US4743425A
Expired / Lapsed
US
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Method of producing ferrous sintered alloys with superior abrasion resistance
Assignee: JFE Steel Corp
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Filing: 1987-09-03
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Granted: 1988-05-10
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Expires: 2007-09-03
Abstract
Abstract A method of producing ferrous sintered alloys comprises the steps of preparing mixed alloy powder containing Fe-P-C eutectic alloy powder which includes phosphorus within the range of 2.0% to 3.0% by weight, carbon not more than 4.0% by weight and one of molybdenum within the range of 8.0% to 11.0% by weight and boron within the range of 0.5% to 3.0% by weight, graphite, and ferroalloy powder containing chromium within the range of 11% to 14% by weight; causing the mixed alloy powder to be subjected to compression molding to have a green compact; and sintering the green compact to have a ferrous sintered alloy containing compound carbides in a matrix structure thereof. The graphite is so selected that the sum total of the graphite and the carbon included in the Fe-P-C eutectic alloy powder constitutes a part within the range of 5% to 8% by weight of the sum total of the graphite and the Fe-P-C eutectic alloy powder. Further, the ferroalloy powder is so selected as to constitute a part within the range of 30% to 70% by weight of the whole mixed alloy powder.
Inventors
- 👤 Shigemi Ohsaki
- 👤 Sumio Kamino
- 👤 Minoru Nitta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:24
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/02; C22C33/0207; C22C33/0214; C22C33/0257; C22C33/0278; C22C33/0285
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
197 words
A method of producing ferrous sintered alloys comprising the steps of; preparing mixed alloy powder containing Fe-P-C eutectic alloy powder which is obtained by quenching a melted metal mixture to solidify the same and includes phosphorus within the range of 2.0% to 3.0% by weight, carbon not more than 4.0% by weight, and one of molybdenum within the range of 8.0% to 11.0% by weight and boron within the range of 0.5% to 3.0% by weight, graphite so selected that the sum total of the graphite and the carbon included in the Fe-P-C eutectic alloy powder constitutes a part within the range of 5% to 8% by weight of the sum total of the graphite and the Fe-P-C eutectic alloy powder, and ferroalloy powder containing chromium within the range of 11% to 14% by weight and so selected as to constitute a part within the range of 30% to 70% by weight of the whole mixed alloy powder, causing said mixed alloy powder to be subjected to compression molding to have a green compact in a predetermined shape, and sintering said green compact to have a ferrous sintered alloy containing compound carbides in a matrix structure thereof.
Claim 2
Independent Claim
197 words
A method of producing ferrous sintered alloys comprising the steps of; preparing mixed alloy powder containing Fe-P-C eutectic alloy powder which is obtained by quenching a melted metal mixture to solidify the same and includes phosphorus within the range of 2.0% to 3.0% by weight, carbon not more than 4.0% by weight, and one of molybdenum within the range of 8.0% to 11.0% by weight and boron within the range of 0.5% to 3.0% by weight, graphite so selected that the sum total of the graphite and the carbon included in the Fe-P-C eutectic alloy powder constitutes a part within the range of 5% to 8% by weight of the sum total of the graphite and the Fe-P-C eutectic alloy powder, and ferroalloy powder containing chromium within the range of 11% to 14% by weight and so selected as to constitute a part within the range of 30% to 70% by weight of the whole mixed alloy powder, causing said mixed alloy powder to be subjected to compression molding to have a green compact in a predetermined shape, and sintering said green compact to have a ferrous sintered alloy containing compound carbides in a matrix structure thereof.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein said Fe-P-C eutectic alloy powder includes chromium within the range of 2.5% to 5.0% by weight.
Claim 4
Dependent Claim
24 words
A method according to claim 1, wherein said Fe-P-C eutectic alloy powder is selected to have a particle size not more than 150 mesh.
Claim 5
Dependent Claim
22 words
A method according to claim 1, wherein said ferroalloy powder is selected to have a particle size not more than 150 mesh.
Claim 6
Dependent Claim
21 words
A method according to claim 1, wherein said graphite is selected to have an average particle diameter not more than 10μ.
Claim 7
Dependent Claim
29 words
A method according to claim 1, wherein said step of sintering the green compact includes a process of pre-sintering said green compact in an ambient atmosphere of hydrogen gas.
Claim 8
Dependent Claim
28 words
A method according to claim 6, wherein said green compact is pre-sintered in the ambient atmosphere of hydrogen gas at about 600° C. in said process of pre-sintering.
Claim 9
Dependent Claim
33 words
A method according to claim 1, wherein said green compact is sintered at temperature within the range of 1060° C. to 1100° C. for 20 to 30 minutes in said step of sintering.
Claim 10
Dependent Claim
21 words
A method according to claim 8, wherein said green compact is sintered in a vacuum furnace in said step of sintering.
Claim 11
Dependent Claim
33 words
A method according to claim 8, wherein said step of sintering includes a process of heating a sintered body obtained by sintering said green compact at about 900° C. for about 30 minutes.
Claim 12
Dependent Claim
50 words
A method according to claim 10, wherein said step of sintering further includes processes of quenching said sintered body in an ambient atmosphere of nitrogen gas and tempering said sintered body having been subjected to quenching at temperature within the range 550° C. to 560° C. for about 100 minutes.
Claim 13
Dependent Claim
30 words
A method according to claim 1, wherein Fe-Mo-Cr-P-C eutectic alloy powder including chromium and molybdenum in addition to iron, carbon and phosphorus is used as said Fe-P-C eutectic alloy powder.
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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) | 1991-05-10 | 1991-11-09 | 1992-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-10 | 1995-11-09 | 1996-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-10 | 1999-11-09 | 2000-05-10 | $7700.00 | Window Closed / Lapsed |