1. Pretreatment before simulation
After drawing the gating system, use ProCAST software to mesh the shell and select an appropriate mesh step to ensure accurate total time and simulation results during the numerical simulation analysis process. Import a steel casting from the Visual Mesh work page. The mesh step of the steel casting is set to 30mm, with a total of 12722 divided face meshes and 45906 volume meshes. Using Mesh’s Checks process, check the mesh division for cracks, intersections, breakage, overlap, and mating problems from 1D, 2D, and 3D in turn. Thoroughly repair these defects during the mesh division stage, and complete the final volume mesh establishment. In the pre-treatment stage, the steel casting material is set as Medium Carbon AISI1040 (ZG270-500), resin sand molding and core making, and the molding sand and sand core material are silicon sand. The sand mold temperature is 25 ℃, the cooling method is COINC, and the heat transfer coefficient between metal and sand mold is 1000 W/(m2 · K). Set parameters such as gravitational acceleration, boundary conditions, and cooling method in sequence.
2. Simulation and Analysis of Molten Metal Filling and Solidification Process
Set the pouring temperature to 1560 ℃ and the pouring speed to 1.6m/s. After setting, use simulation software to simulate the two schemes, and the simulation results are shown in Figure 1 and Figure 2. As can be seen from Figure 1 and Figure 2, there is a lack of pouring defect above the cylindrical part of the shell. Therefore, two open risers have been designed and simulated at the insufficient pouring part. The temperature field of Scheme 1 is shown in Figure 3, and the pore distribution diagram is shown in Figure 4. The temperature field of Scheme 2 is shown in Figure 5, and the pore distribution diagram is shown in Figure 6. The pore volume of Scheme 1 is 28.23 cm3, and that of Scheme 2 is 50.58 cm3. Due to too many defects, the shell steel casting cannot be used.