基于Procast的高Nb-TiAl低压涡轮叶片离心铸造数值模拟

Numerical Simulation of High Nb-Ti Al Low Pressure Turbine Blades Centrifugal Casting Based on Procast

采用Procast铸造模拟软件,模拟了高Nb-Ti Al合金低压涡轮叶片离心铸造过程。在其他工艺参数一定的条件下,研究不同离心转速对叶片充型、凝固过程的影响。模拟结果显示,离心转速越大,叶片中缩孔缩松缺陷体积越小,所生产的铸件越致密。但是,当离心转速达到500 r/min时,金属熔体主要由上部横浇道注入,与两端同时注入方式相比,浇注效率低,而且气体不易排出,容易产生卷气缺陷。并且离心转速大会增加金属熔体对型腔壁的冲刷作用,容易产生夹砂缺陷。综合考虑,最终本模型的最佳离心转速确定为400 r/min。

Centrifugal casting process of high Nb-TiA1 alloy low pressure turbine blades was simulated by Procast software. In the case of other process parameters constant, effects of centrifugal rotational speed on filling and solidification process were studied. Simulation results show that the greater the centrifugal rotational speed was, the smaller the shrinkage defects in the blades and the higher the density of the castings. However, when the centrifugal rotational speed reached 500 r/min, molten metal injected the mould mainly from the upper runner, which had lower pouring efficiency and entrapped air defect compared with both ends injection method. Moreover, larger centrifugal rotational speed would increase the erosion effect on the cavity wall by molten metal, which would lead to scab defect. Finally, the optimal rotational speed of this model was determined to be 400 r/min.