Field Inspection of Phase-Array Ultrasonic for Polyethylene Electrofusion Joints

Session 9B
11:40 am

Seong Hee Kil, Department of Gas Safety R&D Institute, Korea

The electrofusion technique is mainly used for welding polyethylene pipes for the water and natural gas utilities. The electrofusion welding process uses a fitting or a coupling socket with resistive wire wound on the inside. We developed a simple and user friendly ultrasonic non-destructive evaluation (NDE) and inspection device for electrofusion welding. With this device it is possible to detect various flaws including wire deviations and regions with lack of fusion. This paper studies the defect detection technique for electrofusion fittings of polyethylene piping is utilized by the ultrasonic phased array technique to obtain ultrasonic images of electrofusion joints. We inspected for many cases at fields with this technique. The inspection was conducted at the place of apartment construction. The diameter of 300mm polyethylene pipelines were used for supplying city gas to new apartment and also coupling socket was used for joining two polyethylene pipelines. We inspected polyethylene electrofusion joint by using 3.5MHz phase array sensor. The results of inspection by using AIM33 are as follows. Small porosities were observed at the angle of 100, 180, 270 of gas-in direction. Single porosity was detected at the angle of 60, 120, 350 and continued porosity at the angle of 200, 220 of gas-out direction.

Seong Hee Kil, Young Do Jo, Heung Sik Kim
Gas Safety R&D Center, Korea