Numerical Simulation Study on K418 Superalloy Supercharger Turbine Precision Casting Process

In this paper, the precision casting process of K418 high-temperature alloy turbocharger turbine is simulated by using the MAGMA casting simulation software, then the fluid temperature field during casting and liquid phase temperature field during solidification are studied. Combined with the simulation results, a turbocharger turbine is produced, and the metallographic structure of the turbine is analyzed. The simulation results show that in the designed casting system, the casting temperature is 1 550 ℃, and it ensures a good filling capacity of the alloy liquid. The solidification sequence of castings is as follows: blade edge - blade - blade axis - pouring riser - pouring riser center. This sequence ensures that the turbine parts are well formed, and the possible location of defects such as shrinkage is located in the outlet area. The microstructure of the turbine is dense and without defects. The position of the blade is composed of columnar crystals and fine equiaxed crystals. The root of the blade and the axial center of the turbine are arranged equiaxed crystals. The casting system and casting temperature designed in this paper are reasonable and could be used as guiding scheme for the actual production.