Weld neck pipe flanges attach to the pipe by welding the pipe to the neck of the pipe flange. This allows for the transfer of stress from the weld neck pipe flanges to the pipe itself.

This also reduces high stress concentration at the base of the hub of the weld neck pipe flanges. Weld neck pipe flanges are often used for high pressure applications. The inside diameter of a weld neck pipe flange is machined to match the inside diameter of the pipe. 

Weld Neck Pipe flanges with a hub have published specifications that range from 1/2" thru 96". HDFCO provides Weld Neck pipe flanges in all material grades, specifications and sizes