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US4957701A Expired / Lapsed US ⏱️ 0.0 years remaining

High-strength high-Cr ferritic heat-resistant steel

Assignee: Mitsubishi Heavy Industries Ltd
•
Filing: 1988-08-15
•
Granted: 1990-09-18
•
Expires: 2008-08-15
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Abstract

Abstract A high-strength high-Cr ferritic, heat-resistant steel exhibiting improved high-temperature, long-term creep strength and a process for producing the same are disclosed. The steel consists essentially of, by weight %: ______________________________________ C: not more than 0.2%, Si: not more than 1.0%, Mn: 0.1-1.5%, P: not more than 0.03%, S: not more than 0.03%, Ni: not more than 1.0%, Cr: 5.0-15%, Mo: 0.02-3.0%, W: not more than 4.0%, sol. Al: 0.05-0.04%, N: not more than 0.07%, ______________________________________ at least one of V: 0.01-0.4% and Nb: 0.01-0.3%, B: 0-0.02%, at least one of Ca, Ti, Zr, Y, La, and Ce: 0-0.2%, and the balance Fe and incidental impurities, A cl point defined by Formula (1) below being 820 or higher. ##EQU1##

Inventors

  • 👤 Fujimitsu Masuyama
  • 👤 Takashi Daikoku
  • 👤 Hisao Haneda
  • 👤 Kunihiko Yoshikama
  • 👤 Hiroshi Teranishi
  • 👤 Atsuro Iseda

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 20:47
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/26; C22C38/22; C22C38/24; F; F28; F28F; F28F21/00; F28F21/08; F28F21/081; F28F21/082; F28F21/083

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 143 words
A high-strength high-Cr ferritic, heat-resistant steel exhibiting improved high-temperature, long-term creep strength which corresponds to a creep rupture time of at least 2600 hrs., measured in an accelerated creep test carried out at conditions of 650° C.×8 kgf/mm 2 , which consists essentially of, by weight %: ______________________________________ C: 0.05-0.15%, Si: not more than 1.0%, Mn: 0.2-1.0%, P: not more than 0.025%, S: not more than 0.015%, Ni: not more than 0.8%, Cr: 8.0-13%, Mo: 0.5-3%, W: 0.5-3.0%, sol. Al: 0.005-0.04%, N: 0.02-0.07%, V: 0.1-0.4%, Nb: 0.01- 0.05%, B: 0-0.02%, ______________________________________ at least one of Ca, Ti, Zr, Y, La, and Ce each in an amount of : 0-0.2%, and the balance Fe and incidental impurities, the A c1 point defined by Formula (1) below being 850° C. or higher, and the Cr-equivalent defined by Formula (2) below being 17 or less. ##EQU4##
Claim 2
Dependent Claim 143 words
A high-strength high-Cr ferritic, heat-resistant steel exhibiting improved high-temperature, long-term creep strength which corresponds to a creep rupture time of at least 2600 hrs., measured in an accelerated creep test carried out at conditions of 650° C.×8 kgf/mm 2 , which consists essentially of, by weight %: ______________________________________ C: 0.05-0.15%, Si: not more than 1.0%, Mn: 0.2-1.0%, P: not more than 0.025%, S: not more than 0.015%, Ni: not more than 0.8%, Cr: 8.0-13%, Mo: 0.5-3%, W: 0.5-3.0%, sol. Al: 0.005-0.04%, N: 0.02-0.07%, V: 0.1-0.4%, Nb: 0.01- 0.05%, B: 0-0.02%, ______________________________________ at least one of Ca, Ti, Zr, Y, La, and Ce each in an amount of : 0-0.2%, and the balance Fe and incidental impurities, the A c1 point defined by Formula (1) below being 850° C. or higher, and the Cr-equivalent defined by Formula (2) below being 17 or less. ##EQU4##
Claim 3
Dependent Claim 16 words
A high-strength high-Cr ferritic, heat-resistant steel as defined in claim 1, in which B : 0.001-0.02%.
Claim 4
Dependent Claim 34 words
A high-strength high-Cr ferritic, heat-resistant steel as defined in claim 1 in which said at least one of Ca, Ti, Zr, Y, La, and Ce is each present in an amount of : 0.01-0.2%.

References Cited (Backward Citations)

JPS5696056A Cited
JPS58181849A Cited
JPS60165359A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-09-17 1994-03-19 1994-09-18 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-09-17 1998-03-19 1998-09-18 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-09-17 2002-03-19 2002-09-18 $7700.00 Window Closed / Lapsed

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