Non-contact EM measurement of the properties of power station steels taken from service

Analysis of the electromagnetic properties of power station steels, measured using a non-contact EM sensor, is of significance as such properties are indicative of the microstructure of the material. In this paper, we present the measurement of cylindrical power station steel samples (namely P91 and P9 grades) in different conditions. Initially the B-H curves of these steel samples were measured. Then printed circuit board (PCB) coil integrated sensors were used to measure the incremental permeability. Analytical and numerical methods (Finite Elements Methods) were employed to calculate the sensor response of these samples. Experimental results were obtained for a range of samples and their electromagnetic properties inferred by fitting finite element models to the measured results.