Influence of the Thickness of Multilayer Composite Nano-Structured Coating Ti-TiN-(Ti,Al,Si)N on the Tool Life of Metal-Cutting Tools and the Nature of Wear

This article discusses the influence of the thickness of a nano-structured wear-resistant layer of the Ti-TiN-(Ti,Al,Si)N multilayer composite coating on its mechanical and performance properties. The study was focused on the coatings with the following thicknesses of its wear-resistant layers: 2, 3.5, 5, 7, 11, and 15 mu m. The relation between the thickness of a wear-resistant layer and the time of its deposition was investigated, and the effect of the above thickness on hardness and wear resistance in scratch testing was considered. Cutting tests were conducted in turning steel C45 with carbide inserts with the coatings under study at various cutting speeds (v(c) = 250, 300 and 350 m/min). The study found the value of thickness of wear-resistant layer providing the longest tool life at various cutting speeds. The differences in the nature of wear for the coatings with various thicknesses of wear-resistant layers were considered.