US4836980A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of sintering an injection-molded article
Assignee: Chugai Ro Co., Ltd.
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Filing: 1988-01-22
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Granted: 1989-06-06
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Expires: 2008-01-22
Abstract
Abstract In a method of sintering an injection-molded article of raw material powder and organic binder, the injection-molded article already debinderized is initially heated up to a certain reaction temperature at which residual binder is removed from it. In subsequent decarburizing step, the residual binder is removed from the molded article under atmospheric or reduced pressure, while being supplied with H 2 gas. Thereafter, in a reducing and sintering step, the molded article is heated up to a sintering temperature and is held at this temperature under reduced pressure for a predetermined period, with H 2 gas being supplied. H 2 content of the atmosphere in the decarburizing step is kept higher than that in the reducing and sintering step.
Inventors
- 👤 Nobuo Kashiwadani
- 👤 Hitoshi Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:15
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/10; B22F3/1017; B22F3/1021; B22F2201/00; B22F2201/01; B22F2201/10; B22F2201/11; B22F2201/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A method of sintering an injection-molded article of raw material powder and organic binder, said method comprising: heating, within a non-oxidizing atmosphere, the injection-molded article which has already been debinderized; decarburizing and removing residual binder from said injection-molded article at a reaction temperature up to the temperature at which said injection-molded article has been heated in the previous step, with H 2 gas or mixed gas of H 2 gas and Ar gas being supplied herein; and reducing and sintering said injection-molded article by heating up to a sintering temperature and holding said injection-molded article at said sintering temperature under reduced pressure for a predetermined period, with H 2 gas being supplied, wherein the H 2 content of the atmosphere in said decarburizing step is maintained in an amount higher than that in said reducing and sintering step.
Claim 2
Independent Claim
138 words
A method of sintering an injection-molded article of raw material powder and organic binder, said method comprising: heating, within a non-oxidizing atmosphere, the injection-molded article which has already been debinderized; decarburizing and removing residual binder from said injection-molded article at a reaction temperature up to the temperature at which said injection-molded article has been heated in the previous step, with H 2 gas or mixed gas of H 2 gas and Ar gas being supplied herein; and reducing and sintering said injection-molded article by heating up to a sintering temperature and holding said injection-molded article at said sintering temperature under reduced pressure for a predetermined period, with H 2 gas being supplied, wherein the H 2 content of the atmosphere in said decarburizing step is maintained in an amount higher than that in said reducing and sintering step.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1, wherein said reducing and sintering is carried out under the reduced pressure of 1 to 100 Torr.
Claim 4
Dependent Claim
15 words
A method as claimed in claim 1, wherein said injection-molded article comprises stainless steel powder.
Claim 5
Dependent Claim
24 words
A method as claimed in claim 3, wherein said reducing and sintering is carried out under a reduced pressure of 1 to 100 Torr.
References Cited (Backward Citations)
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US4604259A
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US4622068A
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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) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |