Investigation of measurement conditions of eddy current magnetic signature method for evaluating plastic deformation in carbon steels

This paper describes eddy current magnetic signature (EC-MS) method that can evaluate small plastic deformation in carbon steels with high accuracy. In EC-MS method, an incremental magnetic field is superimposed on a magnetization field, and the directions of the incremental field to the magnetization field changes, depending on experimental setups. The objective of this study is to investigate the influence of the measurement conditions on experimental results of EC-MS method. Tensile test specimens are measured by EC-MS method with different directions of the incremental field parallel and perpendicular to the magnetization one. Furthermore, the dependence on the static/quasi-static magnetization field is discussed comparing a continuous waveform of the magnetization field with a stepwise one.