The use of Calphad approach to analyse the phase stability of nitrided 32CrMoV13 grade steel: validation by XRD experiment

The objective of the present work was to study the stability of iron carbonitrides and CrN phases formed during the gas nitriding of 32CrMoV13 grade steel. The nitriding treatment was conducted at 570 °C for 25 h in a gas mixture consisting of NH3 and H2 under a constant nitriding potential 3.6 atm−1/2. The two sublattice model based on Hillert-Staffanson's approach were capable of analysing the stability of each phase as a function of temperature, alloying element content Cr, and nitrogen and carbon contents. The results of thermodynamic calculation have been validated by XRD experiment.