MODELING REAUSTENITIZATION FROM FERRITE CEMENTITE MIXTURES IN FE-C STEELS

The formulation of austenite which occurs upon heating low-alloy steel s is known as reaustenitisation. Phase transformation theory applicabl e to the formulation of austenite from ferrite/cementite mixtures in F e-C steels is described. The assumption of local equilibrium is made. Diffusion of carbon in cementite and ferrite is ignored. Under these a ssumptions, the process is controlled by the diffusion in austenite, t he growing phase. Exact solutions to the equations are compared with r esults obtained using the finite difference method, for one-dimensiona l growth. It is found that the finite difference method is subjected t o numerical inaccuracies which can be considerable. A method to circum vent this problem is described. Reverse time-temperature-transformatio n diagrams for Fe-C steels are presented.