A large body of knowledge on the carburization of engineering alloys used in high-temperature petrochemical processing equipment is being developed. The capability includes: the facility to perform thermochemical assessments of carbide formation on complex alloys in diverse conditions and the capability to predict carburization for various exposure conditions. The alloys considered are widely used, commercial and based upon mixtures of Fe-Cr-Ni-Co. The gaseous exposure conditions considered contain CHa-H2-HzS-H20. The thermochemical data models have been prepared to predict phase formation of potential corrosion products. They are based upon extensive analyses of all available thermochemical data for all possible solid and liquid compounds and solutions based upon all combinations of Fe-Cr-Ni-Co-S-C-O-N and for all possible gaseous species containing S-C-O-H-N. As well, the alloying elements A1, Mo, Nb, Ti, V, W, Mn and Si are fully included in the alloy and carbonitride solution models. Comprehensive solution models are used in Gibbs free energy minimization calculations to assess the interactions of multiple species in variable composition solid and liquid phase alloys, sulfides, oxides, carbides, and nitrides. This capability is used to predict the most stable corrosion product formation, which is then used to infer the dominant corrosion mechanism, in complex conditions.