The flow of heat energy from the cutting edge rim of a self-propelled round annular rotary cutting element (insert) to axial-load and radial-load bearings in a cartridge which rotatably supports the insert on a machine tool body is reduced by defining heat flow paths from the insert rim to cartridge components which engages the bearings to have low thermal conductance relative to heat flow paths from the insert rim to other parts of the cartridge. Control over heat flow path thermal conductance is obtained by selection of materials used between the insert rim and the mentioned cartridge components, by reductions in the cross-sectional areas of the critical heat flow paths, and by combinations of those two techniques. Protection of the bearings from heat enables the insert and the cartridge to be reduced in size. Improved mountings of insert-supportive cartridges to tool bodies are disclosed. The insert and the cartridge preferably are shaped to enable the insert to be positioned on a tool body so that the insert's rake face can have a positive rake orientation relative to a workpiece. Arrangements for controlling cuttings chip formation and for handling cuttings chips also are disclosed.

A cemented carbide including a hard phase, a binding phase, and inevitable impurities. The hard phase satisfies a first hard phase composed mainly of tungsten carbide, and a second hard phase composed mainly of a compound. The compound contains multiple types of metallic elements including tungsten and at least one element selected from carbon, nitrogen, oxygen, and boron. The second hard phase satisfies D10/D90<0.4, wherein D10 denotes a cumulative 10% grain size in an area-based grain size distribution on a surface or cross section of the cemented carbide, and D90 denotes a cumulative 90% grain size in the area-based grain size distribution, and satisfies .sup.2<5.0, wherein .sup.2 denotes the variance of the distance between the centroids of the nearest two of the second hard phases. The average grain size D.sub.W of the first hard phase ranges from 0.8 to 4.0 m and satisfies D.sub.M/D.sub.W<1.0, wherein D.sub.M denotes the average grain size of the second hard phase.

A cutting tool body includes a first member and a second member, both having a substantially cylindrical shape, and arranged such that a tool body central axis coincides with a central axis of each of the first and the second members. The first member has a tool characteristic of a first magnitude and the second member has the tool characteristic of a second magnitude, different from the first magnitude. The cutting tool body includes a transition member arranged between the first and second members and connected at a first end to the first member and at a second end to the second member. The tool characteristic in the transition member is of the first magnitude at the first end and of the second magnitude at the second end. The transition member has a transition region between the first and the second ends in which the tool characteristic transforms from the first magnitude to the second magnitude.

A tool for machining materials has a main part and one or more blades. The main part is made of a low-alloy steel. The socket is welded to the main part, and the blade edges are made of a hard metal. The hard metal contains at least 82 vol. % of tungsten carbide and a metallic binder made of a cobalt-nickel-based alloy. The hardness of the hard metal is greater than 1350 HV10. The socket has a sintered composite, and 40 vol. % to 60 vol. % of the composite is composed of a metal carbide and a metallic binder. At least 95 vol. % of the metallic binder is made of nickel, and the hardness of the composite is less than 800 HV10.

A coated cutting tool comprising a cemented carbide and a coating layer formed on a surface of the cemented carbide, wherein: an average thickness of the coating layer is from 5.0 m or more to 30.0 m or less; and in the cemented carbide, when regarding a region thereof which ranges from the surface of the cemented carbide to a depth of 20.0 m in a direction opposite to the coating layer as a surface region, and also regarding a region thereof on a side opposite to the coating layer across the surface region as an inner region, an average value of KAM values in the surface region KAM.sub.s and an average value of KAM values in the inner region KAM.sub.i satisfy a condition represented by formula (1) below.

0.00|KAM.sub.sKAM.sub.i|0.10(1)

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 process line tool of a cemented carbide comprising in wt %; about 2.9-11 Ni; about 0.1-2.5 Cr.sub.3 C.sub.2; and about 0.1-1 Mo; and a balance of WC, with an average WC grain size less than or equal to 0.5 m.

A coated cutting tool includes a body and a hard and wear resistant coating on the body. The coating has at least one NbN layer with a thickness between 0.2 m and 15 m, wherein the NbN layer includes a phase mixture of a cubic phase, c-NbN, and a hexagonal phase, h-NbN.

A coated cutting tool includes a body and a hard and wear resistant PVD coating on the body, wherein the body is made from a cemented carbide, cermet, ceramics, polycrystalline diamond or polycrystalline cubic boron nitride based materials. The coating includes a first (Ti,Al)-based nitride sub-coating and a second (Ti,Al)-based nitride sub-coating. The first (Ti,Al)-based nitride sub-coating can be a single layer, and the second (Ti,Al)-based nitride sub-coating can be a laminated structure, wherein the first (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-xAl.sub.x)N.sub.z-layer where 0.1<x<0.4, 0.6<z<1.2, and wherein the second (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-x1-y1Al.sub.x1Cr.sub.y1)N.sub.z1 layer where 0.5<x1<0.75, 0.05<y1<0.2, 0.6<z1<1.2.

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 (0,1,8) of a (0,1,8) plane is from 0.5 or more to 3.0 or less.