MONITORING THE MICROSTRUCTURE OF PEARLITIC STEELS BY MAGNETOACOUSTIC EMISSION

Magnetoacoustic emission (MAE) and Barkhausen emission (BE) measuremen ts have been made on hypereutectoid steel samples heat treated to prod uce completely pearlitic microstructures with various interlamellar sp acings. Both the peak height ratio of the MAE profile and the amplitud e of the BE profile were found to increase with increasing interlamell ar spacing. These results can be explained in the context of the domai n structure and the domain wall processes observed by Lorentz microsco py. The correlation of the spacing with the shape of the MAE and BE pr ofiles shows that both techniques are useful for monitoring the pearli te interlamellar spacing. (C) 1997 American Institute of Physics.