Modeling of shrinkage during investment casting of thin-walled hollow turbine blades

The shrinkage ratio is a key parameter in designing the investment casting die for hollow turbine blades of high-performance aircraft engines. To avoid extensive modifications to the die shape, we took a single-crystal hollow turbine blade as the typical part to determine the nonuniform shrinkage distribution while considering its structural characteristics during investment casting. By using the structural identification method, different geometrical structures were identified, and the displacement field was established and verified via numerical prediction and experimental measurement. The deformation characteristics, including the wall-thickness distribution and shrinkage ratio, can be established by deformation decoupling analysis. The optimized die profile designed on the basis of the calculation results is in good agreement with the investment casting die in actual use, which indicates that the proposed method is beneficial for improving the geometrical accuracy of hollow turbine blades.