CA1170481A - Substrate for catalytic system and ferritic stainless steel from which it is formed - Google Patents
Substrate for catalytic system and ferritic stainless steel from which it is formedInfo
- Publication number
- CA1170481A CA1170481A CA000368518A CA368518A CA1170481A CA 1170481 A CA1170481 A CA 1170481A CA 000368518 A CA000368518 A CA 000368518A CA 368518 A CA368518 A CA 368518A CA 1170481 A CA1170481 A CA 1170481A
- Authority
- CA
- Canada
- Prior art keywords
- stainless steel
- ferritic stainless
- substrate
- yttrium
- chromium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
1227 SUBSTRATE FOR CATALYTIC SYSTEM AND FERRITIC STAINLESS STEEL FROM WHICH IT IS FORMED A system comprising a ferritic stainless steel substrate having a tightly adherent oxide coating and a catalytic material thereupon, and the ferritic stainless steel from which the substrate is formed. The ferritic stainless steel is of a chemistry which forms a tightly adherent non-spalling scale suitable for application of a catalytic bearing material. It consists essentially of, by weight, up to 26% chromium, from 1 to 8% aluminum, between 0.01 and 0.1% yttrium, up to 0.1% carbon, up to 2% silicon, balance essentially iron.
Description
The present invention relates to a substrate for a catalytic materlal and to the alloy from which the substrate is formed.
As the particular material used a~ a substrate for the catalyst in automotive catalytic convertors effects the performance of the convertors, there is a need to develop improved substrates. In particular, there is a need for a metallic substrate to replace the ceramic substrates presently in use. Ceramic substrates do not have the mechanical properties; e.g~ ~hock resistance, of metallic substrates. Ceramic substrates are, in addition, inherently thicker than are metallic substrat~s.
t ~
.
l A particular metallic substrate is described in United States Patent No. 3,920,5830 It is a ferritic stainless steel which contains up to lS~ chromium, 0.5 to 12~ aluminum and 0.1 to 3~ yttrium.
Economic and technical problems ha~e been encountered with the use of yttrium, thereby detracting from the benefits of the substrate of Patent No 3,920,583.
Yttrium is an expensive material which is not presently available in abundant quantities, and a material characterized by a low recovery rate during melting.
Through the present invention there is provided a metallic substrate which minimizes the difficulties associated with the substrate of Patent No. 3,920,583. The present invention relates to a substrate wherein the yttrium level of Patent No. 3,920,583 is significantly reduced. It has been determined that high quality substrates can be produced from iron-chromium-aluminum alloys having less than 0.1~ yttrium.
Other references disclosing ferritic stainless steels with chromium, aluminum and yttrium are United States Patent Nos. 3,027,252 and 3,298,826, and reports respectively entitled, WThe Physical Metallurgy And Oxidation Behavior Of Fe-Cr-Al-Y Alloys~ and "Sulfidation - Resistant Alloy For Coal Gasification Servicen. The first report is dated 1 June 1, 1966. It was prepared by C. S. Wukusick under United States Atomic ~nergy Commisslon Contract No.
ATt40~ 2847. The second repor~ was published June 14, 1977. It was prèpared by Roger A. Perkins and M~ S. Bhat for the U.S. Energy Research And Development Administr3tion under Con~ract No. E(49-18)-2299. Neither the reports nor the patents relate to a substrate for a catalytic material nor to an alloy having less than 0.1~ yttrium.
Another reference disclosing ferritic stainless steels with chromium, aluminum and yttrium is United States Patent No. 3,591,365. Although it discloses alloys which may have less than 0.1% yttrium, its alloys req~ire specific additions of gadolinium and/or dysprosium. As with the references disclosed in the preceding paragraphs, it does not pertain to substrates for catalytic materials.
It is accordingly an object of the subject invention to provide a substrate for a catalytic material and an alloy from which the substrate is formed.
