Flange is a shaft and shaft connected parts, used for the connection between the pipe ends.
Integral flange (IF), threaded flange (TH), plate flat-welded flange (PL), butt-welded flange with a neck (WN), flat-welded flange with a neck (SO), socket welded flange (SW), butt-welded ring loose flange (PJ/SE), flat-welded ring loose flange (PJ/RJ), lining flange cover (BL(S)), flange cover (BL).
Plate - welded flanges are the most common type of flanges
Because of the good comprehensive performance of plate flat welding flange, it is widely used in the chemical industry, construction, water supply, drainage, petroleum, light and heavy industry, refrigeration, sanitation, plumbing, fire protection, electric power, aerospace, shipbuilding, and other basic projects.
But the rigidity is poor, so it can not be used for supply and demand, flammable, explosive, and higher vacuum requirements of the chemical process piping system and high, extreme harm occasions.
Sealing surface types are FF and RF.
Butt-welded flange with a neck (WN)
WN Flanges are the flange that has a tapered neck and butt-welded with cylinder or pipe.
Because of the transition structure of the cone neck and the butt welding connection type, the strength and stiffness of the flange are strengthened. And the sealing performance is much better than the flat-welded flange.
Suitable for high pressure, high temperature, or high requirements for sealing occasions
The disadvantage is it needs to be forged, So it has a high cost of material and forging.
Flat-welded flange with a neck(SO)
The full name of the neck flat welded flange is the neck flat welded steel pipe flange. It is a flange that extends steel pipe and pipe fittings into the flange and connects with equipment or pipeline through fillet weld.
Normal sealing surface：Face (RF), Concave (FM), Convex (M), Tenon (T), Groove (G), Full plane (FF).
Advantages: SO flange is also a flat welding flange. It has a short neck, thus improving the strength of the flange and improve the bearing strength of the flange.So it can be used in a higher pressure pipeline.
Disadvantages: the cost of SO flange is higher than the PL type. And due to the characteristics of its shape, it is easier to knock against in transportation.