CALCULATION OF Fe-C-S TERNARY PHASE DIAGRAM.

Abstract

The phase diagram of the Fe-C-S ternary system was calculated on the basis of the Fe-S and Fe-C binary systems analyzed by Hillert and Staffansson, and the present authors, respectively. The selected data on the graphite solubility in the liquid phase were also used for evaluating the ternary thermodynamic parameter. The Gibbs energy of the individual phase was described by assuming that C and S atoms behave as interstitial atoms in the liquid phase, as well as in austenite and ferrite. Moreover, the influence of ferromagnetism on the Gibbs energy of ferrite was taken into account by using a simple and explicit approximation of the Gibbs energy change due to the magnetic transition.