Casting CAE is to use computer to simulate the solidification process of casting through solidification simulation, display the solidification process of casting and defect position on the computer screen, and then guide and improve the casting design process, so as to reduce production cost, shorten the design cycle, and finally achieve the purpose of improving production efficiency.
In 1962, Danish scholar forsund used FDM to calculate the heat transfer in the process of casting solidification, and became the pioneer of CAE software development. In 1989, Professor Sahm of Germany presided over the development of magma, which is the first casting CAE software in the world to realize commercial application.
Since the 1970s, numerical simulation of solidification process has also been carried out in China. In 1980, Shenyang Foundry Research Institute simulated the solidification process of castings by FDM. Although the research of foundry CAE in China started late, it developed rapidly.
At present, casting CAE technology has become an essential tool to produce high-quality castings and predict casting defects such as shrinkage cavity and porosity.
At present, although there are many achievements in the research of shrinkage defects of gray iron at home and abroad, there are still many problems in the design of anti shrinkage process of iron castings
1) Although the foundry workers at home and abroad have made extensive research on the factors affecting the shrinkage cavity and porosity of gray iron and achieved many results, most of them have not made a systematic theoretical study on the gray iron castings.
2) For the design of the anti shrinkage process of the iron castings, although there are many researches in the literature at home and abroad, there are few researches on the comprehensive casting performance, so there is lack of practicability and guidance for the actual production of the gray iron castings.
3) Although the casting CAE is widely used in the casting industry due to its accuracy in the prediction of casting defects, at present, most of the data are for the small and medium-sized castings with relatively simple shapes, while the research on the casting CAE for the large castings with relatively complex shapes is less. Therefore, for large-scale iron castings, the anti shrinkage process design is mostly empirical design, and there is paper leakage in operation, so the trial production cycle is long.
Because of the structure and process characteristics of large iron castings, the probability of shrinkage cavity and porosity is higher than other iron castings. In addition, due to its large tonnage (generally more than 10t) and high production cost, the loss of casting defects is correspondingly large. Therefore, for large-scale iron castings, it is very important to design a suitable process to reduce the shrinkage defects on the basis of satisfying its service performance.
By summarizing the production records of a large-scale casting (column) in our factory, the main factors affecting the shrinkage defects of large-scale iron castings are systematically studied, including the composition of molten iron, molten iron temperature, mold conditions, riser size, so as to qualitatively study the relevant factors of the anti shrinkage process of large-scale iron castings.
According to the above research results, on the premise of considering the service performance of castings, the process design principles of design anti shrinkage factors such as the composition of molten iron, molten iron temperature, mold conditions, pouring and cold iron design in large-scale iron castings are summarized by studying domestic and foreign data and combining with work experience.
Finally, taking two kinds of common large-scale iron ingot mold and crossbeam of our factory as examples, according to the above-mentioned rules, the casting process based on the purpose of shrinkage prevention is formulated. Among them, CAE will be used to verify and modify the developed technology when developing the anti shrinkage process of crossbeam, so as to verify the application of CAE in the anti shrinkage process of large iron castings.
