US4264356A
Expired / Lapsed
US
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Ferritic precipitation-hardened soft magnetic stainless steel
Assignee: Tohoku Special Steel Works Ltd
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Filing: 1979-03-23
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Granted: 1981-04-28
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Expires: 1999-03-23
Abstract
Abstract A ferritic precipitation-hardened soft magnetic stainless steel is disclosed. This steel consists by weight percentage of not more than 0.1% of C, 12.0-22.0% of Cr, 1.5-6.0% of Nb, at least one of Al and Ti, provided that an amount of Al used alone is 0.5-4.0%, an amount of Ti used alone is 0.5-3.0% and an amount of Al and Ti used together is 0.5-4.0% (in the latter case, the amount of Ti does not exceed 3.0%), the remainder being Fe and incidental impurities. The steel exhibits substantially 100% ferrite phase after solution heat- and aging-treatments and has improved magnetic properties, corrosion resistance and hardness.
Inventors
- 👤 Susumu Shinagawa
- 👤 Taizo Suzuki
- 👤 Tuyoshi Otomo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:18
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/50; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
115 words
A ferritic precipitation-hardened soft magnetic stainless steel which has been subjected to solution heat treatment and aging, consisting essentially by weight percentage of not more than 0.1% of carbon, 12.0-22.0% of chromium, 1.5-6.0% of nickel, at least one of aluminum and titanium, provided that an amount of aluminum used alone is 0.5-4.0%, an amount of titanium used alone is 0.5-3.0% and an amount of aluminum and titanium used together is 0.5-4.0% (in the latter case, the amount of titanium does not exceed 3.0%), in which the value F=Al equivalent +1/10 (Cr%-12)-(Ni equivalent-2)≧-0.5 in the solid solution state, balance essentially iron, and exhibiting substantially 100% ferrite phase and having improved magnetic properties, corrosion resistance and hardness.
Claim 2
Dependent Claim
115 words
A ferritic precipitation-hardened soft magnetic stainless steel which has been subjected to solution heat treatment and aging, consisting essentially by weight percentage of not more than 0.1% of carbon, 12.0-22.0% of chromium, 1.5-6.0% of nickel, at least one of aluminum and titanium, provided that an amount of aluminum used alone is 0.5-4.0%, an amount of titanium used alone is 0.5-3.0% and an amount of aluminum and titanium used together is 0.5-4.0% (in the latter case, the amount of titanium does not exceed 3.0%), in which the value F=Al equivalent +1/10 (Cr%-12)-(Ni equivalent-2)≧-0.5 in the solid solution state, balance essentially iron, and exhibiting substantially 100% ferrite phase and having improved magnetic properties, corrosion resistance and hardness.
Claim 3
Dependent Claim
142 words
A ferritic precipitation-hardened soft magnetic stainless steel which has been subject to solution heat treatment and aging, consisting essentially by weight percentage of not more than 0.1% of carbon, 12.0-22.0% of chromium, 1.5-6.0% of nickel, at least one of aluminum and titanium, provided that an amount of aluminum used alone is 0.5-4.0%, an amount of titanium used alone is 0.5-3.0%, an amount of aluminum and titanium used together is 0.5-4.0% (in the latter case, the amount of titanium does not exceed 3.0%), at least one of not more than 6.0% of molybdenum, not more than 3.0% of silicon, not more than 2.0% of copper and not more than 1.0% of niobium, in which the value F=Al equivalent+1/10 (Cr%-12)-(Ni equivalent-2)±-0.5 in the solid solution state, balance essentially iron, and exhibiting substantially 100% ferrite phase and having improved magnetic properties, corrosion resistance and hardness.
Claim 4
Dependent Claim
142 words
A ferritic precipitation-hardened soft magnetic stainless steel which has been subject to solution heat treatment and aging, consisting essentially by weight percentage of not more than 0.1% of carbon, 12.0-22.0% of chromium, 1.5-6.0% of nickel, at least one of aluminum and titanium, provided that an amount of aluminum used alone is 0.5-4.0%, an amount of titanium used alone is 0.5-3.0%, an amount of aluminum and titanium used together is 0.5-4.0% (in the latter case, the amount of titanium does not exceed 3.0%), at least one of not more than 6.0% of molybdenum, not more than 3.0% of silicon, not more than 2.0% of copper and not more than 1.0% of niobium, in which the value F=Al equivalent+1/10 (Cr%-12)-(Ni equivalent-2)±-0.5 in the solid solution state, balance essentially iron, and exhibiting substantially 100% ferrite phase and having improved magnetic properties, corrosion resistance and hardness.
Claim 5
Dependent Claim
28 words
A steel as claimed in claim 1, containing an effective amount up to 2.0% of copper, said amount being effective to improve the corrosion resistance against sea water.
Claim 6
Dependent Claim
28 words
A steel as claimed in claim 2, containing an effective amount up to 2.0% of copper, said amount being effective to improve the corrosion resistance against sea water.
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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) | 1984-04-27 | 1984-10-27 | 1985-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-27 | 1988-10-27 | 1989-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-27 | 1992-10-27 | 1993-04-28 | $7700.00 | Window Closed / Lapsed |