# US 5,348,808 A · Hard sintered body cutting tool

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- Number: US 5,348,808 A
- Document ID: US5348808A
- Status: Granted
- Kind: A
- Application number: 08/067,424
- Filed: 1993-05-25
- Granted: 1994-09-20
- Earliest claimed: 1993-01-07
- Assignees: Sumitomo Electric Industries, Ltd.
- Inventors: Mitsuhiro Goto; Tetsuo Nakai
- Web page: https://patentgrep.com/patent/US5348808A

## CPC

- C22C 26/00: Alloys containing diamond {or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes}
- B01J 3/062: {characterised by the composition of the materials to be processed}
- B22F 7/06: of composite workpieces or articles from parts, e.g. to form tipped tools {(B22F7/002 takes precedence)}
- B23B 27/148: {Composition of the cutting inserts}
- B32B 18/00: Layered products essentially comprising ceramics, e.g. refractory products
- B01J 2203/062: Diamond
- B01J 2203/0645: Boronitrides
- B01J 2203/0655: Diamond
- B01J 2203/066: Boronitrides
- B01J 2203/0685: Crystal sintering
- C04B 2237/36: Non-oxidic
- C04B 2237/361: Boron nitride
- C04B 2237/365: Silicon carbide
- C04B 2237/368: Silicon nitride
- C22C 2026/005: {with additional metal compounds being borides}
- Y10T 428/12049: Nonmetal component
- Y10T 428/12056: Entirely inorganic
- Y10T 428/12146: Nonmetal particles in a component
- Y10T 428/12167: Nonmetal containing
- Y10T 428/12174: Mo or W containing
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

In a hard sintered cutting tool, the tool life can be further increased. In this hard sintered body cutting tool, a rake face of an edge portion is formed by a major surface of a first sintered body layer containing at least 80 percent by volume and less than 98 percent by volume of diamond, while a flank of the edge portion is formed by a second sintered body layer containing at least 30 percent by volume and less than 75 percent by volume of cubic boron nitride (CBN). The first sintered body layer is formed to have a thickness of at least 0.02 mm and less than 0.1 mm, and to be in a thickness ratio of at least 1:5 to the second sintered body layer. Thus, chipping resistance of the rake face is improved by the first sintered body layer, while wear resistance of the flank is improved by the second sintered body layer. As a result, it is possible to suppress progress of local wear and chipping, whereby the life of the cutting tool is increased as compared with the prior art.

## Claims

### Claim 1

A hard sintered body cutting tool comprising:
a first sintered body layer containing at least 80 percent by volume and less than 98 percent by volume of diamond with a remainder being a first binder containing a metal of group VIII of the periodic table and containing at least one material selected from a group of carbides, nitrides and borides of transition metals belonging to the groups IVb, Vb and VIb of the periodic table and solid solutions and mixtures thereof; and
a second sintered body layer containing at least 30 percent by volume and less than 75 percent by volume of cubic boron nitride with a remainder being a second binder containing at least 5 percent by weight and less than 40 percent by weight of Al and at least one Ti compound being selected from a group of TiC, TiN, TiCN, (Ti, any of transition metals, excluding Ti, belonging to the groups IVb, Vb and VIb of the periodic table)C, (Ti, any of transition metals, excluding Ti, belonging to the groups IVb, Vb and VIb of the periodic table)N and (Ti, any of transition metals, excluding Ti, belonging to the groups IVb, Vb and VIb of the periodic table)CN,
said first and second sintered body layers defining an edge portion, a major surface of said first sintered body layer forming a rake face, said second sintered body layer forming a flank,
said first sintered body layer being at least 0.02 mm and less than 0.1 mm in thickness,
said first sintered body layer being in a thickness ratio of at least 1:5 to said second sintered body layer.

### Claim 2 (depends on 1)

The hard sintered body cutting tool in accordance with claim 1, wherein said first binder contains a material selected from a group of (W,Ta)C--Co, WC--Co, MoC--Ni, TiCN--Co, and WB.sub.2 --TiN--Co.

### Claim 3 (depends on 1)

The hard sintered body cutting tool in accordance with claim 1, wherein said Ti compound forming said second binder includes a material selected from a group of (Ti,Hf)C, (Ti,Ta)C and (Ti,W)N.

### Claim 4 (depends on 1)

The hard sintered body cutting tool in accordance with claim 1, wherein Al contained in said second binder is contained in said second binder in a state of an Al compound.