Steel pipe with bell and spigot joints

[0016] Example 2, manufacture a steel-plastic composite pipe with a diameter of φ500×9000, and the lining pipe is made of polyethylene. This embodiment is basically the same as Embodiment 1, the difference is that: the conical surface of the steel pipe socket steel pipe with the socket prepared in Embodiment 1 is provided with a turning groove 6, and using it as the base steel pipe, the steel pipe is manufactured. Plastic composite pipe. The polyethylene lining pipe is compounded and fixed in the base steel pipe 2 with the socket steel pipe 3 and the horn-shaped socket 1 fixedly connected, and a tapered flange is formed on the mouth edge of the socket steel pipe 3 . When connecting, the socket steel pipe 3 of the front steel-plastic composite pipe is in sealing contact with the tapered portion of the polyethylene liner pipe that is compounded with the trumpet-shaped socket 1 of the rear steel-plastic composite pipe through the tapered flange formed on the polyethylene liner pipe

[0017] Example 3, manufacturing a steel-plastic composite insulation pipe with a diameter of φ500×9000, the inner lining pipe is made of polyethylene, and the outer protective pipe is made of PE. This embodiment is basically the same as Embodiment 1, the difference is that the conical surface of the steel pipe socket steel pipe with the socket prepared in Embodiment 1 is provided with a turning groove 6, and using it as the base steel pipe 2, the steel pipe 2 is manufactured. Plastic composite insulation pipe. In the matrix steel pipe 2 that is fixedly connected with the socket steel pipe 3 and the trumpet-shaped socket 1, the polyethylene lining pipe is compounded and fixed, and a tapered flange is formed on the edge of the socket steel pipe 3, and the socket steel pipe 3 and the horn are fixedly connected. The base steel pipe 2 of the shaped socket 1 is covered with a PE outer protection pipe, and a foam insulation layer is arranged between them. When connecting, the socket st