Influence of Basic Physical Phenomena of the Casting-Riser System Solidification Process on Defects Formation in The Casting

L. Sowa, T. Skrzypczak, P. Kwiatoń Department of Mechanics and Machine Design Fundamentals, Faculty of Mechanical Engineering and Computer Science, Czestochowa University of Technology, Dąbrowskiego 73, 42-201 Częstochowa, Poland

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Knowledge about the complex physical phenomena used in the casting process simulation requires continuous, complementary research and the improvement in mathematical modeling. The basic mathematical model taking into account only thermal phenomena often turns out to be insufficient to analyze the process of metal solidification, therefore more complex models are formulated that include coupled thermal and flow phenomena. The mathematical description then consists of the system of Navier-Stokes differential equations, the equations of the continuity of flow and energy. The finite element method was used to numerically model this problem. Numerical simulations of the formation of a steel casting were made, starting from the moment of filling the mould cavity with molten metal and ending with complete solidification. During pouring, the forced movement of the molten metal dominates, and after filling of the mould cavity, mainly natural convective movements occur. In computer simulations, the impact of liquid metal movements on the process of solidification of the alloy in the casting-riser system was assessed, which was the aim of this work. In order to obtain a casting without defects, an appropriate selection of the shape of the riser was made. Also, the locations of possible shrinkage defects were pointed out, trying to ensure right supply conditions, so that the casting was free from these defects, which is important for foundry practice.

DOI:10.12693/APhysPolA.142.48 topics: numerical simulations, Navier-Stokes equations, casting defect, solidification