Ultrasonic Array Approach for the Evaluation of Electrofusion Joints of Polyethylene Gas Piping

Abstract

Polyethylene is a widely used material for piping. Especially the demand of polyethylene piping for gas distribution is being increased. Thousands of kilometers of polyethylene piping have joints, and the joint is the weak point that should be inspected before the pipe begins service. In this study, an ultrasonic array technique is applied for the nondestructive testing of electrofusion joints in polyethylene pipe. An ultrasonic real time imaging system and array transducers are developed for the experiments. In the process of image construction, transmission and dynamic receive focusing are used. Heating wires are individually identified in ultrasonic real time images, which means that the ultrasonic array technology provides enough resolution to tell wire signals from flaw signals. Imperfect fusion joints and soil inclusion are clearly indicated in the images. Even locations of wires are appeared as is. The ultrasonic imaging technique is a very promising method for the nondestructive testing of EF join...