Hastelloy C276
Forged welding neck flanges supplied for:
(Project references available upon request.)
Why choose welding neck flange for high pressure systems?
Because its tapered hub design reduces stress concentration and improves fatigue resistance.
Is full penetration welding required?
Yes, butt welding is recommended for critical services.
Can large diameter WN flange be customized?
Yes, customized production up to large NPS sizes is supported.
