Butt weld flange is also called necked butt weld flange (WN), and in some places it is also called high neck flange. Butt weld flange is one of our common pipe fittings, which refers to a flange with a round pipe neck and transition and connected with a pipe butt weld. Butt weld flange is not easy to deform, good sealing, widely used, has corresponding rigidity and elasticity requirements and reasonable butt weld thinning transition, weld is far from the joint surface and The joint surface is protected from deformation by welding temperature. The sealing surface of the butt weld flange is generally a protruding surface (RF), concave-convex type (FM concave-convex M), tongue-and-groove type is not commonly used. The butt welding flange is suitable for pipelines with large pressure or temperature fluctuations or pipelines with high temperature, high pressure and low temperature, and is also used in pipelines transporting oil, chemicals, flammable and explosive media. butt welding flange and pipe connection using welding method for butt welding, welding and similar pipe welding, generally small pipe diameter using argon arc welding priming, manual welding cover, large pipe diameter using double-sided welding.
Flat weld flange is also called plate flat weld flange (PL), flat weld flange because of simple structure manufacturing, material saving, so the price is relatively cheap. However, the rigidity and sealing are not as good as the neck butt weld flange. The flat weld flange is welded by inserting the pipe into the flange. Due to poor rigidity, flat weld flanges should not be used in flammable, explosive and high vacuum requirements for chemical process piping systems and high and extremely hazardous occasions. Flat welded flanges are widely used in connecting medium and low pressure vessels and pipes. The flat weld flange is suitable for the connection of fluid pipelines with a nominal pressure not exceeding PN2.5MPa. The sealing surface of the flat weld flange can be made in three types: lubricated type, concave-convex type and tongue and groove type. RF surface flat weld flange has the largest application. It is mainly used when the medium conditions are relatively relaxed, such as low-pressure vessels, water supply pipe networks, unpurified compressed air, low-pressure circulating water, etc.
