Welding polyethylene pipes with confidence
Keywords: Welding, Plastics, Polyethers
A e 1M European-funded project has just been completed. It developed a fusion welding machine with an integral ultrasonic non- destructive examination (NDE)system (Plate 2). This has the potential for providing complete confidence in the long-term quality of each weld produced.
The project was managed by TWI and involved twelve other organisations from five European countries.
The objectives were to:
Optimise three ultrasonic NDE techniques for butt welds in PE pipes (TOFD,tandem and creeping wave)
Establish the limits of such an NDE system
Determine critical defect sizes and levels of particulate contamination in PE pipe butt fusion welds
Design and manufacture a prototype welding/NDE machine
These objectives were all met and the results were very encouraging. Work carried out during this project has important implications for the pipeline industry.
Plate 2 A close-up of the ultrasonic probe assembly mounted in an automatic butt fusion welding machine
Although the project only covered one grade of PE, using one welding procedure, the advantage of a combined TOFD, tandem and creeping wave system is that it should be applicable to other grades of PE using other welding procedures as it does not rely on a specific shape or size of weld bead.
For more information, please contact: Mike Troughton at TWI. E-mail: mike.troughton@twi.co.uk
