US5045092A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diamond-containing cemented metal carbide
Assignee: Smith International Inc
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Filing: 1989-05-26
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Granted: 1991-09-03
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Expires: 2009-05-26
Abstract
Abstract Cemented tungsten carbide rock bit inserts have diamond particles dispersed therein for enhanced hardness and wear resistance. The cobalt matrix is primarily the face centered cubic crystal structure for enhanced ductility and toughness. Such inserts are formed by introducing excess non-diamond carbon beyond the stoichiometric proportion in the tungsten carbide. The inserts are pressed at a temperature and pressure where diamond is thermodynamically stable and cooled while maintaining the pressure sufficiently high to prevent decomposition of diamond crystals formed at the elevated temperature. Diamond crystals may be dispersed throughout the cemented tungsten carbon or may be more concentrated near the surface than in the interior.
Inventors
- 👤 Madapusi K. Keshavan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:38
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/46; E21B10/56; B; B23; B23P; B23P5/00; C; C22; C22C; C22C26/00; C23; C23C; C23C30/00; C23C30/005; E21B10/50; E21B10/52
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
68 words
A method for forming a cemented tungsten carbide article with embedded diamond particles comprising the steps of: introducing excess non-diamond carbon beyond the stoichiometric proportion in tungsten carbide into a cemented tungsten carbide article; pressing the article at a temperature and pressure where diamond is thermodynamically stable; and cooling the article out of the thermodynamically stable region while maintaining the pressure sufficiently high to prevent decomposition of diamond.
Claim 2
Independent Claim
68 words
A method for forming a cemented tungsten carbide article with embedded diamond particles comprising the steps of: introducing excess non-diamond carbon beyond the stoichiometric proportion in tungsten carbide into a cemented tungsten carbide article; pressing the article at a temperature and pressure where diamond is thermodynamically stable; and cooling the article out of the thermodynamically stable region while maintaining the pressure sufficiently high to prevent decomposition of diamond.
Claim 3
Dependent Claim
33 words
A method as recited in claim 1 wherein the introducing step comprises: mixing tungsten carbide particles, cobalt and non-diamond carbonaceous material; and sintering the mixture into the shape of the article before pressing.
Claim 4
Dependent Claim
14 words
A method as recited in claim 2 wherein the carbonaceous material comprises a wax.
Claim 5
Dependent Claim
13 words
A method as recited in claim 2 wherein the carbonaceous material comprises graphite.
Claim 6
Dependent Claim
26 words
A method as recited in claim 1 wherein the introducing step comprises: forming a cemented tungsten carbide article; and carburizing the article before the pressing step.
Claim 7
Dependent Claim
19 words
A method as recited in claim 5 wherein the carburizing step comprises carburizing the article during the forming step.
Claim 8
Dependent Claim
27 words
A method as recited in claim 1 wherein the excess carbon content is in the range of from two to fifteen percent by volume of the cobalt.
Claim 9
Dependent Claim
46 words
A method as recited in claim 1 further comprising placing a layer containing diamond crystals adjacent to a surface of the article before the pressing step so that an adherent layer of polycrystalline diamond is formed on the surface of the article upon pressing and cooling.
Claim 10
Independent Claim
55 words
A method for forming a cemented metal carbide article with embedded diamond particles comprising the steps of: introducing excess non-diamond carbon beyond the stoichiometric proportion in the metal carbide into a cemented composite article comprising metal carbide particles and iron group metal; and subjecting the article to diamond making conditions of high pressure and temperature.
Claim 11
Independent Claim
55 words
A method for forming a cemented metal carbide article with embedded diamond particles comprising the steps of: introducing excess non-diamond carbon beyond the stoichiometric proportion in the metal carbide into a cemented composite article comprising metal carbide particles and iron group metal; and subjecting the article to diamond making conditions of high pressure and temperature.
Claim 12
Dependent Claim
35 words
A method as recited in claim 9 wherein the introducing step comprises: mixing metal carbide particles, iron group metal and non-diamond carbonaceous material; and sintering the mixture into the shape of the article before pressing.
Claim 13
Dependent Claim
13 words
A method as recited in claim 10 wherein the carbonaceous material comprises graphite.
Claim 14
Dependent Claim
26 words
A method as recited in claim 9 wherein the introducing step comprises: forming a cemented metal carbide article; and carburizing the article before the pressing step.
Claim 15
Dependent Claim
29 words
A method as recited in claim 9 wherein the excess carbon content is in the range of from two to fifteen percent by volume of the iron group metal.
Claim 16
Dependent Claim
23 words
A method as recited in claim 9 wherein the excess carbon content is up to fifty percent by volume of the composite article.
Claim 17
Independent Claim
62 words
A method for forming an insert for a rock bit comprising the steps of: forming a mixture of tungsten carbide and cobalt particles into a rock bit insert; including in the insert an excess of non-diamond carbon greater than the stoichiometric proportion in the tungsten carbide; and pressing the insert at a sufficient temperature and pressure to form diamond from excess carbon.
Claim 18
Independent Claim
62 words
A method for forming an insert for a rock bit comprising the steps of: forming a mixture of tungsten carbide and cobalt particles into a rock bit insert; including in the insert an excess of non-diamond carbon greater than the stoichiometric proportion in the tungsten carbide; and pressing the insert at a sufficient temperature and pressure to form diamond from excess carbon.
Claim 19
Dependent Claim
21 words
A method as recited in claim 15 comprising: mixing tungsten carbide particles, cobalt and graphite; and sintering the mixture before pressing.
Claim 20
Dependent Claim
22 words
A method as recited in claim 15 comprising forming the cemented tungsten carbide insert and carburizing the insert before the pressing step.
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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) | 1994-09-02 | 1995-03-04 | 1995-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-02 | 1999-03-04 | 1999-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-02 | 2003-03-04 | 2003-09-03 | $7700.00 | Window Closed / Lapsed |