Evaluation of Surface Modifications in High Strength Steel

Author:  D Jiles, R Kern, W Theiner
Source:  Conf Proc: ICSP-6, (p.192-206)
Doc ID:  1996066
Year of Publication:  1996
This paper reports on the application of micromagnetic inspection techniquies to the evaluation of the surface condition of shot peened, high stength HP9430 steel. It is shown from the results that the modification of the surface condition resulting from different shot peening intensities can be detected from the amplitude of the mocromagnetic signals emitted from the surface under alternating magnetic field excitation. It is further demonstrated that the productin of residual stresses in the surface of a steel , as a result of shot peening, causes a broadening of the range of critical field stenghts for domain wall activation. consequently the spectrum of activation fields obtained on a plot of micromagnetic activity versus magnetic field stenght can be used as an indication of the shot peened condition of the material.

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