Patent US4753678A successfully refreshed from Google Patents.
US4753678A
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Sintered hard metal having superior toughness
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1986-02-25
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Granted: 1988-06-28
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Expires: 2006-02-25
Abstract
Abstract A sintered hard metal having superior toughness and superior hardness may be used for micro-drills, tools and wear resistant parts. The metal is a cemented carbide WC formed from tungsten carbide WC as the base alloy and containing 4 to 20 percent by weight of vanadium carbide VC or zirconium nitride. Its micro-structure is that the WC or WC-VC particles are 0.6 mu or less, its Rockwell Hardness HRA is at least 91.5 and its transverse rupture strength is at least 350 kg/mm2.
Inventors
- 👤 Masao Maruyama
- 👤 Atsushi Seki
- 👤 Masayoshi Yatabe
- 👤 Kotaro Hagiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:37
CPC Classifications
B; B22; B22F; B22F3/00; C; C22; C22C; C22C29/00; C22C29/02; C22C29/06; C22C29/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
81 words
A sintered hard metal having superior toughness including cemented carbide containing tungsten carbide as the main component, 0.2 to 0.8 percent by weight selected from the group of vanadium carbide and zirconium nitride as a hard phase and 4 to 20 percent by weight of cobalt as a metal phase, wherein the grain size of said tungsten carbide is less than 0.μ, the Rockwell Hardness HRA is 91 or more and the transverse rupture strength is 350 kgs/mm 2 or more.
Claim 2
Dependent Claim
81 words
A sintered hard metal having superior toughness including cemented carbide containing tungsten carbide as the main component, 0.2 to 0.8 percent by weight selected from the group of vanadium carbide and zirconium nitride as a hard phase and 4 to 20 percent by weight of cobalt as a metal phase, wherein the grain size of said tungsten carbide is less than 0.μ, the Rockwell Hardness HRA is 91 or more and the transverse rupture strength is 350 kgs/mm 2 or more.
Claim 3
Dependent Claim
32 words
A sintered hard metal as in claim 1 wherein the metal does not contain more than 1% by weight of material other than tungsten carbide, vanadium carbide and zirconium nitride and cobalt.
Claim 4
Dependent Claim
49 words
A sintered hard metal as in claim 1 wherein said metal is formed by grinding the said tungsten carbide, anadium carbide or zirconium nitride and cobalt to form ground particles, sintering the ground particles in a vacuum atmosphere and simultaneously pressing the ground particles in a hot isostatic press.
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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) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |