US4959331A
Expired / Lapsed
US
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Alumina-zirconia-silicon carbide-magnesia cutting tools
Assignee: Kennametal Inc
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Filing: 1988-11-03
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Granted: 1990-09-25
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Expires: 2008-11-03
Abstract
Abstract A metalcutting insert is provided with an alumina based ceramic composition composed of (in volume percent, v/o): about 1.5 to 17.5 silicon carbide whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount effective to enhance the metalcutting lifetime of the cutting edge of the insert; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 4 v/o of the alumina based ceramic composition is tetragonal zirconia.
Inventors
- 👤 Pankaj K. Mehrotra
- 👤 Elizabeth R. Billman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:39
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/622; C04B35/64; C04B35/645; C04B35/71; C04B35/78; C04B35/80
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
113 words
A metalcutting insert comprising: a rake face; a flank face; a cutting edge at a juncture of said rake face and said flank face; said cutting insert having an alumina based ceramic composition consisting essentially of: about 1.5 to 17.5 v/o silicon carbide whiskers; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; alumina forming essentially the remainder of said composition; wherein said silicon carbide whiskers, said zirconia and said residue of said magnesia addition are substantially homogeneously dispersed in a matrix formed of said alumina; and wherein at least about 4.0 v/o of said ceramic composition is tetragonal zirconia.
Claim 2
Dependent Claim
113 words
A metalcutting insert comprising: a rake face; a flank face; a cutting edge at a juncture of said rake face and said flank face; said cutting insert having an alumina based ceramic composition consisting essentially of: about 1.5 to 17.5 v/o silicon carbide whiskers; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; alumina forming essentially the remainder of said composition; wherein said silicon carbide whiskers, said zirconia and said residue of said magnesia addition are substantially homogeneously dispersed in a matrix formed of said alumina; and wherein at least about 4.0 v/o of said ceramic composition is tetragonal zirconia.
Claim 3
Dependent Claim
19 words
The metalcutting insert according to claim 1 wherein at least about 6.0 v/o of said composition is tetragonal zirconia.
Claim 4
Dependent Claim
18 words
The metalcutting insert according to claim 1 wherein at least 7 v/o of said composition is tetragonal zirconia.
Claim 5
Dependent Claim
20 words
The metalcutting insert according to claim 1 wherein said residue of said magnesia addition is about 0.03 to 2 v/o.
Claim 6
Dependent Claim
20 words
The metalcutting insert according to claim 1 wherein said residue of said magnesia addition is about 0.04 to 1 v/o.
Claim 7
Dependent Claim
18 words
The metalcutting insert according to claim 1 wherein said silicon carbide whiskers is about 2.5 to 15 v/o.
Claim 8
Dependent Claim
18 words
The metalcutting insert according to claim 1 wherein said silicon carbide whiskers is about 2.5 to 10.5 v/o.
Claim 9
Dependent Claim
16 words
The metalcutting insert according to claim 1 wherein said zirconia is about 7.5 to 17.5 v/o.
Claim 10
Dependent Claim
16 words
The metalcutting insert according to claim 1 wherein said zirconia is about 10 to 15 v/o.
Claim 11
Dependent Claim
20 words
The metalcutting insert according to claim 1 wherein said zirconia has an average particle size of less than 2 microns.
Claim 12
Dependent Claim
23 words
The metalcutting insert according to claim 1 wherein said zirconia has an average particle size of less than or equal to one micron.
Claim 13
Dependent Claim
141 words
A metalcutting insert comprising: a rake face; a flank face; a cutting edge at a juncture of said rake face and said flank face; said cutting insert having an alumina based ceramic composition comprising: about 1.5-17.5 v/o silicon carbide whiskers; about 5 to 17.5 v/o ZrO 2 ; a residue of a magnesia addition added in an amount effective to provide said cutting edge with a lifetime of at least 12 minutes when turning AISI 1045 steel having a Brinell hardness number in the range of 190 to 200, under the conditions of 1000 surface feet/minute, 0.025 inch/revolution and 0.100 inch depth of cut; an aluminum based wherein said silicon carbide whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed; and wherein tetragonal zirconia forms at least 4 v/o of said alumina based ceramic composition.
