Papers by Author: Yi Dan Zeng

Abstract: One of the main reasons for the scrap of cast thin-wall frame aluminum alloy castings is deformation and cracking. It is an effective method for solving the problem by predicting the distribution of casting stress, clarifying the size of the deformation and the location of the crack, and taking necessary measures in the process. This paper uses the ProCAST software to simulate the thermal stress coupling of A356 thin-walled frame castings, analyzes the influence of pouring temperature, pouring speed and mold temperature on the stress field distribution of castings, predicts the hot cracking trend and deformation, and optimizes Casting process..

Abstract: To obtain an A356 aluminum alloy casting with a uniform structure and no internal shrinkage defects, ProCAST software is used to set different filling and solidification process parameters for an A356 aluminum alloy casting with large wall thickness differences, And multiple simulations are conducted to obtain optimized casting process; then, based on the process, the microstructure of the thickest and thinnest part of the casting are simulated. The size, morphology, and distribution of the simulated microstructure of the thinnest part and the thickest part of the casting are very similar. The simulated microstructure is similar to that of the actual casting. This shows that castings with uniform structure and no internal shrinkage defects can be obtained through the optimized casting process .

Abstract: Water-cooled casting is a new casting process. It allows even large castings to solidify rapidly, thereby reducing segregation and grain refinement. It has drawn the attention of both domestic and foreign businesses. Heat transfer at the casting/water-cooled mold interface controls the cooling rate of the casting. During the solidification process, because of the contraction that takes place during casting, an air gap can form between the casting and the water-cooled mold. This air gap hinders heat transfer between the casting and the mold, leading to a rapid drop in the interface heat transfer coefficient (IHTC). The purpose of the present study was to assess the effects of the width of the air gap and the duration of gap formation on IHTC. During the experiment, the casting temperature curve was determined in the presence of the interface air gap, and then inverse calculation was performed using PROCAST software to determine the IHTC of casting/water-cooled mold. Results showed that, after the formation of the air gap, IHTC first exhibited a rapid decrease, followed by an increase and then another decrease; IHTC was found to decrease as gap width increased and as the duration of gap formation increased.

Abstract: A new slurry making method for rheocasting termed “Melt Spreading and Mixing Technique” (MSMT), based on forced uniform solidification theory, has been proposed, by which the bulk metal is dispersed into thin liquid film that is cooled rapidly and uniformly to allow copious nucleation. With a model alloy Al-wt%6.5Si to conduct a series of experiments, feasibility of this method and influence of process parameters upon slurry microstructure were studied. The results show that semisolid slurry for mass production with uniformly fine nondendritic microstructures can be obtained consistently and continuously by optimizing process parameters.