Effect of Plastic Deformation on Magnetostriction of Steel.

Abstract

Magnetostriction curves were measured for plastically deformed steel specimens at various levels of applied stress. It is known that the plastic deformation changes the elastic and magnetic properties, which induces the significant error in the nondestructive stress evaluation by ultrasonics and magnetics. We have already proved that the maximum value in the magnetostriction curve can be used in the nondestructive residual stress measurement in elastically deformed steel. In this study, to reveal the applicability of the maximum magnetostriction method to plastically deformed samples, we measured the stress dependence of the maximum magnetostriction for plastically elongated specimens. It was predicted that the residual compressive stress was introduced in the deformation direction at the surface of the specimen. The evaluated stresses were compared with those by some other methods, showing that the magnetic anisotropy supports the results by the maximum magnetostriction method.