The Primary Simulation Of Solidification In Welding Pour Using Cellular Automaton

The traditional testing method for analying microstructure takes much more time and cost a lot. It can not exactly predict the phenomenon such as dendritic morphology, segregation patterns etc in micro-scale. With the application and development of computer numerical simulation, deterministic or stochastic models were established to simulate the evolution of columnar and equiaxed dendritic morphologies. In this paper, Cellular Automaton(CA), one of the numeric simulation methods, is used for first time to simulate the evolution and morphology of the microstructure in welding.The Cellular Automaton(CA) is coupled with Finite Difference Method(FDM) here to establish the stochastic nucleation and growth model including the 2D decentered square algorithm. The CA is used to simulate the solidification structure, where the FDM is used to calculate the temperature and solute diffusion. In the situation of fast solidification, the temperature and solute distribution in solid-liquid phase and interface, kinetic undercooling, the curvature at dendrite tip, and the growth anisotropy are considered here as factors which have effects on the nucleation and growth of dendrites.At the given welding situation, there is the equiaxed dendritic zone in the center of weld. The CA-FD model is used to simulate the evolution and morphology of equiaxed dendrite and solute distribution, to analyze the different effect on the dendritic morphology when the alloy component and cooling velocity change. The result shows that secondary and tertiary dendrites are observed emanating from primary and secondary dendrites respectively, competative growth between side branches appears. The change of alloy component and cooling velocity have different effect on the equiaxed dendritic growth rates.The zone at welding pour beside melting line is usually columnar dendrite, of which spacing determines the mechanical property of the weld to certain extent. Importing temperature circle and thermal gradient of welding process, this paper uses CA-FD model to simulate the evolution and morphology of equiaxed dendrite and solute distribution. The effect on the primary dendritic...