Also known as tapered hub flanges or high hub flanges, weld neck flanges are a specific type of gasket with a protruding ridge and long neck used to connect pipework and provide you with a high-quality seal.
Weld neck flanges, in particular, are a popular choice when you need to relocate stress in the pipes and flanges, decreasing the concentration towards the flange’s bottom end.
RTJ gaskets, which are round fittings and extend beyond the rim of the pipe’s circumference, are high-performing even in the most extreme temperature and pressure applications.
This post explores weld neck flanges in more detail, providing you with all the information you need to make the most informed decision for your pipework application.
Weld Neck Flanges
As the name suggests, weld neck flanges are typically welded, using precision techniques, to pipes to secure their position. They are available in various materials and grades, making them a versatile sealing solution for a wide range of applications.
Recognised for its long-tapered hub, this ring-type joint gasket consists of a protruding rim with holes to enable it to be attached easily and securely to a bolted flange. This design offers excellent structural value, which can be extremely beneficial to specific applications.
Carbon alloy is the most popular material for these flanges, as it continues to perform well even in extreme temperatures.
However, depending on your requirements, these flanges are also available in stainless steel and nickel (make sure to speak to a member of our team to find out more).
Types of weld neck flange
One of the most popular weld flanges is the long weld neck flange. Often used as a nozzle, this type of weld flange has a reduced weld neck diameter, allowing you to carry out flange welding on smaller-diameter pipes.
The internal diameter and overall thickness of these flanges are the same as the size of the tubing, with welding neck flanges typically manufactured to suit the piping system it is to connect to.
Once in position, manufacturers will then weld the pipe to the neck of the flange, which is how we can transfer the stress from the flange to the pipe, reducing the stress concentration from the base of the hub.
This is one of the most commonly used flanges in the piping industry, with the long-tapered hub of the flange matching the pipe wall thickness, increasing strength and integrity.
Available in both raised and flat face configurations, the most common is the standard or extra-heavy bore.
Weld neck flange specifications range from 1/2 “to 96″—again, they are available in all material grades, specification ranges, and sizes.
Typically used in:
- Oil and gas industry
- Valves and pipework
- Pressure vessel joints
- Onshore and offshore petrochemical industry
Benefits of Weld Neck Flanges
- Mechanical strength – can withstand varying loads without deformation occurring.
- High integrity – continues to offer high performance even under the most extreme conditions.
- Available in all sizes – making it suitable for various pipe fittings and applications.
- Choice of face types – available with a raised face, flat face, and RTJ facing.
- There are various classes and grades available, each providing unique benefits and allowing you to find the right material to suit the application specification.
- Provides reinforcement in specific applications – strengthening pipe systems and providing the perfect sealing solution.
- Due to the flange being welded to the pipe it makes this flange suitable for critical applications.
- Weld flanges are also suitable for high-pressure and high-temperature piping systems and offer excellent stress distribution, high loading capability, low erosion rates, and minimal turbulence.
- Due to their high resistance to bending, this ring-type joint gasket helps connect elbows, tees, and even reducers.
Disadvantages of weld neck flanges
While weld neck flanges offer numerous benefits, they do come at a price—and it is this higher price compared to their flange counterparts (make sure to check out our post on `Slip on Flanges` to find out more) that puts them at a slight disadvantage.
Ring Type Joints
With a range of different weld neck flanges available in various materials and all manufactured to set standards, we provide high-quality RTJs and gaskets to suit multiple applications across various industry sectors.
We work with you to identify the required material and grades, external diameter, pressure specifications and agility, raised or flat face, and density to provide the best sealing solution around.
If you have a specific question about your application or you would like to find out more about the flange types we have available for various pipe fittings, please call us today at 01535 274 776 or email your requirements to sales@specialistsealingproducts.co.uk, and a member of our team will be happy to help.
