Modeling of ferrite structure after deformation in the two-phase region

This study presents some modeling aspects of microstructure development under intercritical (austenite–ferrite two-phase region) forming conditions in microalloyed and low carbon steels. The employed integrated computer model effectively links the advanced finite-element approach simulating metal flow and heat transfer during hot plastic deformation with the submodels describing complex microstructure development. It is proposed that a correct quantitative description of the microstructure allows the selection of processing parameters to control the microstructure inhomogeneity. The effective strain accumulated in the ferrite phase and temperature distributions were combined with the empirical formulas that enable calculation of ferrite grain size with separation between the two mechanisms of refinement process, i.e., transformation from hardened austenite and ferrite recrystallization. The predicted ferrite structures show reasonable agreement with those obtained in various experiments. Hence, the distribution of the mechanical properties will naturally be predicted based on the initial process conditions and using the proposed modeling procedure.