Orenburg State University, Orenburg, Russia
E. S. Kozik, Associate Professor, Candidate of Technical Sciences, e-mail: ele57670823@yandex.ru
E. V. Svidenko, Associate Professor, Candidate of Technical Sciences, email: tzvetkova.katia2016@yandex.ru

In mechanical engineering, a special role belongs to the quality of tools that determine the productivity of machines in many respects and the machining cost in general. The quality of tools can be improved by various types of machining. The development and improvement of technological processes in many industrial sectors are inextricably linked with the use of hard alloys. Sintered hard alloys are of great importance in modern equipment. Such materials are widely used as cutting, wear-resistant, drilling, stamping tools; they gain increasing use in equipment operating at high temperatures and in aggressive environments. Now, there are many methods of testing carried out on hard alloys. This article presents the results of mechanical tests on hard alloy VK8. We determined mechanical properties and strain of a part. The article describes the influence of various types of heat treatment, namely high frequency heating, and heating in the electrolyte in salt bath furnaces, on mechanical and performance properties of hard alloy VK8. Heat treatment was conducted in the salt bath furnace with a composition of 28% NaCl + 72% BaCl₂; T_heating = 795–1235 ^оC. To carry out heating for quenching, we used the high frequency heater, LH-30KW-B, for annealing — the laboratory vacuum furnace, SUOL 0.4.4/1200, filled with graphite. The hard alloy VK8 ingots were tested for bending failure on tensile testing machine model IR5047-50-10 after different heat treatment modes. Microhardness was measured according to the Vickers method on the PMT-3 microhardness tester. Diamond abrasive wear was determined on a special friction tester. To study microstructures of the samples, we used μVizo-МЕТ-221, an optical microscope, and JEOL JCM-6000 Neo Scope II, an electron microscope. Mini-diffractometer MD-10 was used to get X-ray diffraction patterns of the materials under study to conduct their X-ray structure analysis.

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