Non-Destructive Testing of Electrofused Joints and Large Diameter Gas Pipes

The Gas Research Institute and McElroy Manufacturing, Inc. cofunded Project 5091-271-2341 to increase the capability of the UltraMc” Computerized Ultrasonic Inspection System. This project added the 2” Iron Pipe Size (IPS), 3” IPS, 6” IPS, 8” IPS, 10” IPS, 12”, IPS, 50 mm Japan Industrial Size (JIS), 75 mm JIS, 100 mm JIS, 150 mm JIS, 200 mm JIS, 250 mm JIS, 300 mm JIS, 60 mm, 90 mm, 110 mm, 160 mm, 180 mm, 250 mm, and 315 mm pipe sizes. In addition, software and hardware improvements were made that dramatically increased the accuracy of the system. Because of these improvements, approximately 100 systems have been sold in the United States, Canada, Japan, Korea, Italy, Belgium, and Germany.

After completing the cofunded project to increase UltraMc’s capability to inspect large diameter pipes, McElroy was asked to investigate the possible evaluation of electrofused joints. The major Japanese gas companies were experiencing dramatic quality problems sue mostly to contamination. In late McElroy began preliminary work on the ultrasonic inspection of electrofused joints in couplings. The unique capability of the UltraMc system allows for precise examination of the electrofused joint by knowing where the fusion area is in relation to the wire position, fusion zone and inner pipe wall. The wire coil is used to help with the evaluation rather than impede it. This paper will discuss the Phase II project work and the rationale used to develop the prototype EF system, the testing accomplished to date, and the feasibility of this inspection method to be successful.