The present invention is described in terms of a catalytic system comprising a ferritic stainless steel substrate having a tightly adherent oxide coatiny and a catalytic material thereupon, and in terms of the ferritic stainless steel from which the substrate is formed. The ferritic stainless steel is of a chemistry which forms a tightly adherent non-spalling scale suitable for application of a catalytic bearing material. It consists e~sentially of, by weight, up to 26% chromium, from 1 to 8% aluminum, ~'7~
1 between 0.01 and 0.1% yttrium, up to 0.1% carbon, up to 2%
silicon, balance essentially iron. The substrate is in most instances of a thickness of from 0.0005 to 0.01 inch Chromium may be present within the substrate of the present invention as it is known to improve oxidatioil resistance. A maximum limit is placed thereupon as chromium is expensive and renders the alloy more difficult to process. Chromium is usually present within the range of from 5 to 22%, and preferably within the range of from 12 to 20%.
Aluminum is present as it improves the oxidation resistance of the substrate. A maximum limit is placed thereupon as aluminum, like chromium, is expensive and renders the alloy more difficult to process. Aluminum is preferably prasent within the range of from 3 to 6%.
Yttrium is present as it stabilizes the aluminum-bearing scale and makes it both tight and adherent. It is preferably present in amounts between 0.03 and 0.09%.
Carbon and silicon are preferably maintained at respective maximum levels of 0.03 and 0.5%. As ferritic stainless steels have inherently high transition temperatures, which rise with increasing carbon levels, low carbon contents should be specified in order to obtain a more ductile material.
The present invention is not dependent upon any particular means for manufacturing the catalytic system described herein. The system can be produced in accordance 7~
l with the teachings of heretofore referred to Patent No.
3,920,583, or by any other process known to those skilled in the art. Platinum, palladium, irridium, rhodium~ and alloys thereof, are typical catalytic materials. The catalyst serves to provoke oxidation of partially oxidized hydrocarbons; e.g. CO to CO2.
The following examples are illustrative of several aspects of the invention.
Several 0.002 inch thick Fe-Cr~Al alloys were subjected to a cyclic oxidation test in air at 2300F. The alloys were alternately resistance heated and cooled.
Cycles to failure for each were recorded. Some of the samples had yttrium in excess of 0.1%, some were free of yttrium, and another had a yttrium level between 0.01 and 0.1%. The chemistry of the alloys appears hereinbelow in Table I. The carbon content for each is less than 0.03%.
TABLE I.
-COMPOSITION (wt. %) Alloy Cr Al Y Fe A* 16 5 0.23Bal.
B 16 5.3 0.33Bal.
C 16 5.3 0.40Bal.
D 13 4.2 - Bal.
E 16 5.2 - Bal.
F 16 5.3 - Bal.
G 16 4.0 0.08Bal.
*Powder Metallurgy ~eat ,i ~
1 The results of the cyclic oxidation te~ts appear hereinbelow in Table II.
TABLE II.
Alloy Cycles to Failure*
~ F 111 *Average of several values From Table II, it is noted that the oxidation resistance of Alloys A, B and C with yttrium contents in excess of 0.1% was superior to that for Alloys D, E and F
which were devoid of yttrium, and that Alloy G with yttrium between 0.01 and 0.1% fared well in comparison with Alloys A, B and C. The results clearly show that iron-chromium-aluminum alloys with yttrium between 0.01 and 0.1% can be used as substrates for catalytic materials.
It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific examples thereof will support various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific examples of the invention described herein.
As the particular material used a~ a substrate for the catalyst in automotive catalytic convertors effects the performance of the convertors, there is a need to develop improved substrates. In particular, there is a need for a metallic substrate to replace the ceramic substrates presently in use. Ceramic substrates do not have the mechanical properties; e.g~ ~hock resistance, of metallic substrates. Ceramic substrates are, in addition, inherently thicker than are metallic substrat~s.
t ~
.
l A particular metallic substrate is described in United States Patent No. 3,920,5830 It is a ferritic stainless steel which contains up to lS~ chromium, 0.5 to 12~ aluminum and 0.1 to 3~ yttrium.
