Simulation For Shrinkage Defect In Nodular Cast Iron Solidification Process

Spheroidal Graphite iron (S.G iron) is an important metal with merit of high strength, good ductile, low cost and easy production etc. Now it widely used in automobile, farm equipment, ship craft, metallurgy industry and conduit project etc. But for the S.G iron is with the character of mushy solidification and graphitizing expansion, the casting appears great shrink defect easily. This problem is a projecting part in the production of S.G iron and can't be settled thoroughly since long term ago.Numerical simulation technology of the casting solidification process is a kind of method that makes use of computer technology to simulate the process of the casting solidification and show the foundry process visually. This new technology can optimize the product structure, improve the product quality, shorten the period of exploiting product development, reduce the cost and improve the ability of dealing with the market emergency, it play a important role in impelling the technique advancement of foundry. The main task of this paper is to develop prediction & analysis system of shrinkage cavity and porosity defect in a casting for foundry engineering application. This system is to research the method and theory, not refer to merchandise applies.This thesis summarized the development of S.G iron casting and math theory of FEA calculation firstly, and designed the whole structure of application system used in casting projection. The improved Niyama criterion was used to develop shrinkage porosity predict system applied in S.G iron. In order to improve the computation speed and veracity, Dynamic Volume Change Accumulation was applied in the calculation of search isolated zones. The modeling of isolated zones used in predict S.G casting shrinkage void was made perfect based on analyzed the generate theory of S.G shrinkage void and main method of forecasting, and it was used in the system of development.Completed the result of this system and commerce soft, the system of shrinkage voids and porosity was usable and its arithmetic was veracious verified in most case. It had simulated the casting in different shape. The developing tool we choice were sound and convenient for system extension and complete.