There are three types of forged flange sealing surface: flat sealing surface, suitable for occasions with low pressure and non-toxic media; concave-convex sealing surface, suitable for occasions with slightly higher pressure; tongue and groove sealing surface, suitable for flammable, Explosive, toxic media and high pressure occasions. The gasket is a circular ring made of a material that can produce plastic deformation and has a certain strength.

Most of the gaskets are cut from non-metallic plates or made by professional factories according to the specified size. The materials are asbestos rubber sheets, asbestos sheets, polyethylene sheets, etc.; thin metal sheets are also used to wrap non-metallic materials such as asbestos There is also a spiral wound gasket made of thin steel tape and asbestos tape. Ordinary rubber gaskets are suitable for occasions where the temperature is lower than 120°C; asbestos rubber gaskets are suitable for occasions where the temperature of water vapor is lower than 450°C, the temperature of oil is lower than 350°C, and the pressure is lower than 5MPa, and it is generally corrosive. The more commonly used medium is acid-resistant asbestos board.

In high-pressure equipment and pipelines, metal gaskets of lens type or other shapes made of copper, aluminum, No. 10 steel, and stainless steel are used. The contact width between the high pressure gasket and the sealing surface is very narrow, and the processing finish of the sealing surface and the gasket is high