Economic and technical problems ha~e been encountered with the use of yttrium, thereby detracting from the benefits of the substrate of Patent No 3,920,583.
Yttrium is an expensive material which is not presently available in abundant quantities, and a material characterized by a low recovery rate during melting.
Through the present invention there is provided a metallic substrate which minimizes the difficulties associated with the substrate of Patent No. 3,920,583. The present invention relates to a substrate wherein the yttrium level of Patent No. 3,920,583 is significantly reduced. It has been determined that high quality substrates can be produced from iron-chromium-aluminum alloys having less than 0.1~ yttrium.
Other references disclosing ferritic stainless steels with chromium, aluminum and yttrium are United States Patent Nos. 3,027,252 and 3,298,826, and reports respectively entitled, WThe Physical Metallurgy And Oxidation Behavior Of Fe-Cr-Al-Y Alloys~ and "Sulfidation - Resistant Alloy For Coal Gasification Servicen. The first report is dated 1 June 1, 1966. It was prepared by C. S. Wukusick under United States Atomic ~nergy Commisslon Contract No.
ATt40~ 2847. The second repor~ was published June 14, 1977. It was prèpared by Roger A. Perkins and M~ S. Bhat for the U.S. Energy Research And Development Administr3tion under Con~ract No. E(49-18)-2299. Neither the reports nor the patents relate to a substrate for a catalytic material nor to an alloy having less than 0.1~ yttrium.
Another reference disclosing ferritic stainless steels with chromium, aluminum and yttrium is United States Patent No. 3,591,365. Although it discloses alloys which may have less than 0.1% yttrium, its alloys req~ire specific additions of gadolinium and/or dysprosium. As with the references disclosed in the preceding paragraphs, it does not pertain to substrates for catalytic materials.
It is accordingly an object of the subject invention to provide a substrate for a catalytic material and an alloy from which the substrate is formed.
The present invention is described in terms of a catalytic system comprising a ferritic stainless steel substrate having a tightly adherent oxide coatiny and a catalytic material thereupon, and in terms of the ferritic stainless steel from which the substrate is formed. The ferritic stainless steel is of a chemistry which forms a tightly adherent non-spalling scale suitable for application of a catalytic bearing material. It consists e~sentially of, by weight, up to 26% chromium, from 1 to 8% aluminum, ~'7~
1 between 0.01 and 0.1% yttrium, up to 0.1% carbon, up to 2%
silicon, balance essentially iron. The substrate is in most instances of a thickness of from 0.0005 to 0.01 inch Chromium may be present within the substrate of the present invention as it is known to improve oxidatioil resistance. A maximum limit is placed thereupon as chromium is expensive and renders the alloy more difficult to process. Chromium is usually present within the range of from 5 to 22%, and preferably within the range of from 12 to 20%.
Aluminum is present as it improves the oxidation resistance of the substrate. A maximum limit is placed thereupon as aluminum, like chromium, is expensive and renders the alloy more difficult to process. Aluminum is preferably prasent within the range of from 3 to 6%.
Yttrium is present as it stabilizes the aluminum-bearing scale and makes it both tight and adherent. It is preferably present in amounts between 0.03 and 0.09%.
Carbon and silicon are preferably maintained at respective maximum levels of 0.03 and 0.5%. As ferritic stainless steels have inherently high transition temperatures, which rise with increasing carbon levels, low carbon contents should be specified in order to obtain a more ductile material.
The present invention is not dependent upon any particular means for manufacturing the catalytic system described herein. The system can be produced in accordance 7~
l with the teachings of heretofore referred to Patent No.
3,920,583, or by any other process known to those skilled in the art. Platinum, palladium, irridium, rhodium~ and alloys thereof, are typical catalytic materials. The catalyst serves to provoke oxidation of partially oxidized hydrocarbons; e.g. CO to CO2.
The following examples are illustrative of several aspects of the invention.
Several 0.002 inch thick Fe-Cr~Al alloys were subjected to a cyclic oxidation test in air at 2300F. The alloys were alternately resistance heated and cooled.
