DILATOMETRIC AND METALLOGRAPHIC STUDIES FOR VERIFYING PHASE TRANSFORMATIONS MESOSCALE MODEL

The aim of the study was to perform a series of dilatometric experiments, which would be used to further verify and validate a phase transformation mesoscale model based on the cellular automata method. As a result of the study, a CCT graph for steel S355J was developed, which was the basis for further studies of phase transformation kinetics. Subsequently, the study of microstructure using light and scanning microscopy allowed for a qualitative determination of the occurrence of individual structural components in each dilatometric sample. The results of the quantitative analysis of microstructures were used to determine the average primary austenite grain size, as well as to develop a digital material representation. The studies of phase transformation kinetics were carried out using an original computer tool for quantitative dilatometric analysis. Thus, the curves of volume fraction changes of individual structural components as a function of time and temperature were obtained on the basis of data directly from the recorded dilatometric tests. The presented results of quantitative dilatometric analysis with final volume fractions of individual structural components for various cooling rates are a valuable source of data for the direct validation of the mesoscale model of phase transformations.