The diploma work Thermodynamic characterisation of PK318N stainless steel was carried out with the aim of determining the transformation temperatures during heating or cooling of PK318N steel sample. In doing so, we used Thermo-Calc program and differential scanning calorimetry (DSC) analysis of samples from different locations of EMS ingot head made by SIJ Metal Ravne d.o.o. Five different samples (two from the centre, two from the edge and one from the material in final state) were taken from the ingot head at which the chemical composition was determined, and one sample from the edge was also plastically transformed. The results of thermodynamic calculations are the equilibrium isopleth phase diagrams Fe-Fe3C and diagrams of the phase amount as a function of temperature. The results of DSC analysis are the heating and cooling curves of the samples, which show the transformation tempereatures and reaction enthalpies. The comparison of the results of thermodynamic calculations and DSC analysis made it possible to determine the phase equilibria as a function of temperature and the effect of faster heating/cooling on the nonequilibrium state. The DSC curves of individual samples were compared with each other and we found that the sample whose chemical composition deviates the most from the average also deviates most at transformation temperatures.