Cellular automaton simulation of microstructure evolution during austenitedecomposition under continuous cooling conditions

A two-dimensional diffusion based model is developed to describe transforma tion of austenite into ferrite and pearlite under continuous cooling condit ions. The nucleation of ferrite is assumed to occur over grain boundaries a nd the nucleation of pearlite is assumed to be taking place all over the gr ain and at growing ferrite-austenite interfaces, when the composition and t emperature conditions are favourable. A cellular automaton algorithm with t ransformation rules based on this model is used for the growth of ferrite a nd pear-lite, Model predicted results for continuous cooling transformation s are verified by comparing the model predicted microstructure features wit h the experimental measurements for two sets of plain carbon steels of diff erent composition and austenite grain size. Using the model, it is possible to generate results like undercooling to start ferrite and pearlite transf ormations, which are difficult to obtain experimentally.