Theoretical Feasibility of Secondary Welding
Secondary welding is technically feasible when PE pipe electrofusion joints leak, but it requires specific conditions. First, it's necessary to confirm whether the leak is located within the original weld area. If it's mechanical damage outside the heat-affected zone, welding is not suitable. The weld surface must be thoroughly cleaned to remove oxide layers and contaminants, and the pipe wall thickness loss should not exceed 10%. Temperature control is crucial; the secondary heating should be 10-15℃ lower than the initial welding temperature to avoid material degradation.
Three Major Challenges in Practice
Material Performance Changes: The initial welding alters the molecular structure, and secondary heating may lead to localized carbonization.
Sealing Reliability: Existing weld marks can affect the flow path of the new weld material.
Equipment Compatibility: A welding machine with precise temperature control is required; ordinary equipment is insufficient.
Better Alternative Solutions
Welding is recommended to be abandoned in the following situations: obvious aging cracks appear on the pipe surface; joint misalignment exceeds 5% of the pipe diameter; the leak point is located at the root of the socket. Consider using a specialized repair kit or replacing the entire joint. For pressure pipelines, it is recommended to directly replace the joint to ensure long-term sealing.
