Equilibrium characterization and thermodynamic calculations on highly alloyed refractory steels

• Experimental phase equilibrium measurements on industrial refractory steels.
• Thermodynamic Calphad calculations of the phase equilibrium.
• Benchmark of different thermodynamic databases.
• Comparison between experimental and calculated results.

A comparison has been made between the phase equilibrium calculated within the Calphad method with different thermodynamic databases (TCFE7, TCNI5, TTNI7) and experimental data obtained on a Nb–Ti-modified industrial HP grade. The experimental measurements include phase equilibrium data at different temperatures and liquidus/solidus determination. The obtained agreement between experiments and calculations is generally good. Conclusions are made concerning the most suitable thermodynamic database to describe highly alloyed austenitic refractory steels.