This paper identifies and describes the parameters of a numerical model generating the microstructure in the integrated heating-remelting-cooling process of steel specimens. The numerical model allows the heating-remelting-cooling process to be simulated comprehensively. The model is based on the Monte Carlo (MC) method and the finite element method (FEM), and works within the entire volume of the steel sample, contrary to previous studies, in which calculations were carried out for selected, relatively small areas. Experimental studies constituting the basis for the identification and description of model parameters such as: probability function, initial number of orientations, number of cells and number of MC steps were carried out using the Gleeble 3800 thermo-mechanical simulator. The use of GPU capabilities improved the performance of the numerical model and significantly reduced the simulation time. Thanks to the significant acceleration of simulation times, it became possible to comprehensively implement a numerical model of the heating-transformation-cooling process in the entire volume of the test sample. The paper is supplemented by results of performance tests of the numerical model and results of simulation tests.

The aim of the performed experiments was to determine the influence of a cooling rate on the evolution of microstructure and hardness of the steel 27MnCrB5. By using dilatometric tests performed on the plastometer Gleeble 3800 and by using mathematical modelling in the software QTSteel a continuous cooling transformation diagram for a heating temperature of 850°C was constructed. Conformity of diagrams constructed for both methods is relatively good, except for the position and shape of the ferrite nose. The values of hardness, temperatures of phase transformations and the volume fractions of structural phases upon cooling from the temperature of 850°C at the rate from 0.16°C · s–1 to 37.2°C · s–1 were determined. Mathematically predicted proportion of martensite with real data was of relatively solid conformity, but the hardness values evaluated by mathematical modelling was always higher.