Cutting tool

摘要

The object of the present invention is to provide a cutting tool in which the hard coating layer demonstrates superior chipping resistance. In order to achieve this object, the present invention provides a cutting tool provided with a tool base composed with tungsten carbide-based cemented carbide or titanium carbonitride-based Cermet, and a hard coating layer provided on the surface thereof; wherein the hard coating layer comprises: (a) a Ti compound and/or Zr compound layer, which is a lower layer, comprising one or more layers of a TiC layer, TiN layer, TiCN layer, TiCO layer, TiCNO layer, ZrC layer, ZrN layer, ZrCN layer, ZrCO layer and ZrCNO layer formed by chemical vapor deposition, and having an overall mean layer thickness of 0.5-20 µm, and (b) an aluminum oxide layer having an ± crystal structure in the state of being formed by chemical vapor deposition, which is an upper layer, comprising the highest peak in the inclination section within a range of 0-10 degrees in the case of emitting an electron beam onto individual crystal grains having a hexagonal crystal lattice present within the measuring range of the surface polishing plane, measuring the inclination of the (0001) crystal plane of the crystal grains relative to the normal of the surface polishing plane using a field emission scanning electron microscope, dividing the measured inclinations within a range of 0-45 degrees indicated by the individual crystal grains for each pitch of 0.25 degrees, and preparing a pole plot graph by tabulating the measured inclinations present in each section for each section, and having the mean layer thickness is 1-30 µm.