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Patent US5217683A successfully refreshed from Google Patents.
US5217683A
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Steel powder composition
Assignee: Hoeganaes Corp
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Filing: 1991-10-21
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Granted: 1993-06-08
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Expires: 2011-10-21
Abstract
Abstract A steel powder composition useful in the production, by powder-metallurgical methods, of sintered parts with high density, good dimensional accuracy, hardenability, and strength is prepared from an admixture of two pre-alloyed iron powders of different compositions, the first being a pre-alloy of iron and molybdenum, and the second being a pre-alloy of iron with carbon and at least one transition element including chromium, manganese, vanadium, or columbium.
Inventors
- 👤 Robert J. Causton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:15
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/02; C22C33/0257; C22C33/0264; C22C33/0207; B; B22; B22F; B22F2998/00; B22F2998/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
151 words
A method of making a sintered steel part comprising the steps of (1) providing a steel powder composition comprising (a) a first pre-alloyed iron-based powder containing about 0.5-3.0 percent by weight dissolved molybdenum; said first iron-based powder in intimate admixture with (b) a second pre-alloyed iron-based powder containing at least 0.15 percent by weight carbon and at least about 25% by weight of a transition element component, wherein said transition element component comprises at least one element selected from the group consisting of chromium, manganese, vanadium, and columbium; wherein said second powder is in said admixture in a proportion to provide at least about 0.05 weight percent of said transition element component to the steel powder composition; (2) compacting said steel powder composition in a die at a pressure of about 30-60 tons per square inch; and (3) sintering said compacted composition at a temperature of at least about 2050° F.
Claim 2
Independent Claim
151 words
A method of making a sintered steel part comprising the steps of (1) providing a steel powder composition comprising (a) a first pre-alloyed iron-based powder containing about 0.5-3.0 percent by weight dissolved molybdenum; said first iron-based powder in intimate admixture with (b) a second pre-alloyed iron-based powder containing at least 0.15 percent by weight carbon and at least about 25% by weight of a transition element component, wherein said transition element component comprises at least one element selected from the group consisting of chromium, manganese, vanadium, and columbium; wherein said second powder is in said admixture in a proportion to provide at least about 0.05 weight percent of said transition element component to the steel powder composition; (2) compacting said steel powder composition in a die at a pressure of about 30-60 tons per square inch; and (3) sintering said compacted composition at a temperature of at least about 2050° F.
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein said first pre-alloyed iron-based powder contains about 0.5-2.5% by weight molybdenum and is substantially free of other alloying elements.
Claim 4
Dependent Claim
44 words
The method of claim 2 wherein said second pre-alloyed iron-based powder contains at least 50% by total weight of said transition element component, and wherein at least 75% by weight of said transition element component is chromium, manganese, vanadium, columbium, or mixtures of these.
Claim 5
Dependent Claim
21 words
The method of claim 3 wherein said steel powder composition contains about 0.1-4% by total weight of said transition element component.
Claim 6
Dependent Claim
21 words
The method of claim 4 wherein steel powder composition further comprises up to about 1% by total weight of powdered graphite.
Claim 7
Dependent Claim
17 words
The method of claim 4 wherein said second pre-alloyed powder contains about 3-9% by total weight carbon.
Claim 8
Dependent Claim
16 words
The method of claim 3 wherein said steel powder composition contains about 0.3-2.0% by weight manganese.
Claim 9
Dependent Claim
16 words
The method of claim 3 wherein said steel powder composition contains about 0.5-2.0 weight percent chromium.
Claim 10
Dependent Claim
16 words
The method of claim 3 wherein said steel powder composition contains about 0.05-0.5 weight percent vanadium.
Claim 11
Dependent Claim
16 words
The method of claim 3 wherein said steel powder composition contains about 0.05-0.5 weight percent columbium.
Claim 12
Dependent Claim
19 words
The method of claim 1 wherein said sintering step is performed at a temperature range of about 2050-2400° F.
Claim 13
Dependent Claim
19 words
The method of claim 11 wherein said sintering step is performed at a temperature range of about 2050°-2100° F.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-06-07 | 1996-12-07 | 1997-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-07 | 2000-12-07 | 2001-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-07 | 2004-12-07 | 2005-06-08 | $7700.00 | Window Closed / Lapsed |