Claim 14
Dependent Claim
141 words
A metalcutting insert comprising: a rake face; a flank face; a cutting edge at a juncture of said rake face and said flank face; said cutting insert having an alumina based ceramic composition comprising: about 1.5-17.5 v/o silicon carbide whiskers; about 5 to 17.5 v/o ZrO 2 ; a residue of a magnesia addition added in an amount effective to provide said cutting edge with a lifetime of at least 12 minutes when turning AISI 1045 steel having a Brinell hardness number in the range of 190 to 200, under the conditions of 1000 surface feet/minute, 0.025 inch/revolution and 0.100 inch depth of cut; an aluminum based wherein said silicon carbide whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed; and wherein tetragonal zirconia forms at least 4 v/o of said alumina based ceramic composition.
Claim 15
Dependent Claim
16 words
The metalcutting insert according to claim 12 wherein said lifetime is at least about 15 minutes.
Claim 16
Dependent Claim
16 words
The metalcutting insert according to claim 12 wherein said lifetime is at least about 20 minutes.
Claim 17
Dependent Claim
14 words
The metalcutting insert according to claim 12 containing at least 6 v/o tetragonal zirconia.
Claim 18
Dependent Claim
14 words
The metalcutting insert according to claim 12 containing at least 7 v/o tetragonal zirconia.
Claim 19
Dependent Claim
14 words
The metalcutting insert according to claim 12 containing at least 8 v/o tetragonal zirconia.
Claim 20
Dependent Claim
18 words
The metalcutting insert according to claim 12 wherein said alumina based matrix is entirely alumina except for impurities.
Claim 21
Dependent Claim
20 words
The metalcutting insert according to claim 12 wherein said zirconia has an average particle size no greater than 5 μm.
Claim 22
Dependent Claim
20 words
The metalcutting insert according to claim 12 wherein said zirconia has an average particle size of less than 2 μm.
Claim 23
Dependent Claim
21 words
The metalcutting insert according to claim 1 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 24
Dependent Claim
21 words
The metalcutting insert according to claim 5 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 25
Dependent Claim
21 words
The metalcutting insert according to claim 8 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 26
Dependent Claim
21 words
The metalcutting insert according to claim 9 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 27
Dependent Claim
21 words
The metalcutting insert according to claim 12 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 28
Dependent Claim
21 words
The metalcutting insert according to claim 13 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 29
Dependent Claim
21 words
The metalcutting insert according to claim 14 wherein said silicon carbide whiskers are prevent at a level of about 1.5 v/o.
Claim 30
Dependent Claim
21 words
The metalcutting insert according to claim 18 wherein said silicon carbide whiskers are present at a level of about 1.5 v/o.
Claim 31
Dependent Claim
21 words
The metalcutting insert according to claim 18 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 32
Dependent Claim
21 words
The metalcutting insert according to claim 5 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 33
Dependent Claim
21 words
The metalcutting insert according to claim 8 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 34
Dependent Claim
21 words
The metalcutting insert according to claim 9 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 35
Dependent Claim
21 words
The metalcutting insert according to claim 12 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 36
Dependent Claim
21 words
The metalcutting insert according to claim 13 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 37
Dependent Claim
21 words
The metalcutting insert according to claim 18 wherein said silicon carbide whiskers are present at a level of about 2.5 v/o.
Claim 38
Dependent Claim
21 words
The metalcutting insert according to claim 12 wherein said silicon carbide whiskers are present at a level of about 5 v/o.
Claim 39
Dependent Claim
21 words
The metalcutting insert according to claim 18 wherein said silicon carbide whiskers are present at a level of about 5 v/o.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |