采用真空感应熔炼+离心铸造的工艺制备Incoloy825管材，研究其组织的凝固行为和微观晶粒特征。使用ProCAST软件建立真空离心铸造仿真模型，模拟计算合金充型与凝固过程。结果表明：浇注温度为1480~1520 ℃时，金属液成型效果好。铸型转速达到800 r/min以上时，金属液沿铸型壁均匀分布。当浇注温度在1480 ℃以上时，缩孔率减小到0%~1.33%。在浇注温度为1520 ℃、铸型转速为800 r/min工艺下，铸件下、中、上部的开始凝固时间分别为9.61、12.53 s和14.32 s。根据仿真结果制定最优工艺参数并进行铸造实验后，对铸件的微观组织进行分区分析，观察到从铸件中心区到外层区的枝晶平均长度从271 μm逐渐减小至121 μm，显示出组织沿冷却方向存在较高的晶粒尺寸梯度。

To investigate the solidification behavior and microstructure characteristics of Incoloy825 alloy pipe by using the vacuum centrifugal casting （VCC） process， a simulation model of VCC is established using ProCAST software to simulate and calculate the filling and solidification process of the alloy. The results show that the metal liquid exhibits good forming effects at pouring temperatures between 1480 ℃ and 1520 ℃. When the mold rotation speed exceeds 800 r/min， the metal liquid can be uniformly distributed along the mold wall. The pouring temperature above 1480 ℃ reduces the shrinkage rate to 0%-1.33%. At the pouring temperature of 1520 ℃ and the mold rotation speed of 800 r/min， the initial solidification time for the lower， middle， and upper parts of the casting is 9.61， 12.53 s， and 14.32 s， respectively. Based on the simulation results， optimal process parameters are determined and casting experiments are conducted. Microstructure analysis of the castings reveals that the average length of dendrites from the center to the outer layer of the casting gradually decreases from 271 μm to 121 μm， indicating a significant grain size gradient along the cooling direction of the microstructure.