Abstract:Large-scale and complex thick-walled titanium alloy casings produced by investment casting are key components in heavy-duty gas turbine. Characterized by their large contour size, substantial wall thicknesses, and complex shapes, these castings often face challenges such as difficult monolithic molding, numerous shrinkage pore and shrinkage cavity defects, and low dimensional accuracy, limiting the assembly and use of high-power gas turbines. The solidification temperature field and flow field during centrifugal investment casting process were investigated using the ProCAST software. Results show that the potential isolated liquid phase regions are identified. According to the characteristics of centrifugal casting, the mathematical models for designing spiral runner and inclined riser are derived. Based on this, an integrated gating system is developed, which combines exhaust gas and slag collection, flow regulation, and temperature field optimization, thereby significantly reducing solidification defects in castings. Furthermore, a wax mold splicing scheme is designed, and a wax mold tree for the gating system is constructed, featuring a straight runner, cross runner, and inner runner with cross-sectional area ratios of 1:2.5:6. Additionally, through the integration of dimensional calibration and shell reinforcement tooling, high-quality castings with complete filling, good metallurgical quality, and precise dimensional accuracy are achieved. This work provides effective technical guidance for the manufacturing of titanium alloy casings in heavy-duty gas turbines, and the gating system configuration offers reference value for other large-scale and complex thick-walled titanium alloy castings.