Influence of uniaxial plastic deformation on surface magnetic field in steel

Under geomagnetic field, surface magnetization measurements were made on 1045 and a3 steels samples uniaxially deformed to differing magnitudes of plastic strain, to study the dependence of surface magnetic field and its distribution on plastic deformation. The results indicated initial increase in surface magnetic field with increasing plastic strain followed by a decrease at higher plastic deformation. At still higher plastic deformation, the surface magnetic field was found to be almost independent of plastic strain. In the middle part of the sample, the uneven plastic deformation interrupted the linear distribution of surface magnetic field. The behavior of surface magnetic field and its distribution with plastic deformation were largely controlled by the different mechanisms of interaction of domain walls with isolated dislocation, dislocation tangles and dislocation cellular structures.