Resource-saving technology of heat treatment of parts that quickly wear out in mining equipment

• The research object is steel 40Cr(casting) (Standard in Ukraine), an analogue of steel 5135 according to ASTM A29. • Developed a resource-saving technology of heat treatment of steel 40Cr(casting) to increase its wear resistance. • Recommended intermittent quenching with soaking in water for 30 seconds followed by air cooling. • The proposed technology will make it possible to increase the service life of parts made of steel 40Cr(casting) almost twice. The service life of mining equipment is determined by the durability of only a few, the most responsible parts. Ladles, which are operated in severe conditions of hydroabrasive wear combined with shock loads, are the most fast-wearing element of ball grinding mills. Interrepair cycles of this equipment are determined by the durability of the ladles. It is shown that heat treatment is the most important factor affecting the size and distribution of structural components of steel, which largely depend on its mechanical and operational properties. On the basis of the constructed diagram of the isothermal decomposition of supercooled austenite for modified 40Cr(casting) (Standard of Ukraine) steel, the possibility of obtaining, during continuous cooling in various sections, castings of "ladles" of bainitic structure, in which, after high tempering, a ferrite-cementite mixture with a spherical shape of cementite is formed, providing a high complex of physical and mechanical properties and wear resistance. The developed resource-saving technology of thermal treatment of ladles, which consists in intermittent quenching followed by tempering, made it possible to increase their operational durability by approximately 2 times compared to ordinary 40Cr(casting) steel and increase the maintenance intervals of ball grinding mills.