Electrofusion welding is a process that uses a molded socket fitting that contains an electrically resistive heating coil. The scraped pipe surfaces are inserted into the sockets and clamped where an electric current passes through the coil for a specified time. The surrounding polymer transfers heat to the pipe after heating takes place. The formation of a homogenous joint occurs due to the high melt pressure that occurs when cold zones at the ends of the fitting.
How To Prepare Electro-fusion Welding Element
Cleaning the welding materials – It is the first step that involves removing any traces of foreign materials such as grease, dust, and mud from the inner and outer surfaces of the pipes. Cleaning uses clean water, a soft paper towel, and clean rags free of line dipped in a liquid cleaner.
Cutting the ends of the welding element – The pipes should lay flat and perpendicularly to their axis for cutting. Cuts are made using appropriate pipe cutters or equipment that functions with a fixed guide blade. Any beveled and polythene fragments should be removed by deburring the outer edges of the end.
Marking the scraping zone – You should use a marker to identify at least one-third of the circumference of the pipe. Ensure the length of the scraping is greater than the length of the coupling depth of the electro-fusion fitting by at least 10 mm on each end.
Removing the oxidized surface layer – You can use mechanical or manual scrapers to remove the oxidation layer from the entire outer surface of the elements.
Cleaning the scraped surfaces – Make sure you use a suitable cleaner to clean the ends affected by welding again. Ensure all surfaces are dry before proceeding to the next stage. Repeat this process for the inner surface of the electro-fusion heating.
Marking the insertion depth – Mark the insertion depth at least one-third of the circumference of both ends in the welding elements using a marker.
Insertion of the welding elements in the electro-fusion fitting – Ensure you do not force any element into the fitting; therefore, check the out-of-roundness and the diameter. Follow the indication you put on the previously marked insertion depth.
Connect the terminals of the control unit to the electro-fusion fitting – Check if the diameters of the fitting and connection terminals correspond. The welding parameters indicated in the bar should be transferred to the control unit using the optical reader. Perform the welding cycle if everything coincides.
Mark the joint – Remember to write the hours and minutes indicated in the clock showing the end of the fusion time using a marker. Mark the joint with its abbreviation or its name and wait for the cooling process.
Why Is Scrapping Essential In The Electro-fusion Process?
The scraping process aims at eliminating the oxidation layer in PE (polyethylene) pipes and is done towards the pipe`s end. You should not use sandpaper or abrasive paper because they damage the surface of the pipe and leave particles on it. Mechanical scrapers are effective because they control the surface of penetration and eliminate a layer of material. Before scraping, mark the area with a visible color to ensure you do not scratch the unwanted surfaces. The worker`s experience and expertise determine the efficacy of manual scraping.
However, people make mistakes sometimes by giving too much width between the pipe and the welded fitting eliminating excessive quantity of material. It results in the production of melted PE outside of the fitting. Use of rags soaked in alcohol on the scratched areas can add pollutions to the surface; if it is not well evaporated that can damage the welding procedure. Welding that is done outdoors exposes the scratched surface to dirt if it stays outside the bag.