What is a flange

Common types of flanges
1. Classified by connection method:
-Slip on Flange: Welded on the outer diameter of the pipeline, low cost, suitable for low pressure.
-Weld Neck Flange: With a neck, it is welded to the pipeline and is resistant to high pressure and high temperature.
-Threaded Flange: Connected by threads without welding, commonly used for small-diameter pipelines.
-Socket Weld Flange: The pipe is inserted into the inner hole of the flange and welded, with high strength.
-Lap Joint Flange: It is flexibly connected to the pipe end for easy alignment of bolt holes.
2. Classified by sealing surface:
-Flat Face (FF): The sealing surface is flat and used for low pressure.
-Raised Face (RF): The sealing surface is slightly raised and commonly used for medium to high pressure.
-Ring Joint Face (RTJ): with an annular groove, used for high pressure and high temperature (such as petrochemical industry).
Standard for flanges
Different countries/industries have different standards, commonly including:
-National Standard (GB/T), American Standard (ANSI/ASME), European Standard (EN), Japanese Standard (JIS), German Standard (DIN), etc.
The material of the flange
Choose according to the usage environment:
-Carbon steel (Q235, A105): universal type, low cost.
-Stainless steel (304, 316): corrosion-resistant, used in food and chemical industries.
-Alloy steel (16Mn, CrMo): resistant to high pressure and high temperature.
-Plastic flanges (PVC, PP): used for corrosive media.
Application scenarios
-Oil/gas pipelines, chemical plants, water supply systems, ship pipelines, electrical equipment, etc.