US4043839A
Expired / Lapsed
US
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Internal nitridation of cobalt-base superalloys
Assignee: Allegheny Ludlum Corp
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Filing: 1976-05-24
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Granted: 1977-08-23
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Expires: 1996-05-24
Abstract
Abstract A method of internally nitriding and thereby strengthening cobalt-base superalloys having at least 33% cobalt, up to 0.15% carbon, no more than 25% nickel and from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, tantalum and zirconium. The method comprises the steps of: heating the cobalt-base alloy at a temperature of from 1600° to 2500° F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns.
Inventors
- 👤 Albert G. Hartline, III
- 👤 Lynn E. Kindlimann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:14
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/08; C23C8/24
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
158 words
A method of strengthening cobalt-base superalloys by internal nitridation of substantially the entire volume of said alloys, which comprises the steps of: heating a cobalt-base alloy containing at least 33% cobalt as the major constituent, chromium, up to 25% nickel, up to 0.15% carbon, from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, and tantalum, balance residuals and those elements which enhance the properties of cobalt-base alloys, at a temperature of from 1600° to 2500° F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns, said nitrides being from the group consisting of titanium nitride, vanadium nitride, niobium nitride and tantalum nitride, said nitrides being distributed substantially throughout said nitrided alloy; said cobalt base alloy being less than 25 mils thick.
Claim 2
Independent Claim
158 words
A method of strengthening cobalt-base superalloys by internal nitridation of substantially the entire volume of said alloys, which comprises the steps of: heating a cobalt-base alloy containing at least 33% cobalt as the major constituent, chromium, up to 25% nickel, up to 0.15% carbon, from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, and tantalum, balance residuals and those elements which enhance the properties of cobalt-base alloys, at a temperature of from 1600° to 2500° F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns, said nitrides being from the group consisting of titanium nitride, vanadium nitride, niobium nitride and tantalum nitride, said nitrides being distributed substantially throughout said nitrided alloy; said cobalt base alloy being less than 25 mils thick.
Claim 3
Dependent Claim
16 words
A method according to claim 1, wherein said cobalt-base superally contains from 1 to 3% titanium.
Claim 4
Dependent Claim
21 words
A method according to claim 1, wherein said cobalt-base superalloy is heated at a temperature of from 1800° to 2200° F.
Claim 5
Dependent Claim
19 words
A method according to claim 1, including the additional step of treating said cobalt-base superalloy, to remove excess nitrogen.
Claim 6
Dependent Claim
32 words
A method according to claim 1, wherein nitrogen is diffused into said cobalt-base superalloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 2 microns.
Claim 7
Dependent Claim
32 words
A method according to claim 1, wherein nitrogen is diffused into said cobalt-base superalloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 1 micron.
Claim 8
Dependent Claim
28 words
A method according to claim 1, wherein said nitrogen-bearing atmosphere is from the group consisting of ammonia, nitrogen, and mixtures thereof with each and with other non-oxidizing gases.
Claim 9
Independent Claim
161 words
A method of strengthening cobalt-base superalloys by internal nitridation of substantially the entire volume of said alloys, which comprises the steps of: heating a cobalt-base alloy containing at least 33% cobalt as the major constituent, chromium, up to 25% nickel, up to 0.15% carbon, from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, tantalum and zirconium, balance residuals and those elements which enhance the properties of cobalt-base alloys, at a temperature of from 1600° to 2500° F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns, said nitrides being from the group consisting of titanium nitride, vanadium nitride, niobium nitride, tantalum nitride and zirconium nitride, said nitrides being distributed substantially throughout said nitrided alloy; said cobalt base alloy being less than 25 mils thick.
Claim 10
Independent Claim
161 words
A method of strengthening cobalt-base superalloys by internal nitridation of substantially the entire volume of said alloys, which comprises the steps of: heating a cobalt-base alloy containing at least 33% cobalt as the major constituent, chromium, up to 25% nickel, up to 0.15% carbon, from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, tantalum and zirconium, balance residuals and those elements which enhance the properties of cobalt-base alloys, at a temperature of from 1600° to 2500° F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns, said nitrides being from the group consisting of titanium nitride, vanadium nitride, niobium nitride, tantalum nitride and zirconium nitride, said nitrides being distributed substantially throughout said nitrided alloy; said cobalt base alloy being less than 25 mils thick.
Claim 11
Dependent Claim
21 words
A method according to claim 8, wherein said cobalt-base superalloy is heated at a temperature of from 1800° to 2200° F.
Claim 12
Dependent Claim
19 words
A method according to claim 8, including the additional step of treating said cobalt-base superalloy, to remove excess nitrogen.
Claim 13
Dependent Claim
32 words
A method according to claim 8, wherein nitrogen is diffused into said cobalt-base superalloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 2 microns.
Claim 14
Dependent Claim
32 words
A method according to claim 8, wherein nitrogen is diffused into said cobalt-base superalloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 1 micron.
Claim 15
Dependent Claim
28 words
A method according to claim 8, wherein said nitrogen-bearing atmosphere is from the group consisting of ammonia, nitrogen, and mixtures thereof with each and with other non-oxidizing gases.
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) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |