The present invention relates to a cutting tool, which performs, like a drill or a ball end mill, cutting while rotating in a state in which the center of the tip end is in contact with a work material, and includes a wear-resistant layer formed at the tip end thereof, wherein a portion of the wear-resistant layer is selectively removed through tip end polishing from the center of the tip end of the drill or the ball end mill to a predetermined area, so as to restrain micro-brittle wear generated in an ultra-low speed region, and thus remarkably improving the cutting lifespan of the cutting tool such as the drill or the ball end mill.

A coating for carbide substrates employs a nanostructured coating in conjunction with a non-nanostructured coating. The nanostructured coating is produced by the addition of a refining agent flow, particular hydrogen chloride gas, during deposition, and may be produced as multiple individual titanium and titanium-based nanostructured layers varying functional materials in a series. The combination of a nanostructured coating and non-nanostructured coating is believed to produce a cutting tool insert that exhibits longer life. Pre-treating the substrate with a mixture of compressed air and abrasive medium prior to coating the substrate and post-treating the coated substrate with a mixture of water and abrasive medium after the coating process is believed to further enhance the wear resistance and usage life of the cutting tool.

The present invention relates to a cutting tool, which performs, like a drill or a ball end mill, cutting while rotating in a state in which the center of the tip end is in contact with a work material, and includes a wear-resistant layer formed at the tip end thereof, wherein a portion of the wear-resistant layer is selectively removed through tip end polishing from the center of the tip end of the drill or the ball end mill to a predetermined area, so as to restrain micro-brittle wear generated in an ultra-low speed region, and thus remarkably improving the cutting lifespan of the cutting tool such as the drill or the ball end mill.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coated cutting tool having a rake surface and a flank, in which the coating layer includes an -type aluminum oxide layer, wherein: the -type aluminum oxide layer has, on an opposite side to the substrate, a first interface, being the rake surface or a surface substantially parallel to the rake surface, a second interface, being the flank or a surface substantially parallel to the flank, and an intersecting edge between the first interface and the second interface; and the -type aluminum oxide layer satisfies 60011300, 90022250 and 11>22. (In the above formulae, 11 denotes a residual stress value (MPa) in a direction parallel to the intersecting edge, 22 denotes a residual stress value (MPa) in a direction orthogonal to the intersecting edge, and each of the residual stress values is a value measured by a 2D method).

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 surface-coated cutting tool has a rake face and a flank face, and includes a base material and a coating formed on the base material. The base material has a cutting edge face connecting the rake face to the flank face. The coating includes an aluminum oxide layer containing a plurality of aluminum oxide crystal grains. The aluminum oxide layer includes: a first region made up of a region A on the rake face and a region B on the flank face; a second region on the rake face except for the region A; and a third region on the flank face except for the region B. The aluminum oxide layer satisfies a relation: ba>0.5, where a is an average value of TC(006) in the first region in texture coefficient TC(hkl), and b is an average value of TC(006) in the second or third region in texture coefficient TC(hkl).

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.

A cutting edge tip of a cubic boron nitride sintered body has improved joint strength to a substrate of a cemented carbide. A cutting edge tip of a cubic boron nitride sintered body has improved crater wear resistance. A tool 10 of the present invention includes a substrate 12 of a cemented carbide and a cutting edge tip 14 of a cubic boron nitride sintered body joined to the substrate 12. The cutting edge tip 14 has a thickness covering an upper surface 12a to a lower surface 12b of the substrate 12. The cubic boron nitride sintered body contains 50 volume % or more and 95 volume % or less of cubic boron nitride and 5 volume % or more and 50 volume % or less of a binder phase. The cubic boron nitride has an average grain size of 1.0 m or more and 6.0 m or less.

An insert includes a first surface having a corner portion, a second surface, a third surface, and a cutting edge. The cutting edge is provided with a first cutting edge located on the corner portion and a second cutting edge adjacent to the first cutting edge, and the third surface is provided with a first portion located along the first cutting edge and a second portion located along the second cutting edge. the second portion includes a first region having a first end portion and a second end portion, and a second region having a third end portion and a fourth end portion. An inclination angle 212 at the second end portion is greater than an inclination angle 211 at the first end portion, and an inclination angle 222 at the fourth end portion is smaller than an inclination angle 221 at the third end portion.