Compared with the developed countries in the west, the foundation of engine manufacturing in China is weak, and the continuity and perfection of engine block casting process are generally insufficient. The process design is highly empirical, and the informatization and digitization degree is low, which makes the design of gating and riser system difficult and the casting defect rate is high. In order to solve this problem, this paper uses a mathematical statistics based method to study the gating and riser technology, using a lot of information and advanced experience of casting enterprises, combined with the existing academic achievements, to carry out statistical research, data analysis and process optimization of actual casting cases, and develop the gating and riser process system
(1) By analyzing the casting and riser process information data of cylinder block iron castings, it can be concluded that the design of casting and riser process for cylinder block iron castings is based on the theory of large hole outflow and shrinkage modulus method. The shrinkage modulus coefficient of feeding riser has a negative correlation with the quality and modulus of the casting. Small castings are fed with large risers, while large castings with small risers or even without risers. Cold irons are mainly used for small castings, and their thickness has a positive correlation with the average thickness of castings, and then tend to be stable. The selection of flow coefficient of gating system is related to the way of introducing molten metal The results show that the pouring time is related to the quality of casting, and the relationship between pouring time and casting quality is logarithmic. The principle of slow pouring for small castings and fast pouring for large castings is followed.
(2) The hot side riser bottom pouring open type, top duckbill multiple risers middle pouring closed open type, top duckbill multiple risers ladder closed open type and no riser ladder semi closed type are recommended for cylinder block iron castings. The process principle: Based on the quality of iron castings, for small cylinder castings with mass less than 200kg, the open process of hot side riser and bottom injection can be used; for small and medium-sized cylinder castings, the mass distribution is in the range of If the vertical height of the cylinder block is large, the top duckbill multi riser ladder closed open process can be used; for medium and large cylinder castings, the non riser and ladder semi closed process is preferred if the mass is more than 1000 kg.
(3) Based on B / S architecture, a digital gating and riser system is developed Technology to achieve access to data sources; designed administrator login, casting basic information, casting process parameters, gating system design, feeding system design, casting calculation tools, user information seven modules; the system program interface can better meet the needs of users, with the advantages of humanization of operation, rationalization of process, data reliability and so on.
(4) The digital gating and riser process system was applied to realize the digital gating and riser process design of typical cylinder block iron castings (material: HT200), and the pouring test of typical cylinder body iron castings was completed. The results show that the graphite state at the joint of crankshaft is A-type without obvious graphite block. The length of graphite is 100-150 μ m, the size is fine and the distribution is uniform. The tensile strength is 246.87-250.14mpa. The tensile strength is high, which meets the requirements of casting technology.
In order to adapt to the development trend and special requirements of informatization and digitization in the casting industry, the research on casting riser technology of cylinder block iron castings can be extended to other typical parts in the future, and the research on casting defect system, casting material system and online inoculation system can be carried out, and the continuous innovation and upgrading of cylinder block casting industry can be realized by using big data mining and artificial intelligence technology.
