A coated cutting tool comprising a substrate and a coating layer provided on a surface of the substrate, wherein: the coating layer comprises at least one -type aluminum oxide layer; and a texture coefficient TC (0,0,12) of a (0,0,12) plane of the -type aluminum oxide layer is from 4.0 or more to 8.4 or less; and a texture coefficient TC (1,0,10) of a (1,0,10) plane thereof is from 0.4 or more to 3.0 or less.

A coated cutting tool comprising a substrate comprising a cubic boron nitride sintered body and a coating layer formed on the substrate, wherein the coating layer comprises a Ti carbonitride layer comprising Ti(C.sub.xN.sub.1-x); an average thickness of the Ti carbonitride layer is 0.5 m or more and 5.0 m or less; in the Ti carbonitride layer, R75 is higher than R25; in the Ti carbonitride layer, a texture coefficient TC (111) of a (111) plane is 1.0 or more and 2.0 or less; and in X-ray diffraction measurement of the Ti carbonitride layer, an absolute value of a difference between a maximum value and a minimum value of 2 is 0.1 or less on the (111) plane when the measurement is performed at each of angles of 0, 30, 50 and 70.

A cutting tool including a rake face, a flank face, and a cutting edge portion, comprising a substrate and an AlTiN layer, the AlTiN layer including cubic Al.sub.xTi.sub.1-xN crystal grains, Al having an atomic ratio x of 0.7 or more and less than 0.95, the AlTiN layer including a central portion, the central portion at the rake face being occupied in area by (200) oriented Al.sub.xTi.sub.1-xN crystal grains at a ratio of 50% or more and less than 80%, the central portion at the cutting edge portion being occupied in area by (200) oriented Al.sub.xTi.sub.1-xN crystal grains at a ratio of 80% or more.

It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

A coating includes a layer having an alumina matrix and at least one of zirconia grains and hafnia grains in the alumina matrix. An average grain size of the at least one of the zirconia grains and hafnia grains is 100 nm or less. A coated cutting tool includes a substrate and the coating bonded to the substrate. The substrate has a rake face, a flank face, and a cutting edge formed at the intersection of the rake face and the flank face.

A cutting tool according to one aspect of the present disclosure includes a substrate and a diamond layer coating the substrate. A cutting tool according to one aspect of the present disclosure includes a rake face, a flank contiguous to the rake face, and a cutting edge configured by a ridge formed by the rake face and the flank. The rake face has a first rake face and a second rake face located between the first rake face and the flank. The second rake face and a surface of the substrate located on the side of the rake face form a negative angle. The second rake face is formed at the diamond layer.

A rotary cutting tool includes a main body and a shank. The main body has a tip end. The shank is continuous with the main body on the side opposite to the tip end. The main body is provided with a first cutting edge having a positive twist angle, and a second cutting edge having a negative twist angle and separated from the first cutting edge. Each of the first cutting edge and the second cutting edge extends continuously from the tip end to the shank.

A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.

A cutting blade having a plurality of different coatings on surfaces thereof, including an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, wherein the upper surface intersects the side surface to form at least one cutting edge unit, the cutting edge unit includes a main cutting edge and a secondary cutting edge, the upper surface includes at least one set of cutting planes, the cutting planes include a main cutting surface and a secondary cutting surface, the main cutting surface intersects the side surface to form the main cutting edge, the secondary cutting surface intersects the side surface to form the secondary cutting edge, a main coating is provided on the main cutting surface, a secondary coating is provided on the secondary cutting surface, and the main coating and the secondary coating are independent from each other.

A hard coating includes a thin film layer which has a total thickness of 0.5-10 m and has an overall composition of Al.sub.1-a-bTi.sub.aMe.sub.bN (0.2<a0.6, 0<b0.15), where Me is a nitride constituent element having a thermal expansion coefficient of greater than 2.710.sup.6/ C. and less than 9.3510.sup.6/ C., wherein the thin film layer has a structure in which a nano-multilayered-structure of thin layers A, B and C, thin layer B being disposed between thin layer A and thin layer C, is repeatedly laminated at least once.