Cycles to failure for each were recorded. Some of the samples had yttrium in excess of 0.1%, some were free of yttrium, and another had a yttrium level between 0.01 and 0.1%. The chemistry of the alloys appears hereinbelow in Table I. The carbon content for each is less than 0.03%.
TABLE I.
-COMPOSITION (wt. %) Alloy Cr Al Y Fe A* 16 5 0.23Bal.
B 16 5.3 0.33Bal.
C 16 5.3 0.40Bal.
D 13 4.2 - Bal.
E 16 5.2 - Bal.
F 16 5.3 - Bal.
G 16 4.0 0.08Bal.
*Powder Metallurgy ~eat ,i ~
1 The results of the cyclic oxidation te~ts appear hereinbelow in Table II.
TABLE II.
Alloy Cycles to Failure*
~ F 111 *Average of several values From Table II, it is noted that the oxidation resistance of Alloys A, B and C with yttrium contents in excess of 0.1% was superior to that for Alloys D, E and F
which were devoid of yttrium, and that Alloy G with yttrium between 0.01 and 0.1% fared well in comparison with Alloys A, B and C. The results clearly show that iron-chromium-aluminum alloys with yttrium between 0.01 and 0.1% can be used as substrates for catalytic materials.
It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific examples thereof will support various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific examples of the invention described herein.
Claims (14)
1. In a system comprising a ferritic stainless steel substrate having a tightly adherent oxide coating and a catalytic material thereupon, said ferritic stainless steel being of a chemistry which forms a tightly adherent non-spalling scale suitable for application of a catalytic bearing material; the improvement comprising a ferritic stainless steel substrate consisting essentially of, by weight, up to 26% chromium, from 1 to 8% aluminum, between 0.01 and 0.1% yttrium, up to 0.1% carbon, up to 2% silicon, balance essentially iron.
2. The system according to claim 1, wherein said ferritic stainless steel substrate has from 5 to 22%
chromium.
chromium.
3. The system according to claim 2, wherein said ferritic stainless steel substrate has from 12 to 20%
chromium.
chromium.
4. The system according to claim 1, wherein said ferritic stainless steel substrate has from 3 to 6%
aluminum.
aluminum.
5. The system according to claim 1, wherein said ferritic stainless steel substrate has between 0.03 and 0.09% yttrium.
6. The system according to claim 1, wherein said ferritic stainless steel substrate has less than 0.03%
carbon.
carbon.
7. The system according to claim 1, wherein said ferritic stainless steel substrate has from 12 to 20%
chromium, from 3 to 6% aluminum, between 0.03% and 0.09%
yttrium and up to 0.03% carbon.
chromium, from 3 to 6% aluminum, between 0.03% and 0.09%
yttrium and up to 0.03% carbon.
8. A ferritic stainless steel consisting essentially of, by weight, up to 26% chromium, from 1 to 8%
aluminum, between 0.01 to 0.1% yttrium, up to 0.1% carbon, up to 2% silicon, balance essentially iron.
aluminum, between 0.01 to 0.1% yttrium, up to 0.1% carbon, up to 2% silicon, balance essentially iron.
9. A ferritic stainless steel according to claim 8, having from 5 to 22% chromium.
10. A ferritic stainless steel according to claim 9, having from 12 to 20% chromium.
11. A ferritic stainless steel according to claim 8, having from 3 to 6% aluminum.
12. A ferritic stainless steel according to claim 8, having between 0.03 and 0.09% yttrium.
13. A ferritic stainless steel according to claim 8, having up to 0.03% carbon.
14. A ferritic stainless steel according to claim 8, having from 12 to 20% chromium, from 3 to 6%
aluminum, between 0.03 and 0.09% yttrium and up to 0.03 carbon.
