This flange is circumferencially welded into the system at its neck. It is designed to be joined to a piping system by buttwelding. It is relatively expensive because of its long neck, but is preferred for high stress applications. The neck, or hub transmits stresses to the base of the hub to the wall thickness at the butt weld, provide important reinforcement of the flange. The bore of the flange matches the bore of the pipe, reducing turbulence and erosion. The weld-neck is therefore favoured in critical applications.