Weld Neck Flange

Weld Neck Flange, (also known as a tapered hub or high-hub flange) is engineered for piping systems operating under severe conditions, including high pressure, extreme temperatures, and fluctuating loads. Its design features a long, tapered hub that is butt-welded directly to the pipe. This structure allows stress to transfer smoothly from the flange to the pipe wall, preventing stress concentration and significantly improving the joint’s fatigue life.

Forged for maximum durability, these WN flanges include a protruding neck and a raised face that ensures a leak-proof seal when bolted. Because of their superior structural integrity, Weld Neck Flanges are the standard choice for critical applications in the oil and gas, petrochemical, and power generation sectors.

Welding neck flange benefits include:

• Excellent stress distribution along the tapered hub.
• Unrestricted flow with a low pressure drop across the valve (low delta P).
• High cyclical loading capability.
• Causes minimal turbulence.
• Low erosion rates.
• Means for a direct connection to elbows, tees, or reducers.
• On larger diameter flanges, there is more available space to perform non-destructive testing on the weld (difficult on some flange designs due to the location of the weld).
• High resistance to bending moments due to the long hub.

Click here to know Weld Neck Flanges vs. Slip-On Flange

Material:

Welding neck flanges come in various materials, chosen to meet industry standards and application needs. The material used depends on factors like temperature, pressure, and the type of fluids being transported. Common materials for weld neck flanges include:

• Carbon steel (ASTM A105)
• Alloy steel (ASTM A182, with variations like F11 and F22)
• Stainless steel (ASTM A182, including grades like F304/F304L, F316/F316L)
• Duplex steel (UNS S31803)
• Nickel alloys (e.g., Inconel 600 and 625, Hastelloy C22 and C276)

The material choice ensures that the weld neck flange can handle the specific operating conditions while maintaining its strength.

Dimensions and Sizes

Weld neck flanges come in various sizes to fit pipes of different diameters. Common dimensions for weld neck flanges under ASME B16.5 (Class 150) include:

• 1/2″ NPS with an inside diameter of 0.62″ and an outside diameter of 3.50″.
• 3/4″ NPS with an inside diameter of 0.82″ and an outside diameter of 3.88″.
• 1″ NPS with an inside diameter of 1.05″ and an outside diameter of 4.25″.
• 2″ NPS with an inside diameter of 2.07″ and an outside diameter of 6.00″.
• 5″ NPS with an inside diameter of 5.05″ and an outside diameter of 10.00″.
• 6″ NPS with an inside diameter of 6.065″ and an outside diameter of 11.00″.
• 10″ NPS with an inside diameter of 10.02″ and an outside diameter of 16.00″.
• 20″ NPS with an inside diameter of 19.25″ and an outside diameter of 27.50″.
• 24″ NPS with an inside diameter of 23.25″ and an outside diameter of 32.00″.
  Custom sizing options are also available for larger outer diameters up to 60″.

Pressure classes range from Class 150 to Class 2500, with flange face types including RF (Raised Face) and RTJ (Ring Type Joint).

Application:

WN steel pipe flanges find extensive use in industries such as oil and gas, petrochemical, chemical processing, power generation, and shipbuilding. They are commonly employed in pipeline systems, connecting pipes, valves, and equipment. With their excellent sealing capabilities and structural integrity, WN flanges offer reliable performance in demanding environments.

Some common scenarios include:

• High-pressure systems
• Wide temperature and pressure fluctuations
• High-temperature environments
• Handling volatile and hazardous fluids
• Working in very cold conditions

Inspection:

We maintain strict quality control measures throughout the manufacturing process to ensure that our WN steel pipe flanges meet the highest standards. Each flange undergoes rigorous inspection and testing, including dimensional checks, visual inspection, material analysis, and hydrostatic testing.

Delivery:

We strive to provide efficient and prompt delivery of our products. Our logistics team ensures safe packaging and timely shipment to your desired location, both domestically and internationally. Expedited delivery options are available upon request.

Note:

For detailed product specifications and customization options, please refer to our product catalog or contact our sales team for further assistance.

Our advantage 

1. 30,000-ton production capacity guarantee | Stable supply of large-scale project needs
2. Dual-standard certified steel pipes | API 5L + EN 10219 dual compliance assurance
3. Precision Cutting Services | Ready-to-use pipe end treatments
4. Oil and Gas Project Logistics System | Exclusive Shipping Solutions Covering Central Asia/Middle East