A novel circumferential eccentric eddy current probe and its application for defect detection of small-diameter tubes

Abstract When it comes to the detection of defects in small-diameter tube, eddy current testing (ECT) using Bobbin probe is the traditional method. Although this way is quite efficient, it is not available to obtain the circumferential information of the defect due to its inherent disadvantage. In this study, a novel probe has been proposed which can obtain both axial and circumferential information of defects, still with high efficiency. During testing, the probe carries out axial scan for defect searching in axial direction, and when defect is discovered, the circumferential eccentric rotating scan module will be executed. Thus, this novel probe can achieve multiple defect information with high efficiency. The specific research contents are as follows. Firstly, the eccentric and rotatable EC probe is designed suitably for small-diameter tubes, with the simulation model built up for signal analysis. Then, the feasibility of this novel probe is verified by integrating the obtained simulation data, showing the advantages of the developed probe for obtaining both axial and circumferential multiple information of defects in small-diameter tube. Finally, the novel probe is fabricated, and the testing system is established. The corresponding experiments are conducted, certifying the superiority and efficiency of the new type of probe further.