surface-coated cermet cutting tool hard coating layer to exhibit the chipping resistance with excellent high-speed heavy cutting

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cermet-made cutting tool, whose hard coating layer exhibits excellent chipping resistance in high-speed multi-cutting.;SOLUTION: In this cermet tool, a hard coating layer composed of: (a) a lower layer which is a Ti compound layer having a total average layer thickness of 3 to 20μm: and (b) an upper layer which is a vapor deposition α-type Al₂O₃ layer having a total average layer of 4 to 20μm, is formed on the surface of a tool base by vapor deposition. The vapor deposition α-type Al₂O₃ layer has a two upper and lower layer structure composed of a lower layer having the ratio of 35 to 65% occupying the average layer thickness of the whole Al₂O₃ layer and the remaining upper layer. Electron beams are applied to the individual crystal grains using a field emission type scanning electron microscope, and in the case of measuring an angle of inclination of the normal of (0001) plane which is a crystal plane of crystal grain by a specified measuring method, the upper layer and the lower layer are respectively constructed by a vapor deposition α-type Al₂O₃ layer having: the highest peak in section of inclination angle within a specified range; and the total of frequencies existing within the range of 5 to 15 degrees, which shows an inclination angle frequency distribution graph.;COPYRIGHT: (C)2006,JPO&NCIPI