On the Origin of Peaks of Differential Magnetic Permeability in Low-Carbon Steels after Plastic Deformation

The physical origin of peaks in the field dependence of differential magnetic permeability of low-carbon steels after their plastic tensile deformation have been theoretically studied; they are caused by the irreversible displacements of the 90° domain walls. The angular difference between the [100] axes of the two neighboring grains with the large-angle boundaries has been determined; it corresponds to the peaks of differential permeability. It also controls the value of residual compressive stress. The results obtained are in perfect agreement with the corresponding experimental data.