Neck flat welding flanges are the same as plate flat welding flanges. Steel pipes, pipe fittings, etc. are extended into the flange to be connected with equipment or pipelines through fillet welds.
The sealing surface forms include: raised surface (RF), concave surface (FM), convex surface (M), tenon surface (T), groove surface (G), full plane (FF), ring connection surface (RJ)..... .
American Standard Flange
Japanese standard flange
German standard flange
Ministry of Chemical Industry Standards
Pressure vessel flange
Butt welding pipe fittings