A coated cutting tool, comprising: a substrate; and a coating layer formed on a surface of the substrate, wherein the coating layer includes a lower layer and an upper layer in this order from the substrate side toward the surface side of the coating layer, and the upper layer is formed on a surface of the lower layer, the lower layer contains a compound having a composition represented by (Al.sub.xTi.sub.1-x)N, an average thickness of the lower layer is 1.0 μm or more and 15.0 μm or less, the upper layer contains an α-Al.sub.2O.sub.3 layer containing α-Al.sub.2O.sub.3, an average thickness of the upper layer is 0.5 μm or more and 15.0 μm or less, and in the α-Al.sub.2O.sub.3 layer, a texture coefficient TC (1, 1, 6) of a (1, 1, 6) plane is 2.0 or more and 6.0 or less.

An object of the invention is to provide a coated cutting tool whose tool life can be extended by having excellent wear resistance and fracture resistance. The coated cutting tool includes: a substrate; and a coating layer formed on a surface of the substrate, in which the coating layer includes a lower layer, an intermediate layer, and an upper layer in this order from a substrate side to a surface side of the coating layer, the lower layer includes one or more Ti compound layers formed of a specific Ti compound, the intermediate layer contains TiCNO, TiCO, or TiAlCNO, the upper layer contains α-type Al.sub.2O.sub.3, an average thickness of the lower layer is 2.0 μm or more and 8.0 μm or less, an average thickness of the intermediate layer is 0.5 μm or more and 2.0 μm or less and is 10% or more and 20% or less of a thickness of the entire coating layer, an average thickness of the upper layer is 0.8 μm or more and 6.0 μm or less, and in the intermediate layer, a ratio of a length of CSL grain boundaries to a total length 100% of a total grain boundary is 20% or more and 60% or less.

A coated cutting tool and a process for the production thereof id provided. The coated cutting tool consists of a substrate body of WC-Co based cemented carbide and a coating, the coating including a first (Ti,Al)N multilayer, a first gamma-aluminium oxide layer, and a set of alternating second (Ti,Al)N multilayers and second gamma-aluminium oxide layers.

In a vanadium nitride film formed on a surface of a base material, a ratio V [at %]/N [at %] between a vanadium element concentration and a nitrogen element concentration in the film is 1.08 or more and a chlorine element concentration in the film is 1 at % or more and 5 at % or less.

A coated cutting tool for metal machining has a base body of cemented carbide, cermet, ceramics, steel or high-speed steel, and a wear resistant coating deposited thereon. The coating includes a layer of Ti.sub.1-xAl.sub.xC.sub.yN.sub.z with 0.40≤x≤0.95, 0≤y≤0.10 and 0.85≤z≤1.15, and a portion of MeC.sub.aN.sub.b, 0≤a≤1, 0≤b≤1, a+b=1, present on the layer of Ti.sub.1-xAl.sub.xC.sub.yN.sub.z. The portion of MeC.sub.aN.sub.b covers from 5 to 28% of the layer of Ti.sub.1-xAl.sub.xC.sub.yN.sub.z. A process for the production of the coated cutting tool and the use of the coated cutting tool in machining of stainless steel is also provided.

A coated tool includes a base and a coating layer on the base. The coating layer includes a first layer including Al.sub.2O.sub.3 particles, and a second layer on the first layer. The second layer includes, sequentially from the base, a first film, a second film in contact with the first film, and a third film in contact with the second film. The first to third films individually include Ti. The first film, the second film and the third film individually include at least one kind selected from C and N. The coated tool satisfies a relationship of a first N content>a third N content>a second N content, in which the first N content is an N content in the first film, the second N content is an N content in the second film, and the third N content is an N content in the third film.

A surface coated cutting tool comprises: a tool substrate and a coating layer on a surface of the tool substrate; wherein the coating layer comprises a lower layer, an intermediate layer, and an upper layer, in sequence from the tool substrate toward the surface of the tool. The lower layer comprises an A layer having an average composition represented by formula: (Al.sub.1-xCr.sub.x)N, where x is 0.20 to 0.60; the intermediate layer comprises a B layer having an average composition represented by formula: (Al.sub.1-a-bCr.sub.aSi.sub.b)N, where a is 0.20 to 0.60 and b is 0.01 to 0.20; and the upper layer comprises a C layer having an average composition represented by formula: (Ti.sub.1-α-βSi.sub.αW.sub.β)N where α is 0.01 to 0.20 and β is 0.01 to 0.10; and the upper layer has a repeated variation in W level with an average interval of 1 nm to 100 nm between adjacent local maxima and minima.

Provided is a cutting tool comprising a base body and a hard carbon film arranged on the base body, in which, when the cross section of the hard carbon film is observed using a high angle annular dark field scanning transmission electron microscope, the area proportion of black regions with an equivalent circle diameter of 10 nm or more is 0.7% or less, and the hard carbon film has a hydrogen content of 5 atom% or less.

A coated cutting tool having a substrate and a coating is provided. The coating includes an inner α-Al.sub.2O.sub.3-multilayer and an outer α-Al.sub.2O.sub.3-single-layer. The thickness of the inner α-Al.sub.2O.sub.3-multilayer is less than or equal to 35% of the sum of the thickness of the inner α-Al.sub.2O.sub.3-multilayer and the thickness of the outer α-Al.sub.2O.sub.3-single-layer. The sum of the thickness of the inner α-Al.sub.2O.sub.3-multilayer and the outer α-Al.sub.2O.sub.3-single-layer is 2-15 μm. The inner α-Al.sub.2O.sub.3-multilayer consists of alternating sublayers of α-Al.sub.2O.sub.3 and sublayers of TiCO, TiCNO, AlTiCO or AlTiCNO. The inner α-Al.sub.2O.sub.3-multilayer can include at least 5 sublayers of α-Al.sub.2O.sub.3.

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.