1.Preparation for welding. The preparations for hot-melt welding construction are as follows: ① Put pipes on the basic frame; ② Prepare enough supports to ensure that the pipe to be welded can be at the same height as the center line of basic frame and can be moved easily; ③ Set up Set the temperature of the heating plate to be 200～230℃; ④Turn on the power of the welding machine, turn on the heating plate, planning tool and oil pump switch and test run.
2.Welding. The welding process is as follows: check the pipe and clean the pipe end→tighten the pipe→mill the pipe end with planning tool→check the dislocation and gap of the pipe end→heat the pipe and observe the minimum crimp height→the pipe is welded and cooled to the specified time→take out the pipe. During the welding process, the operator should refer to the various parameters of the welding parameter for operation, and if necessary, should make appropriate adjustments according to changes in weather and ambient temperature.
3.Welding parameters: temperature, time, and pressure.
4.Welding inspection practice has proved that the most vulnerable part of polyethylene gas pipeline to damage and leak is the pipeline interface. The key to the success and failure of the project is the quality of the pipeline connection. Therefore, strict interface quality acceptance is very important for underground gas pipeline engineering. The polyethylene pipe joints need to be subjected to destructive tests to check the internal quality.
