The Influence of Zirconium and Titanium Nitride Based Coatings on Tribodeformation Processes of Friction While Cutting with Carbide Inserts

Abstract

The article is devoted to an experimental study of the influence of wear-resistant coatings ZrN, TiN + ZrN, (Ti–Zr)N, ZrN–(Ti–Zr)N–TiN, and TiN, deposited on T15K6 hard alloy inserts, on the tribological and deformation characteristics of the process of turning 45 and 12Kh18N10Т steel workpieces, and subsequent comparison of the calculated values of the maximum temperatures of the rake face of the lathe cutter. When processing 45 steel, a significant reduction in contact and average temperature in the cutting zone is ensured by a combination of tribological and deformation indicators when using TiN + ZrN and ZrN + (Ti,Zr)N + TiN compositions. When turning 12Kh18N10T stainless steel, the presence of coatings on carbide inserts had a lesser effect on the course of deformation processes. The main effect of modifying the working surfaces of the tool is to change the thickness of the zone of secondary plastic deformations and to reduce the length of contact between the chips and the rake face. In this case, the greatest effect in reducing surface temperatures due to the influence on the complex of tribostrain indicators and enhancing the thermodissipative capabilities of the contact zone is demonstrated by ZrN and ZrN + (Ti,Zr)N + TiN coatings. Based on the results of full-scale experiments and digital modeling using the obtained experimental data, it was established that the temperature distributions in the area of tribocoupling of chips with the surface of a hard alloy in the presence of a multilayer coating on it are associated with the wear of metal-cutting tools, which makes it possible to evaluate the impact of wear-resistant coatings through changes in the temperature regime in the contact zone. Such an influence of surface modification on a set of tribostrain indicators, which also determine the nature of the distribution of contact temperatures, should be taken into account when developing new compositions and structures of wear-resistant coatings along with their physical and mechanical properties at the microlevel.