Inspection Method for Thinning of Metal Pipes Using Electromagnetic Wave Polarization Characteristics

ABSTRACT Serious defects in metal piping systems used in factories, power stations, and similar facilities can cause serious accidents. Regular inspections for metal pipework are therefore important. However, all conventional nondestructive inspection (NDI) methods are often time‐consuming and inconvenient. To address this issue, we propose a simpler and more innovative inspection technique based on electromagnetic waves. In this study, we introduce a new, highly sensitive NDI method for metallic pipework using the ‘polarization’ properties of electromagnetic waves. This method utilizes the ability of a metal tube to act as a circular waveguide, radiating electromagnetic waves along its length. A key feature of this approach is that the transfer function changes significantly when the polarization direction of the electromagnetic waves at the transmitting and receiving ends is changed. This measurement method enables the detection of disturbances in the electromagnetic polarization caused by reduced wall in metal pipe with high sensitivity. Consequently, it facilitates groundbreaking inspections that quickly and easily detect the presence of defects, such as reduced wall, across the entire metal pipe being measured.