A coated cutting tool comprising: a substrate; and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer, an intermediate layer and an upper layer in this order from the substrate side; the lower layer comprises one or more Ti compound layers containing a Ti compound of Ti and an element of at least one kind selected from the group consisting of C, N, O and B; and the intermediate layer comprises an α-Al.sub.2O.sub.3 layer containing α-Al.sub.2O.sub.3; and the upper layer comprises a TiCN layer containing TiCN; an average thickness of the coating layer is within a specific range, and an average thickness of the upper layer is within a specific range; in a cross section perpendicular to the surface of the substrate, the grains in the TiCN layer constituting the upper layer satisfies a specific condition.

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.

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 coated cutting tool according to the present invention is a coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer, an intermediate layer formed on a surface of the lower layer, and an upper layer formed on a surface of the intermediate layer; the lower layer is a predetermined Ti compound layer with a predetermined average thickness; the intermediate layer is an α-type aluminum oxide layer with a predetermined average thickness; the upper layer is a Ti carbonitride layer with a predetermined average thickness; and a texture coefficient of a predetermined plane of each of the α-type aluminum oxide layer and the Ti carbonitride layer falls within a predetermined range.

A surface-coated cutting tool has a rake face and a flank face, and includes a base material and a coating formed on the base material. The base material has a cutting edge face connecting the rake face to the flank face. The coating includes an aluminum oxide layer containing a plurality of aluminum oxide crystal grains. The aluminum oxide layer includes: a first region made up of a region A on the rake face and a region B on the flank face; a second region on the rake face except for the region A; and a third region on the flank face except for the region B. The aluminum oxide layer satisfies a relation: b−a>0.5, where a is an average value of TC(006) in the first region in texture coefficient TC(hkl), and b is an average value of TC(006) in the second or third region in texture coefficient TC(hkl).

The present disclosure relates to a method of treating a cutting tool of a cemented carbide or cermet substrate, wherein the cutting tool is subjected to shot peening at a temperature of or above 100° C. The cutting tool typically has a rake face, a flank face and a cutting edge extending therebetween. The shot peening is performed at least on the rake face of the cutting tool. The present disclosure also relates to a cutting tool treated with the method.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer including at least one Ti compound layer containing a specific Ti compound, an intermediate layer including an α-type Al.sub.2O.sub.3 layer containing α-type Al.sub.2O.sub.3, and an upper layer including a TiCN layer containing TiCN; the respective layers are laminated in this order from the substrate side toward a surface side of the coating layer; an average thickness of the coating layer is from 5.0 μm or more to 30.0 μm or less; and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the intermediate layer and is parallel to the surface of the substrate and a normal to a (001) plane of a particle of an α-type Al.sub.2O.sub.3 layer, and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the upper layer and is parallel to the surface of the substrate and a normal to a (111) plane of a particle of a TiCN layer, respectively satisfy predetermined conditions.

A rotary cutting tool includes a base material, a first diamond layer, and a second diamond layer. The base material includes a head portion, a body portion, and a shoulder portion defining a boundary portion between the head portion and the body portion. The first diamond layer covers the body portion and the shoulder portion and exposes the head portion. The second diamond layer covers the head portion, is provided on the first diamond layer in the shoulder portion, and does not cover the body portion.

A surface-coated cutting tool includes a base material and a coating. A hard layer in the coating includes a plurality of crystal grains having a sodium chloride-type crystal structure. The crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of Al.sub.xTi.sub.1-x and a second layer composed of nitride or carbonitride of Al.sub.yTi.sub.1-y are alternately stacked. The total thickness of the first layer and the second layer adjacent to each other is 3 nm or more and 40 nm or less. An angle of intersection between a normal direction to (111) plane that is a crystal plane of the crystal grain and the normal direction to the surface of the base material, an area ratio of the crystal grains having the angle of intersection of 0 degree or more to less than 10 degrees is 40% or more.