US4359349A
Expired / Lapsed
US
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Method for heat treating iron-nickel-chromium alloy
Assignee: ENERGY United States, Department of
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Filing: 1980-04-03
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Granted: 1982-11-16
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Expires: 2000-04-03
Abstract
Abstract A method for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a bimodal distribution of gamma prime phase within a network of dislocations, the alloy consisting essentially of about 25% to 45% nickel, 10% to 16% chromium, 1.5% to 3% of an element selected from the group consisting of molybdenum and niobium, about 2% titanium, about 3% aluminum, and the remainder substantially all iron. To obtain optimum results, the alloy is heated to a temperature of 1025 DEG C. to 1075 DEG C. for 2-5 minutes, cold-worked about 20% to 60%, aged at a temperature of about 775 DEG C. for 8 hours followed by an air-cool, and then heated to a temperature in the range of 650 DEG C. to 700 DEG C. for 2 hours followed by an air-cool.
Inventors
- 👤 Howard F. Merrick
- 👤 Michael K. Korenko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:15
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/50; C21; C21D; C21D8/00; C22C38/44; C22C38/48
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
A method for heat treating an iron-nickel-chromium alloy consisting essentially of about 25% to 45% nickel, 10% to 16% chromium, 1.5% to 3% of an element selected from the group consisting of molybdenum and niobium, about 1% to 3% titanium, about 0.5% to 3.0% aluminum and the remainder substantially all iron; which method comprises the steps of heating the alloy to a temperature in the range of 1000° C. to 1100° C. for 30 seconds to 1 hour followed by a furnace-cool, cold-working the alloy 10% to 80%, heating the alloy to a temperature of about 750° C. to 800° C. for 4-15 hours followed by an air-cool, and then heating the alloy to a temperature in the range of 650° C. to 700° C. for 2-20 hours followed by an air-cool.
Claim 2
Independent Claim
132 words
A method for heat treating an iron-nickel-chromium alloy consisting essentially of about 25% to 45% nickel, 10% to 16% chromium, 1.5% to 3% of an element selected from the group consisting of molybdenum and niobium, about 1% to 3% titanium, about 0.5% to 3.0% aluminum and the remainder substantially all iron; which method comprises the steps of heating the alloy to a temperature in the range of 1000° C. to 1100° C. for 30 seconds to 1 hour followed by a furnace-cool, cold-working the alloy 10% to 80%, heating the alloy to a temperature of about 750° C. to 800° C. for 4-15 hours followed by an air-cool, and then heating the alloy to a temperature in the range of 650° C. to 700° C. for 2-20 hours followed by an air-cool.
Claim 3
Dependent Claim
25 words
The method claim 1 wherein the alloy is initially heated to a temperature in the range of 1025° C. to 1075° C. for 2-5 minutes.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said alloy is cold-worked by cold rolling 20% to 60%.
Claim 5
Dependent Claim
13 words
The method of claim 3 wherein said alloy is cold-rolled 30% to 50%.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein said alloy is in the form of a tube and is cold-worked by drawing the tube to produce a reduction of 15% to 35%.
Claim 7
Dependent Claim
16 words
The method of claim 5 wherein said reduction is within the range of 20% to 30%.
Claim 8
Dependent Claim
26 words
The method of claim 1 wherein, after cold-working, said alloy is heated to a temperature of about 775° C. for 8 hours followed by an air-cool.
Claim 9
Dependent Claim
68 words
The method of claim 1 wherein the method steps comprise heating to a temperature of 1025° C. to 1075° C. for 2-5 minutes followed by a furnace-cool, cold-working the alloy 20% to 60%, heating the alloy to a temperature of about 775° C. for 8 hours followed by an air-cool, and then heating the alloy to a temperature of 700° C. for 2 hours followed by an air-cool.
Claim 10
Dependent Claim
11 words
The method according to claim 1 wherein said element is molybdenum.
Claim 11
Dependent Claim
28 words
The method according to claim 1 or 9 further comprising the forming of a microstructure in said alloy having dislocations and a bimodal distribution of gamma prime precipitates.
Claim 12
Dependent Claim
23 words
The method according to claim 10 wherein said dislocations comprise interwoven dislocated cell structures which are pinned by said bimodal gamma prime precipitates.
References Cited (Backward Citations)
US3046108A
Cited
US4236943A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |