Because the sand mold casting process is very complex and difficult to study, it still depends on experience to a great extent in actual production. Liquid metal enters the mold cavity after pouring, how the flow field and temperature field change, and how the defects of sand mold casting are produced, these processes also have great blindness for engineers.
With the rapid development of computer technology in recent years, the application of computer and its software in the field of product design, development, analysis and manufacturing has become one of the main methods to improve the comprehensive competitiveness in industrial production. The numerical simulation technology of sand mold casting makes full use of numerical analysis, database and visualization technology, and combines the theories of heat transfer, hydrodynamics and solidification to simulate the forming process of sand mold casting, simulate the physical field distribution of sand mold casting in the process of mold filling, solidification and cooling, and judge the defect position by various criteria, Thus, a method of quality prediction is provided for sand mold casting production. The main research contents are as follows:
1) Temperature field simulation
Based on the basic theory of heat transfer, the heat transfer process of sand mold casting is analyzed, and the temperature field distribution in the solidification and cooling process of sand mold casting is obtained, so as to predict the shrinkage, porosity and other sand mold casting defects.
2) Flow field simulation
Based on the basic principle of hydrodynamics, the metal melt flow in the pouring process of sand mold casting is analyzed, and the flow field distribution diagram is obtained, which can optimize the pouring system and predict the sand mold casting defects such as air entrainment, slag inclusion and sand flushing.
3) Combined simulation of flow and heat transfer
Based on the principles of hydrodynamics and heat transfer, the heat transfer process is calculated while simulating the mold filling process of sand mold castings. It can predict the defects such as cold shut, insufficient pouring and air wrapping. It can also obtain the temperature field distribution of sand mold castings after mold filling, so as to provide accurate and reliable initial conditions for subsequent solidification simulation.
4) Tissue simulation
It is divided into macro, micro and mesoscopic microstructure simulation. Some mathematical models are used to calculate the nucleation number, microstructure transformation process and dendrite growth rate, and predict the microstructure and properties of sand mold castings.
The stress field simulation uses the principle of mechanics to analyze the stress distribution in the molding process of sand mold castings and predict the defects such as hot crack, cold crack and deformation.