Electrofusion welding: preparation is everything
Scraping, roundness, barcode and cooling — step by step
Introduction
In electrofusion welding, the fitting has built-in heating wires. The welding unit sends current through the wires for a set time. Then the surface of the pipe and the inside of the fitting melt together.
Scrape the pipe
The outer surface of the pipe must be scraped off before welding. This is done with a rotary scraper. A hand scraper must not be used for scraping. It may only be used to deburr the edge.
| Pipe size | Minimum scraping depth |
|---|---|
| DN25 to DN225 | 0.2 mm |
| Above DN225 | 0.3 mm |
Round, clean and secure
- 01Check whether the pipe is oval. Use a re-rounding tool and leave it on during both welding and cooling.
- 02Mark the insertion depth on the pipe so you can see that it is fully inserted into the fitting.
- 03Clamp the pipe and fitting so that nothing can move during welding and cooling.
The machine reads the barcode
The fitting has a barcode according to ISO 13950. The welding unit reads it and adjusts the welding time itself to the temperature around you. Still check that the time and voltage on the fitting match what the unit shows.
Cooling
- 01Wait for the full cooling time stated on the fitting.
- 02Never cool the joint with water.
- 03A large joint can take up to 24 hours to get below 45 °C.