Three-dimensional diffusion model for austenitisation of ferritic spheroidal graphite irons

A mathematical model has been developed for studying the diffusion kinetics of carbon during the austenitisation of a ferritic ductile ii on. In modelling the diffusion process, the finite difference method was used and the diffusion equation was solved using the Crank-Nicolson (implicit)form. The results obtained were compared with those from the conventional error function estimates. For short diffusion distances, that is, spheroidal graphite irons with a high nodule count, the diffusion times required to attain carbon equilibrium suggested by the finite difference and error function methods were similar. For medium to low nodule counts, the times predicted by the error function estimate were less than those suggested by the finite difference analysis. MST/4134.