Thermodynamic foundations of the rational cutting modes choice under conditions of machining

Abstract

Durability and tribological tests of standard grades of high-speed steels and experimental single-carbide hard alloys with modified cobalt binder, created on the basis of the standard VK8 grade, under conditions of friction and turning of structural steels 45 and 12Х18Н10Т were carried out. The experiments were carried out for various cutting speeds and friction in order to determine the dependence of the optimal modes from the point of view of reducing the wear rate for cutting materials with different structural and thermodynamic characteristics. It has been experimentally established that high-speed steels with high values of thermal entropy have greater wear resistance in comparison with low-entropy grades, and cutting (sliding) speeds corresponding to minimal wear rates are higher for them. For experimental hard alloys grades characterized by greater thermal entropy values of the binder lower wear rates at optimal cutting speeds compared to the base alloy were also recorded; the values of the optimal cutting speeds for these materials are also higher. Thus, high-entropy cutting materials allow machining at higher speeds, while reducing the wear intensity.