A magnetic head-based eddy current array for defect detection in ferromagnetic steels

Abstract

Defects on the surface and subsurface of the ferromagnetic steels can easily lead to structural failures. Eddy current testing is one of the most popular techniques for defect detection. In this paper, the direct current (DC) magnetization and a magnetic head-based eddy current array (MHECA) are integrated to propose the DCMHECA technique. This method can address the low testing efficiency of single probe testing and the channel multiplexing of array testing, and meanwhile detect deep surface and subsurface defects. The experimental results verify that the proposed DCMHECA can be used to locate rectangular and hole defects and quantify their depths with little channel interferences, which are indicated by low difference rates.