Influence of the substrate material on the effectiveness of coatings in metal cutting

Abstract

Considerable studies concerning metal cutting in the past have been devoted to tungsten carbide tools and their coatings. As a result, a wide range of carbide substrates has been developed for more than 30 kinds of hard coatings or combination of coatings, ranging from single layer to as much as 13 layers of coatings in multi-layer coated tools. Some of these technological "spill-overs" helped in the evolution of another new generation of cutting-tool materials, namely coated cermets, which not only use less of strategic raw materials such as tungsten and cobalt, but also exhibit excellent wear properties such as good resistance to diffusion wear and the ability to retain a higher hardness at elevated temperatures. A comparison, based on CNC lathe turning, was made of these two types of substrate materials, namely carbides and cermets, coated with some of the more common hard coatings such as TiN, TiC, TiCN, and Al2O3 using physical vapour deposition (PVD). The results are analysed and discussed. © 1993.