Patent US3713812A successfully refreshed from Google Patents.
US3713812A
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US
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Ferritic stainless steels with improved drawability and resistance to ridging
Assignee: United States Steel Corp
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Filing: 1970-08-03
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Granted: 1973-01-30
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Expires: 1990-08-03
Abstract
Abstract A method for increasing the deep drawability, as represented by r value, of ferritic stainless steels. A complex equation shows the interrelation of the various alloying elements. Within the compositional range similar to that of type 430 steel, the r value may be increased by employing C and Cr at the lower end of the range and employing Si at the higher end of the range. Increasing the amount of Mn will increase r value for a type 430 steel, but will have just the opposite effect if Cb is present to any appreciable degree.
Inventors
- 👤 K Brickner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:22
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C21; C21D; C21D8/00; C21D8/02; C21D8/04
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
A method for enhancing the deep drawability of ferritic stainless steels within the range, C trace to 0.15% Mn trace to 2.25% Si trace to 2.0% Cr 14.0 to 21.0% Mo trace to 1.1% Cb trace to 1.1% balance Fe and incidental residual impurities which comprises, combining the above elements in proportions in which the desired r value is represented by the equation: r 1.22 -1.10 (%C) -0.174 (%Mn) +0.169 (%Si) -0.015 (%Cr) +0.083 (%Cb) +1.15 (%C -0.097) (%Cr -17.05) -3.41 (%C -0.097) (%Cb -0.50) +0.602 (%Mn -0.53)2 -0.861 (%Mn -0.53) (%Cb -0.50) so as to achieve an r value equal to or greater than 1.6.
Claim 2
Independent Claim
106 words
A method for enhancing the deep drawability of ferritic stainless steels within the range, C trace to 0.15% Mn trace to 2.25% Si trace to 2.0% Cr 14.0 to 21.0% Mo trace to 1.1% Cb trace to 1.1% balance Fe and incidental residual impurities which comprises, combining the above elements in proportions in which the desired r value is represented by the equation: r 1.22 -1.10 (%C) -0.174 (%Mn) +0.169 (%Si) -0.015 (%Cr) +0.083 (%Cb) +1.15 (%C -0.097) (%Cr -17.05) -3.41 (%C -0.097) (%Cb -0.50) +0.602 (%Mn -0.53)2 -0.861 (%Mn -0.53) (%Cb -0.50) so as to achieve an r value equal to or greater than 1.6.
Claim 3
Dependent Claim
32 words
The method of claim 1, wherein columbium is only present as an incidental residual impurity, and which further includes employing more than 1.1% Mn and less than 17.0% Cr and 0.06% C.
Claim 4
Dependent Claim
18 words
The method of claim 2, wherein greater than 1.0% Si is employed to further enhance the r value.
Claim 5
Dependent Claim
25 words
The method of claim 1, wherein when columbium is present as a purposeful alloy addition, Mn is employed in an amount no greater than 0.35%.
Claim 6
Dependent Claim
18 words
The method of claim 4, wherein 0.7 to 1.1% columbium is added to further increase the r value.
Claim 7
Dependent Claim
20 words
The method of claim 5, which includes employing more than 1.0% Si and less than 0.03% C and 16.5% Cr.
Claim 8
Dependent Claim
95 words
An annealed, ferritic stainless steel within the range, C trace to 0.15% Mn trace to 2.25% Si trace to 2.0% Cr 14.0 to 21.0% Mo trace to 1.1% Cb trace to 1.1% balance Fe and incidental residual impurities having an enhanced deep drawability, as represented by an r value greater than 1.6, and consisting essentially of those combinations of the above elements which satisfy the equation: -0.38 -1.10 (%C) -0.174 (%Mn) +0.169 (%Si) -0.015 (%Cr) +0.083 (%Cb) +1.15 (%C -0.097) (%Cr -17.05) -3.41 (%C -0.097) (%Cb -0.50) +0.602 (%Mn -0.53)2 -0.861 (%Mn -0.53) (%Cb -0.50).
Claim 9
Dependent Claim
95 words
An annealed, ferritic stainless steel within the range, C trace to 0.15% Mn trace to 2.25% Si trace to 2.0% Cr 14.0 to 21.0% Mo trace to 1.1% Cb trace to 1.1% balance Fe and incidental residual impurities having an enhanced deep drawability, as represented by an r value greater than 1.6, and consisting essentially of those combinations of the above elements which satisfy the equation: -0.38 -1.10 (%C) -0.174 (%Mn) +0.169 (%Si) -0.015 (%Cr) +0.083 (%Cb) +1.15 (%C -0.097) (%Cr -17.05) -3.41 (%C -0.097) (%Cb -0.50) +0.602 (%Mn -0.53)2 -0.861 (%Mn -0.53) (%Cb -0.50).
Claim 10
Dependent Claim
26 words
The steel of claim 7 consisting essentially of, C trace to 0.06% Mn 1.1-2.25% Si trace to 2.0% Cr 14.0-17.0% balance Fe and incidental residual impurities.
Claim 11
Dependent Claim
10 words
The steel of claim 8, containing more than 1.0% Si.
Claim 12
Dependent Claim
18 words
The steel of claim 8, additionally containing from 0.5 to 0.9% Mo and greater than about 15.5% Cr.
Claim 13
Dependent Claim
30 words
The steel of claim 7, consisting essentially of, C trace to 0.03% Mn trace to 0.35% Si trace to 2.0% Cr 14.0-16.5% Cb 0.7-1.1% balance Fe and incidental residual impuritiEs.
Claim 14
Dependent Claim
10 words
The steel of claim 11, containing more than 1.0% Si.
Claim 15
Dependent Claim
18 words
The steel of claim 11, additionally containing from 0.5 to 0.9% Mo and greater than about 15.5% Cr.
Claim 16
Dependent Claim
30 words
The steel of claim 7, consisting essentially of, C trace to 0.03% Mn greater than 1.4% Si trace to 2.0% Cr 14-16.5% Cb 0.7-1.1% balance Fe and incidental residual impurities.
Claim 17
Dependent Claim
10 words
The steel of claim 14, containing more than 1.0% Si.
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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) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |