Mitsubishi Materials Corporation

Chihiro Sakurazawa

Toshihiko Matsuo

Wardoyo Akhmadi Eko

Tadakazu Ohashi

A drill bit insert attached to a tip portion of a drill bit to perform drilling, includes: an insert body () that includes: a rear end portion buried in a bit body of the drill bit; and a tip portion protruding from a surface of the drill bit and tapered toward a tip side of the insert body, in which a surface of at least the tip portion of the insert body () made of polycrystalline cubic boron nitride compact () sintered using a catalytic metal containing Al and at least one selected from the group consisting of Co, Ni, Mn, and Fe and containing 70 vol % to 95 vol % of cubic boron nitride.

Drill bit insert and drill bit

In a drill bit insert of the present invention, an insert body of the drill bit insert includes: a rear end portion forming a columnar shape or a disk-like shape; an intermediate portion having an outer diameter smaller than that of the rear end portion; and an end portion having an outer diameter from the center line of the insert gradually decreasing toward the tip side, the hard surface layer is coated on the insert body from a surface of the end portion of the insert body to an outer periphery of the intermediate portion, and an outer diameter of the hard surface layer on the intermediate portion is equal to that of the rear end portion.

A rotary cutting tool including a polycrystalline diamond material of the invention includes: a tool body rotated about an axis with a carbide substrate made of cemented carbide and a flute provided at a tip portion thereof; a PCD layer sintered integrally with the carbide substrate, provided on an inside face of the flute facing in a rotation direction; and a cutting edge provided on the PCD layer to have the inside face as a rake face, in which a margin portion continuous with a rear side of the flute in the rotation direction is formed on an outer periphery of the tip portion, the cutting edge is formed at a ridge portion of the rake face, and a thickness of the PCD layer is &#x2153; to 1 times a width of the margin portion.

Rotary cutting tool including polycrystalline diamond material

A drill bit button insert is attached to a button inserts mounted in a drill bit and performs a drilling. The drill bit button insert includes a tip body and an abrasive layer that is formed of a diamond sintered body harder than the tip body and is coated at least at the button insert working surface of the tip body. The abrasive layer has two or more high hardness layers and a low hardness layer having a hardness lower than that of the high hardness layers disposed between the high hardness layers. The high hardness layers and the low hardness layer are provided from the surface side of the abrasive layer toward the tip body side.

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Tsukuba, Japan

Chihiro Sakurazawa