Provided is a coated cutting tool of long tool life and that affords superior machined surface quality. A coated cutting tool includes a substrate, and a coating layer formed on the substrate. The coated cutting tool includes at least one flank face, at least one rake face, and a honing section rounded and connecting the flank face and the rake face. The coating layer includes a lower layer, an intermediate layer and an upper layer, in this order from the side of the substrate. The lower layer is composed of one, or two or more Ti compound layers made up of a Ti compound of Ti and at least one element selected from the group consisting of C, N, O and B. The intermediate layer contains α-type Al.sub.2O.sub.3. The upper layer contains a compound represented by following formula (1): Ti(C.sub.1-x-yN.sub.xO.sub.y) (1). An average thickness of the coating layer on the flank face side is 5.0 μm more and 30.0 μm or less. A first cross section positioned at a distance of up to 1 μm towards the substrate, from an interface of the intermediate layer and the upper layer side, the cross section being parallel to an interface of the substrate and the lower layer, satisfies the condition represented by following expression (i): RSA≥40 (i). A second cross section, positioned at a distance of up to 1 μm from the interface of the upper layer and the intermediate layer side towards an interface on the opposite side, the cross section being parallel to the interface of the substrate and the lower layer, satisfies the condition represented by following expression (ii): RSB≥40 (ii). The intermediate layer is exposed at least at the honing section.

A cutting tool includes: a substrate; a hard layer provided on the substrate; and a titanium carbonitride layer provided on the hard layer, wherein a thickness of the titanium carbonitride layer is more than or equal to 2 μm, a hardness of the titanium carbonitride layer at a room temperature is more than or equal to 35 GPa, and a Young's modulus of the titanium carbonitride layer at the room temperature is more than or equal to 800 GPa.

A coated cutting tool of the present invention comprises a substrate and a coating layer formed on a surface of the substrate, wherein the coating layer comprises a lower layer and an upper layer formed on a surface of the lower layer, the lower layer comprises a specified Ti compound layer having a specified average thickness, the upper layer comprises an α-aluminum oxide layer having a specified average thickness, the Ti compound layer comprises at least one Ti carbonitride layer, the Ti carbonitride is composed of Ti(C.sub.xN.sub.1-x) (0.65<x≤0.90), and a texture coefficient TC(331) of a (331) plane in the Ti carbonitride layer satisfies a specified range.

A coating for carbide substrates employs a nanostructured coating in conjunction with a non-nanostructured coating. The nanostructured coating is produced by the addition of a refining agent flow, particular hydrogen chloride gas, during deposition, and may be produced as multiple individual nanostructured layers varying functional materials in a series. The combination of a nanostructured coating and non-nanostructured coating is believed to produce a cutting tool insert that exhibits longer life. Pre-treating the substrate with a mixture of compressed air and abrasive medium prior to coating the substrate and post-treating the coated substrate with a mixture of water and abrasive medium after the coating process is believed to further enhance the wear resistance and usage life of the cutting tool.

The present invention relates to a coated cutting tool including a substrate and a coating. The coating has an inner α-Al.sub.2O.sub.3-multilayer and an outer α-Al.sub.2O.sub.3-single-layer. The thickness of the inner α-Al.sub.2O.sub.3-multilayer is 50% to 80% of the sum of the thickness of the inner α-Al.sub.2O.sub.3-multilayer and the thickness of the outer α-Al.sub.2O.sub.3-single-layer. The sum of the thickness of the inner α-Al.sub.2O.sub.3-multilayer and the outer α-Al.sub.2O.sub.3-single-layer is 2-15 μm. The α-Al.sub.2O.sub.3-multilayer has alternating sublayers of α-Al.sub.2O.sub.3 and sublayers of TiCO, TiCNO, AlTiCO or AlTiCNO, the α-Al.sub.2O.sub.3-multilayer having at least 8 sublayers of α-Al.sub.2O.sub.3.

A coated cutting tool includes a substrate and a hard coating film. The hard coating film includes a b layer which is disposed on the substrate, a c layer which is a multilayer coating film laminated on the b layer and in which a c1 layer of a nitride or a carbonitride containing Al and Cr and a c2 layer of a nitride or a carbonitride containing Ti and Si are alternately laminated with a film thickness of 50 nm or less, respectively, and a d layer which is disposed on the c layer and is a nitride or a carbonitride of TiSi. The c layer contains 0.10 atomic % or less of Ar with respect to a total amount of a metal (including metalloid) element and a non-metal element.

An object of the invention is to provide a coated cutting tool whose tool life can be extended by having excellent wear resistance and fracture resistance. The coated cutting tool includes: a substrate; and a coating layer formed on a surface of the substrate, in which the coating layer includes a lower layer, an intermediate layer, and an upper layer in this order from a substrate side to a surface side of the coating layer, the lower layer includes one or more Ti compound layers formed of a specific Ti compound, the intermediate layer contains TiCNO, TiCO, or TiAlCNO, the upper layer contains α-type Al.sub.2O.sub.3, an average thickness of the lower layer is 2.0 μm or more and 8.0 μm or less, an average thickness of the intermediate layer is 0.5 μm or more and 2.0 μm or less and is 10% or more and 20% or less of an average thickness of the entire coating layer, an average thickness of the upper layer is 0.8 μm or more and 6.0 μm or less, and in the intermediate layer, a ratio of a length of CSL grain boundaries and a ratio of a length of Σ3 grain boundaries are in specific ranges.

A method of producing a cubic boron nitride sintered material includes: forming an organic cubic boron nitride powder by attaching an organic substance onto a cubic boron nitride source material powder; preparing a powder mixture including more than or equal to 85 volume % and less than 100 volume % of the organic cubic boron nitride powder and a remainder of a binder source material powder by mixing the organic cubic boron nitride powder and the binder source material powder, the binder source material powder including WC, Co and Al; and obtaining the cubic boron nitride sintered material by sintering the powder mixture.

Provided is a cutting tool including a base material and a coating layer provided on the base material, the coating layer including a titanium carbonitride layer provided on the base material, an intermediate layer provided on the titanium carbonitride layer in contact therewith, and an alumina layer provided on the intermediate layer in contact therewith, the intermediate layer being composed of a compound made of titanium, carbon, oxygen, and nitrogen, the intermediate layer having a thickness of more than 1 μm, when P.sub.N1 atomic % represents an atomic ratio of the nitrogen in an interface between the intermediate layer and the alumina layer, and P.sub.N2 atomic % represents an atomic ratio of the nitrogen at a point A away from the interface by 1 μm on a side of the intermediate layer, a ratio P.sub.N1/P.sub.N2 of the P.sub.N1 to the P.sub.N2 being more than or equal to 1.03.

The drill has a rake face, a flank face, and an outer circumferential surface. The flank face is continuous to the rake face. The outer circumferential surface is continuous to both the rake face and the flank face. A ridgeline between the rake face and the flank face constitutes a cutting edge. A ridgeline between the rake face and the outer circumferential surface constitutes an outer circumferential end. A groove is provided cyclically in the rake face to extend at an angle relative to an axis of the drill, the angle being larger than a helix angle of the drill. The groove has a depth of more than or equal to 1.5 μm.