低镍奥氏体不锈钢定向凝固组织CAFE法模拟

通过对ProCAST&CAFE软件进行二次开发建立凝固过程动态边界条件,模拟低镍奥氏体不锈钢定向凝固过程中的温度场和固相分数,并探讨抽拉速率对凝固微观组织的影响。结果表明,随着抽拉速率的增大,等温线变密,糊状区变窄;铸件一次枝晶臂逐渐细化,边缘侧向散热逐渐远小于中心纵向散热造成一次枝晶轴向偏差度逐渐减小,晶粒择优取向效果提高。与此同时,模拟结果与实验结果吻合较好,模拟计算形核、生长及取向过程较为合理。

CAFE simulation of directional solidification structure of low nickel austenitic stainless steel

In this paper, through the secondary development of ProCAST&CAFE software, the dynamic boundary conditions of solidification process were established, the temperature field and solid fraction in the directional solidification process of low nickel austenitic stainless steel were simulated, and the effect of the pull rate on solidification microstructure was discussed. The results shows that the withdrawal rate is in the range of 15~200 μm/s, as the solidification speed increases, the isotherm becomes dense,gummy zone narrowing. And as the solidification rate increases, the primary dendrite arm gradually refines and the secondary dendrite arm becomes dense and coarse. In addition, as the withdrawal rate increases in the range of 15 to 200 μm/s, the lateral heat dissipation of the edge of the casting is gradually smaller than that of the central longitudinal heat dissipation, and the axial deviation of the dendrites is reduced from 27.66 ° to 25.964 °. At the same time, the comparative analysis simulation results are in good agreement with the experimental results, and the simulation calculation process is more reasonable.