Weld Neck Flanges have a long tapered hub and are often used for high pressure applications. These flanges are designed to be joined to a Piping system by Bun Welding. The Neck, or Hub, transmits stresses to the Pipe, reducing stress concentrations at the base of the Flange.

The gradual transition of thickness from the base of the Hub to the wall thickness at the Bun Weld, provides important reinforcement of the Flange. The bore of the Flange matches the bore of the Pipe, reducing turbulence and erosion. These flanges are ideal for extreme fluctuations of temperature and in environments where there may be high pressure or high temperature being dealt with.