US3859086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of enhancing powder compactibility
Assignee: Huntington Alloys Corp
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Filing: 1971-12-30
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Granted: 1975-01-07
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Expires: 1991-12-30
Abstract
Abstract Method of improving compactibility and sintering characteristics of spherical metal powders, comprising selectively removing the less chemically resistant surface regions of the powders, to roughen the powder surfaces and thereafter compacting and sintering the thus-roughened powders.
Inventors
- 👤 Nathan Lewis Church
- 👤 Edwin Snape
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:07
CPC Classifications
C; C22; C22C; C22C19/00; C22C19/03; C22C19/05; C22C19/051; C22C19/055; B; B22; B22F; B22F1/00; B22F1/14; B22F1/145; B22F2999/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A PROCESS FOR IMPROVING THE COMPACTIBILITY OF METAL POWDERS OF SUBSTANTIALLY SPHERICAL CONFIGURATION AND OF RELATIVELY POOR INITIAL COMPACTIBILITY, COMPRISING: I. SUBJECTING SAID POWDERS TO THE ACTION OF A CORRODENT WHICH SELECTIVELY CHEMICALLY ATTACKS THE LESS CHEMICALLY RESISTANT REGIONS OF THE POWDER SURFACES SO AS TO THEREBY ROUGHEN SURFACES ON A FINE SCALE; II. COMPACTING SAID ROUGHENED PARTICLES BY SUBJECTING THE PARTICLES TO A COMPRESSIVE FORCE SUFFICIENT TO CAUSE THE PARTICLES TO FORM A SELF-SUSTAINING BODY; AND THEREAFTER III. SINTERING SAID BODY AT A TEMPERATURE OF UP TO ABOUT 2,100*F. OR HIGHER.
Claim 2
Dependent Claim
92 words
A PROCESS FOR IMPROVING THE COMPACTIBILITY OF METAL POWDERS OF SUBSTANTIALLY SPHERICAL CONFIGURATION AND OF RELATIVELY POOR INITIAL COMPACTIBILITY, COMPRISING: I. SUBJECTING SAID POWDERS TO THE ACTION OF A CORRODENT WHICH SELECTIVELY CHEMICALLY ATTACKS THE LESS CHEMICALLY RESISTANT REGIONS OF THE POWDER SURFACES SO AS TO THEREBY ROUGHEN SURFACES ON A FINE SCALE; II. COMPACTING SAID ROUGHENED PARTICLES BY SUBJECTING THE PARTICLES TO A COMPRESSIVE FORCE SUFFICIENT TO CAUSE THE PARTICLES TO FORM A SELF-SUSTAINING BODY; AND THEREAFTER III. SINTERING SAID BODY AT A TEMPERATURE OF UP TO ABOUT 2,100*F. OR HIGHER.
Claim 3
Dependent Claim
42 words
The process defined in claim 1 in which the roughened particles are compressed under a force of about 10 to about 70 tons per square inch to produce a body having a green density of about 65 to about 85% of theoretical.
Claim 4
Dependent Claim
55 words
The process defined in claim 1 wherein said spherical powder particles are rendered more susceptible to said selective chemical attack by a preliminary heating step which comprises heat treeating said powders to produce therein at least two metallurgical phases, one of said phases being dispersed in a matrix comprising a second one of said phases.
Claim 5
Dependent Claim
87 words
The process defined in claim 1 wherein the metal powder consists of stainless steel consisting essentially of about 12 to about 35% chromium, up to about 30% nickel, up to about 3% copper, up to about 0.5% carbon, up to about 0.5% oxygen, up to about 0.2% nitrogen, up to about 0.4% sulfur, up to about 0.4% phosphorus, up to about 2% silicon, up to about 10% manganese, up to about 15% cobalt, up to about 10% molybdenum, up to about 5% tungsten, and the balance iron.
Claim 6
Dependent Claim
84 words
The process defined in claim 3 wherein the powder consists essentially of, by weight, about 18 to about 35% chromium, about 2 to about 12% nickel, up to about 0.2% carbon, up to about 2% manganese, up to about 2% silicon, up to about 2% cobalt, up to about 3% molybdenum, up to about 5% tungsten, and the balance essentially iron, the preliminary heat treatment comprises annealing the powders so as to produce therein a metallurgical structure of austenite dispersed in a ferrite matrix.
Claim 7
Dependent Claim
103 words
The process defined in claim 3 wherein the powder consists essentially of, by weight, about 20 to about 35% chromium, about 0 to about 24% nickel, up to about 0.2% carbon, up to about 2% manganese, up to about 2% silicon, up to about 2% cobalt, up to about 3% molybdenum, up to about 5% tungsten, and the balance essentially iron and the preliminary heat treatment is carried out to produce in the powder two metallurgical phases respectively comprising sigma phase and one of austenite and ferrite, the sigma phase being dispersed in a matrix of one of said ferrite and austenite phases.
Claim 8
Dependent Claim
73 words
The process defined in claim 1 wherein the powder particles have an initial average diameter of about 40 to 400 microns and the selective chemical attack is carried out to a depth of about 1 to about 20 microns, the compacting being carried out at a pressure of about 10 to about 70 tons per square inch to produce a body having a green density of about 65% to about 85% of theoretical.
Claim 9
Dependent Claim
43 words
The process defined in claim 1 wherein the Chemical attack is carried out so as to remove the surface regions of said particles to a depth sufficient to weaken the surface portions thereof, thereby allowing ready deformation at the surfaces of said particles.
Claim 10
Dependent Claim
20 words
The process defined in claim 1 wherein the selective chemical attack comprises treating said spherical particles in a bromine-alcohol solution.
Claim 11
Dependent Claim
46 words
The process defined in claim 9 wherein the spherical powder particles include oxides at the surfaces thereof and the selective chemical attack is preceded by a step comprising the treatment of the spherical powder with an acid solution so as to remove the oxides substantially completely.
Claim 12
Dependent Claim
80 words
The process defined in claim 1 wherein the metal powder is of a nickel-base superalloy consisting essentially of, by weight, about 10 to about 25% chromium, up to about 30% cobalt, up to about 25% molybdenum, up to about 10% tungsten, up to about 6% columbium, up to about 5% aluminum, up to about 5% titanium, up to about 20% iron, up to about 1% manganese, up to about 1% silicon, up to about 0.25% carbon, and the balance nickel.
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) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |