US3719476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Precipitation-hardenable stainless steel
Assignee: Armco Inc
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Filing: 1969-08-29
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Granted: 1973-03-06
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Expires: 1989-08-29
Abstract
Abstract Precipitation-hardenable stainless steel combining strength and corrosion-resistance and method of hardening the same. The steel contains the four essential ingredients chromium, cobalt, molybdenum and copper, with remainder iron, the chromium amounting to about 11 to 18 percent, the cobalt about 5 to 14 percent, the molybdenum about 1 to 9 percent, and the copper about 1 to 5 percent. Neither the carbon nor the nitrogen content should exceed about 0.15 percent. Where desired, tungsten and/or vanadium may be partially substituted for molybdenum, this in amounts up to about 6 percent. As annealed, the steel is martensitic. Hardening from the annealed condition is had by heating at descending or cascading precipitation temperatures, i.e., 1,000* to 1,300* F. and then 850* to 1,000* F. In precipitation-hardened condition it is suited to a wide variety of applications in the food-handling, petro-chemical and aircraft industries.
Inventors
- 👤 H Tanczyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:47
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt, about 4 percent to about 8 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.10 percent, nitrogen not exceeding 0.10 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 2
Dependent Claim
79 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt, about 4 percent to about 8 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.10 percent, nitrogen not exceeding 0.10 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 3
Dependent Claim
93 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 13 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt with the sum of the chromium and cobalt contents not exceeding about 25 percent, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.05 percent, nitrogen not exceeding 0.10 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 4
Dependent Claim
93 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 13 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt with the sum of the chromium and cobalt contents not exceeding about 25 percent, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.05 percent, nitrogen not exceeding 0.10 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 5
Dependent Claim
82 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 13 percent chromium, about 9.39 percent to about 11 percent cobalt, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, about 0.01 percent to about 0.06 percent carbon, nitrogen not exceeding 0.06 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 6
Dependent Claim
82 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 13 percent chromium, about 9.39 percent to about 11 percent cobalt, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, about 0.01 percent to about 0.06 percent carbon, nitrogen not exceeding 0.06 percent, columbium up to about 0.50 percent, and remainder substantially all iron.
Claim 7
Dependent Claim
85 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.10 percent, nitrogen not exceeding 0.10 percent, nickel below 1 percent, columbium about 0.01 percent to about 0.5 percent, and remainder substantially all iron.
Claim 8
Dependent Claim
85 words
Martensitic stainless steel, precipitation-hardenable to strengths exceeding 220,000 psi, with elongation at least 10 percent and reduction in area at least 30 percent, essentially consisting of about 11 percent to about 15 percent chromium, about 9.39 percent to about 12 percent cobalt, about 4 percent to about 6 percent molybdenum, about 2 percent to about 4 percent copper, carbon not exceeding 0.10 percent, nitrogen not exceeding 0.10 percent, nickel below 1 percent, columbium about 0.01 percent to about 0.5 percent, and remainder substantially all iron.
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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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |