Volgograd State Technical University, Volgograd, Russia

N. A. Kidalov, Dr. Eng., Prof., Head of the Dept. of Foundry Machinery and Technology, e-mail: nich@vstu.ru
A. A. Belov, Cand. Eng., Associate Prof., Dept. of Foundry Machinery and Technology, e-mail: aa-belov@bk.ru
N. V. Belova, Cand. Eng., Associate Prof., Dept. of Foundry Machinery and Technology, Junior Researcher, Dept. of Science and Innovations
S. R. Polyak, Postgraduate Student, Second Category Engineer, Dept. of Foundry Machinery and Technology

The article presents a study of the effect of a complex technological additive on the resi dual strength of sand-liquid glass mixtures in the temperature range from 300 to 1000 °C, which indirectly allows to estimate the knockout of casting molds and cores under conditions of obtaining thin-walled and large-sized steel castings. The following materials were used as components of the complex additive: spent coffee grounds with a fraction of 0.2–0.4 mm, which is a by-product after the extraction of ground beans when making coffee in coffee machines, refractory clay from the Berlin deposit with an aluminum oxide content of 28–33 %, and metallurgical dust formed during the purification of gases exhausted from arc steel-smelting furnaces and representing a fine powder with a fraction of 5–40 μm with an iron oxide content of up to 76%. The experiments showed that the use of a complex additive in the sand-liquid glass mixture leads to significant softening of the test samples in all the temperature ranges under consideration. In addition, it is necessary to note the volumetric nature of the destruction of the test samples with a complex additive in the temperature range from 800 to 1000 °C, which is important when knocking out cores from hard-to-reach cavities in the resulting castings. By laboratory testing of the additive in the sand-liquid glass mixture to obtain specified cavities in a steel casting of the “lower body” part, the possibility of using the developed composition at higher heating temperatures of casting cores, reaching, according to the results of finite element modeling, more than 1200 °C, was shown.

The reported study was funded by VSTU according to the research project No. 8/647-24.
V. F. Zharkova, senior lecturer of the chair for Foundry Machines and Technology of Volgograd State Technical University, took part in the work.

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