A series of physical and chemical changes will occur in the filling process of sand castings, such as heat transfer, oxidation, heat loss and so on. These changes will directly affect the production quality of sand castings. Therefore, many defects produced in the casting production process are closely related to the filling process of sand castings. Therefore, it is very important to study the filling process of sand castings.
However, for a long time, the numerical simulation carried out by foundry workers mainly focuses on the research on the solidification process of sand castings, ignoring the filling process, which makes the simulation can only predict the defects such as shrinkage cavity and porosity in the solidification process, but not the defects such as cold shut, slag inclusion and insufficient pouring in the filling process.
Therefore, in order to better predict casting defects, it is necessary to carry out meaningful research on the numerical simulation of mold filling process of sand castings, so that the sand casting process can be optimized according to the flow state of molten metal, and provide initial temperature conditions for some subsequent solidification simulation research and analysis.
The traditional numerical simulation of solidification process is based on this certain assumption, such as assuming that the sand casting is “instantaneously filled”, and the initial temperature of each part of the sand casting is the pouring temperature, etc. Of course, for thick and large sand castings, this assumption is still reasonable, but for those relatively thin-walled sand castings, this assumption will bring a certain degree of error. Therefore, in some cases, these assumptions must be corrected, and various phenomena related to the filling process must be considered, so as to accurately obtain the numerical simulation results of the filling process and provide reliable initial conditions for solidification simulation. It can be seen that the numerical simulation of the filling process is a very important part of the numerical simulation of sand mold casting process.