As we all know, the casting process is an extremely complex high-temperature, dynamic and changing process, and the casting defects such as shrinkage porosity and shrinkage cavity in the solidification process of castings are also difficult to be observed directly. In the past, in order to improve casting defects, it was often necessary to carry out the process of “design trial production test improvement design” repeatedly, which consumed a lot of human and material resources, increased the cycle and cost of product research and development, and greatly affected the yield in actual production. Therefore, with the rapid development of the digital age, computer aided engineering analysis (CAE) technology has been widely used in the field of casting, and has become the most cutting-edge technical research field of casting.
Casting CAE technology uses computer software to simulate the whole process of casting from mold filling to solidification, including temperature field simulation, stress field simulation, microstructure simulation, performance prediction and casting defect prediction.
The goal of computer numerical simulation is to establish an appropriate mathematical model and use the appropriate numerical method to solve the heat, momentum and mass transfer process of metal solution in the filling and solidification process by computer, so as to obtain the law of reaction process and guide the results of improvement practice. At present, casting simulation is mainly divided into the following aspects:
(1) Flow field simulation. Based on the principle of hydrodynamics, the casting filling process is analyzed. In addition, the heat transfer in the process can be calculated and the defects such as shrinkage porosity and shrinkage cavity can be predicted. At present, the mold filling flow field simulation has been developed more mature, and the accuracy and practicability are the main concerns.
(2) Temperature field simulation. Based on the principle of heat transfer, the heat transfer process of castings is analyzed to judge whether the temperature field distribution of castings is reasonable.
(3) Stress field simulation. It mainly simulates the stress field when solid-liquid two phases coexist, including the residual stress and residual deformation in the casting. The deformation of the casting can be analyzed by visual block diagram.
(4) Organization simulation. It is divided into macro structure simulation and micro structure simulation. Using the mathematical model of solidification principle, the nucleation number, crystal growth rate and microstructure transformation are calculated. The main research methods include mesoscopic scale and phase field method.