Before welding, check whether both ends of the pipe to be welded are cut flat (if the end faces are uneven, they should be trimmed). Position the welding surface at the center of the pipe's wave valley, align the two pipes to be welded on the same axis (ensure the disconnected parts are as aligned as possible); leave a 1-3mm gap at the joint to facilitate welding (but the maximum gap should generally not exceed 5mm). If the requirements are not met, use tools to perform local trimming of the joint. Trimming can be done from the outside or inside (for pipes with a diameter of φ800 and above). The welding area must be kept clean and dry, free from dust and other impurities; both the inner and outer surfaces of the welding area should be polished to remove the oxidized layer.

2.2. The welding rods used for welding should generally be provided by the pipe manufacturer as part of a matching set. They must be made of the same polyethylene material used in the production of the pipes or a material that is highly compatible with the pipes. The cross-section of the welding rod should be circular, with consistent thickness, and meet the welding performance requirements of the selected welding gun. The welding rod must also be clean, dry, and free from stains.

2.3. It must be emphasized that a high-quality extrusion welder with a hot air device should be used. During welding, the hot air device must preheat the polyethylene at the seam ends of the pipes, ensuring that the extruded molten polyethylene integrates seamlessly with the pipes. All welded cross-sections must be full, without any missed welds or fractures.

2.4. For pipes with a diameter greater than 800mm, double-sided welding (both inside and outside) is generally required.

2.5. Set the melting material and hot air temperature according to environmental conditions; maintain a certain welding pressure on the melting material; allow for a correspondingly slow cooling time.