Flange is also called flange or flange plate. Parts that connect pipes to each other are connected to the pipe ends. There are holes in the flanges, and the bolts make the two flanges tightly connected. The flanges are sealed with gaskets. Flanged pipe fittings refer to pipe fittings with flanges (flanges or sockets). It can be made by casting (not shown), or by threaded connection or welding. Flange (joint) consists of a pair of flanges, a gasket and several bolts and nuts. The gasket is placed between the sealing surfaces of the two flanges. After the nut is tightened, the specific pressure on the gasket surface will be deformed after reaching a certain value, and the uneven parts on the sealing surface will be filled, so that the connection will be tight without leakage. Flange connection is a detachable connection. According to the connected parts, it can be divided into container flange and pipe flange. According to the structural type, there are integral flanges, loose flange and threaded flanges. Common integral flanges include flat welded flanges and welded flange. The rigidity of welded flange is poor, so it is suitable for the occasion of pressure p≤4MPa. Welded flange, also known as high neck flange, is rigid and suitable for occasions with high pressure and temperature.Used to build railway bridges, highway bridges and sea-crossing bridges. It requires high strength and initial performance, and can bear the load and impact of vehicles. It also needs good fatigue resistance, certain low-temperature initial performance and atmospheric corrosion resistance. The space between the bracket and the cushion block should also be filled with epoxy mortar, which can not only ensure the compactness of the gap, but also achieve the same strength as the cushion block. After the bracket is installed, the steel plate of the embedded part at the bottom of the beam is fixed on the steel plate at the top of the bracket with bolts.