Modeling Dissolution of Vanadium Carbide and Carbonitride in Fe–C–V(–N) Austenite

Abstract

A computer model is constructed to simulate the dissolution of V carbide and carbonitride with size distribution in steels. Assuming local equilibrium of carbon, nitrogen, and V at the particle/matrix interface, the dissolution rate is calculated using the mean-field and invariant field approximations. The fraction of particles and size distribution (PSD) of V carbide are in good agreement with those in an Fe-C-V alloy reported in the literature. The V mass fraction and PSD of carbonitride, measured by extraction replica in this study, were also reproduced well by simulation in an Fe-C-V-N alloy (N~20 ppm). Moreover, simulation with an equilibrium tie-line passing through the bulk alloy composition, as often done in the calculation of precipitate dissolution rate, yielded a large error.