Magnetic Studies of Residual Stress in Iron and Steel Induced by Uniaxial Deformation

Abstract

The nature of the residual stress in steel after uniaxial plastic deformation was investigated magnetically. The B-H curve measured in the residual stress state after elongation was similar to the one under compressive stress, and the induced magnetic anisotropy was uniaxial with the easy axis at right-angles to the previous direction of elongation. By employing a newly developed magnetic probe, which detects the sign and the magnitude of the induced uniaxial magnetic anisotropy under deformation, the magnetic yielding phenomenon was observed at the mechanical yield point. The probe output was highest at this point, compared with that observed during the subsequent cycles of loading. These results are interpreted semiquantitatively on the basis of the microscopic stress distribution and the anisotropy of the magnetostrictive strain.