Weld Neck Flange

Weld neck flanges

Weld neck flanges also known as a high-hub flange and tapered hub flange, are the most common type of flange, featuring an extension with a weld bevel at the end. This type of flange is designed to butt weld directly to pipes, providing a superior and relatively seamless connection. In larger sizes and higher pressure classes, this is almost exclusively the flange connection used. If only one bored flange style wereavailable in modern applications, the weld neck would be the preferred choice.

Our Supply Range

Material: Carbon, Alloy and Stainless Steel
Standards: ANSI, MSS, AWWA, DIN, UNI, JIS, BS, SABS, EN1092, GOST, also we can produce according to customers’ drawings.Sizes: 1/2'' to 24'', Customized up to 96''
Pressure Ratings: Class 150 to 2500
Face Type: RF, FF, RTJ

Two Shapes of Welding Neck Flange

1. Long Welding Neck: Simplified called as LWN flange, also known as nozzle flanges or “long neck” flanges, these items were designed specifically with the pressure vessel and tank fabrication industry in mind. They are usually made as a one-piece construction with the intention of replacing a standard weld neck and pipe weld combination. The lack of a necessary weld connection is the defining feature of this flange style.

2. Reducing Weld Neck Flange: As it's name it is like a combination of pipe reducer and flange, so it could be welded to a smaller pipe directly.

Face Type

Welding neck flanges come with different face types that determine how they interface with gaskets and other components. Here are the common face types for welding neck flanges:

1. RF (Raised Face): This type features a raised area around the flange face. The raised section provides a contact area for the gasket, ensuring a better seal and accommodating higher pressures. It is the most commonly used face type.

2. FF (Flat Face): In this design, the flange surface is flat and level with the pipe’s end. The gasket provides the seal, and this type is generally used in applications with lower pressures and where the gasket is crucial for sealing.

3. RTJ (Ring Type Joint): This flange type includes a groove for a metal ring gasket. The RTJ face is designed to handle very high pressures and temperatures, making it suitable for critical applications where a robust and reliable seal is necessary.

Each face type is chosen based on the pressure, temperature, and sealing requirements of the application.

Standards Referred for WN flange

Material Standards

ASTM A105/N For carbon steel weld neck flange

ASTM A182 F11, F22 for alloy steel

ASTM A182 F304 / F304L, F316 / F316L for stainless steel weld neck flange.

Manufacturing Standards: 

ANSI, MSS, AWWA, DIN, UNI, JIS, BS, SABS, EN1092, GOST, also we can produce according to customers’ drawings.

FAQ about Weld Neck Flange

1. What is a weld neck flange?

   A weld neck flange is a type of flange with a long neck and a tapered section that is welded directly to a pipe, providing a strong, seamless connection.

2. What are the advantages of using weld neck flanges?

   They offer a high strength, smooth transition between the pipe and flange, excellent for high-pressure and high-temperature applications, and help to minimize stress concentrations.

3. What materials are weld neck flanges typically made from?

   They are commonly made from carbon steel, stainless steel, alloy steel, and other metals depending on the application's requirements.

4. How do I choose the right weld neck flange?

   Consider factors such as the pipe size, pressure rating, temperature, and material compatibility. The flange should match the specifications of the connected pipe and system.

5. What are the different face types available for weld neck flanges?

   Weld neck flanges can have Raised Face (RF), Flat Face (FF), or Ring Type Joint (RTJ) faces, each suited for different sealing requirements and pressure conditions.

6. Can weld neck flanges be used for all pipe sizes and pressures?**

   They are versatile and used across a wide range of sizes and pressures, but the design and material must be suitable for the specific application and operating conditions.

7. How is a weld neck flange installed?

   It is welded to the pipe end, and then the flange is aligned and bolted to a matching flange or component.

8. Are weld neck flanges suitable for all types of fluids and gases?

   Yes, they can handle various fluids and gases, but the material and flange design must be compatible with the specific media being transported.

9. What maintenance is required for weld neck flanges?

   Regular inspection for corrosion, leaks, and wear is important. Ensure proper alignment and tightening of bolts to maintain a good seal.