Document Type

Conference Proceeding


Review of Progress in Quantitative Nondestructive Evaluation

Publication Date



Burlington, VT


This paper reports on a recent study aimed at developing the stress-induced magnetic anisotropy (SMA) technique for characterizing residual stresses in case hardened steel components. The results of SMA measurements performed on flat induction hardened steel discs with different case depths confirm the feasibility of detecting principal stress axes by measuring the angular variation of magnetic permeability. The permeability signals along the principal axes were found to vary monotonically with the residual stresses measured by XRD, but the signals are in general smaller for samples with a larger case depth. The magnetomechanical properties of the martensitic case and ferritic/pearlitic core of the induction hardened sample were studied by measuring magnetostriction curves from strip samples that were cut from the case and core regions, respectively. The case strip shows a significantly lower magnetostriction than the core strip, indicating a weaker stress dependence of magnetic properties for the martensitic case than for the ferritic/pearlitic bulk of the case hardened samples.


Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

This article appeared in AIP Conference Proceedings 1430 (2012): 1445–1451 and may be found at

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American Institute of Physics




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