A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer including at least one Ti compound layer containing a specific Ti compound, an intermediate layer including an -type Al.sub.2O.sub.3 layer containing -type Al.sub.2O.sub.3, and an upper layer including a TiCN layer containing TiCN; the respective layers are laminated in this order from the substrate side toward a surface side of the coating layer; an average thickness of the coating layer is from 5.0 m or more to 30.0 m or less; and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the intermediate layer and is parallel to the surface of the substrate and a normal to a (001) plane of a particle of an -type Al.sub.2O.sub.3 layer, and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the upper layer and is parallel to the surface of the substrate and a normal to a (111) plane of a particle of a TiCN layer, respectively satisfy predetermined conditions.

A cutting tool for metal cutting includes a substrate at least partially coated with a 3-30 ?m coating. The substrate is of cemented carbide, cermet or ceramic. The coating includes one or more layers, wherein at least one layer is a Ti(C,N) layer having a thickness of 3-25 ?m. The Ti(C,N) layer is composed of columnar grains with a mean grain size ?25 nm and ?35 nm.

A cutting tool including a substrate at least partially coated with a coating is provided. The coating includes a ?-Al.sub.2O.sub.3 layer, wherein the ?-Al.sub.2O.sub.3 layer in a portion O1 of the ?-Al.sub.2O.sub.3 layer within 1 ?m from the bonding layer, as measured with EBSD, exhibits Schmid factors calculated for the {0001} <11-20> slip system with the normal force applied at a 45? angle to the surface normal of the ?-Al.sub.2O.sub.3 layer, wherein the Schmid factor distribution was determined and wherein >90% of the analyzed area had a Schmid factor between 0.4 and 0.5, preferably >97% of the analyzed area had a Schmid factor between 0.4 and 0.5.

A surface-coated cutting tool includes a base material and a coating. A hard layer in the coating includes a plurality of crystal grains having a sodium chloride-type crystal structure. The crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of Al.sub.xTi.sub.1-x and a second layer composed of nitride or carbonitride of Al.sub.yTi.sub.1-y are alternately stacked. The total thickness of the first layer and the second layer adjacent to each other is 3 nm or more and 40 nm or less. An angle of intersection between a normal direction to (111) plane that is a crystal plane of the crystal grain and the normal direction to the surface of the base material, an area ratio of the crystal grains having the angle of intersection of 0 degree or more to less than 10 degrees is 40% or more.

A coated cutting tool insert includes a substrate of cemented carbide, cermet, ceramics, steel or cubic boron nitride having deposited thereon a coating having a total thickness of 60 ?m, including one or more layers having a wear resistant layer of ?-Al.sub.2O.sub.3 of a thickness of 1 to 45 ?m deposited by chemical vapour deposition (CVD). The ?-Al.sub.2O.sub.3 layer includes at least two portions, a first thickness portion and a second thickness portion immediately on top of the first thickness portion. The first thickness portion has an essentially columnar ?-Al.sub.2O.sub.3 grain structure, and at a transition from the first thickness portion to the second thickness portion the grain boundaries of at least 1 out of 25 neighboring grains of the ?-Al.sub.2O.sub.3 grains undergo a directional change into a direction that is essentially perpendicular, 90?45 degrees, to the grain boundaries in the first thickness portion.

There is provided a throw-away tip which includes a blade containing diamond and is excellent in chip processability. The throw-away tip comprises a body and a blade provided to the body and having a cutting edge, the blade containing 80% by volume or more of diamond, the blade having a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween, the recess having a side surface having an inclined surface that recedes continuously as a distance thereof from the land surface increases in magnitude and that has a shape identical to that of a portion of a side surface of a shape of a body of revolution.

A coated cutting tool includes a substrate of cemented carbide, cermet, ceramics, steel or cubic boron nitride and a multi-layered wear resistant coating. The multi-layered wear resistant coating has a total thickness from 5 to 25 m and includes refractory coating layers deposited by chemical vapour deposition (CVD) or moderate temperature chemical vapour deposition (MT-CVD). The multi-layered wear resistant coating has at least one pair of layers (a) and (b), with layer (b) being deposited immediately on top of layer (a). Layer (a) is a layer of aluminium nitride having hexagonal crystal structure (h-AlN) and a thickness from 10 nm to 750 nm. Layer (b) is a layer of titanium aluminium nitride or titanium aluminium carbonitride represented by the general formula Ti.sub.1-xAl.sub.xC.sub.yN.sub.z with 0.4x0.95, 0y0.10 and 0.85z1.15, having a thickness from 0.5 m to 15 m, and at least 90% of the Ti.sub.1-xAl.sub.xC.sub.yN.sub.z of layer (b) has a face-centered cubic (fcc) crystal structure.

In an embodiment, a cutting insert includes an upper surface, a one or more side surfaces, and a cutting edge. The upper surface includes a first corner portion, and a first side that is adjacent to the first corner portion. The side surfaces are adjacent to the upper surface. The cutting edge is disposed on at least a portion of a section where the upper surface and the side surfaces intersect. The cutting edge includes first, second, third and fourth cutting edges. The first cutting edge is disposed at the first corner portion and has a convex curved shape. The second cutting edge is next to the first cutting edge, and has a linear shape. The third cutting edge is next to the second cutting edge, and has a convex curved shape. The fourth cutting edge is next to the third cutting edge on the first side.

A cutting tool includes a substrate at least partially coated with a coating, the substrate being a cemented carbide, cermet or ceramic. The coating has a layer of Ti(C,N), a layer of Al.sub.2O.sub.3 and there between a bonding layer. The Ti(C,N) layer is composed of columnar grains, wherein an average grain size D.sub.422 of the Ti(C,N) layer is 25-50 nm, and wherein the Ti(C,N) layer includes a portion B1 that is adjacent to the bonding layer. An average grain size of the Ti(C,N) grains in portion B1 is larger than the average grain size D.sub.422 in the whole Ti(C,N) layer. In the portion B1 of Ti(C,N) layer the Ti(C,N) grains has an average grain size of 130-300 nm.

In one aspect, cutting tools are provided comprising radiation ablation regions defining at least one of refractory surface microstructures and/or nanostructures. For example, a cutting tool described herein comprises at least one cutting edge formed by intersection of a flank face and a rake face, the flank face formed of a refractory material comprising radiation ablation regions defining at least one of surface microstructures and surface nanostructures, wherein surface pore structure of the refractory material is not occluded by the surface microstructures and surface nanostructures.