This surface-coated cutting tool includes a cutting tool body made of tungsten carbide-based cemented carbide and a hard coating layer deposited on a surface of the cutting tool body, in which the hard coating layer has at least one (Ti.sub.1-xAl.sub.x)N layer (0.4≦X≦0.7, X is an atomic ratio) with an average layer thickness of 0.5 to 10 μm, the (Ti, Al)N layer has a cubic crystal structure, and Ia−Ib<5 is satisfied when Ia (%) is an average absorptance of the hard coating layer at a wavelength of 400 to 500 nm and Ib (%) is an average absorptance of the hard coating layer at a wavelength of 600 to 700 nm.

A coated cutting tool includes a substrate and a coating layer formed onto the surface of the substrate. The coating layer contains an outermost layer. The outermost layer contains NbN. The NbN contains cubic NbN and hexagonal NbN. When a peak intensity at a (200) plane of cubic NbN is made I.sub.c, a peak intensity at a (101) plane of the hexagonal NbN is made I.sub.h1, and a sum of peak intensities at a (103) plane and a (110) plane of the hexagonal NbN is made I.sub.h2 in X-ray diffraction analysis, a ratio [I.sub.h1/(I.sub.h1+I.sub.c)] of I.sub.h1 based on a sum of I.sub.c and I.sub.h1 is 0.5 or more and less than 1.0, and a ratio [I.sub.h1/(I.sub.h1+I.sub.h2)] of I.sub.h1 based on a sum of I.sub.h1 and I.sub.h2 is 0.5 or more and 1.0 or less.

Rotatable, solid cutting tool with both right-hand spirals and left-hand spirals, each of which includes an interrupted cutting edge having individual cutting edges. Individual cutting edges of the right hand spirals are axially staggered helically around a circumference of a cutting portion with respect to individual cutting edges of the left hand spirals so that, at each axial position along an axial length of the cutting portion, each radial cross-section includes both at least one individual cutting edge on a right hand spiral and at least one individual cutting edge on a left hand spiral. Individual cutting edges have a length along an outer circumference of the cutting tool that is the same for individual cutting edges of the right hand spiral and individual cutting edges of the left hand spirals. Cutting edges on differently handed spirals are both right handed cutting edges or both left handed cutting edges.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is −1.5 μm to −0.5 μm. A skewness Rsk at the third breaker part is −0.2 μm or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

A coated cutting tool comprises a substrate and a coating layer formed on a surface of the substrate, and has a rake face and a flank. The coating layer comprises an alternating laminate structure in which first compound layers containing AlN and second compound layers containing a compound are laminated in an alternating manner, the compound having a composition represented by formula (1) below:

(Ti.sub.1-xAl.sub.x)N  (1)

(wherein x satisfies 0.40≤x≤0.70). An average thickness T.sub.1 per first compound layer is 5 nm or more to 160 nm or less, and an average thickness T.sub.2 per second compound layer is 8 nm or more to 200 nm or less. A ratio of T.sub.1 to T.sub.2 is 0.10 or more to 0.80 or less. An average thickness T.sub.3 of the alternating laminate structure is 2.5 μm or more to 7.0 μm or less. A ratio (H/E) of hardness H to elastic modulus E is 0.065 or more to 0.085 or less at the rake face or the flank.

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, A1 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.

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 includes a base material, and a coating film covering the base material in contact with the base material. The base material is a cubic boron nitride sintered material. The coating film is a ceramic. An amount of oxygen in the coating film is less than or equal to 0.040 mass percent.

A cutting tool according to the present disclosure has a rake face, a flank face, and a cutting edge. The cutting edge is located between the rake face and the flank face. The cutting tool includes a substrate composed of a cubic boron nitride sintered material, and an oxide layer that covers the substrate and that constitutes at least part or whole of the rake face, the flank face, and the cutting edge. The oxide layer includes at least one element selected from a group consisting of titanium, aluminum, zirconium, and cobalt. A thickness of the oxide layer is 2 μm or less.

To improve the adhesion resistance and wear resistance of a surface-coated cutting tool. The surface-coated cutting tool includes a tool substrate, and a single-component coating layer composed of a composite nitride of Cr (chromium), Al (aluminum), and V (vanadium) and disposed on the surface of the tool substrate. The composite nitride is characterized by being represented by a compositional formula: Cr.sub.aAl.sub.bV.sub.cN satisfying the following relations:
0.11≤a≤0.26;
0.73≤b≤0.85;
0<c≤0.04; and
a+b+c≤1
(wherein a, b, and c each represent an atomic proportion). The single-component coating layer has both a hexagonal phase and a cubic phase.