Computer Simulation Of Austenite Grain Growth In HAZ Of Ultra-Fine Grain Steel

In this paper. Monte Carlo (MC) technique was used to simulate the grain growth in heat-affected zone of an ultra-fine grain steel. The ultra-fine grain steel is the 21th century oriented new generation steel. We have developed the three dimension non-isothermal MC simulation system, and applied it to simulate the austenite grain growth in the HAZ of ultra-fine grain steel. The simulated results were compared with experimental results. Some factors influencing the grain growth were studied in detail using MC technique.The MC simulation of grain growth can provide not only grain growth kinetics but also detailed information on temporal grain morphology evolution. Furthermore, MC technique can easily simulate the "thermal pin" phenomenal caused by steep temperature gradient near the weld interface. The experimental data based (EBD) model proposed by Gao was used to establish the relation between IMCS and real time temperature kinetics in our simulation.MC simulation is the main methodology in our research. Based upon the 3D isothermal MC software, an integrate 3D non-isothermal MC simulation system was developed, which is a Microsoft Windows based computer program. Input the temperature field data and material properties, the program can simulate the evolution of grain structure, both image of simulated grain structure and numerical datum reflecting grain size distribution can be produced by the program. We apply the system to the ultra-fine grain steel welding, the simulated mean grain size in CGHAZ agreed well with the corresponding independent experimental data.In this paper, three factors influencing the grain growth, the steep temperature gradient in HAZ. the grain boundary liquid and the precipitates particle, were studied specially using MC technique.Our research indicates significant promise for understanding grain growth phenomena in HAZ, based on the 3D MC technique. The simulations of austenite grain growth in HAZ of ultra-fine grain steel make foundation for future research work.