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US3736131A
Expired / Lapsed
US
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Ferritic-austenitic stainless steel
Assignee: Armco Inc
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Filing: 1970-12-23
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Granted: 1973-05-29
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Expires: 1990-12-23
Abstract
Abstract An austenitic-ferritic stainless steel consisting essentially of up to about 0.06 percent carbon, about 4.0 to less than 11.0 percent manganese, about 19 to about 24 percent chromium, about 0.12 to about 0.26 percent nitrogen, nickel up to about 3.0 percent, and remainder substantially iron except for incidental impurities. The austenite-ferrite balance, ranging between 10 percent and 50 percent austenite, is stable, and the steel exhibits high toughness, corrosion resistance and excellent weldability.
Inventors
- 👤 R H Espy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:20
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/001; C22C38/18; C22C38/38
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
32 words
The stainless steel of claim 1, containing about 0.02 percent carbon, about 6.0 percent manganese, about 21.0 percent chromium, about 0.20 percent nitrogen, about 0.20 percent nickel, and about 0.40 percent silicon.
Claim 2
Dependent Claim
17 words
The stainless steel of claim 1, wherein carbon is present in an amount of about 0.02 percent.
Claim 3
Dependent Claim
17 words
The stainless steel of claim 1, wherein manganese is present in the amount of about 6.0 percent.
Claim 4
Dependent Claim
17 words
The stainless steel of claim 1, wherein chromium is present in the amount of about 21.0 percent.
Claim 5
Dependent Claim
17 words
The stainless steel of claim 1, wherein nitrogen is present in the amount of about 0.20 percent.
Claim 6
Dependent Claim
17 words
The stainless steel of claim 1, wherein nickel is present in the amount of about 0.20 percent.
Claim 7
Dependent Claim
23 words
The stainless steel of claim 1, wherein molybdenum is substituted for chromium on a 1:1 basis in amounts up to about 5 percent.
Claim 8
Dependent Claim
15 words
The stainless steel of claim 1, including columbium in amounts up to about 1 percent.
Claim 9
Dependent Claim
58 words
A stainless steel having a two-phase structure comprising between 20 percent and 30 percent austenite in a ferrite matrix, consisting essentially of about 0.02 percent carbon, about 6.0 percent manganese, about 21.0 percent chromium, about 0.20 percent nitrogen, about 0.20 percent nickel, phosphorus and sulfur low, about 0.40 percent silicon, copper and cobalt low, and balance substantially iron.
Claim 10
Dependent Claim
86 words
Welded articles having a two-phase structure comprising between 10 percent and 50 percent austenite in a ferrite matrix, consisting essentially of up to about 0.06 percent carbon, about 4.0 percent to less than 11.0 percent manganese, about 19 percent to about 24 perCent chromium, about 0.12 percent to about 0.26 percent nitrogen, nickel up to about 3.0 percent, phosphorus and sulfur up to about 0.03 percent each, silicon up to about 1.0 percent, copper and cobalt up to about 0.5 percent each, and remainder substantially iron.
Claim 11
Dependent Claim
87 words
Cold headed fasteners having a two-phase structure comprising between 10 percent and 50 percent austenite in a ferrite matrix, consisting essentially of up to about 0.06 percent carbon, about 4.0 percent to less than 11.0 percent manganese, about 19 percent to about 24 percent chromium, about 0.12 percent to about 0.26 percent nitrogen, nickel up to about 3.0 percent, phosphorus and sulfur up to about 0.03 percent each, silicon up to about 1.0 percent, copper and cobalt up to about 0.5 percent each, and remainder substantially iron.
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) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |