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.

The current invention proposes sharpening thin hardened metal blades with the hard turning process using a holder designed to hold the blades in a firm and stiff manner and a ceramic cutting tool held in a fixture. Generally, the cutting tool is held stationary in its fixture while the workpiece, in its holder, is rotated such that it repeatedly comes into controlled contact with the cutting tool. In sharpening operations such as proposed here, it is critical to (i) hold the workpiece firmly and rigidly, and (ii) position the cutting tool in a precise, predictable and reliable manner.

A tangential cutting insert for a turning tool is described, which comprises a first tangential cutting insert side and a second tangential cutting insert side, wherein one of the tangential cutting insert sides is assigned more than two cutting edges, and the cutting edges are arranged in a star shape about a tangential cutting insert center axis. The tangential cutting insert is produced completely from cubic crystalline boron nitride, polycrystalline cubic boron nitride, polycrystalline diamond, or ceramic. In addition, a cutting tool with such a tangential cutting insert is presented. A method for producing a tangential cutting insert is also explained.

An insert may include a sintered silicon nitride including -Si.sub.3N.sub.4 as a main component. The area up to 0.5 mm deep from a surface of the sintered silicon nitride is a first region. The first region may include an oxygen content of less than 0.8% by mass. The first region may include ReMgSi.sub.2O.sub.5N (Re is at least one of Yb and Y). A cutting tool may include a holder that extends from a first end toward a second end and includes a pocket on a side of the first end, and the insert located at the pocket.

A method for processing a CMC airfoil includes nesting an airfoil fiber preform in a cavity of a fixture that has first and second tool segments, closing the fixture by rotating a first tool segment about a hinge, the closing causing the tool segments to clamp on a tail portion of the fiber preform and thereby conform the tail portion to the fixture. While in the fixture, the fiber preform is then partially densified with an interface coating material to form a partially densified fiber preform. While still in the fixture, one or more cooling holes are drilled into the trailing edge of the partially densified fiber preform. After the drilling, the partially densified fiber preform is removed from the fixture and further densified with a ceramic matrix material to form a fully densified CMC airfoil.

A cutting insert has a surface that relates to cutting, the surface comprising cBN sintered material, ceramics, or cermet. The cutting insert comprises: a rake face; a flank face; a chamfer located between the rake face and the flank face; and a cutting edge formed by a ridgeline at which the flank face and the chamfer intersect. The cutting edge comprises a cutting edge portion for push cutting, a cutting edge portion for pull cutting, and a connecting cutting edge portion located between the cutting edge portion for push cutting and the cutting edge portion for pull cutting. In the chamfer located along the cutting edge, the chamfer located along the connecting cutting edge portion has a minimum width.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.

Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes Al.sub.2O.sub.3 (alumina), WC (tungsten carbide) and ZrO.sub.2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al.sub.2O.sub.3; and (2) a grain boundary of crystal grains of the Al.sub.2O and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO.sub.2, and the balance being the Al.sub.2O.sub.3, and wherein the ZrO.sub.2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

An insert based on an aspect includes a first face, a second face located opposite to the first face, a third face located between the first face and the second face, and a cutting edge located on an intersection of the first face and the third face. The first face includes a first region inclined so as be close to the second face as being separated away from the cutting edge. A virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face. A ten-point average of roughness the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b, and Rz1a is larger than Rz1b.

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, when regarding a texture coefficient of a (0,0,6) plane as a TC18 (0,0,6), and also regarding a texture coefficient of a (0,0,12) plane as a TC18 (0,0,12), the TC18 (0,0,6) is the highest texture coefficient and the TC18 (0,0,12) is the second highest texture coefficient.