aluminum, between 0.03 and 0.09% yttrium and up to 0.03 carbon.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11564780A | 1980-01-28 | 1980-01-28 | |
| US115,647 | 1980-01-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1170481A true CA1170481A (en) | 1984-07-10 |
Family
ID=22362627
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368518A Expired CA1170481A (en) | 1980-01-28 | 1981-01-14 | Substrate for catalytic system and ferritic stainless steel from which it is formed |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0033203A3 (en) |
| JP (1) | JPS56121641A (en) |
| CA (1) | CA1170481A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4661169A (en) * | 1982-04-12 | 1987-04-28 | Allegheny Ludlum Corporation | Producing an iron-chromium-aluminum alloy with an adherent textured aluminum oxide surface |
| US4414023A (en) * | 1982-04-12 | 1983-11-08 | Allegheny Ludlum Steel Corporation | Iron-chromium-aluminum alloy and article and method therefor |
| FR2587635B1 (en) * | 1985-09-20 | 1989-01-27 | Onera (Off Nat Aerospatiale) | PROCESS FOR OBTAINING AN ELONGATED ELEMENT (IN PARTICULAR TAPE OR WIRE) CONSISTING OF AN ALLOY, ELONGATED ELEMENT THUS OBTAINED AND APPLICATIONS THEREOF |
| EP0467110B1 (en) * | 1990-07-12 | 1994-11-23 | Forschungszentrum Jülich Gmbh | Catalyst for removing hydrogen from a hydrogen, oxygen and vapour containing atmosphere |
| JPH04147945A (en) * | 1990-10-11 | 1992-05-21 | Nisshin Steel Co Ltd | High al-containing ferritic stainless steel excellent in high temperature oxidation resistance and toughness |
| JP3176403B2 (en) * | 1991-12-20 | 2001-06-18 | 新日本製鐵株式会社 | High strength stainless steel foil for corrugating and method for producing the same |
| DE19642497C1 (en) * | 1996-10-15 | 1997-07-24 | Krupp Vdm Gmbh | Iron@-chromium@-aluminium@ alloy foil production |
| DE10310865B3 (en) * | 2003-03-11 | 2004-05-27 | Thyssenkrupp Vdm Gmbh | Use of an iron-chromium-aluminum alloy containing additions of hafnium, silicon, yttrium, zirconium and cerium, lanthanum or neodymium for components in Diesel engines and two-stroke engines |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB833446A (en) * | 1956-05-23 | 1960-04-27 | Kanthal Ab | Improved iron, chromium, aluminium alloys |
| US3027252A (en) * | 1959-09-29 | 1962-03-27 | Gen Electric | Oxidation resistant iron-chromium alloy |
| US3298826A (en) * | 1964-04-06 | 1967-01-17 | Carl S Wukusick | Embrittlement-resistant iron-chromium-aluminum-yttrium alloys |
| US3591365A (en) * | 1969-01-16 | 1971-07-06 | Santoku Metal Ind | Heat resisting corrosion resisting iron chromium alloy |
| GB1471138A (en) * | 1974-05-06 | 1977-04-21 | Atomic Energy Authority Uk | Supports for catalyst materials |
| JPS51104424A (en) * | 1975-03-13 | 1976-09-16 | Nippon Steel Corp | YOSETSUNETSUEIKYOBUGA ENJINHAIGASUGYOKETSUSUINYORU TAIRYUKAIFUSHOKUSEINISUGURETA FUERAITOKEISUTENRESUKO |
| GB1598827A (en) * | 1977-03-31 | 1981-09-23 | Atomic Energy Authority Uk | Alloys |
| US4230489A (en) * | 1978-04-28 | 1980-10-28 | United Kingdom Atomic Energy Authority | Alloys of Fe, Cr, Si, Y and Al |
-
1981
- 1981-01-14 CA CA000368518A patent/CA1170481A/en not_active Expired
- 1981-01-14 EP EP81300144A patent/EP0033203A3/en not_active Ceased
- 1981-01-28 JP JP1145281A patent/JPS56121641A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0033203A3 (en) | 1981-08-26 |
| EP0033203A2 (en) | 1981-08-05 |
| JPS56121641A (en) | 1981-09-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |