MAGNETIC MEMORY TESTING: Studies on stress-magnetism coupling effect for 35 steel components

Abstract

The stress-magnetism effect can be used as a novel and convenient potential NDE method, called the magnetic memory method. However, whether and how this can be used as a quantitative measurement are still subjects that are as yet rarely studied by researchers. In this paper, circle tensile stress within the elastic region was applied to a ferromagnetic sample under geomagnetic field. The relationships between the surface leakage magnetic field and the tensile stress are presented. The stress-magnetic field equivalent model is derived and discussed and reconciled with the experimental results. A new model of stress-permeability that represents the relationship of the material permeability versus stress is proposed, which reconciles with the experimental results. It confirms that quantitative measurement and estimation of the integrity of ferromagnetic items by magnetic memory testing is feasible.