US4274840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wear resistant composite insert, boring tool using such insert, and method for making the insert
Assignee: Smith International Inc
•
Filing: 1979-01-08
•
Granted: 1981-06-23
•
Expires: 1999-01-08
Abstract
Abstract A wear insert for earth boring tools, such as drill bits, has diamonds imbedded in a sintered matrix of tungsten-carbide and Invar. The matrix prior to sintering has a particle size of from about 0.5 to about 10 microns. Invar represents from about 3% to about 20% by weight of the matrix. The diamonds are arrayed in a desired pattern in a matrix preform; compression of the resultant preform at pressures of from about 10 to about 20 tons per square inch consolidates preform. The consolidated preform is sintered at a temperature just below the melting point of Invar in a neutral atmosphere of nitrogen and hydrogen formed of dissociated ammonia. Nitrogen results in the wetting of the diamonds. Hydrogen presents a reducing atmosphere.
Inventors
- 👤 Robert J. Housman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:04
CPC Classifications
C; C22; C22C; C22C26/00; E; E21; E21B; E21B10/00; E21B10/46; E21B10/50; E21B10/52; E21B10/56; E21B10/567
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A method of making a wear resistant insert for earth boring tools and the like consisting essentially of the steps of: (a) mixing powdered Invar with powdered tungsten-carbide; (b) placing diamonds in a desired array in the mixture; (c) compressing the mixture of Invar and tungsten-carbide and diamonds to consolidate them; and then (d) sintering the Invar at a temperature below the melting point of Invar and in an atmosphere of nitrogen and hydrogen to form a matrix for the tungsten-carbide and diamonds.
Claim 2
Independent Claim
83 words
A method of making a wear resistant insert for earth boring tools and the like consisting essentially of the steps of: (a) mixing powdered Invar with powdered tungsten-carbide; (b) placing diamonds in a desired array in the mixture; (c) compressing the mixture of Invar and tungsten-carbide and diamonds to consolidate them; and then (d) sintering the Invar at a temperature below the melting point of Invar and in an atmosphere of nitrogen and hydrogen to form a matrix for the tungsten-carbide and diamonds.
Claim 3
Dependent Claim
20 words
The process claimed in claim 1 wherein the powdered tungsten-carbide is from about 0.5 to about 10 microns in size.
Claim 4
Dependent Claim
29 words
The process claimed in claim 2 wherein the Invar is present in amounts of from about 3 to about 20 weight percent of the mixture of Invar and tungsten-carbide.
Claim 5
Dependent Claim
30 words
The process claimed in claim 2 wherein the Invar is present in the mixture of Invar and tungsten-carbide in the amounts of from about 6 to about 16 weight percent.
Claim 6
Dependent Claim
15 words
The process claimed in claim 2 wherein the sintering atmosphere is formed by dissociating ammonia.
Claim 7
Dependent Claim
15 words
The process claimed in claim 4 wherein the sintering atmosphere is formed by dissociating ammonia.
Claim 8
Dependent Claim
14 words
The process claimed in claim 6 wherein the sintering temperature is about 1425° C.
Claim 9
Dependent Claim
21 words
The process claimed in claim 2 wherein the compression pressure is from about 10 to about 20 tons per square inch.
Claim 10
Dependent Claim
17 words
The process claimed in claim 8 wherein the compression pressure is about 16 tons per square inch.
Claim 11
Dependent Claim
29 words
The process claimed in claim 8 wherein the Invar is present in amounts of from about 3 to about 20 weight percent of the mixture of Invar and tungsten-carbide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |