Solid modeling of turbine rear exhaust pipe by Lost Foam Casting

The research object comes from the turbine rear exhaust pipe of ZHY casting. The turbine rear exhaust pipe is the connecting pipe connecting the supercharger and the muffler. In the process of vehicle driving, the turbine rear exhaust pipe needs to bear the exhaust gas generated by the combustion of the mixture of gasoline and air in the cylinder. Therefore, it must have seismic resistance, wear resistance, heat resistance and air tightness. At present, the production of the enterprise mainly adopts lost foam casting, which has the phenomena of low product qualification rate, long production cycle and much material waste. The rear exhaust pipe of the turbine produced has the problems of air leakage and easy fracture during the driving of the vehicle. Using modern numerical simulation technology of lost foam casting, through computer numerical simulation of lost foam castings, the trial production cycle of products can be shortened, the efficiency can be improved, and the defects of products can be reduced at the same time. It has certain guiding significance for improving the blindness of process formulation and the number of tests, and provides a basis for enterprises to produce qualified lost foam castings in the shortest time.

The three-dimensional solid dimensions of lost foam castings are provided by the enterprise. According to the solid structure of lost foam castings and combined with the dimensional data provided by the enterprise, the solid model of turbine rear exhaust nozzle is established by using the three-dimensional modeling software Pro / E. The lost foam casting of turbine rear exhaust pipe is poured with four pieces in one box. The assembly of lost foam casting and gating system is obtained by Pro / E solid modeling method.

With the help of ProCAST software, the lost foam casting process is evaluated and optimized, and the changes of insufficient filling, shrinkage cavity and porosity in the process of metal lost foam casting are simulated to guide the further process improvement. After many times of meshing and comparison, the exhaust nozzle is finally obtained Mesh format volume grid file; The total number of grids obtained is 1213240 nodes and 6881836 units.

Based on the numerical simulation theory of lost foam casting, the numerical simulation of turbine rear exhaust pipe is carried out by using the numerical simulation software platform. According to the structural characteristics of the exhaust pipe after the turbine, the gating system, sand core and pattern are calculated and designed. The research of this paper solves the problems of low yield and too many internal shrinkage defects in lost foam casting production of turbine rear exhaust pipe, which has certain guiding significance for shortening the product development cycle and reducing the production cost, and can also be used as a reference for the optimization of casting process of other products.