Improper Pipe Surface Preparation Becomes Leading Cause of Welding Failure
According to industry quality incident statistics, improper handling of the pipe surface oxide layer is the primary cause of electrofusion welding failures, accounting for the highest proportion of all quality incidents and deserving serious attention from all construction personnel.
Time:
2026-07-01
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According to industry quality incident statistics, improper handling of the pipe surface oxide layer is the primary cause of electrofusion welding failures, accounting for the highest proportion of all quality incidents and deserving serious attention from all construction personnel.
Technical experts explain that during extrusion, transportation, and outdoor storage, PE pipes gradually develop a thin, dense oxide layer on their surface. This oxide film differs significantly in microstructure from the internal pipe material—it has lower molecular weight and contains polar groups, resulting in poor compatibility with molten polyethylene. If this oxide layer is not thoroughly removed before welding, it acts as a physical barrier, preventing polyethylene molecules from the fitting's inner wall and the pipe's outer wall from mutually diffusing in the molten state. Even with completely correct welding parameters, the joint strength will fail to meet design requirements.
The correct procedure involves using a specialized manual scraper or electric rotary scraper to evenly remove the oxide layer from the pipe's welding zone outer surface, controlling the scraping thickness between 0.1mm and 0.2mm. The scraped surface should display a uniform fresh material color without obvious tool marks or unevenness. Assembly and welding should be completed within 15 minutes of scraping to prevent the surface from becoming recontaminated by dust, moisture, or oil. Experts specifically remind that the inner wall of electrofusion fittings receives special treatment at the factory and its packaging must not be opened before welding assembly to avoid contamination or oxidation of the inner wall.
More Information
What are the most critical construction steps during the electrofusion welding process?
The core of electrofusion welding lies in "cleaning, scraping, alignment, fixing, and cooling." Among these, scraping off the oxide layer is the most critical step.
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What are the key requirements for matching electrofusion fittings with pipes?
Same polymer family: Fittings and pipes must be polyethylene (PE). Do not mix PE with PVC, PP or other plastics.
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What are the compatibility requirements for electrofusion fittings?
The compatibility requirements for electrofusion fittings primarily include the following aspects:
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How to correctly select and match the specifications and materials of electrofusion fittings?
When selecting electrofusion fittings, the primary principle is to ensure a perfect match between the fitting and the pipe.
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What are the most critical construction steps during the electrofusion welding process?
The core of electrofusion welding lies in "cleaning, scraping, alignment, fixing, and cooling." Among these, scraping off the oxide layer is the most critical step.
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How to intuitively judge whether an electrofusion welded joint is qualified?
After welding and natural cooling, the joint quality can be preliminarily judged through visual inspection.
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