Theoretical and experimental study of phase equilibria in austenitic steels

In this work thermodynamic equilibria for a Fe-Cr-Mo-Ni-C system mere calcu lated and compared with those determined experimentally in examined austeni tic stainless steels. Calculations of equilibria were realized by means of PD-pp software package in temperature range 850-1350 K. Modelling of thermo dynamic equilibria is based on the Hillert-Staffansson sublattice model. The M23C6 carbide was experimentally found to be the most stable phase. On the other hand, intermetallic phases sigma and Laves are present in equilib ria at lower temperatures only. The M6C carbide is in thermodynamic equilib rium only in the steel with the highest carbon content. Performed calculati ons are in reasonable agreement with experiment.