US4726853A
Expired / Lapsed
US
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Ferritic stainless steel strip or sheet, in particular for exhaust systems
Assignee: UGINE GUEUGNON SA A CORP OF FRANCE
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Filing: 1986-10-27
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Granted: 1988-02-23
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Expires: 2006-10-27
Abstract
Abstract The invention concerns a strip or sheet of ferritic stainless steel of the following composition (% by weight): (C+N)<.060; Si<0.9; Mn<1; Cr=15 to 19; Mo<1; Ni<0.5; Ti<0.1; Cu<0.4; S<0.02; P<0.045; Zr=0.10 to 0.40, and 7(C+N)</=Zr</=7(C+N)+0.15; Nb=0.25 to 0.55, in non-combined form; Al=0.020 to 0.080; Fe=the balance, in which Al is essentially in solid solution. The process for the production of the sheet or strip comprises a final annealing operation which is carried out at between 980 DEG and 1020 DEG C., typically for 0.5 to 5 minutes at between 990 DEG and 1010 DEG C. The strip or sheet according to the invention is used for any application requiring an economic compromise in regard to ductility (sheet and welds), hot resistance and resistance to corrosion, for example in motor vehicle exhaust manifolds.
Inventors
- 👤 Pascal Gressin
- 👤 Pierre Pedarre
- 👤 Jean Decroix
- 👤 Philippe Maitrepierre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:54
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C22; C22C; C22C38/00; C22C38/18; C22C38/26; C22C38/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
70 words
Ferritic stainless steel strip or sheet which is intended in particular for the production of exhaust systems, consisting essentially of, in % by weight: (C+N)<0.060; Si<0.9; Mn<1; Cr=15 to 19; Mo<1; Ni<0.5; Ti<0.1; Cu<0.4; S<0.02; P<0.045; Zr=0.10 to 0.40, and 7(C+N)≦Zr≦7(C+N)+0.15; Nb=0.25 to 0.55, in non-combined form; Al=0.020 to 0.080; and Fe, balance, wherein the Al is in solid solution except for an amount which is no greater than 0.003%.
Claim 2
Dependent Claim
70 words
Ferritic stainless steel strip or sheet which is intended in particular for the production of exhaust systems, consisting essentially of, in % by weight: (C+N)<0.060; Si<0.9; Mn<1; Cr=15 to 19; Mo<1; Ni<0.5; Ti<0.1; Cu<0.4; S<0.02; P<0.045; Zr=0.10 to 0.40, and 7(C+N)≦Zr≦7(C+N)+0.15; Nb=0.25 to 0.55, in non-combined form; Al=0.020 to 0.080; and Fe, balance, wherein the Al is in solid solution except for an amount which is no greater than 0.003%.
Claim 3
Dependent Claim
12 words
Ferritic stainless steel strip or sheet according to claim 1, wherein (C+N)<0.040.
Claim 4
Dependent Claim
14 words
Ferritic stainless steel strip or sheet according to claim 1, wherein Nb=0.30 to 0.52.
Claim 5
Dependent Claim
23 words
Ferritic stainless steel strip or sheet according to claim 1, wherein: (C+N)<0.040; Cr=16 to 18; Ni<0.3; Nb=0.33 to 0.50; and Al=0.020 to 0.045.
Claim 6
Dependent Claim
163 words
Process for the production of ferritic stainless steel strip or sheet consisting essentially of, in % by weight: (C+N)<0.060; Si<0.9; Mn<1; Cr=15 to 19; Mo<1; Ni<0.5; Ti<0.1; Cu<0.4; S<0.02; P<0.045; Zr=0.10 to 0.50, and 7(C+N)-0.1≦Zr≦7(C+N)+0.2; Nb=0.25 to 0.55, when Zr≧7(C+N); Nb=0.25+7(C+N)-Zr to 0.55+7(C+N)-Zr when Zr<7(C+N); Al=0.020 to 0.080; and Fe, balance, wherein the Al is in solid solution except for an amount which is no greater than 0.003%, comprising the steps of: hot rolling to a thickness between 2.5 and 5 mm; annealing the hot rolled strip or sheet at 800° to 1000° C. under substantially non-oxidizing conditions; shot blasting to clean the annealed strip or sheet; cold rolling the shot blasted strip or sheet to a delivery thickness between 0.6 and 3 mm; final annealing the cold rolled strip or sheet at between 980° and 1020° C.; and subjecting the final annealed strip or sheet to a cold working pass or "skin" pass producing a degree of elongation of less than 1%.
Claim 7
Dependent Claim
163 words
Process for the production of ferritic stainless steel strip or sheet consisting essentially of, in % by weight: (C+N)<0.060; Si<0.9; Mn<1; Cr=15 to 19; Mo<1; Ni<0.5; Ti<0.1; Cu<0.4; S<0.02; P<0.045; Zr=0.10 to 0.50, and 7(C+N)-0.1≦Zr≦7(C+N)+0.2; Nb=0.25 to 0.55, when Zr≧7(C+N); Nb=0.25+7(C+N)-Zr to 0.55+7(C+N)-Zr when Zr<7(C+N); Al=0.020 to 0.080; and Fe, balance, wherein the Al is in solid solution except for an amount which is no greater than 0.003%, comprising the steps of: hot rolling to a thickness between 2.5 and 5 mm; annealing the hot rolled strip or sheet at 800° to 1000° C. under substantially non-oxidizing conditions; shot blasting to clean the annealed strip or sheet; cold rolling the shot blasted strip or sheet to a delivery thickness between 0.6 and 3 mm; final annealing the cold rolled strip or sheet at between 980° and 1020° C.; and subjecting the final annealed strip or sheet to a cold working pass or "skin" pass producing a degree of elongation of less than 1%.
Claim 8
Dependent Claim
21 words
Process according to claim 5, additionally comprising intermediate annealing and cleaning the strip or sheet following the step of cold rolling.
Claim 9
Dependent Claim
25 words
Process according to claim 5 or 6, wherein the final annealing is carried out at 990° C. to 1010° C. for 0.5 to 5 minutes.
Claim 10
Dependent Claim
9 words
Process according to claim 5 or 6, wherein (C+N)<0.040.
Claim 11
Dependent Claim
11 words
Process according to claim 5 or 6, wherein Nb=0.30 to 0.52.
References Cited (Backward Citations)
US4155752A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-22 | 1991-08-24 | 1992-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-22 | 1995-08-24 | 1996-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-22 | 1999-08-24 | 2000-02-23 | $7700.00 | Window Closed / Lapsed |