As shown in the figure, the shrinkage cavity distribution with volume fraction greater than 0.05 predicted by numerical simulation technology under the original process scheme of gearbox box is shown. Taking the maximum shrinkage rate and the total shrinkage amount as the standard, the analysis and simulation results can be seen that the shrinkage area is mainly concentrated in the thick part at the bottom of the gearbox and the upper half of the gearbox. As shown in red, the maximum shrinkage rate is 0.862. The total shrinkage amount of the gearbox is 132.17cc calculated by visual cast in ProCAST software. A large number of shrinkage cavities are distributed in the main part of the casting, which has a great impact on the quality of the casting, and the casting will be scrapped due to the unqualified inspection of shrinkage cavity casting defects.
This is consistent with the main reasons for product scrapping in actual production, indicating that the numerical simulation effect is obvious. The main causes of shrinkage casting defects are unreasonable process scheme design and unscientific process parameter setting, which leads to the volume shrinkage of castings without feeding during condensation. Firstly, optimize the casting process scheme, set up a reasonable gating system, and then optimize the casting process parameters to eliminate the shrinkage casting defects and ensure the casting quality.