抄録
Pulsed eddy current imaging non-destructive technique was used for detection of subsurface defects in ferromagnetic materials. In this work, an excitation probe coil is wounded around two small pickup coils arranged in a differential measurement set up. In order to avoid the non-linear behavior of the ferromagnetic material a static magnetic field is applied. The magnetically saturated metal behaves then like a non-magnetic one. This set up improves the performance of eddy current testing for detecting the defects, cracks, mass loss, and the corrosion defects in the ferrous materials. The results are very good since defects up to 10mm in depth are detected and observed in the c-scan image.
