With the rapid development of China’s energy, metallurgy and other industries, the trend of large-scale equipment urgently needs high-quality steel ingots for supporting large sand castings and large forgings. At present, the manufacturing level of large castings and forgings in China is not high. Many large key and high-end castings and forgings depend on imports and are controlled by others. The specific performance is that the practical database of large sand castings needs to be established, the solidification defects need to be accurately predicted, the gating and riser need to be optimized, and the technical problems of near net shape, fast manufacturing and sand mold control required by large sand castings need to be solved urgently.
Large sand castings have the characteristics of single piece and small batch production. It is not allowed to produce through repeated test and continuous adjustment of process. How to ensure the solidification sequence of sand castings and the full feeding of sand castings is an important condition for controlling the forming, microstructure and properties of sand castings, reducing sand casting defects and obtaining high-quality large steel castings. The computer simulation technology of sand casting process combines the experimental results of physical simulation with numerical analysis technology to study the distribution and change law of flow field, temperature field, stress-strain field and so on in the process of mold filling, solidification, cooling and shrinkage. The computer simulation of sand casting process can provide a basis for formulating the best process scheme and ensuring the quality of large sand castings, shorten the trial production cycle and reduce the production cost.
It is proposed to obtain the thermophysical parameters of glass quartz sand used in actual sand casting production through the method of actual measurement and reverse calculation, establish the database of thermophysical parameters of water glass sand mold, and use professional software to explore the determination of heat transfer coefficient at the interface between casting and mold in the process of sand casting. The sand casting process of a typical large casting – rolling mill frame is simulated by finite element method, and the distribution law of temperature field and stress field is studied; The possible sand casting defects such as shrinkage cavity, porosity and crack in the frame are analyzed. Ensuring the rationality of the actual sand casting process has practical guiding significance for sand casting production.