3D Simulation Of Grain Growth In Welding Heat-Affected Zone By Monte Carlo Technique

During the welding process, the coarsen grain in the heat affected zone (HAZ) significantly reduce the material plasticity and toughness, which causes the mechanical property of the weld joints decrease. In this paper, MC technique is adopted to simulate the process of grain growth in HAZ and predict final grain size distribution. To simulation of grain growth, the relative software is developed.According to the base principium of MC technique and the characteristic of grain growth in HAZ, the 3D MC model is established. In the model, two simulation domains are selected to obtain the different grain structure evolution; the discrete form of simulation domain and the mode of initializing elements orientation are determined; the 3D MC computation model is established to simulate the process of grain growth; three kinds of boundary conditions are defined to consider the effect of adjoin domains to the grain growth of simulation domain.The simulation software of grain growth in HAZ is designed based on the 3D MC model. The whole system contains three parts: pretreatment, MC simulation and post treatment, and each part performs its own function by corresponding modules. In the two treatment modules of domain data, the simulation domain is selected and dispersed,domain data and temperature data are obtained. In the treatment module of temperature data, selection probability of each site is calculated. In the MC computation module, the simulation of grain growth in the condition of con-temperature and welding is implemented. In the module of regression, the constants of the 3D MC model are regressed. In the drawing module of graph, geometric figure of simulated domain, thermal circulation curve and selection probability of each site and grain size distribution are visual.With the developed software, the process of grain growth in HAZ is simulated. During con-temperature grain growing, the change of average grain size and topology that is obtained is coincident well with the grain growth kinetics and the actual process of grain growth. The final grain size distribution...