Knowledge Center

How is butt welding done?

1. Place the pipes in the machine and tighten the clamps; check that the axes are aligned.
2. Face both ends flat and parallel with the facing unit. Shavings should come off as a continuous ribbon.
3. Bring the ends together and check gap and misalignment (misalignment must not exceed 10% of wall thickness).
4. Bring the heater plate to 220 ± 10 °C and clean it with alcohol.
5. Bead-up: Press the ends against the plate under pressure until the specified bead height is reached.
6. Heat soak: Reduce the pressure to almost zero and wait for the heat soak time.
7. Changeover: Remove the plate quickly and join the ends as fast as possible.
8. Fusion & cooling: Increase pressure gradually and hold it until the cooling time is over.

How is electrofusion welding done?

1. Cut the pipe square to its axis (a guillotine pipe cutter is recommended).
2. Remove the oxide layer in the fusion zone evenly with a scraper.
3. Clean the surface with alcohol and let it dry; do not touch the cleaned area by hand.
4. Mark the insertion depth of the fitting on the pipe and fit it in place.
5. Secure the pipes with a positioner; they must not move during welding.
6. Connect the machine cables, enter the fitting’s welding parameters and start welding.
7. Check that the fusion indicators have popped up and observe the cooling time.

SDR – pressure class (water)

For water at 20 °C, safety factor C = 1.25. Wall thickness is given for a Ø110 mm pipe as an example.

In natural gas lines, PE100 SDR11 fittings are rated for 10 bar operating pressure.

Wall thickness & welding times

Enter the pipe diameter and SDR to calculate wall thickness, pressure class and approximate butt welding times.

Approx. pipe weight: –

Approximate butt welding times

Values are approximate, based on the DVS 2207-1 guideline. In practice, the pipe manufacturer’s values and the machine’s welding table take precedence.