Phase Precipitation Prediction in the X65 Steel Grade and Modified UNS N06625 Alloy

This study presents the results of a simulation that investigated phase precipitation in an X65 steel grade and modified alloy 625 system. The simulation was performed with Thermo-Calc 2023b and the Ni-database TTNI8. The information that was gathered helps to provide essential details, such as the chemical compositions that were used in the diluted simulations. In the simulations, X65 is compared to 0.01% Nb 625, 2.1% Nb 625, and 3.6% Nb 625. The solvus temperature for all phases is investigated under equilibrium conditions across a temperature range from 400 K to 2000 K. The influences of niobium content on phase precipitation in X65 steel and modified 625 alloy are evident. Increasing niobium content results leading to precipitation of multiple phases during solidification and thermal exposure.