Kinetics and dilatometric behaviour of non-isothermal ferrite-austenite transformation

A model that describes the ferrite - austenite transformation during contin uous heating in Armco iron and three very low carbon, low manganese steels with a fully ferritic initial microstructure is presented. This model allow s calculation of the volume fractions of austenite and ferrite during trans formation as a function of temperature, and hence knowledge of the austenit e formation kinetics under non-isothermal conditions in fully ferritic stee ls. Moreover, since dilatometric analysis is a technique very often used to study phase transformations in steels, a second model, which describes the dilatometric behaviour of the material and calculates the relative change in length that occurs during the ferrite -austenite transformation, has als o been developed. Both kinetics and dilatometric models have been validated by comparison of theoretical and experimental dilatometric heating curves. Predicted and experimental results are in satisfactory agreement.