430不锈钢凝固显微组织模拟的3D CAFE模型

3D CAFE model for simulating the solidification microstructure of 430 stainless steel

在同时考虑传热、流动和溶质扩散基础上建立了预测铁素体不锈钢多元合金凝固组织的3D CAFE模型,揭示了430不锈钢凝固过程中温度、固相率及晶粒形貌的变化规律.模型中采用高斯分布描述形核密度与过冷度的关系,应用KGT模型描述枝晶的生长过程.根据Fe--C--17%Cr平衡相图确定了430不锈钢的凝固路径,在考虑凝固收缩的基础上预测了铸锭的疏松和缩孔分布.组织模拟结果与实际铸锭基本一致,二者的温度变化和组织结构特征也基本吻合.

Taking heat transfer, flow of liquids, and solute diffusion into account, a three-dimensional cellular automata-finite element （3D CAFE） model was built to simulate the solidification microstructure of 430 stainless steel. Based on the model, the change laws of temperature, solidification fraction and grain morphology in the steel ingot were revealed during the solidification process. In the model, Gaussian distribution was employed to describe the relationship between the grain nucleation density and the degree of undercooling, and the KGT model was adopted to describe the dendrite growth. According to the Fe-C-17%Cr equilibrium phase diagram, the solidification path was determined, and the distribution of porosities and shrinkage cavities in the steel ingot was predicted. The temperature history and the final microstructure simulated by the model are in agreement with experimental results.