Stainless Steel Weld Neck Flanges are designed to be joined to a piping system by butt welding. Weld neck flanges is relatively expensive because of its long neck, but is preferred for high stress applications. 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 butt weld provides important reinforcement of the metal flange. The bore of the stainless steel weld neck flanges matches the bore of the pipe, reducing turbulence and erosion.