US4844755A
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High-strength heat-resisting ferritic steel pipe and tube
Assignee: Nippon Steel Corp
•
Filing: 1988-08-29
•
Granted: 1989-07-04
•
Expires: 2008-08-29
Abstract
Abstract A high-strength, heat-resisting ferritic steel pipe or tube for boiler use containing 0.03 to 0.15% C, 0.1 to 1.5% Mn, 8 to 13% Cr, 1.8 to 3.0% W, 0.05 to 0.30% V, 0.02 to 0.12% Nb, 0.02 to 0.05% N, 0.02 to 0.4% Mo, and up to 0.25% Si. This pipe or tube has an improved high-temperature creep rupture strength and an excellent weldability and toughness.
Inventors
- 👤 Katukuni Hashimoto
- 👤 Yasuo Otoguro
- 👤 Toshio Fujita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:08
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/24; C22C38/22; C22C38/26; Y; Y10; Y10S; Y10S148/00; Y10S148/902; Y10S148/909
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.4%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 2
Dependent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.4%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 3
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 1, wherein said C content is from 0.03 to 0.12% in weight.
Claim 4
Dependent Claim
60 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.4%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________
with the remainder consisting of Fe and unavoidable impurities.
Claim 5
Dependent Claim
60 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.4%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________
with the remainder consisting of Fe and unavoidable impurities.
Claim 6
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 3, wherein said C content is from 0.03 to 0.12% in weight.
Claim 7
Dependent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.1-0.4%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 8
Dependent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.1-0.4%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 9
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 5, wherein said C content is from 0.03 to 0.12% in weight.
Claim 10
Dependent Claim
60 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.1-0.4%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 11
Dependent Claim
60 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.1-0.4%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 12
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 7, wherein said C content is from 0.03 to 0.12% in weight.
Claim 13
Dependent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.1%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 14
Dependent Claim
58 words
A high-strength heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.1%,
Si: 0.25% or less,
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 15
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 9, wherein said C content is from 0.03 to 0.12% in weight.
Claim 16
Dependent Claim
60 words
A high-strength, heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.1%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 17
Dependent Claim
60 words
A high-strength, heat-resisting ferritic steel in the form of a pipe or a tube having an improved creep rupture strength, said steel consisting, in weight percentage, of: ______________________________________
C: 0.03-0.15%,
Mn: 0.1-1.5%,
Cr: 8.0-13.0%,
W: 1.8-3.0%,
V: 0.05-0.30%,
Nb: 0.02-0.12%,
N: 0.02-0.05%,
Mo: 0.02-0.1%,
Si: 0.25% or less,
B: 0.001-0.008%
______________________________________ with the remainder consisting of Fe and unavoidable impurities.
Claim 18
Dependent Claim
20 words
A high-strength, heat-resisting ferritic steel according to claim 11, wherein said C content is from 0.03 to 0.12% in weight.
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) | 1992-07-03 | 1993-01-02 | 1993-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-03 | 1997-01-02 | 1997-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-03 | 2001-01-02 | 2001-07-04 | $7700.00 | Window Closed / Lapsed |