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US4055416A
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Tantalum modified ferritic iron base alloys
Assignee: National Aeronautics and Space Administration
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Filing: 1976-01-21
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Granted: 1977-10-25
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Expires: 1996-01-21
Abstract
Abstract Strong ferritic alloys of the Fe-Cr-Al type containing 0.4% to 2% tantalum have improved fabricability without sacrificing high temperature strength and oxidation resistance in the 800 DEG C (1475 DEG F) to 1040 DEG C (1900 DEG F) range.
Inventors
- 👤 Robert E. Oldrieve
- 👤 Charles P. Blankenship
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:26
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/26
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
58 words
A ferritic steel alloy having improved high temperature strength at temperatures to 1,040° C, improved oxidation resistance to 1,150° C, and good cold formability consisting essentially of, in weight percents; 15.0% to 20.0% chromium, 2.0% to 4.0% aluminum, 0.4% to 1.0% silicon, 0.4% to 1.0% titanium, 0.01% to 0.05% carbon, 0.4% to 1.5% tantalum and the balance iron.
Claim 2
Dependent Claim
58 words
A ferritic steel alloy having improved high temperature strength at temperatures to 1,040° C, improved oxidation resistance to 1,150° C, and good cold formability consisting essentially of, in weight percents; 15.0% to 20.0% chromium, 2.0% to 4.0% aluminum, 0.4% to 1.0% silicon, 0.4% to 1.0% titanium, 0.01% to 0.05% carbon, 0.4% to 1.5% tantalum and the balance iron.
Claim 3
Dependent Claim
27 words
An alloy as claimed in claim 1 containing about 18% chromium, 2% aluminum, 1% silicon, 0.4% titanium, 0.04% carbon, 0.5% to 1.3% tantalum and the balance Fe.
Claim 4
Dependent Claim
11 words
An alloy as claimed in claim 2 containing about 1.3% tantalum.
Claim 5
Dependent Claim
11 words
An alloy as claimed in claim 2 containing about 0.5% tantalum.
Claim 6
Dependent Claim
21 words
An alloy as claimed in claim 1 containing about 0.4 to 1.0% nickel, 0.5% manganese, 0.02% phosphorous and about 0.01% sulfur.
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) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |