Nondestructive characterization of flake graphite cast iron by magnetic adaptive testing

Three series of flake graphite cast iron samples having different chemical compositions and different heat treatments within each series were investigated by the method of magnetic adaptive testing. The flat samples were magnetized by an attached yoke, and sensitive descriptors were obtained from the proper evaluation, based on the measurements of series of magnetic minor hysteresis loops, without magnetic saturation of the samples. Results of the non-destructive magnetic tests were compared with the destructive mechanical measurements of Brinell hardness and linear correlation was found between them in all cases, where the influence of chemical composition and influence of heat treatment were considered. •A novel magnetic nondestructive method was applied for investigation of three series of flake graphite cast iron.•Material structure was modified by different cooling rates, which resulted different values of hardness.•Linear correlation was found between the optimally chosen magnetic parameters and the actual value of the Brinell hardness.•Advantages of this method was discussed.