The hdpe flange is customized by manufacturers, not easy to deform, good in sealing, and widely used. It has corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition. The distance between the welding port and the joint surface is large, and the joint surface is free from welding temperature deformation. The complex horn-shaped body structure is suitable for pipelines with large fluctuations in pressure or temperature or high temperature, high pressure and low temperature pipelines. It is generally used for the connection of pipelines and valves with a PN greater than 2.5MPa; hdpe flang is also used for expensive and easy transportation. On pipelines of flammable and explosive media.