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 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 cutting tool, which performs, like a drill or a ball end mill, cutting while rotating in a state in which the center of the tip end is in contact with a work material, and includes a wear-resistant layer formed at the tip end thereof, wherein a portion of the wear-resistant layer is selectively removed through tip end polishing from the center of the tip end of the drill or the ball end mill to a predetermined area, so as to restrain micro-brittle wear generated in an ultra-low speed region, and thus remarkably improving the cutting lifespan of the cutting tool such as the drill or the ball end mill.

A surface-coated cutting tool has a hard coating layer including an upper layer α, an adhesion layer β, and a lower layer γ. The upper layer α is formed of an α-Al.sub.2O.sub.3 layer formed under low temperature conditions. The adhesion layer β includes a TiCN layer having a thickness of 0.5 μm or more in an outermost layer and contains 0.5 to 3 μm to a maximum depth of 0.5 μm toward the inside in a layer thickness direction of the TiCN layer from the interface between the TiCN layer and the upper layer α. The lower layer γ is formed of (Ti.sub.1-XAl.sub.X)(C.sub.YN.sub.1-Y) of a single phase of a NaCl type face-centered cubic structure, in which an average content ratio X.sub.avg of Al and an average content ratio Y.sub.avg of C in this composition formula satisfy 0.60≤X.sub.avg≤0.95 and 0≤Y.sub.avg≤0.005.

A coated tool may include a base member including a first surface, and a coating layer. The coating layer may include a plurality of voids located side by side in a first layer in a direction along an interface, which is a boundary between the first layer and a second layer. The second layer may include a lower layer part and an upper layer part, and an angle formed by a normal line of (001) surface of the constituent particles with respect to a cross section of the second layer is an orientation difference, the lower layer part of the second layer includes a ratio of the particles whose orientation difference is 10° or more of 50% or more, and the upper layer part of the second layer includes a ratio of the particles whose orientation difference is 10° or less of 80% or more.

An insert based on an aspect includes a first face, a second face located opposite to the first face, a third face located between the first face and the second face, and a cutting edge located on an intersection of the first face and the third face. The first face includes a first region inclined so as be close to the second face as being separated away from the cutting edge. A virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face. A ten-point average of roughness the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b, and Rz1a is larger than Rz1b.

A surface-coated cutting tool having a rake face and a flank face includes a base material and a coating formed on the base material. The base material is a cemented carbide or a cermet. 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(110) in the first region in texture coefficient TC(hkl), and b is an average value of TC(110) in the second or third region in texture coefficient TC(hkl).

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 cutting tool includes a substrate and a coating that covers the substrate, the coating includes an α-Al.sub.2O.sub.3 layer, and the α-Al.sub.2O.sub.3 layer has an orientation index TC(0 0 12) of a (0 0 12) plane not smaller than 4 and not larger than 8.5, an orientation index TC(2 0 14) of a (2 0 14) plane not smaller than 0.5 and not larger than 3, and a total of the orientation index TC(0 0 12) and the orientation index TC(2 0 14) not larger than 9.

A coated cutting tool includes a substrate of cemented carbide and a coating. The cemented carbide is made of WC and a binder phase of one or more of Co, Fe and Ni. The carbon content in the cemented carbide is a substoichiometric carbon content SCC, wherein −0.13 wt %≤SCC<0 wt %, or −0.30 wt %≤SCC≤−0.16 wt %. The coating includes one or more layers being a metal carbide, metal nitride or metal carbonitride, the metal being at least one of Zr and Hf, and wherein Ti is present in an amount of at most 10 at-% of the amount metal. The one or more layers is situated between the substrate and the aluminum oxide layer.