When building a pipeline, the length of the pipes used are not always known. By manufacturing the pipe separate from the flange plate, the welders can cut the pipe to length and weld a flange plate in place to join the pipes at any needed length. The plates can also be welded to the pipe on a slight bias, allowing two pipes to be joined that may not be precisely lined up.
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.
Flange plates with chamfers and bevels are used to assist in lining up two pipes which are out of alignment. Plates with a studding outlet are plates that have studs inserted around the plate in place of bolt holes. This type of plate allows the pipes to be joined by sliding one flange plate over the studs on a second flange plate and then nuts are tightened to secure the two.
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.
America Series:Class 150 ,Class 300, Class 600, Class 900A ,Class 1500,Class 2500.
Flange Facing Types
America Series:Flat face(FF),Raised face(RF),Tongue(T),Groove(G),Female(F),Male(M),Ring type joints face(RJ/RTJ)
Europe Series:Type A(Flat Face),Type B(Raised Face),Type C(Tongue),Type D(Groove),Type E(Spigot),Type F(Recess),Type G(O-Ring Spigot),Type H(O-Ring Groove)
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