Steel castings are widely used in the fields of mining machinery, transportation, locomotive traction, lifting machinery, and wind power. Sand casting is still used in the production of many steel castings due to its wide applicability and low production costs. Zheng Baotang has well simulated the process plan for the steel casting of the 17-type coupler body of a railway freight car. The casting process parameters are as follows: the pouring temperature is 1580 ℃, and the pouring speed is 75 cm/s when the mold is filled for 30 seconds. Han Bao et al. conducted optimization design and numerical simulation on the casting process of wheel axle steel castings. The research results showed that the pouring temperature was 1570 ℃ and the pouring speed was 10kg/s. Liu Chen et al. used computer simulation to optimize the sand mold casting process for beam steel castings. At a pouring temperature of 1550 ℃, the yield of the process was 72%. Sand casting shell steel castings have a large machining allowance and are prone to defects such as porosity, inclusions, insufficient pouring, shrinkage, and porosity during production, resulting in a low casting qualification rate. The ProCAST software is used to simulate the impact of casting process parameters on the pore volume size of the steel shell castings, providing theoretical guidance for the sand casting process design of the steel shell castings, thereby reducing the testing workload and reducing the trial production cycle and cost of the castings, Reduce casting defects, improve casting quality and economic benefits.
According to the technological characteristics of the shell casting, three pouring process schemes were designed. The effects of pouring temperature and pouring speed on the filling and solidification process of the sand mold casting shell and the pore volume of the casting were studied using computer simulation software; The research results can provide a reference for the design of sand mold casting process for shell steel castings, shorten the trial production cycle, reduce production costs, and improve economic benefits. The conclusions obtained are as follows:
1) In the first and second process options, there were casting defects above the casting due to insufficient pouring, while in the third process option, the volume of shrinkage cavities and porosity defects was significantly reduced, which was better;
2) In the third process plan, the order of primary and secondary factors affecting the volume of pore defects is pouring temperature>pouring speed, and pouring temperature has a significant impact on the test results. When the pouring temperature is 1560 ℃ and the pouring speed is 1.6 m/s, the minimum volume of pore defects in the shell casting is 1.416 cm3, and the casting qualification rate is 96%.
The disadvantage is that the simulation software has certain differences in the parameter settings of the coating layer in the sand casting mold cavity compared to actual production. In the future, it can be added to the simulation to set the coating layer material and thickness, thereby making the simulation results more realistic. In addition, this study simulates and analyzes the effects of pouring location and casting process parameters on the mold filling and solidification process of steel shell castings in sand mold casting. In the future, research will be conducted on the internal stress generated during the solidification process.