Samara State Technical University (Samara, Russia)

К. V. Nikitin, Head of the Department of Foundry and High-Performance Technologies, Dean of the Faculty of Mechanical Engineering, Metallurgy and Transport, Doctor of Technical Sciences, Professor, kvn-6411@mail.ru
I. Yu. Timoshkin, Associate Professor of the Department of Foundry and High-Performance Technologies, Candidate of Technical Sciences, Associate Professor
V. N. Dyachkov, Associate Professor of the Department of Foundry and High-Performance Technologies, Candidate of Technical Sciences
R. М. Biktimirov, Associate Professor of the Department of Foundry and High-Performance Technologies, Candidate of Technical Sciences
К. А. Denisov, Engineer of the Department of Foundry and High-Performance Technologies
S. V. Evtushenko, Master’s Student of the Department of Foundry and High-Performance Technologies

This paper presents a review of temporary mold casting processes from the perspective of producing high-precision castings. The features of refractory fillers used in cold-hardening molding mixtures and ceramic shell molds for investment casting are analyzed. A trend toward the development and application of new refractory fillers as alternatives to silica sand, providing improved physical and technological properties of molding mixtures, is identified. It is established that synthetic bauxite sand (SBS) is a promising candidate for this purpose. At the same time, the available literature contains very limited information on its use in cold-hardening molding mixtures for temporary mold production. The results of evaluating the feasibility of using SBS for manufacturing temporary molds intended for aluminum alloy castings are presented. It is shown that SBS, when used as a refractory filler, provides superior technological and mechanical properties of cold-hardening mixtures compared with conventional silica sand-based mixtures. Owing to the higher thermal conductivity of SBS-based mixtures, a finer macrostructure is formed in the castings. The study also demonstrates the feasibility of using SBS for manufacturing temporary molds for immersion casting. The molds exhibit the required mechanical strength, ensure complete reproduction of the casting geometry, and prevent burn-on at the mold-casting interface. It is concluded that synthetic bauxite sand is a high-quality molding material and can serve as an effective alternative to traditional silica sand in the production of temporary molds based on cold-hardening molding mixtures.
The work was carried out with the financial support of the Russian Science Foundation under project No. 26-93-20005 and the qualified research customer LLC Polymet (Tolyatti).

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