The effect of low-cycle loading on phase transformations and substructure development in the Kh18N10T steel

Martensite formation in the Kh18N10T steel and its effect on strength and substructure of the metal have been studied in low cycle loading tests in the temperature range from 20 deg to -196 deg C. The phase changes and formation of substructure were investigated by electron microscopy and X-ray diffraction. It was shown that below -30 deg the martensite transformation obeys the γ→epsilon→α mechanism, the epsilon-phase being unobservable. Low cycle loading at -30 deg C results in higher strength of the steel. Under the conditions of martensite transformation, microcracks are generated in glide bands and their propagation is parallel to the bands. It is suggested that the failure is most likely to occur in plates of the epsilon-phase