Iron mold coated with sand has long manufacturing cycle, high cost and complex process test. Once the process design fails, it will cause huge economic losses. Therefore, it is of great significance to use numerical simulation technology to predict casting defects such as shrinkage porosity, shrinkage cavity and inclusion before mold manufacturing. The numerical simulation software is used to carry out computer trial injection, calculate the flow field temperature field, visually display the pouring and solidification process, and judge the location of possible casting defects, so as to optimize the process parameters, design the reasonable iron mold wall thickness and sand coating thickness, as well as the reasonable pouring system. This can effectively reduce the uncertainty in the casting process design, ensure the quality of nodular iron castings and shorten the trial production cycle.
The research on solidification numerical simulation technology and shrinkage casting defect criterion has been very mature in steel castings. However, the research on the solidification process of nodular iron castings is much less, which has not been reported until the 1990s.
Sun Xun and Wang Junqing from Shenyang Foundry Research Institute first proposed the application of numerical simulation of liquid metal filling and heat transfer in the casting process design of nodular cast iron. In 1993, Yueguang Guo and Lin Han of Huazhong University of technology proposed the application of solidification numerical simulation in automotive nodular iron castings. In 1996, min Guangguo and others studied the application of numerical simulation in process optimization of crankshaft castings. After 2000, the application research of numerical simulation in iron mold sand coated nodular iron castings began. For example, Liang Zuojian and Zhao Haidong of Tsinghua University established the mathematical model of numerical simulation of iron mold sand coated solidification process in 2001, simulated and calculated the new products of nodular iron four cylinder crankshaft, and improved the original process according to the simulation results.
Until 2013, the research on iron mold sand coating simulation of nodular iron castings was still deepening and expanding, such as Kou Weiwei and pan Dongjie’s research on the numerical simulation of sand coated iron mold casting of flywheel castings, Chen Xia and Wen Tong’s simulation analysis of the molding and solidification process of sand coated iron mold casting of wheel disc, etc. However, at the same time, the relevant research on nodular cast iron crankshaft and iron mold sand coating process is rare. One of the tasks of this subject is to further explore the important role of numerical simulation in improving the iron mold sand coating process of nodular cast iron crankshaft on the basis of previous research.