In pipeline engineering, flanges are mainly used for the connection of pipelines. Wire flanges can be used for low-pressure pipelines, and welding flanges should be used for those with more than 4kg of pressure.

Butt welding flange is mainly used in the environment of moderate medium conditions, such as low pressure unpurified compressed air, low pressure circulating water, its advantage is that the price is cheaper. The sealing surface of butt welded flange can be divided into three types: smooth type, concave and convex type and tenon type. Smooth butt welding flange has a wide range of applications, and the other two ways of butt welding flange is also more in use. The structure of butt welding flange is reasonable, the strength and stiffness are large, can withstand high temperature and high pressure, repeated bending and temperature fluctuations and other harsh environment, and will not reduce the sealing performance.

Butt welded flange is a kind of pipe fitting, it refers to the flange with neck and a round pipe transition and butt welded with the pipe. At present, it is widely used, because the butt welding flange is not easy to deform, sealed well, widely used, has the corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition.