US3723102A
Expired / Lapsed
US
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High strength iron-chromium-nickel alloy
Assignee: Airco Inc
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Filing: 1970-06-15
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Granted: 1973-03-27
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Expires: 1990-06-15
Abstract
Abstract Iron-chromium-nickel alloys having improved physical properties containing between 16 and 18 percent chromium and between 7 and 9 percent nickel, low levels of carbon and nitrogen, not more than 6 ppm of insoluble volatile metallic impurities and not more than about 20 ppm soluble volatile metallic impurities. The alloys have yield strengths above 70 KSI at room temperature and impact strengths above 20 foot pounds at -320* F.
Inventors
- 👤 J Lowe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:01
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
34 words
An iron-chromium-nickel alloy in accordance with claim 1 wherein the crystalline configuration of the alloy is between about 5 and about 15 percent ferrite, between about 30 and about 40 percent austenite, balance martensite.
Claim 2
Dependent Claim
97 words
An iron-chromium-nickel alloy consisting essentially of nickel, chromium and iron and lying within the area bound by lines ABCD of FIG. 1 and containing less than about 250 ppm of carbon plus nitrogen, not more than about 6 ppm total of the insoluble volatile metallic impurities lead, bismuth, cadmium, sodium, potassium, silver, calcium, magnesium and barium and not more than 20 ppm total of the soluble volatile metallic impurities zinc and antimony, said alloy having a yield strength at room temperature above 70 KSI and an impact strength at -320* F. of at least 20 foot pounds.
Claim 3
Dependent Claim
34 words
An iron-chromium-nickel alloy in accordance with claim 3 wherein the crystalline configuration of the alloy is between about 5 and about 15 percent ferrite, between about 30 and about 40 percent austenite, balance martensite.
Claim 4
Dependent Claim
107 words
An iron-chromium-nickel alloy in accordance with claim 1 which comprises between about 16.25 and about 17.5 percent by weight chromium, between about 8.0 and about 8.7 percent by weight nickel, less than about 250 ppm of carbon plus nitrogen, not more than about 6 ppm total of the insoluble volatile metallic impurities lead, bismuth, cadmIum, sodium, potassium, silver, calcium, magnesium and barium, and not more than 20 ppm total of the soluble volatile metallic impurities zinc and antimony, the balance being iron, said alloy having a yield strength at room temperature above 70 KSI and an impact strength at -320* F. of at least 20 foot pounds.
Claim 5
Dependent Claim
34 words
An iron-chromium-nickel alloy in accordance with claim 5 wherein the crystalline configuration of the alloy is between about 5 and about 15 percent ferrite, between about 30 and about 40 percent austenite, balance martensite.
Claim 6
Dependent Claim
42 words
An iron-chromium-nickel alloy in accordance with claim 1 which includes up to about 0.5 percent by weight silicon, up to about 0.5 percent by weight aluminum, up to about 0.1 percent by weight phosphorous, and not more than about 200 ppm oxygen.
Claim 7
Dependent Claim
42 words
An iron-chromium-nickel alloy in accordance with claim 3 which includes up to about 0.5 percent by weight silicon, up to about 0.5 percent by weight aluminum, up to about 0.1 percent by weight phosphorous, and not more than about 200 ppm oxygen.
Claim 8
Dependent Claim
42 words
An iron-chromium-nickel alloy in accordance with claim 5 which includes up to about 0.5 percent by weight silicon, up to about 0.5 percent by weight aluminum, up to about 0.1 percent by weight phosphorous, and not more than about 200 ppm oxygen.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |