CUTTING TOOL MADE OF SURFACE COATED CUBIC BORON NITRIDE-BASE VERY HIGH PRESSURE SINTERED MATERIAL EXHIBITING EXCELLENT CHIPPING RESISTANCE IN HIGH-SPEED CUTTING HARD MATERIAL HARD TO CUT

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cubic boron nitride-base very high pressure sintered material exhibiting excellent chipping resistance in high-speed cutting a hard material hard to cut.

SOLUTION: The cutting tool made of surface coated cubic boron nitride-base very high pressure sintered material is constructed by a very high pressure sintered material of green compact made of 13-30% titanium nitride, 6-18% aluminum and/or aluminum oxide, and residual boron nitride (by mass% in each), and has texture in which a very high pressure sintered reaction product is interposed in the interface between a cubic boron nitride phase forming a dispersed phase and a titanium nitride phase forming a continuous phase. (a) A hard coating layer includes: a lower layer having an average layer thickness ranging from 1-3 μm; and an upper layer having an average layer thickness ranging from 0.3-3 μm, (b) the lower layer is formed of a layer satisfying a specified composition formula: [Ti1-XAlX]N, and (c) the upper layer has an alternately stacking layer structure of a thin layer A and a thin layer B which respectively have an average layer thickness ranging from 0.05-0.3 μm, and the thin layer A is formed of a layer satisfying a specified composition formula: [Ti1-XAlX]N.

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