Study on the conductivity model of SCC by using a new eddy current probe

Abstract

Usually, the stress corrosion crack (SCC) has a complex shape of non-zero conductivity. Its shape is very difficult to reconstruct accurately by using eddy current testing signals. At present, most defaults being dealt with are shallow cracks with a simple shape, which are not consistent with the actual cases. In order to detect the deep SCC in metal materials quantitatively, a new eddy current probe with capability of deep penetrating is proposed in the paper. Based on the research results of current literature, the conductivity model of deep SCC is established. ANSYS software is used to analyze the influence of crack inclination, branching position and branch number on eddy current signals to build the equivalent model of SCC. Simulation results show that the new probe is more sensitive to complex SCC than the conventional pancake probe, and can distinguish whether the SCC having branches or not and what the branching position is. The quantitative results of SCC obtained by using a calibration curve show that the detection signals picked up by the new probe can effectively be used to deduce the depth of branching SCC.