Features of the decay of cementite of hypereutectoid carbon steels under various conditions and conditions

This paper presents the results of a study of the decay of the Fe3C phase during thermal cycling near the temperature of the phase transition of the second kind, which is 210$^\circ$ (Curie point of cementite). As a result of the conducted studies, it was found that structurally free tertiary cementite, present in low-carbon steels, is primarily susceptible to decay. In pre-eutectoid and eutectoid steels, cementite as an independent phase may be present in the composition of granular perlite. It was revealed that in the structure of steel U10 with the initial state of granular perlite, the maximum volume fraction (about 0,8%) of graphite is observed during thermal cycling near A0 cementite. At the same time, the greatest effect of a drop in density (by 1,85%) of samples that have passed the thermocyclic treatment, compared with the initial state, was also noted.