NONDESTRUCTIVE EVALUATION OF SPHEROIDIZED STEEL USING MAGNETOACOUSTICAND BARKHAUSEN EMISSION

Magnetoacoustic emission (MAE) and Barkhausen emission (BE) measuremen ts have been made on pearlitic steel samples annealed to produce spher oidized microstructures with various sizes and distributions of carbid es. It was found that spheroidization of the pearlitic structure and c oarsening of carbide particles result in a decrease in the peak height ratio of the MAE profile and the formation of a second peak in the BE profile. These results can be interpreted from observations of the do main structure by Lorentz microscopy. The sensitivity of the MAE and B E profiles to the carbide size and morphology makes both techniques us eful for monitoring the microstructure of spheroidized steels.