Kinetic Modelling of Powder-Pack Boronized 4Cr5MoSiV1 Steel by Two Distinct Approaches

Abstract

This work attempts to model the powder-pack boronizing kinetics of 4Cr5MoSiV1 steel in the interval of 1133 and 1253 K in order to predict the layers’ thicknesses. The first approach is referred to as the bilayer model and relies on the conservation principle of mass balance equations at the two phase fronts accounting for the linearity of boron distribution across each boride phase. The second approach deals with the application of dimensional analysis to simulate the boronizing kinetics of 4Cr5MoSiV1 steel. Using the bilayer model and the classical parabolic law, the boron activation energies in FeB and Fe2B were evaluated and discussed in light of the literature data. The estimated boron activation energies from the bilayer model were respectively equal to 164.92 and 153.39 kJ mol−1. These values were very comparable to those calculated from the classical parabolic law. Finally, it was proven that the dimensional analysis was able to simulate the layers’ thicknesses for the selected processing parameters.