Presenting a novel NDT Eddy Current probe for crack detection on rough welds and steel with variable permeability

Abstract

Alternating current field measurement is a long lasting industry standard for eddy current non-destructive testing. This method is often preferred when searching for surface breaking cracks on metals and welds. The challenges of this method are reduced accuracy at high liftoff, vulnerability to high surface roughness and variable metal permeability.In this paper an inline dual coil magnetic probe is presented. Signal processing methods from the communication community such as broadband calibration and matched filtering are applied to improve signal to noise ratio.The proposed solution improves the SNR by 3 dB when compared to other existing equipment. Moreover, the solution also becomes resilient to surface roughness, high liftoff and variable permeability. In the end the methods found has the future potential to improve detection of cracks.