Classification of flanges
pipeline flange can be divided into five basic types according to the connection mode with the pipe: flat welding flange, butt welding flange, threaded flange, socket welding flange, and loose sleeve flange. There are many types of sealing surface of flange, generally commonly used as convex surface (RF), concave surface (FM), concave and convex surface (MFM), mortise and groove surface (TG), plane (FF), ring connection surface (RJ). The butt welding steel flange is used for the matching welding of the flange and the pipe, and its structure is reasonable, with large strength and stiffness, which can withstand high temperature and high pressure, repeated bending and temperature fluctuation, with reliable sealing, and the butt welding flange with a nominal pressure of 0.25~2.5MPa adopts concave and convex sealing surface. Because stainless steel has good corrosion resistance, it keeps structural components with engineering integrity. Chromium-containing stainless steel also integrates mechanical strength and high extensibility, which is easy to process and manufacture components, which can meet the needs of architects and structural design staff. Stainless steel flange in order to prevent corrosion due to the flange heating, welding current should not be too large, about 20% less than carbon steel welding rod, the arc should not be too long, between the layer is fast cold, with narrow welding path is appropriate. When the stainless steel flange fittings are welded, the carbide is discharged by repeated heating to reduce corrosion resistance and mechanical properties. Another stainless steel with flat neck welding flange and with the neck of welding flange cost difference, because the use of different occasions, with the weight of the neck flat welding flange is relatively light, the price is cheaper, with the neck of welding flange process is relatively complex point, the weight is heavy, so the price is higher than with the neck flat welding flange, there is the lathe processing, processing cost is not the same.
