Flange connection is an important connection method for pipeline construction. The flange is divided into threaded connection (wire connection) flange and welding flange. Low-pressure small-diameter wire flanges, high-pressure and low-pressure large-diameters both use welding flanges. The thickness of flanges and the diameter and number of connecting bolts are different for different pressures.
According to different levels of pressure, flange gaskets also have different materials, from low-pressure asbestos gaskets, high-pressure asbestos gaskets and PTFE gaskets to metal gaskets. The flange connection is easy to use and can withstand greater pressure. In industrial pipelines, flange connections are widely used.

The flange gasket is to achieve the sealing effect of the flange. 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-metal plates, or made by professional factories according to the specified size. The materials are asbestos rubber plates, asbestos plates, PTFE plates, polyethylene plates, etc.; there are also thin metal plates (white iron, Stainless steel) metal-clad gasket made by wrapping non-metallic materials such as asbestos