Thermodynamic formula for the A_cm temperature of low alloy steels

Many thermodynamic studies have been formed to calculate the phase diagrams, which provides various basic information for predicting the quantitative kinetics of phase transformations in low alloy steels. The temperature values on the phase boundaries of austenite/(ferrite + austenite) and austenite/(cementite + austenite) at a certain carbon content are called A_e3 and A_cm temperatures of steel. The A_e1 temperature is defined as the eutectoid temperature corresponding to the intersection point of two phase boundaries of austenite. The partitioning effects of alloying elements such as nickel (Ni), chromium (Cr) and molybdenum (Mo) occurring during the austenite decomposition on the phase diagrams of the steels have been investigated with ortho-equilibrium (OE) and paraequilibrium (PE) models in low alloy steels.