Detecting Cold Weld Defects in HDPE Piping Thermal Fusion Welds Based on Microwave Technique

Abstract

In the present paper, an effective method for detecting the cold weld defects in the thermal fusion weld of high-density polyethylene (HDPE) pipelines based on microwave technique is proposed. Using a microwave testing system, HDPE piping welds containing cold weld defects caused by insufficient heating time were examined by frequency sweep within the range of 9.2-9.9 GHz. At the frequencies that were most sensitive to the cold weld defects, the measured reflection coefficient S11 showed greatly different values between the good weld and those containing cold weld defects. The readily detectable differences in S11 value make the detection of the cold weld defects possible and feasible. This work provides insights for non-destructive testing of technical defects in HDPE piping welds.