一様渦電流プローブの探傷性の調査

抄録

Weld zone of structure is very important to ensure the intensity of the structure. However, weld zone of the structure is difficult to detect flaws with general nondestructive testing technologies since weld zone has uneven surface.

Since the uniform eddy current (UEC) testing using straight pattern of eddy current has unique characteristics, which are differential and self-nulling, and only when there is a flaw, the flaw signal is generated, the UEC probe has possibility to apply to flaw detection on weld zone of the structure. Therefore, the configurations of UEC probes to apply to flaw detection on weld zone were investigated. The configuration of the general UEC probe consists of one to four excitation coils and one to two detection coils. The excitation coils of the UEC probe are generally rectangular with tangential orientation, and the detection coil is generally circular with the orientation of the pancake.

From the investigation of UEC probe, the orientation of the excitation coil in the tangential position shows a weak induction since the only part of excitation coil contribute to induce UEC although the good quality of UEC can be introduced. Therefore, we proposed several UEC probes with a pancake oriented, which can induce the large UEC, and show good detectability of flaws.

In the presentation, the principle of flaw detection of several UEC probes we proposed will be explained. In addition, the theoretical and experimental results with the UEC probes will also be indicated.