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 INTERMITTENT 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 high speed intermittent 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 boron nitride of 30 to 95 mass%, (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, Cr, and Si, the composite nitride layer being formed by vapor deposition and satisfying a specific composition formula; and (c) the upper layer has an alternately laminated layer structure composed of thin layers A and thin layers B having a mean layer thickness of 0.01 to 0.3 μm respectively, wherein the thin layers A are composed of a composite nitride layer of Ti, Cr, and Si satisfying a specific composition formula, and the thin layers B are composed of a Ti nitride (TiN) layer.;COPYRIGHT: (C)2007,JPO&INPIT