Institute of Engineering and Metallurgy of the Khabarovsk Federal Research Center of the Far Eastern Branch of the Russian Academy of Sciences, Komsomolsk-on-Amur, Russia

А. V. Tkacheva, Senior Researcher, Candidate of Physical and Mathematical Sciences, e-mail: 4nansi4@mail.ru
А. А. Evstigneeva, Engineer, e-mail: annka.ewstic@mail.ru
А. N. Evstigneev, Senior Researcher, Doctor of Technical Sciences, Professor, e-mail: iss@knastu.ru

A study of the temperature stresses that occur in a ceramic spherical shell material in the first seconds after casting the metal is presented. The alloys widely used in production are AL22, BrA9ZH3L and VT14L. The influence exerted on the stress-strain state of the shell material by the preliminary heating temperature of the mold which helps to reduce the temperature gradient at the time of casting and therefore to lower the values of maximum stresses leading to mold destruction has been studied. The influence of the supporting filler on the stress state of the shell mold is analyzed. For these purposes, the temperature and mechanical problems have been solved. It is assumed that the ceramic shell mold either has free outer walls or is completely immersed in the supporting filler, and the funnel into which the metal is poured does not affect the stress-strain state, therefore, the temperature and mechanical problems are reduced to one-dimensional. The temperature is determined by the solution of the Fourier heat equation with boundary conditions defining the equality of heat fluxes and temperatures at the boundaries of the liquid and solid phases of the metal and the inner surface of the shell mold, and the conditions of the relationship between the heat flow due to thermal conductivity from the outer wall and the heat flow from the environment. The solution to the temperature problem is found by running through an implicit scheme. Within the framework of the theory of thermoelasticity, an analytical solution has been found for small stress deformations and displacement by integrating the equilibrium equation. It is established that the maximum stress has a compressive character and is formed directly at the moment of pouring liquid metal on the inner surface of the ceramic shell mold, and their dependence on the calcination temperature is linear. The uniqueness of the obtained result lies in the fact that for the three alloys, the normalized dependence of the calcination temperature and maximum stresses practically runs into one another.
The research was conducted within the framework of the state assignment of the Khabarovsk Federal Research Center of the Far Eastern Branch of the Russian Academy of Sciences.

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