A coated cutting tool, comprising: a substrate; and a coating layer formed on the substrate, wherein the coating layer includes a lower part layer and an upper part layer formed on the lower part layer, the lower part layer has an average thickness of 2.0 m or more and 15.0 m or less, and is formed of a Ti oxycarbonitride layer including a compound having a composition represented by formula (1) below:

Ti(C.sub.1-x-yN.sub.xO.sub.y)(1)

(where, x denotes an atomic ratio of an N element based on a total of a C element, the N element, and an O element, y denotes an atomic ratio of the O element based on a total of the C element, the N element, and the O element, and 0.35x0.60 and 0.01y0.10 are satisfied),
a FWHM of a rocking curve of a plane (4,2,2) of the lower part layer, which is obtained through X-ray diffraction, is 20 or less, the upper part layer is formed of an -aluminum oxide layer having an average thickness of 1.0 m or more and 15.0 m or less, and a FWHM of a rocking curve of a plane (0,0,12) of the upper part layer, which is obtained through X-ray diffraction, is 20 or less.

An insert based on an aspect includes a first surface having a corner portion, a second surface, a third surface, and a cutting edge located on at least part of a portion on which the first surface and the third surface intersect. The cutting edge is provided with a first cutting edge located on the corner portion and a second cutting edge adjacent to the first cutting edge, and the third surface is provided with a first portion located along the first cutting edge and a second portion located along the second cutting edge. Additionally, the second portion includes a first region having a first end portion and a second end portion, and a second region having a third end portion and a fourth end portion. An inclination angle 212 at the second end portion is greater than an inclination angle 211 at the first end portion, and an inclination angle 222 at the fourth end portion is smaller than an inclination angle 221 at the third end portion.

A tool has a main part of hard metal, cermet, ceramic, steel, high-speed steel, and a single or multilayer wear protection coating applied onto the main part by CVD and which has a thickness from 3 m to 25 m. The wear protection coating has at least one Ti.sub.1xAl.sub.xC.sub.yN.sub.z layer with stoichiometric coefficients 0.70x<1.0y<0.25 and 0.75z<1.15 and a thickness from 1.5 m to 17 m. The T.sub.1xAl.sub.xC.sub.yN.sub.z layer has a lamellar structure with lamellae with thickness of no more than 150 nm, preferably no more than 100 nm, particularly preferably no more than 50 nm. Lamellae are made of periodically alternating regions of the Ti.sub.1xAl.sub.xC.sub.yN.sub.z layer with alternatingly different stoichiometric proportions of Ti and Al, having the same crystal structure (crystallographic phase), and the Ti.sub.1xAl.sub.xC.sub.yN.sub.z layer has at least 90% vol. % of face centered cubic (fcc) crystal structure.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises at least one -type aluminum oxide layer; and, in the -type aluminum oxide layer, when regarding a texture coefficient of a (0,0,6) plane as a TC18 (0,0,6), and also regarding a texture coefficient of a (0,0,12) plane as a TC18 (0,0,12), the TC18 (0,0,6) is the highest texture coefficient and the TC18 (0,0,12) is the second highest texture coefficient.

A cutting insert according to an aspect includes a top surface and a side surface. At least a part of a ridge line where the top surface and the side surface intersects is a cutting edge. The cutting edge includes a first portion located at a corner portion, a second portion adjacent to the first portion, a third portion close to the second portion, a fourth portion close to the third portion, and a fifth portion adjacent to the fourth portion. When viewed from directly above, a curvature radius of the second portion is less than a curvature radius of the first portion, a curvature radius of the third portion is greater than the curvature radius of the first portion, and a curvature radius of the fourth portion is less than the curvature radius of the third portion.

In an embodiment, a coated tool is disclosed. The coated tool includes a base material, a first layer on the base material, and a second layer coated on the first layer. The first layer contains diamond crystals therein and has a first mean crystal size. The second layer contains diamond crystals therein and has a second mean crystal size that is smaller than the first mean crystal size. The first and the second layers contain hydrogen, and have a first hydrogen content and a second hydrogen content respectively. The second hydrogen content is larger than the first hydrogen content.

A method for manufacturing a cutting insert includes preparing a base body provided with a through hole and including one of cermet and ceramic, mounting the base body on a holding member by passing the through hole of the base body over a projection including metal and formed on the holding member, and abutting the base body against the projection, forming a coated body by forming a coating layer on the surface of the base body, and cooling the coated body and removing the coated body from the projection.

Chip discharge during high-feed machining and low-feed machining particularly in a high-depth-of-cut state or the like is improved so as to provide adaptability to a wide range of cutting conditions during low depth and high depth cutting and during low-feed and high-feed machining and allow so-called freedom of feed during cutting to be improved. A cutting insert includes a cutting edge body and a substrate to which the cutting edge body is joined. The cutting edge body has a prismatic shape having a longitudinal direction and a lateral direction perpendicular to the longitudinal direction and includes a cutting edge formed on an intersecting edge between a peripheral side surface and an upper surface of the cutting edge body having the prismatic shape and a recessed part formed at a position on the upper surface of the cutting edge body which is more distant from the intersecting edge than from the cutting edge. The substrate has a projected part upwardly projecting from the upper surface of the cutting edge body.

A metal cutting insert has a substrate body of cemented carbide, cermet, or ceramic and at least one cutting edge defined between a rake face and a relief face. The cutting insert has a CVD coating including a layer of aluminum titanium nitride having a cubic face centered lattice structure, represented by a formula (Al.sub.xTi.sub.1-xM.sub.y)C.sub.zN.sub.1-z wherein a stoichiometry coefficient of aluminum is 0.30<x<0.95, wherein M is at least one element selected from the group consisting of Cl and Ar, with a stoichiometry coefficient of which is 0?y<0.01, and wherein a stoichiometry coefficient of carbon is 0?z<0.3. The (Al.sub.xTi.sub.1-xM.sub.y)C.sub.zN.sub.1-z layer satisfies a relationship 10<|S.sub.1-S.sub.2|<500 MPa wherein S.sub.1 is the residual stress measured on the rake face, and S.sub.2 is the residual stress measured on the relief face.

A cutting tool such as a drill (1) in which a coating layer (6) is provided to the surface of a base body (5) having a rod shape, which is equipped with a cutting edge (2) provided to at least the tip portion (A) of the base body (5) having a rod shape and a chip discharge section (4) provided adjacent to the cutting edge (2) so as to extend rearwards (i.e., towards the rear end) from the tip portion (A), the coating layer (6) comprising a mixture phase of diamond and graphite and having a diamond content ratio which is lower in a rear end located 10 mm rearward from the tip than in the tip portion (A).