A cutting tool includes a substrate of cemented carbide having hard constituents in a metallic binder. The hard constituents include WC. The WC content in the cemented carbide is 80-95 wt %. The cemented carbide has a Fe+Ni+Co+Cr content of 3-13 wt %, an atomic ratio of 0.05<Fe/(Fe+Ni+Co+Cr)<0.35, an atomic ratio of 0.05<Ni/(Fe+Ni+Co+Cr)<0.35, an atomic ratio of 0.05<Co/(Fe+Ni+Co+Cr)<0.35 and an atomic ratio of 0.05<Cr/(Fe+Ni+Co+Cr)<0.35. The crack resistance W measured on the rake face of the cutting tool is at least 25% higher than the W measured on a cross section of the bulk area of the cutting tool.

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 tool includes a base and a coating film on the base. The coating film includes an Al.sub.2O.sub.3 layer, and a surface layer on the Al.sub.2O.sub.3 layer. The surface layer has a first erosion rate of 0.1 μm/min or less. The first erosion rate is obtained from measurement by causing a liquid A, in which 3 mass % of amorphous Al.sub.2O.sub.3 particles having a mean particle diameter of 1.1-1.3 μm is dispersed in purified water, to collide with the surface layer. The surface layer has a second erosion rate of 2.0 μm/min or more. The second erosion rate is obtained from measurement by causing a liquid B, in which 3 mass % of spherical Al.sub.2O.sub.3 particles having a mean particle diameter of 2.8-3.2 μm is dispersed in purified water, to collide with the surface layer.

A coated cutting tool includes a substrate with a rake side, a clearance side and a cutting edge, and a coating including a first layer and a second layer. The second layer includes an inner layer and an outer layer, wherein the first layer is exposed through an opening in the inner layer and the opening extends over at least a portion of the width of the cutting edge. Thereby, a double layer is provided in critical areas, whereas a single layer is provided in other areas. Preferably, the double oxide layer includes aluminum oxide layers. A method for manufacturing the coated cutting tool is also provided.

The disclosure relates to a method of manufacturing a cutting tool including the steps of: providing a cutting tool blank including a cutting edge, defined by a cross-sectional wedge angle (β). The wedge angle has a variation along the cutting edge, and material is removed from the cutting edge with a constant material removal rate per length unit of the edge, such as to form a corresponding variation of edge rounding along the cutting edge. The disclosure further relates to a cutting tool including the cutting edge defined by the cross-sectional wedge angle having a variation along the cutting edge and wherein the cutting edge has a corresponding variation of edge rounding along the cutting edge.

The present disclosure provides a multilayer coated cutting material having increased wear resistance at high temperatures, a method for manufacturing the same, and a cutting tool insert for mechanical machining including the same. According to an embodiment of the present disclosure, the multilayer coated cutting material includes a cemented carbide, cermet, ceramic, a cubic crystal boron nitride-based material or a hard alloy body of high-speed steel, and a cutting layer positioned on the base material and configured in multiple layers.

The present disclosure provides a multilayer coated cutting material having increased wear resistance at high temperatures, a method for manufacturing the same, and a cutting tool insert for mechanical machining including the same. According to an embodiment of the present disclosure, the multilayer coated cutting material includes a cemented carbide, cermet, ceramic, a cubic crystal boron nitride-based material or a hard alloy body of high-speed steel, and a cutting layer positioned on the base material and configured in multiple layers.

A surface-coated cutting tool includes a lower layer including a Ti compound layer, an intermediate layer including an α-Al.sub.2O.sub.3 layer, and an upper layer including a Zr-containing α-Al.sub.2O.sub.3 layer. The outermost layer of the lower layer contains 0.5 to 3 at % of oxygen. The frequencies of inclination angles between a normal line to a (0001) plane of Al.sub.2O.sub.3 grains of the intermediate layer and a normal line to a surface of a tool body have a highest peak in an inclination angle division of 0 to 10°. The ratio of the frequencies is 50 to 70%. The frequencies between the normal line to the (0001) plane of Al.sub.2O.sub.3 grains of the entirety of the intermediate and the upper layers and the normal line to the tool body surface have a highest peak in an inclination angle division of 0 to 10°. The ratio of the frequencies is 75% or more.

A surface-coated cutting tool has a hard coating layer and a tool body, which is coated with a lower layer including a TiCN layer having at least an NaCl type face-centered cubic crystal structure and an upper layer formed of a TiAlCN layer having a single phase crystal structure of NaCl type face-centered cubic crystals or a mixed phase crystal structure of NaCl type face-centered cubic crystals and hexagonal crystals. The tool body is further coated with an outermost surface layer including an Al.sub.2O.sub.3 layer, when the layer of a complex nitride or complex carbonitride of Ti and Al is expressed by the composition formula: (Ti.sub.1-xAl.sub.x)(C.sub.yN.sub.1-y), the average amount Xave of Al in Ti and Al and the average amount Yave of C in C and N (both Xave and Yave are atomic ratios) respectively satisfy 0.60≦Xave≦0.95 and 0≦Yave≦0.005.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an α-Al.sub.2O.sub.3 layer. The α-Al.sub.2O.sub.3 layer contains a plurality of α-Al.sub.2O.sub.3 crystal grains and a plurality of κ-Al.sub.2O.sub.3 crystal grains, and has a TC(006) of more than 5 in a texture coefficient TC(hkl). A ratio of C.sub.κ to a sum of C.sub.α and C.sub.κ: [C.sub.κ/(C.sub.α+C.sub.κ)×100](%) is 0.05 to 7%, where C.sub.α is a total number of peak counts of the α-Al.sub.2O.sub.3 crystal grains obtained from measurement data of x-ray diffraction for the coating, and C.sub.κ is a total number of peak counts of the κ-Al.sub.2O.sub.3 crystal grains obtained from the measurement data of the x-ray diffraction for the coating.