A Comparative Study on Methods of Distinction Between Near- and Far-Side Defects as Techniques Used Alongside with the Magnetic Flux Leakage Testing

Abstract Results of the finite element analysis show that a far-side defect in steel plate, with depth greater by 10% plate thickness than near-side defect, can produce very similar magnetic flux leakage (MFL) signal. Due to fact measurement MFL itself lead misclassification as one, and thus underestimation its depth, comparative study three complementary techniques was performed. The following were studied: surface topology air-gap reluctance system (STARS), residual (RMFL) stray (SMFL). Numerical results showed case STARS SMFL, signatures signals observed for investigated defects, but not defects. signature RMFL observed, however peak-to-peak value only about 8% corresponding defect.