Numerical Simulation of Austempering Heat Treatment of a Ductile Cast Iron

Abstract

This paper presents a coupled thermo-mechanical-metallurgical formulation to predict thedimensional changes and microstructure of a ductile cast iron part as a consequence of anaustempering heat process. To take into account the different complex phenomena which arepresent in the process, the stress-strain law and plastic evolution equations are defined within thecontext of the associate rate-independent thermo-plasticity theory. The metallurgical modelconsiders the reverse eutectoid, ausferritic, and martensitic transformations using macro- andmicro-models. The resulting model is solved using the finite element method. The performanceof this model is evaluated by comparison with experimental results of a dilatometric test. Theresults indicate that both the experimental evolution of deformation and temperature are wellrepresented by the numerical model.