Flange plates make it possible to remove a section of pipe or to add onto a pipeline with ease. Without the flange plates, the pipes would require cutting and welding in order to be separated or added onto. This would be much more expensive and the pipe line would be out of service for a greater length of time.
Flange plate designs are uniform in any given size regardless of materials used to create them. This allows a 6-inch (15 cm) black pipe flange to mate perfectly with a 6-inch stainless steel flange. The flange plates will have a serrated finish on the inside mating surface, which allows the plate to seat into the gasket material. This ensures a perfect seal between two joining pipes.
There are many different styles of flange plates that are used for different purposes. The blind plate acts as a cover or cap for a pipe and is used to seal or block off a pipe. The slip-on style of plate allows the plate to be slid onto a pipe and then welded in place. Using the socket weld-style of plate on the ends of two pipes allow them to be easily connected and disconnected.
Carbon steel: ASTM A105,ASTM A105N,GB 20,C22.8.
Alloy steel: ASTM/ASME A182 F1-F12-F11-F22- F5-F9- F91
Stainless steel: ASTM/ASME A182 F304-304L-304H-304LN-304N
ASTM/ASME A182 F316-316L-316H-316LN-316N-316Ti
ASTM/ASME A182 F321-321H, F347-347H
Low temperature steel: ASTM/ASME A350 LF2.
High performance steel: ASTM/ASME A694 F42 , F52, F56, F60, F65, F70