The Exploring Of The Simulation Of Solidification Microstructure In Electron Beam Welding

The solidification microstructure of welding pool has an important effect on the performance of welding joints. The traditional experiment methods are time-consuming and difficult to do, so many scholars turned to study the simulation of microstructure. And cellular automaton is usually used on the simulation of microstructure.In this paper, a local area is intercepted, and the interception of the local area from a welding pool accords to pool boundary curvature at different positions. Local areas in different parts of welding poor apply different methods. And different microscopic temperature field is attained by different interpolation method.Based on the physical background of welding pool solidification, two-dimensional cellular automaton model to simulate the growth of columnar crystals is established. The paper discussed the distribution of solute concentration of grains and the influence on columnar grain growth in the small region near the fusion line under different the base metal grain density and the cooling rate. Temperature fields on different temperature gradients, uniform changes in temperature gradient and the non-uniform temperature gradient have a great impact on the growth of columnar crystal .Simulation results show that the solute concentration of the solid phase which are parallel to the growth direction increases as the distance between the cell which is studied and the nucleation sites becomes greater; Among the cells which are perpendicular to the growth direction, ones which are sited between the columnar crystals have high solute concentration; with the cooling rate increases, the average growing rate of grains increased; as nucleation density increases, the radius of columnar crystals is smaller. Then which can be inferred is that with the number of base-metal grain increasing, the average radius of the columnar crystals on the entire pool is smaller.