Study on solidification process of centrifugal casting

In the process of filling, the temperature of molten metal decreases continuously, and after filling, the cooling process continues until it is cooled to room temperature, which is the solidification process of casting. Many scholars at home and abroad have studied the solidification process of liquid metal in centrifugal casting. In their research, most researchers ignore the flow of liquid metal, and the focus of research is also different.

Liu Zhiming and Jiang Buju established a one-dimensional heat conduction model of centrifugal casting, simplified the problem to the heat conduction problem of infinite cylinder, deduced the finite difference scheme of heat conduction equation, and programmed the numerical simulation of solidification process, and discussed the solidification mode and defect formation mechanism of cast pipe.

Taking the water-cooled horizontal centrifugal casting as the research object, Li Tieliang and Wang Lihui established the axisymmetric model of heat transfer analysis of the pipe mold for the first time by using the finite element numerical simulation method. After considering the boundary conditions and the latent heat of crystallization, the temperature field and thermal stress field of the pipe mold with time were simulated by the finite element software ANSYS, and the failure mechanism of the pipe mold was discussed .

Taking the horizontal centrifugal casting of roll ring as the research object, Huang Yihong et al. Established a two-dimensional coupled model of liquid steel flow and heat transfer, analyzed the flow and heat transfer of liquid steel by using the large-scale CFD software FLUENT, studied the flow velocity, pressure distribution and eccentricity of liquid steel under gravity and centrifugal force field, as well as the temperature field in the solidification process, and discussed the flow field The effect of dynamic on heat transfer. However, in their research, they all simplified the practical problems to a certain extent, assuming that the liquid metal fills the mold cavity instantaneously, ignoring the flow and axial heat transfer of the liquid metal, simplifying the problem to two-dimensional, and assuming that the density, specific heat and other physical parameters of the metal do not change with the change of temperature. These assumptions may make the research results deviate from the actual results to a certain extent.

In the first mock exam, a numerical model for the solidification process of horizontal centrifugal casting is presented based on the shallow water equation. In the model, the solution domain is divided into four layers (as shown), which are cast, solidified metal, liquid metal and air. The numerical results of the free surface shape and temperature distribution in the solidification process are obtained by using ANSYS FLUENT software, and Bohacck is used to solve the problem. The results are analyzed and discussed. The centrifugal force, Coriolis force, viscous force, gravity and energy transfer are considered in the model. The heat transfer between the molten metal and the mold, as well as the heat loss caused by the heat radiation and convection on the outer and inner walls of the mold are also considered.

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