Evaluation of stress-loaded ferromagnetic structures using the magnetic recording method and extended signal analysis

This paper presents a new method of analysis of results obtained using the Magnetic Recording Method (MRM), which was applied to inspect tensile stress-loaded ferromagnetic samples. The MRM method comprised a two-step procedure. In the first step, a strictly defined magnetic pattern is recorded on the samples using an array of permanent magnets, and then the original residual magnetization is measured. Next, the samples are subjected to static stress. In the second step, the residual magnetization measurement is repeated. Comparative analysis of the measurement results allows for an accurate and unambiguous assessment of applied stress in steel components. Moreover, the magnetization was measured again after three years to investigate the effect of time on magnetization patterns. The study confirms that the method is stable and has a negligible time dependence.