On the influence of cyclic loadings on the magnetic permeability of ferritic-pearlitic AISI 1045 steel

In this paper, the changes in magnetic permeability of ferritic-pearlitic AISI 1045 steel during cyclic loading were investigated using a Micromagnetic Multiparameter Microstructure and stress Analysis (3MA) sensor. For this, insitu and ex-situ magnetic measurements were carried out at cyclically loaded specimens at different cycle numbers in the high cycle fatigue regime. The magneto-mechanical interaction measured during tensile and compressive stresses showed a nonlinear behavior of the magnetic permeability with respect to mechanical stress. Moreover, values extracted from 3MA measurements were plotted against the cycle number and cycle number to failure to indicate the fatigue-induced evolution of magnetic permeability and estimate fatigue life, respectively. The obtained magnetic measurements were correlated with the temperature and electrical resistance change of material during fatigue as well as the surface hardness of the specimens after failure.