Welding neck flanges

The heavy welding neck flanges are also named heavy WN flanges, which are

hot formed from a circular section of steel plate having a very small co-axial

hole in the flange center. The steel around the hole is shear-formed downward

and outward by a tapered die plug which is forced by the small hole forming an

integral neck on the weld neck flange. A supporting ring die is radiused at its

inner corner to form a suitable fillet radius at the junction of the neck with

the flange proper. A suitable pre-forming or post-forming operation may be

required to compensate for any deflection in the work piece out of planar

configuration.