Sumitomo Electric Hardmetal Corp.

Sumitomo Electric Industries, Limited

Shinya Uesaka

Satoru Kukino

Tetsuo Nakai

Yasuyuki Kanada

Tomohiro Fukaya

Keiji Kinoshita

Hiroki Yonekura

Naoki Sakata

Takuichiro Tayama

Katsumi Okamura

Hitoshi Sumiya

Junichi Shiraishi

Kunishige Tanaka

A cutting insert including a substrate having a seat recessed from a top surface at a corner and a superhard sintered body bonded to the seat. The body includes a cutting edge, a rake face with positive rake angle, and chip breaker including, in plan view, a projection projecting from a line that crosses a bisector of the corner toward a tip end of an arc edge of the cutting edge. A first breaker wall is formed between a top edge of the projection and the rake face. A second breaker wall is formed between a ridge line extending from a base end of the projection to a side surface of the body and the rake face. Another ridge line formed between the rake face and the side surface is inclined whereby a distance to a bottom surface of the substrate decreases as a distance from the cutting edge increases.

Cutting insert

Throwaway insert for metal cutting tool

The present high-strength, highly thermally conductive sintered compact of cubic boron nitride contains cubic boron nitride (cBN) grains and a binder binding the grains. More specifically, it is formed of at least 40% by volume and at most 85% by volume of cBN grains, and a binder corresponding to the remainder and formed of at least one selected from the group consisting of a nitride, a carbide, a boride, and an oxide of an element belonging to the 4a, 5a and 6a groups of the periodic table and a solid solution thereof, an aluminum compound, and an unavoidable impurity, and the cBN grains contain at most 0.03% by mass of Mg and at least 0.001% by mass and at most 0.05% by mass of Li.

High-strength, highly thermally conductive sintered compact of cubic boron nitride

The object of the present invention is to provide a cutting tool consisting of fine grain cBN free from a binder and having a grain size of at most 1 &mgr;m and having a high hardness, high strength and excellent heat resistance. The feature thereof consists in a cutting tool compring, as an edge part, a cubic boron nitride sintered compact containing cubic boron nitride having an average grain diameter of at most 1 &mgr;m, in which the cubic boron nitride sintered compact has, at the said edge part, an I /I of (220) diffraction intensity (I ) to (111) diffraction intensity (I ) ratio of at least 0.05 in X-ray diffraction of arbitrary direction and impurities are substantially not contained in the grain boundaries.

Cutting tool of a cubic boron nitride sintered compact

A coated cubic boron nitride (cBN) sintered body most suitable for a cutting tool having excellent resistance to wear and heat in the high-speed cutting of steel has been developed. The sintered body comprises (a) a base material made of a sintered body comprising at least 99.5 vol. % cBN and (b) a hard coating 0.1 to 10 &mgr;m in thickness formed on at least part of the surface of the base material by the PVD method. It is desirable that the hard coating comprise at least one compound layer consisting mainly of (a) at least one metal element selected from Al and the IV a-group elements and (b) at least one element selected from C, N, and O. It is desirable to provide between the base material and the hard coating an intermediate layer comprising a compound consisting mainly of boron and at least one metal element selected from the IV a-group elements.

Coated sinter of cubic-system boron nitride

High-pressure phase boron nitride base sinter

A sintered body consists of high-pressure phase boron nitride, a residual binder phase and an unavoidable impurity, and contains high-pressure phase boron nitride powder which is previously coated with a binder before sintering. The coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and has an average thickness of 5 to 300 nm. Binder powder other than the coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and a contact ratio of high-pressure phase boron nitride particles in surface-to-surface contact with each other is at least 20% and less than 50%. The resulting high-pressure phase boron nitride-based hard and tough sintered body for a cutting tool is improved in wear resistance and chipping resistance.

Hard and tough sintered body

A cutting tool for milling comprises an insert consisting of a cubic boron nitride sintered body having heat conductivity of at least 400 W/m.K at 120.degree. C. and a thermal expansion coefficient within the range of at least 3.0.times.10.sup.-6 /K and not more than 4.0.times.10.sup.-6 /K in the temperature range of 20.degree. C. to 600.degree. C. According to this cutting tool for milling, sufficient tool life can be attained in high-speed face milling under a wet condition and high-speed end milling under a wet condition.

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Hyogo, Japan

Shinya Uesaka