Patent US4050932A successfully refreshed from Google Patents.
US4050932A
Expired / Lapsed
US
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Colloidal graphite forging lubricant and method
Assignee: Motors Liquidation Co
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Filing: 1976-08-05
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Granted: 1977-09-27
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Expires: 1996-08-05
Abstract
Abstract An improved colloidal graphite hot forming lubricant and hot forming process for high density ferrous powdered metal articles using this lubricant. Extremely fine powdered copper is included in an otherwise conventional colloidal graphite hot forming lubricant. High quality, including high density, ferrous metal articles are produced by coating a ferrous powdered metal preform with this lubricant, presintering the coated preform at a higher temperature of 2100° - 2500° F. for a short time by induction heating, allowing the presintered preform to cool to a desired hot forming temperature below 2000° F., and then hot forming the preform in the usual manner. Lubricant-preform interaction at the higher temperature is precluded, making long presintering times and special presintering equipment necessary.
Inventors
- 👤 Harold G. Lemmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:50
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/12; B22F3/14; B22F1/00; B22F1/10; C; C10; C10M; C10M103/00; B22F3/02; B22F2003/026; B22F2998/00; B22F2998/10; C10M2201/00; C10M2201/02; C10M2201/04; C10M2201/041; C10M2201/042; C10M2201/05; C10M2207/00; C10M2207/02; C10M2207/021; C10N; C10N2040/00; C10N2040/20; C10N2040/24; C10N2040/241; C10N2040/242; C10N2040/243; C10N2040/244; C10N2040/245; C10N2040/246; C10N2040/247; C10N2040/30; C10N2040/32; C10N2040/34; C10N2040/36; C10N2040/38; C10N2040/40; C10N2040/42; C10N2040/44; C10N2040/50; C10N2070/00; C10N2070/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
134 words
A method for hot forming highest quality ferrous powdered metal articles without a prior separate presintering operation, said method comprising the steps of: coating an unsintered powdered steel preform with a colloidal graphite forging lubricant containing at least about 2%, by weight, powdered copper for suppressing an adverse lubricant-preform interaction above a temperature of about 2050° F., said powdered copper having an average particle size less than about 50 microns, induction heating said lubricant-coated preform to a temperature of about 2100°-2500° F. to sinter said preform without incurring an attendant adverse lubricant-preform interaction, cooling said preform to a hot forming temperature below about 2000° F., and hot forming said lubricant-coated preform into a predetermined shape and thereby form a powdered metal article having high ductility, high impact strength, and a metal density exceeding 99%.
Claim 2
Independent Claim
134 words
A method for hot forming highest quality ferrous powdered metal articles without a prior separate presintering operation, said method comprising the steps of: coating an unsintered powdered steel preform with a colloidal graphite forging lubricant containing at least about 2%, by weight, powdered copper for suppressing an adverse lubricant-preform interaction above a temperature of about 2050° F., said powdered copper having an average particle size less than about 50 microns, induction heating said lubricant-coated preform to a temperature of about 2100°-2500° F. to sinter said preform without incurring an attendant adverse lubricant-preform interaction, cooling said preform to a hot forming temperature below about 2000° F., and hot forming said lubricant-coated preform into a predetermined shape and thereby form a powdered metal article having high ductility, high impact strength, and a metal density exceeding 99%.
Claim 3
Independent Claim
154 words
A method of hot forming a ferrous powdered metal article that includes concurrent presintering of a ferrous powdered metal preform during the same heating operation and with the same induction heating equipment used to heat presintered ferrous powdered metal preforms to hot forming temperatures, heating an unsintered ferrous powdered metal preform to a temperature of about 250°-600° F., dipping said heated preform into a colloidal graphite hot forming lubricant containing about 2%-4%, by weight, powdered copper, said powdered copper having a particle size no greater than about 15 microns, induction heating said preform to a temperature of about 2300°-2400° F. for about 1 minute to sinter said preform without incurring an attendant adverse lubricant-preform interaction, cooling said preform to a temperature of about 1400°-1800° F., and hot forming said lubricant-coated preform into a predetermined shape and thereby form a powdered metal article having high ductility, high impact strength, and a metal density exceeding 99%.
Claim 4
Independent Claim
154 words
A method of hot forming a ferrous powdered metal article that includes concurrent presintering of a ferrous powdered metal preform during the same heating operation and with the same induction heating equipment used to heat presintered ferrous powdered metal preforms to hot forming temperatures, heating an unsintered ferrous powdered metal preform to a temperature of about 250°-600° F., dipping said heated preform into a colloidal graphite hot forming lubricant containing about 2%-4%, by weight, powdered copper, said powdered copper having a particle size no greater than about 15 microns, induction heating said preform to a temperature of about 2300°-2400° F. for about 1 minute to sinter said preform without incurring an attendant adverse lubricant-preform interaction, cooling said preform to a temperature of about 1400°-1800° F., and hot forming said lubricant-coated preform into a predetermined shape and thereby form a powdered metal article having high ductility, high impact strength, and a metal density exceeding 99%.
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) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |