A surface-coated cutting tool includes a tool body, a lower layer, and an upper layer. The lower layer consists of a W layer, a metal carbide layer, and a metal carbonitride layer. The W layer is formed from a surface of the tool body to a depth of 10 to 500 nm. The metal carbide layer includes any one of Ti, Cr, Zr, Hf, Nb, and Ta. The upper layer is alternately laminated with an A layer and a B layer and has a total thickness of 1.0 to 8.0 m. The A layer has a thickness of 0.1 to 5.0 m and is represented by (Al.sub.xCr.sub.1-x)N (0.40x0.80). The B layer has a thickness of 0.1 to 5.0 m and is represented by (Al.sub.1-a-b-c-sTi.sub.aCr.sub.bSi.sub.cY.sub.d)N (0a0.40, 0.05b0.40, 0c0.20, and 0.01d0.10).

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 surface coated cutting tool comprises a base material and a coating layer that coats the base material, the coating layer including an alternate layer composed of a first unit layer and a second unit layer alternately stacked, the first unit layer being composed of a nitride containing aluminum and zirconium, in the first unit layer, when the total number of metal atoms constituting the first unit layer is represented as 1, a ratio thereto of the number of atoms of the zirconium being not less than 0.65 and not more than 0.95, the second unit layer being composed of a nitride containing titanium and aluminum, in the second unit layer, when the total number of metal atoms constituting the second unit layer is represented as 1, a ratio thereto of the number of atoms of the aluminum being larger than 0.40 and not more than 0.70.

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.

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, a texture coefficient TC (0,0,12) of a (0,0,12) plane is from 4.0 or more to 8.4 or less, and a texture coefficient TC (1,2,11) of a (1,2,11) plane is from 0.5 or more to 3.0 or less.

A cutting tool comprises a rake face and a flank face, the cutting tool being composed of a substrate made of a cubic boron nitride sintered material and a coating provided on the substrate, the coating including a MAIN layer, the MAIN layer including crystal grains of M.sub.xAl.sub.1-xN in the cubic crystal system, n.sub.F<n.sub.R being satisfied, where n.sub.F represents a number of voids per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer, and n.sub.R represents a number of voids per 100 m in length of the MAIN layer on the rake face in a cross section of the MAIN layer, n.sub.D being 3 or less, where n.sub.D represents a number of droplets per 100 m in length of the MAIN layer on the flank face in a cross section of the MAIN layer.

Provided is a surface-coated cutting tool including a base material and a coating including a super-multilayer-structure layer where A layers and B layers different from the A layers in composition are alternately laminated. The super-multilayer-structure layer includes an X area and a Y area those are alternately repeated. In the X area, A layers having a thickness A.sub.X and B layers having a thickness B.sub.X are alternately laminated. In the Y area, A layers having a thickness A.sub.Y and B layers having a thickness B.sub.Y are alternately laminated. The thickness A.sub.X is larger than the thickness A.sub.Y, and the thickness B.sub.X is smaller than the thickness B.sub.Y. Each of the A layers and the B layers comprising one or more elements selected from a group consisting of Ti, Al, Cr, Si, Ta, Nb, and W, and one or more elements selected from a group consisting of C and N.

A cutting tool comprising a substrate and a coating layer formed on the substrate, wherein the coating layer has, from a side closer to the substrate, a lower layer that contains a compound having a composition represented by (Al.sub.xTi.sub.1-x)N, and an upper layer that is formed on the lower layer and contains a compound having a composition represented by (Al.sub.yTi.sub.1-yN, the average thickness of the lower layer is 1.0 m or more and 10.0 m or less; the average thickness of the upper layer is 1.0 m or more and 10.0 m or less; and an area ratio GOS.sub.i of crystal grains having a GOS value of 1 degree or lower in the lower layer and an area ratio GOS.sub.s of crystal grains having a GOS value of 1 degree or lower in the upper layer satisfy GOS<GOS.sub.s.

A surface-coated cutting tool includes: a tool body formed of a tungsten carbide-based cemented carbide; a lower layer and an upper layer provided on the tool body. The lower layer is formed of a W layer. A metal carbide layer is formed directly on the W layer. A metal carbonitride layer is formed directly on the metal carbide layer. The upper layer has an alternately laminated structure of A layer and B layer. The A layer is formed of an (Al, Ti)N layer represented by (Al.sub.xTi.sub.1-x)N (where x is an atomic ratio and satisfies 0.40x0.70). The B layer is formed of an (Al, Ti, Cr, Si, Y)N layer represented by (Al.sub.1-a-b-c-dTi.sub.aCr.sub.bSi.sub.cY.sub.d)N (where a, b, c, and d are atomic ratios and satisfy 0a0.40, 0.05b0.40, 0c0.20, and 0.01d0.10).

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 (111) 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 (111) oriented Al.sub.xTi.sub.1-xN crystal grains at a ratio of 80% or more.