Magnetomechanical behavior for assessment of fatigue process in ferromagnetic steel

In this work, the change of magnetization as a function of applied stress has been investigated for test specimens of AISI 1018 steel. The various stages of fatigue damage process are characterized by the magnetomechanical measurements recorded by an APS 428D fluxgate magnetometer. Of great significance is the fact that the stress-magnetic field hysteresis loop area changes systematically with the progression of fatigue. The magnetomechanical hysteresis demonstrates conspicuous changes in the initial stage of fatigue loading, then reverts to a relatively stable phase, and finally, drastic variations appear again as the cyclic loadings approach terminal failure. This work demonstrated that it is possible to correlate the progress of fatigue in ferromagnetic steels with the nondestructive evaluation technique of the magnetomechanical effect. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4769364]