1. SLIP-ON FLANGE
: it has a low hub because the pipe slips into the flange prior to weling. It is welded both inside and ourside to provide sufficient strength and prevent leakage. Slip-on flanges are all bored slightly larger than the OD of the matching pipe.
2. WELIDING NECK FLANGE
: it is normally referred to as the "hign hub" flanges. it is designed to transfer stresses to the pipe, thereby reducing high stress concentrations at the base of the flanges.
3. SOCKET WELDING FLANGE
: it is similar to a slip-on flange except it has a bore and a counterbore dimension. the counterbore is slightly lareger than the OD of the matching pipe. the diameter of the smaller bore is the same as the ID of the matching pipe.
4. THREADED(SCREWED) FLANGE
: it is similar to the slip-on flange, but the bore is threaded. it can be assembled without welding.
5. BLIND FLANGE
: it is a flange without a bore. it is used to close off the ends of a piping system and/or a pressure vessel opening.