TEMPERATURE DEPENDENCE OF THE FRONT LATHE TOOL SURFACE ON EVOLUTIONARY CHANGES IN TRIBO-DEFORMATION INDICATORS OF PROCESSING

Abstract

The study objective is modeling the temperature distribution on the surface of a heavily loaded tribocontact - front surface of a lathe tool - chips taking into account evolutionary changes in the cutting system. The task to which the paper is devoted is to assess the influence of evolutionary changes of tribodeformation parameters of the cutting process on the average and maximum temperature of the front surface of the lathe tool. Research methods. Contact temperatures are found out on the basis of mathematical modeling using data obtained during field experiments at longitudinal turning of 15X2NMFA steel blanks without cooling by T15K6 hard alloy plates. During resistance tests, the chip contact length with the front surface and the chip reduction coefficient used for calculation are determined, as well as the average temperature in the cutting zone, the value of which is used to assess the adequacy of the results obtained by digital modeling. The novelty of the work. Forecasting the temperature increase on the front surface of the cutter, taking into account the contribution of evolutionary changes in tribodeformation parameters of cutting. The results of the study. In the studied cutting system, according to the results of resistance tests, a decrease in the chip reduction coefficient is recorded over the processing time. The temperature distribution on the front surface of the cutter is modeled in two versions: taking into account the evolutionary adjustment of the chip reduction coefficient and related parameters – sliding velocity and thickness of the plastically deformed layer in the chip, and without taking into account their changes. It is found out that modeling adjusted for changes in tribological indicators allows to obtain calculated values of the temperature of the front surface closest to the experimentally recorded of average temperature in the cutting zone. Conclusions: Forecasting contact temperatures adjusted for evolutionary changes in tribodeformation parameters will allow to determine more accurately the moment in the evolution of the cutting system at which critical temperature values can be reached, and further processing is associated with the risk of critical wear or deterioration of the treated surface.