Modelling of isothermal formation of pearlite and subsequent reaustenitisation in eutectoid steel during continuous heating

Three different morphologies of pearlite have been formed isothermally at t hree different temperatures in a eutectoid steel. Moreover, the interlamell ar spacing of the pearlite was calculated using the Zener and Hillert theor etical method. Experimental results suggest that the growth of pearlite is mainly controlled by volume diffusion of carbon in austenite, in the temper ature range studied in this steel, In addition, a model that describes pear lite to austenite transformation during continuous heating in a eutectoid s teel has been developed. The influence of structural parameters, such as in terlamellar spacing and edge length of pearlite colonies, an the transforma tion kinetics has been experimentally studied and considered in the modelin g. It has been found that the kinetics of pearlite to austenite transformat ion are slower the coarser the initial pearlite microstructure, Experimenta l validation of this model has been carried out and a good agreement (an ac curacy level of higher than 90% in square correlation factor) between the e xperimental and calculated values has been found.