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US3865644A
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High strength, corrosion resistant, austenite-ferrite stainless steel
Assignee: Saab Bofors AB
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Filing: 1973-04-09
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Granted: 1975-02-11
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Expires: 1993-04-09
Abstract
Abstract An aging, austenite-ferritic, stainless steel having very high strength, good ductility and notch-impact resistance as well as excellent resistance to general and intercrystalline corrosion, has the following composition, given in percent, by weight: C maximum value 0.15 preferably 0.01 - 0.10 Si maximum value 2 preferably a maximum of 1.0 Mn maximum value 5 preferably a maximum of 2.0 Cr 20 - 30 preferably 24 - 27 Ni 4 - 9 preferably 5.5 - 7.5 Mo 1 - 3 preferably 1.3 - 1.8 Nb 0.1 - 2.5 preferably 0.1 - 1.6 Ti maximum value 1.5 preferably a maximum of 1.0 Al 0.1 - 2 preferably 0.5 - 1.0 N maximum value 0.15 preferably a maximum of 0.1 THE REMAINDER BEING MADE UP OF IRON AND THE IMPURITIES AND OTHER MATERIAL USUALLY PRESENT IN THIS TYPE OF STEEL. It is further necessary to weigh out the quantity of niobium and titanium in proportion to the quantity of carbon and nitrogen in such manner that the atomic percentage of niobium plus the atomic percentage of titanium > OR = the atomic percentage of carbon plus the atomic percentage of nitrogen.
Inventors
- 👤 Lars Ivar Hellner
- 👤 Hans Elof Johansson
- 👤 Lars-Ake Norstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:46
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/48; C22C38/44
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
142 words
A CORROSION-RESISTANT, AUSTENITE-FERRITIC STEEL WHICH CONTAINS 10% TI 35% BY VOLUME OF AUSTENITE, SAID STEEL BEING ADAPTED TO ATTAIN AN INCREASE IN STRENGTH BY AGE-HARDENING, WHILE RETAINING GOOD DUCTILITY AND NOTCH-IMPACT RESISTANCE AS WELL AS EXCELLENT RESISTANCE TO INTERCYSTALLINE CORROSION, SAID STEEL CONSISTING ESENTIALLY OF THE FOLLOWING COMPOSITION BY WEIGHT: C, A MIXIMUM OF 0.15% SI, A MIXIMUM OF 2% MN, A MAXIMUM OF 5% CR, FROM 20% TO 30% NI, FROM 4% TO 9% MO, FROM 1% TO 3% NB, FROM 0.1% TO 2.5% TI, A MIXIMUM OF 1.5& AL, FROM 0.1% TO 2%, AND N, 2 MAXIMUM OF 0.15%, THE REMAINDER OF SAID COMPOSITION CONSISTUTING IRON AND IMPURITIES, THE ATOMIC PERCENTAGE OF NB PLUS THE ATOMIC PERCENTAGE OF IT IN SAID STEEL COMPOSITION BEING EQUAL TO OR GREATER THAN THE ATOMIC PERCENTAGE OF C LUS THE ATOMIC PERCENTAGE OF N.
Claim 2
Dependent Claim
142 words
A CORROSION-RESISTANT, AUSTENITE-FERRITIC STEEL WHICH CONTAINS 10% TI 35% BY VOLUME OF AUSTENITE, SAID STEEL BEING ADAPTED TO ATTAIN AN INCREASE IN STRENGTH BY AGE-HARDENING, WHILE RETAINING GOOD DUCTILITY AND NOTCH-IMPACT RESISTANCE AS WELL AS EXCELLENT RESISTANCE TO INTERCYSTALLINE CORROSION, SAID STEEL CONSISTING ESENTIALLY OF THE FOLLOWING COMPOSITION BY WEIGHT: C, A MIXIMUM OF 0.15% SI, A MIXIMUM OF 2% MN, A MAXIMUM OF 5% CR, FROM 20% TO 30% NI, FROM 4% TO 9% MO, FROM 1% TO 3% NB, FROM 0.1% TO 2.5% TI, A MIXIMUM OF 1.5& AL, FROM 0.1% TO 2%, AND N, 2 MAXIMUM OF 0.15%, THE REMAINDER OF SAID COMPOSITION CONSISTUTING IRON AND IMPURITIES, THE ATOMIC PERCENTAGE OF NB PLUS THE ATOMIC PERCENTAGE OF IT IN SAID STEEL COMPOSITION BEING EQUAL TO OR GREATER THAN THE ATOMIC PERCENTAGE OF C LUS THE ATOMIC PERCENTAGE OF N.
Claim 3
Dependent Claim
18 words
The steel of claim 1 wherein the volume of austenite in said steel is between 10% and 25%.
Claim 4
Dependent Claim
76 words
The steel of claim 1 wherein the composition of said steel, given in percent by weight, consists essentially of: C, a maximum of 0.10% Si, a maximum of 1.0% Mn, a maximum of 2.0% Cr, from 22% to 28% Ni, from 5% to 8% Mo, from 1% to 2% Nb, from 0.1% to 2.5% Ti, a maximum of 1.5% Al, from 0.1% to 2%, and N, a maximum of 0.1% and the remainder as previously recited.
Claim 5
Dependent Claim
76 words
The steel of claim 1 wherein the composition of said steel, given in percent by weight, consists essentially of: C, a maximum of 0.10% Si, a maximum of 1.0% Mn, a maximum of 2.0% Cr, from 24% to 27% Ni, from 5.5% to 7.5% Mo, from 1.3% to 1.8% Nb, from 0.1% to 2.5% Ti, a maximum of 1.5% Al, from 0.1% to 2%, and N, a maximum of 0.1% and the remainder as previously recited.
Claim 6
Dependent Claim
76 words
The steel of claim 1 wherein the composition of said steel, given in percent by weight, consists essentially of: C, a maximum of 0.10% Si, a maximum of 1.0% Mn, a maximum of 2.0% Cr, from 24% to 27% Ni, from 5.5% to 7.5% Mo, from 1.3% to 1.8% Nb, from 0.1% to 2.5% Ti, a maximum of 1.5% Al, from 0.5% to 1.0%, and N, a maximum of 0.1% and the remainder as previously recited.
Claim 7
Dependent Claim
76 words
The steel of claim 1 wherein the composition of said steel, given in percent by weight, consists essentially of: C, from 0.01% to 0.10% Si, a maximum of 1.0% Mn, a maximum of 2.0% Cr, from 24% to 27% Ni, from 5.5% to 7.5% Mo, from 1.3% to 1.8% Nb, from 0.1% to 1.6% Ti, a maximum of 1.0% Al, from 0.5% to 1.0%, and N, a maximum of 0.1% and the remainder as previously recited.
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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |