Features of Behavior of Magnetic Properties during Elastic Deformation of 20GN Hull Steel in Various Initial Stress–Strain States

We present the results of studying the behavior of magnetic properties, including longitudinal magnetostriction, of 20GN hull steel samples predeformed plastically by stretching to various degrees (up to 17.5%) under conditions of subsequent elastic uniaxial stretching. It is shown that the parameters of magnetic hysteresis considered in this paper change nonmonotonically with the increase of applied stresses with the formation of extrema. The values of the applied stresses at which these extrema are formed depend on the level of residual compression stresses induced by preliminary plastic stretching along the direction of its action. The results of measurements of the dependences of differential magnetic permeability and magnetostriction on the magnetic field strength in the studied samples are compared. The values of applied stresses at which the sign of magnetostriction of plastically predeformed samples changes during subsequent elastic deformation are experimentally determined; it is shown that these values coincide with the values of stresses when the extrema of the functions of the maxima of field dependence of the differential magnetic permeability on the tensile load are formed.