US4421557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Austenitic stainless steel
Assignee: Crucible Materials Corp
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Filing: 1982-10-26
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Granted: 1983-12-20
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Expires: 2002-10-26
Abstract
Abstract An austenitic stainless steel having good corrosion resistance, particularly in chloride environments; this is achieved by the use of a rare earth element, preferably lanthanum, singly or in combination with nitrogen, along with nickel and molybdenum at relatively low levels for an austenitic stainless steel. The composition includes 15 to 25% chromium, greater than 16 to 25% nickel, 3 to 7% molybdenum, with a rare earth element consisting of lanthanum within the range of 0.005 to 0.05% in combination with 0.1 to 0.5% nitrogen.
Inventors
- 👤 Paul A. Rossomme
- 👤 John J. Eckenrod
- 👤 Curtis W. Kovach
- 👤 Kenneth E. Pinnow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:35
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/44; C22C38/001
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
67 words
An austenitic stainless steel having good corrosion resistance in chloride environments at relatively low nickel and molybdenum levels, said steel consisting essentially of, in weight percent, carbon 0.01 to 0.1, manganese 12 max., silicon 1 max., chromium 15 to 25, nickel greater than 16 to 25, molybdenum 3 to 7, a rare earth element consisting of lanthanum 0.005 to 0.05, nitrogen 0.1 to 0.50 and balance iron.
Claim 2
Dependent Claim
67 words
An austenitic stainless steel having good corrosion resistance in chloride environments at relatively low nickel and molybdenum levels, said steel consisting essentially of, in weight percent, carbon 0.01 to 0.1, manganese 12 max., silicon 1 max., chromium 15 to 25, nickel greater than 16 to 25, molybdenum 3 to 7, a rare earth element consisting of lanthanum 0.005 to 0.05, nitrogen 0.1 to 0.50 and balance iron.
Claim 3
Dependent Claim
11 words
The steel of claim 1 having copper up to about 3%.
Claim 4
Dependent Claim
10 words
The steel of claim 1 having 0.1 to 0.3% nitrogen.
Claim 5
Dependent Claim
9 words
The steel of claim 1 having manganese 3% max.
Claim 6
Dependent Claim
14 words
The steel of claim 1 having molybdenum within the range of 3 to 5.5%.
Claim 7
Dependent Claim
15 words
The steel of claim 1 having nickel within the range greater than 16 to 20%.
Claim 8
Dependent Claim
67 words
An austenitic stainless steel having good corrosion resistance in chloride environments at relatively low nickel and molybdenum levels, said steel consisting essentially of, in weight percent, carbon 0.01 to 0.1, manganese 12 max., silicon 1 max., chromium 15 to 25, nickel greater than 16 to 20, molybdenum 3 to 5.5, a rare earth element consisting of lanthanum 0.005 to 0.05, nitrogen 0.1 to 0.50 and balance iron.
Claim 9
Dependent Claim
67 words
An austenitic stainless steel having good corrosion resistance in chloride environments at relatively low nickel and molybdenum levels, said steel consisting essentially of, in weight percent, carbon 0.01 to 0.1, manganese 12 max., silicon 1 max., chromium 15 to 25, nickel greater than 16 to 20, molybdenum 3 to 5.5, a rare earth element consisting of lanthanum 0.005 to 0.05, nitrogen 0.1 to 0.50 and balance iron.
Claim 10
Dependent Claim
9 words
The steel of claim 7 having manganese 3% max.
Claim 11
Dependent Claim
11 words
The steel of claim 7 having copper up to about 3%.
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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) | 1986-12-19 | 1987-06-20 | 1987-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-19 | 1991-06-20 | 1991-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-19 | 1995-06-20 | 1995-12-20 | $7700.00 | Window Closed / Lapsed |