Through the model established by SolidWorks software, the MeshCAST module in ProCAST software can be imported for mesh division and repair of valve body, and tetrahedral mesh is used for mesh division. After division, there are 41558 face meshes and 529446 volume meshes. The result of grid division is shown in the figure.
The contact of EPC foam pattern with liquid metal will produce a large amount of gas, which can be discharged through the sand mold. The correct selection of thermophysical parameters of foam pattern and sand mold can effectively improve the accuracy of lost foam casting simulation. See Table 1 and Table 2 for the thermophysical data.
|Density/(kg · m ^ – 3)||25|
|Specific heat capacity/(kJ · kg ^ – 1 · Kv ^ – 1)||3.7|
|Latent heat/(kJ · kg ^ – 1)||100|
|Thermal conductivity/(W · mv-1 · K ^ – 1)||0.15|
|Solid phase temperature/℃||330|
|Liquid phase temperature/℃||350|
The simulation parameters of ProCAST software are set as follows: the gate cup material is assigned ZG230-450, the sand mold material is Sand Permeable Foam, the stress type is defined as rigid body, and the foam pattern material is assigned FOAM.
|Density/(kg · m ^ – 3)||1520|
|Thermal conductivity/(W · m ^ – 1 · K ^ – 1)||0.53|
|Specific heat capacity/(kJ · kg ^ – 1 · K ^ – 1)||1.22|
|Air permeability/cm ^ 2||1×10^-7|
The type of contact surface between metal and foam is EQUIV, the type of contact surface between foam and sand mold, the type of contact surface between metal and sand mold is COINC, the heat exchange coefficient between foam and sand mold is 150 W/(m2 · K), the heat exchange coefficient between metal and sand mold is 500 W/(m2 · K), the cooling mode of pouring position is air cooling, the initial pouring temperature is set to 1580 ℃, the initial temperature of foam pattern and sand mold is set to 25 ℃, and the pouring speed is set to 89 mm/s, The vacuum degree is set to 0.05 MPa, and the simulation type parameter is switched to the lost foam casting mode.