Patent US3871200A successfully refreshed from Google Patents.
US3871200A
Expired / Lapsed
US
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Method and apparatus for producing sintered metal product
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1973-07-02
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Granted: 1975-03-18
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Expires: 1993-07-02
Abstract
Abstract A method for producing a sintered metal product, which comprises forming a lubricating coating such as zinc stearate on the surface of a billet composed of a sintered metal of low to medium density, maintaining it at a working temperature ranging from room temperature to 750*C., applying a back pressure to the billet and extruding it. A single action press can be used which is equipped with a punch for applying the back pressure. The sintered metal product obtained has uniform high density and is free from surface and inner cracks with its inner pores not enlarged.
Inventors
- 👤 Mineo Onoda
- 👤 Takahiko Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:12
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/20; B22F3/02; B22F2003/026; B22F2003/202; Y; Y10; Y10S; Y10S29/00; Y10S29/031; Y10S29/047
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
116 words
In a method for producing a sintered metal product, including the steps of: lubricant cooling the surface of a sintered metal pre-form billet of low to medium density, and extruding said billet under pressure through a die in one direction while maintaining it at a temperature ranging from room temperature to 750*C., the improvement comprising: the step of simultaneously applying a back pressure to said billet during extrusion in a direction opposite to that of extrusion with said back pressure being at least twenty per cent of extrusion pressure; whereby, the sintered metal product thus obtained has a higher, more uniform density and is free from surface and inner crack with its inner pores not enlarged.
Claim 2
Dependent Claim
116 words
In a method for producing a sintered metal product, including the steps of: lubricant cooling the surface of a sintered metal pre-form billet of low to medium density, and extruding said billet under pressure through a die in one direction while maintaining it at a temperature ranging from room temperature to 750*C., the improvement comprising: the step of simultaneously applying a back pressure to said billet during extrusion in a direction opposite to that of extrusion with said back pressure being at least twenty per cent of extrusion pressure; whereby, the sintered metal product thus obtained has a higher, more uniform density and is free from surface and inner crack with its inner pores not enlarged.
Claim 3
Dependent Claim
33 words
The method of claim 1 wherein said lubricant coating is formed by tumbling the billet in a mixture of a powdery solid lubricant and elastic beads which do not scar the sintered metal.
Claim 4
Dependent Claim
44 words
The method of claim 2 wherein said lubricant coating is formed by spraying a mixture of a liquid solvent and a solid lubricant which remains after evaporation of the solvent to the billet heated to a temperature above the evaporation temperature of the solvent.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |