THE CHROMIUM EQUIVALENTS OF SELECTED ELEMENTS IN AUSTENITIC STAINLESS-STEELS

Using the well-established thermodynamic description of the Fe-Cr-Ni s ystem, we have computed-the austenite-ferrite equilibrium in Fe-Cr-Ni- X quaternary systems, where X is a ferrite-stabilizing element. The re sults are considered reliable, especially for small additions of X. Fr om the computed equilibria, the Cr equivalents of a number of ferrite stabilizers, Al, Mo, Nb, Si, Ti, V, and W, have been derived. They sho w satisfactory agreement with the known experimental range. The distin guishing feature of the thermodynamic calculations is that the Cr equi valents are established as a function of annealing temperature as well as Ni content, in contrast to the fixed values reported in the empiri cal diagrams obtained under variable experimental conditions.