Numerical simulation-driven optimization of the counter-gravity adjusted-pressure casting process for large thin-wall Ni-based superalloy combustion chamber casings

With the increasing demand for high thrust-to-weight ratio in aerospace engines, the production of Ni-based superalloy castings with large, thin-wall structures has become increasingly critical. This study utilizes ProCast software to optimize the counter-gravity adjusted-pressure casting (APC) process for fabricating a Ni-based superalloy combustion chamber casing with complex thin-wall geometries. According to shrinkage porosity prediction results, the optimized APC process parameters are determined (pouring temperature of 1530 °C, holding pressure of 25 kPa, and initial mold temperature of 1000 °C). Filling simulations conducted under the optimized parameters reveal a stable three-stage filling sequence: (1) the bottom horizontal region filling; (2) thin-wall region filling; (3) difficult-to-fill region filling. Solidification simulations demonstrate delayed cooling at deep recesses of inner and outer rings due to reduced heat transfer rates. Microstructural characterization indicates finer grains and γ′ precipitates in thin-wall regions compared to flange regions, correlating with enhanced yield strength (529 MPa–588 MPa) in thin-wall sections. This study provides valuable insights into the optimization of APC process for large, thin-wall Ni-based superalloy components.