A flange is an external or internal rib, or rim (lip), for strength, as the flange of an iron beam or Ibeam (or a T-beam); or for a guide, as the flange of a train wheel; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc, or on the lens mount of a camera. Thus a flanged rail is a rail with a flange on one side to keep wheels, etc., from running off. The term "flange" is also used for a kind of tool used to form flanges. Weld Neck Flanges are drilled(machined) with the wall thickness of the flange having the same dimensions of the matching pipe, the lighter the pipe is, the larger the bore, conversely, the heavier the pipe, the small the bore, they are normally used for highpressure, cold or hot temperature.