SURFACE COATED CUTTING TOOL WHICH IS MADE OF CUBIC BORON NITRIDE BASE ULTRA HIGH PRESSURE SINTERED MATERIAL AND HAS HARD COATED LAYER SHOWING EXCELLENT CHIPPING RESISTANCE IN HEAVY CUTTING OF HIGH HARDNESS STEEL

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool which is made of cubic boron nitride base ultra high pressure sintered material, and has a hard coated layer showing excellent chipping resistance in heavy cutting of high hardness steel.;SOLUTION: In the surface coated cutting tool which is made of cubic boron nitride base ultra high pressure sintered material and has the hard coated layer formed by vapor deposition on the surface of an insert made of ultra high pressure sintered material containing 30 to 95 mass% of boron nitride, (a) the hard coating layer is composed of a lower layer having a mean layer thickness of 1.5 to 6 μm and an upper layer having a mean layer thickness of 0.3 to 3 μm; (b) the lower layer is composed of a composite nitride layer of Ti and Si, the composite nitride layer being formed by vapor deposition and satisfying the following composition formula, [Ti_1-XSi_X]N, (where X is 0.02 to 0.1 by atomic ratio); and (c) the upper layer has an alternately laminated layer structure composed of thin layer A and thin layer B having a mean layer thickness of 0.01 to 0.3 μm respectively, wherein the thin layer A is composed of a composite nitride layer of Ti and Si satisfying the following composition formula, [Ti_1-XSi_X]N, (where X is 0.02 to 0.1 by atomic ratio), and the thin layer B is composed of a titanium nitride (TiN) layer.;COPYRIGHT: (C)2007,JPO&INPIT