电渣重熔GH984G定向凝固组织CAFE法模拟

CAFE simulation of electroslag remelting GH984G directional solidification structure

电渣重熔凝固组织的控制直接关系到高温合金的品质与实际生产应用。针对电渣重熔GH984G的定向凝固过程,同时考虑传热和溶质扩散,基于CAFE法与C语言结合,建立了三维电渣重熔凝固过程组织演变的CAFE模型,并对凝固过程温度场和凝固组织演变进行模拟预测。结果表明,铸锭温度场和熔池深度都是首先为较浅平状态,然后不断加深至最后稳定;在电极熔化初始,金属熔池浅平,枝晶生长方向是竖直向上,之后金属熔池不断加深,底部竖直向上的柱状晶方向变为斜向上约26°。同时在铸锭的中心线上出现了等轴晶,等轴晶形核长大后与柱状晶镶嵌生长。此外,随着电极熔速变大,渣金界面上涨速度也随之变大,且熔池深度相应变宽变深。模拟结果与试验结果基本吻合,从而验证了模型与形核参数的适用性。

The control of electroslag remelting solidification structure is directly related to the quality of superalloys and actual production applications.Aiming at the directional solidification process of electroslag remelting GH984G,considering heat transfer and solute diffusion,based on the combination of CAFE method and C language,a threedimensional microstructure evolution model of the electroslag remelting solidification process is established,and the temperature field and solidification structure evolution are simulated and predicted.The results show that,the ingot temperature field and bath depth are shallow and flat at first,then deepen until finally stable.At the beginning of electrode melting,the molten pool is shallow and the growth direction of the dendrite is vertical upward,and then the molten pool deepens continuously,and the vertical upward columnar crystal direction at the bottom becomes about 26°oblique upward.At the same time,equiaxed crystals appear on the centerline of the ingot,and the equiaxed crystals grow with columnar crystals after nucleation and growth.Besides,with the increase of the electrode melting rate,the rising speed of the slag metal interface increases,and the depth bath becomes wider and deeper.The simulation results are consistent with the experimental results,which verifies the applicability of the model and nucleation parameters.