Sumitomo Electric Hardmetal Corp.

Sumitomo Electric Industries, Limited

Daiji Tabayashi

Shinya Imamura

Yasuki Kido

Haruyo Fukui

Yoshiharu Utsumi

Yoshihiro Saito

Kazuya Tokuda

Hajime Takamatsu

Hideki Moriguchi

Makoto Setoyama

Junya Okida

Miki Miyanaga

Sachiko Koike

Shigeaki Uemura

Provided is a cutting tool comprising a base body and a hard carbon film arranged on the base body, in which the hard carbon film includes an amorphous phase and a graphite phase, the degree of crystallinity of the hard carbon film is no more than 6.5%, and the degree of orientation of the graphite phase is no more than 6.

Cutting tool

Provided is a cutting tool that can have a long tool life even when used to cut soft metals in particular. The cutting tool comprises a base body and a hard carbon film arranged on the base body, the hard carbon film includes an amorphous phase and a graphite phase, the density of the hard carbon film is no less than 2.5 g/cmand no more than 3.5 g/cm, the degree of crystallinity of the hard carbon film is no more than 6.5%, and the average coordination number of the amorphous phase is no less than 2.5 and no more than 4.

A cemented carbide comprises a first hard phase comprising tungsten carbide particles and a binder phase including Co and Cr. In any surface or any cross section of the cemented carbide, a region in which there is a distance X of 5 nm or less between surfaces respectively of tungsten carbide particles adjacent to each other, with the surfaces facing each other along a length L of 100 nm or more, is referred to as a WC/WC interface, and a ratio C(R)/C(C) has an average value of 0.17 or more, where C(R) and C(C) represent peak values of atomic percentages of Cr and Co, respectively, at a WC/WC interface having a distance X of 1 nm or more and 5 nm or less and having therein an atomic percentage of Co higher than an average value of atomic percentages of Co in the tungsten carbide particles+2 at %.

Cemented carbide and cutting tool

A cemented carbide comprising a first hard phase composed of tungsten carbide particles and a binder phase including Co, the cemented carbide having a ratio Nt/Na of 0.9 or more, where, in any surface or any cross section of the cemented carbide, a region in which there is a distance X of 5 nm or less between surfaces respectively of tungsten carbide particles adjacent to each other, the surfaces facing each other along a length L of 100 nm or more, is referred to as a WC/WC interface, and Na represents a total number of WC/WC interfaces and Nt represents a number of WC/WC interfaces having distance X of 1 nm or more and 5 nm or less and having therein an atomic percentage of Co higher than an average value of atomic percentages of Co in the tungsten carbide particles.

A surface-coated cutting tool of the present invention includes a substrate and a coated layer formed on the substrate, and the coated layer is a physical-vapor-deposition layer having a thickness of 10 &#x3bc;m or more. A surface region having a thickness of 1 &#x3bc;m from a surface of the coated layer includes a first region whose integrated residual stress is a compressive stress and a second region whose integrated residual stress is a tensile stress, and the integrated residual stress of the surface region falls within the range of &#x2212;1.5 to 1.5 GPa in any region included in the surface region.

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Itami, Japan

Daiji Tabayashi