Ultrasonic imaging of electrofusion welded polyethylene pipes employed in utilities industry

Electrofusion welding (EFW) is a widely used technique for joining polyethylene pipes in the oil, gas and water industry. Like many welding and joining methods, the joints created by EFW can exhibit a range of flaw types that can be attributed to process variables such as: poor preparation of the parent material, contamination of the weld surfaces prior to welding and operator and/or equipment failure during the welding process. This paper describes ultrasonic testing using 128-channel linear array with a DYNARAY system to acquire data from a range of joints created using EFW. The samples were created in the laboratory with a range of defects that represent those commonly observed in the field. The samples were subsequently destructively tested using tensile testing of the coupling-pipe interface. Good corroboration was achieved between the observed weld quality from the ultrasonic data and the weld strength determined by the destructive testing.