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US4678523A
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Corrosion- and wear-resistant duplex steel
Assignee: Haynes International Inc
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Filing: 1986-07-03
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Granted: 1987-07-07
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Expires: 2006-07-03
Abstract
Abstract Disclosed is a "duplex" stainless steel especially suited for use in conditions requiring a high degree of wear and corrosion resistance; for example structural fasteners, such as nuts and bolts as used in chemical processing. The alloy typically contains, in weight percent, 12 cobalt, 20 chromium, 11 nickel, 5 silicon, 1.5 molybdenum, 2 copper, up to 0.2 nitrogen and up to 0.01 carbon. The "duplex" structure preferably consists of about 30% ferrite and the balance essentially austenite.
Inventors
- 👤 Narasi Sridhar
- 👤 Paul Crook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:47
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/52; B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/30; B23K35/3053; B23K35/308; B23K35/3086
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
88 words
A stainless steel having a duplex structure consisting of about 5 to 60% ferrite and the balance essentially austenite consisting essentially of, in weight percent, less than 0.1 carbon, 6 to 16 cobalt, 16 to 26 chromium, 7 to 20 nickel, 3 to 6 silicon, up to 4 molybdenum, up to 3 copper, less than 0.4 nitrogen, and the balance iron plus impurities, wherein the ratio of cobalt to silicon is between 1 and 4.5 to provide a desirable combination of wear and corrosion resistance to the steel.
Claim 2
Dependent Claim
88 words
A stainless steel having a duplex structure consisting of about 5 to 60% ferrite and the balance essentially austenite consisting essentially of, in weight percent, less than 0.1 carbon, 6 to 16 cobalt, 16 to 26 chromium, 7 to 20 nickel, 3 to 6 silicon, up to 4 molybdenum, up to 3 copper, less than 0.4 nitrogen, and the balance iron plus impurities, wherein the ratio of cobalt to silicon is between 1 and 4.5 to provide a desirable combination of wear and corrosion resistance to the steel.
Claim 3
Dependent Claim
48 words
The stainless steel of claim 1 wherein alloy contains less than 0.06 carbon, 10 to 14 cobalt, 19 to 21 chromium, 9 to 13 nickel, 4.5 to 5.5 silicon, 1 to 3 each molybdenum and copper, up to 0.2 nitrogen, and the ratio is between 1.5 and 3.5.
Claim 4
Dependent Claim
44 words
The stainless steel of claim 1 wherein the alloy contains less than about 0.01 carbon, about 12 cobalt, about 20 chromium, about 11 nickel, about 5 silicon, about 1.5 molybdenum, about 2 copper, up to about 0.2 nitrogen and the ratio is about 2.5.
Claim 5
Dependent Claim
30 words
The stainless steel of claim 1 in the form of a casting or a wrought product or a hard-facing material or a welding material or a sintered powder metallurgy product.
Claim 6
Dependent Claim
9 words
The alloy of claim 1 containing about 30% ferrite.
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) | 1990-07-06 | 1991-01-05 | 1991-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-06 | 1995-01-05 | 1995-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-06 | 1999-01-05 | 1999-07-07 | $7700.00 | Window Closed / Lapsed |