Weld Inspection of Piping Elbow Using Flexible PAUT Probe

Abstract

AbstractIn order to optimize the operation of power generation equipment, structures, and facilities, and to maintain safety and reliability for a long period of time, non-destructive testing (NDT) has to be conducted to secure the structural integrity. Among the various NDT methods, radiographic testing (RT) is mainly used for the production/installation and scheduled maintenance of power generation facilities according to relevant codes and specifications, and they mostly have a significant effect on process delay and economic loss that occur due to duplicate application of RT and ultrasonic testing (UT). Therefore, the phased array ultrasonic testing (PAUT) is actively introduced and utilized as a new volumetric examination technique, which can reduce the use of the RT as much as possible and replace the RT in the industrial field. The PAUT is capable of high-speed inspection because not only it can control the injection of the ultrasonic beam electronically, but it can also easily test specimens with complicated shapes, which are difficult to be detected with the conventional UT. It is not easy to obtain objective and reliable testing data because the probe contact is difficult when the PAUT is used to examine the welded part with curved shapes such as a piping elbow welding part. Keywords: Please list a maximum of 6 keywords or phrases. Therefore, in this study, instead of using a wedge, which was essentially used for the inspection of the pipe with curvature structures in the conventional studies, a 5 MHz, 32 Ch Linear flexible PAUT probe that can examine a piping elbow welding part was designed and manufactured, and the usefulness was verified. In order to verify the usefulness, welding specimens were manufactured according to the ASME standard and artificial defects were processed. Finally, the possibility to overcome the limitations of the existing PAUT technologies and to improve the reliability of test results were confirmed through and signal acquisition and analysis.