Siberian State Industrial University, Novokuznetsk, Russia:

A. A. Umansky, Dr. Eng., Associate prof., Director of the Institute of Metallurgy and Materials Science, e-mail: umanskii@bk.ru
A. S. Simachev, Cand. Eng., Director of the Center for Collective Use “Materials Science”, e-mail: simachev_as@mail.ru
L. V. Dumova, Leading Engineer, Center for Collective Use "Materials Science", e-mail: doumova@bk.ru
S. O. Safonov, Postgraduate Student

In order to develop optimal modes of heat treatment of grinding balls made of K76F grade rail steel, a series of laboratory experimental studies were carried out, in which the cooling capacity of the polymer water-soluble quenching medium PCM was studied with varying its concentration and temperature, and the microstructures of grinding balls heat-treated using the specified quenching medium were analyzed. Studies of the cooling capacity of the polymer quenching medium PCM have shown that at a concentration of the specified polymer in an aqueous solution at a level of 2 % to 4 %, the cooling rate of K76F steel at temperatures of the quenching medium in the range of 20-30 °C practically does not differ and decreases when the temperature reaches 40 °C. On the basis of metallographic studies, the features of the microstructure of grinding balls made of K76F steel after heat treatment carried out using a polymer quenching medium PCM at its various concentrations and tem eratures were
determined. As a result, it was found that varying the parameters of the specified quenching medium makes it possible to obtain balls with a different set of properties. In particular, the use of a 2 % polymer solution PCM with a temperature in the range of 20–30 °C as a quenching medium ensures the production of balls of high hardness (IV hardness group according to GOST 7524–2015), and the use of a 4 % solution of PCM with a temperature of 20–30 °C leads to the production of balls of lower hardness (I and II hardness groups according to GOST 7524–2015), but with increased impact resistance.
The study was supported by the grant of the Russian Science Foundation No. 22-29-20170, grant of the Kemerovo region – Kuzbass.

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