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US3658604A
Expired / Lapsed
US
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Method of making a high-speed tool steel
Assignee: Carboloy Inc
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Filing: 1969-12-29
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Granted: 1972-04-25
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Expires: 1989-12-29
Abstract
Abstract High-speed tool steels are prepared by a powder metallurgical process comprising pressing to shape a powdered mixture of 15-75 weight percent tungsten monocarbide and a matrix of cobalt and iron, the cobalt-to-iron ratio ranging from 0.65 to 2.0. The pressed mixture is then sintered to full density by partially liquefying the ferrous phase of the alloy. The sintered compact is then hardened by heat treatment to transform the ferrous matrix to martensite.
Inventors
- 👤 Thomas E Hale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:25
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/02; C22C33/0257; C22C33/0278; C22C33/0292; C22C29/00; C22C29/02; C22C29/06; C22C29/067; C22C29/08; C22C38/00; C22C38/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
37 words
The process of claim 1 in which the sintered composition is hardened by heating to a temperature at which the iron-cobalt matrix becomes austenitic and then rapidly cooling to room temperature to transform the matrix to martensite.
Claim 2
Dependent Claim
25 words
The process of claim 2 in which the sintered composition is further heat-treated by the additional step of tempering by heating to achieve precipitation hardening.
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) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |