Welding neck flanges are connected to pipelines by welding grooves on necks with pipes. The welding property and corrosion resistance of WN flanges are relatively better than
slip on flanges. For a welding neck flange, it has to be welded from both sides. Welding neck flanges are generally used for connecting pipelines that bearing medium or high pressures. The bearing pressure of a welding neck flange is at least PN 2.5MPa. The application of WN flanges is able to decrease stress concentration.
According to different bearing-pressures of welding neck flanges, the gaskets of them are made from diverse materials. There are asbestos gaskets for weld neck flanges that bearing low or high pressures, as well as metallic gaskets.
In actual production and research work, different technologies and methods are accepted. On the basis of this, changes might occur concerning detail elements of welding neck flanges. Manufacturers usually added some certain elements to improve the performance and value of flanges.
WN flanges are easy to use and can bear relatively high pressures. In pipeline systems, it is universal to connect pipes with welding neck flanges. In residential pipeline systems, pipes usually have small diameters and suffer from low pressures. Thus, welding neck flanges are rarely applied here. Nevertheless, equipment or pipelines connected with WN flanges and others would be found everywhere in a boiler room or a work site.
Strong points of welding neck flanges:
1. Connecting pipelines and maintaining the sealing performance of pipes.
2. Be convenient to change of certain pipes.
3. Be convenient to tear down and exam the pipelines.
4. Be convenient to block certain pipes.