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.

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 cutting tool includes a substrate of cemented carbide including hard constituents in a metallic binder. The hard constituents includes WC and the WC content in the cemented carbide is 80-96 wt%. The cemented carbide has a Ni content of 2.5-13 wt%, a weight ratio of Fe / Ni < 1.5 and a weight ratio of Co / Ni < 0.825. The cutting tool includes a rake face, a flank face and a cutting edge there between, wherein the hardness H is measured with Vickers indentation and the crack resistance W is the ratio of the load to the total crack lengths of the cracks in the corners of said Vickers indentation. The product of the hardness at the rake face H(rake) and the crack resistance at the rake face W(rake) for the cutting tool is H(rake)*W(rake) > 2000 HV100*N/.Math.m.

A cutting tool includes a substrate of cemented carbide including hard constituents in a metallic binder. The hard constituents includes WC and the WC content in the cemented carbide is 80-96 wt%. The cemented carbide has a Ni content of 2.5-13 wt%, a weight ratio of Fe / Ni < 1.5 and a weight ratio of Co / Ni < 0.825. The cutting tool includes a rake face, a flank face and a cutting edge there between, wherein the hardness H is measured with Vickers indentation and the crack resistance W is the ratio of the load to the total crack lengths of the cracks in the corners of said Vickers indentation. The product of the hardness at the rake face H(rake) and the crack resistance at the rake face W(rake) for the cutting tool is H(rake)*W(rake) > 2000 HV100*N/.Math.m.

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.

A coated cutting tool having a substrate and a surface coating, wherein the coating includes a Ti(C,N) layer of at least one columnar fine-grained MTCVD Ti(C,N) layer with an average grain width of 0.05-0.2 μm and an atomic ratio of carbon to the sum of carbon and nitrogen (C/(C+N)) contained in the MTCVD Ti(C,N) layer is in average 0.50-0.65.

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.

Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift λ′ (cm.sup.−1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift λ (cm.sup.−1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1):
λ′−λ≥−0.10  (1).

A turning insert includes a top surface, a bottom surface, and side surfaces connecting the top and bottom surfaces. A reference plane is located parallel to and between the top surface and the bottom surface. A center axis intersects and extends perpendicular to the reference plane. Three nose portions are formed symmetrically around the center axis. Each nose portion has a first cutting edge, a second cutting edge and a convex nose cutting edge connecting the first and second cutting edges. As seen in in a top view, the first and second cutting edges on the same nose portion form a nose angle of 25-50°. The first cutting edge includes a first sub-portion and a second sub-portion. A distance from the nose cutting edge to the first sub-portion is shorter than a distance from the nose cutting edge to the second sub-portion.

This disclosure relates to a polycrystalline diamond (PCD) body comprising a PCD material formed of intergrown diamond grains forming a diamond network, and an iron-containing binder.