US3615904A
Expired / Lapsed
US
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Method of improving nitride-strengthened stainless steel properties
Assignee: Allegheny Ludlum Corp
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Filing: 1969-02-28
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Granted: 1971-10-26
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Expires: 1989-02-28
Abstract
Abstract A method for improving the properties of nitride-strengthened, stainless steel containing as a dispersoid therein particles of metal nitride which are present at an interparticle spacing of less than about 10 microns and which have a free energy of formation of greater than about -21,000 cal/mol. The method comprises the steps of heating the steel to a temperature which is generally in excess of 800* F. and subsequently compressing it. Pressure is conveniently applied by roll pressing and is generally sufficient to compress the member by at least 5 percent. A compressed nitride-strengthened, stainless steel article substantially free of pores and containing as a dispersoid therein particles of metal nitride which are present at an interparticle spacing of less than about 10 microns and which have a free energy of formation of greater than about -21,000 cal/mol.
Inventors
- 👤 Lynn E Kindlimann
- 👤 Alexander B Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:28
CPC Classifications
C; C21; C21D; C21D8/00; C23; C23C; C23C8/00; C23C8/80
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
20 words
A method according to claim 1 wherein said member is heated to a temperature in excess of about 800* F.
Claim 2
Dependent Claim
15 words
A method according to claim 1 wherein said compressing is accomplished by rolling said member.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein said member is heated to a temperature of from about 1,800* F. to about 2,200* F. and wherein said compressing is accomplished by rolling said member.
Claim 4
Independent Claim
83 words
A method of improving the high-temperature rupture strength characteristics of nitride-strengthened, stainless Steel, comprising the following steps: a. providing a nitride-strengthened stainless steel member containing as a dispersoid therein particles of metal nitride of a metal from the group consisting of titanium, aluminum, vanadium, and columbium, said nitride particles being present at an interparticle spacing of less than about 2 microns; b. heating said member to a temperature of from about 800* F. to about 2,400* F; and c. roll pressing said member.
Claim 5
Dependent Claim
12 words
A method according to claim 5 wherein said dispersoid is titanium nitride.
Claim 6
Dependent Claim
23 words
A method according to claim 5 wherein said member is heated to a temperature of from about 1,800* F. to about 2,200* F.
Claim 7
Dependent Claim
69 words
A compressed nitride-strengthened, stainless steel article having a rupture strength of no less than about 4 K.s.i. for 130 hours at 2,000* F; said steel article being substantially free of pores and containing as a dispersoid therein particles of a metal nitride having a free energy of formation of greater than about -21,000 cal./mole, said nitride particles being present at an interparticle spacing of less than about 10 microns.
Claim 8
Dependent Claim
25 words
An article according to claim 8 wherein said dispersoid is a nitride of a metal from the group consisting of titanium, aluminum, vanadium and columbium.
Claim 9
Dependent Claim
12 words
An article according to claim 8 wherein said dispersoid is titanium nitride.
Claim 10
Dependent Claim
22 words
An article according to claim 8 wherein said dispersoid particles are present at an interparticle spacing of less than about 2 microns.
Claim 11
Dependent Claim
51 words
A roll-pressed nitride-strengthened, stainless steel article substantially free of pores; said steel article containing as a dispersoid therein particles of a metal nitride of a metal from the group consisting of titanium, aluminum, vanadium and columbium, said nitride particles being present at an interparticle spacing of less than about 2 microns.
Claim 12
Dependent Claim
12 words
An article according to claim 12 wherein said dispersoid is titanium nitride.
Claim 13
Dependent Claim
26 words
An article according to claim 12 wherein said steel has a rupture strength of no less than about 4 K.s.i. for 130 hours at 2,000* F.
Claim 14
Dependent Claim
33 words
An article according to claim 12 wherein said dispersoid is titanium nitride and wherein said steel has a rupture strength of no less than about 4 K.s.i. for 130 hours at 2,000* F.
Claim 15
Dependent Claim
15 words
A method according to claim 2 wherein said member is compressed at least 5 percent.
Claim 16
Dependent Claim
15 words
A method according to claim 7 wherein said member is compressed at least 5 percent.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |