EP0480461B1 - Aluminium enthaltender rostfreier ferritischer Stahl mit hoher Beständigkeit gegen Hochtemperatursoxydation und hoher Zähigkeit - Google Patents

Aluminium enthaltender rostfreier ferritischer Stahl mit hoher Beständigkeit gegen Hochtemperatursoxydation und hoher Zähigkeit Download PDF

Info

Publication number
EP0480461B1
EP0480461B1 EP91117384A EP91117384A EP0480461B1 EP 0480461 B1 EP0480461 B1 EP 0480461B1 EP 91117384 A EP91117384 A EP 91117384A EP 91117384 A EP91117384 A EP 91117384A EP 0480461 B1 EP0480461 B1 EP 0480461B1
Authority
EP
European Patent Office
Prior art keywords
high temperature
oxidation resistance
content
steel
temperature oxidation
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.)
Revoked
Application number
EP91117384A
Other languages
English (en)
French (fr)
Other versions
EP0480461A1 (de
Inventor
Hiramatsu Nisshin-Seiko-Kabushikikaisha Naoto
Uematsu Nisshin-Seiko-Kabushikikaisha Yoshihiro
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Nisshin Co Ltd
Original Assignee
Nisshin Steel Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=17487384&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0480461(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Nisshin Steel Co Ltd filed Critical Nisshin Steel Co Ltd
Publication of EP0480461A1 publication Critical patent/EP0480461A1/de
Application granted granted Critical
Publication of EP0480461B1 publication Critical patent/EP0480461B1/de
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

Links

Images

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

Definitions

  • the present invention relates to an aluminum (Al)-containing ferritic stainless steel for use in automobile exhaust-gas-treating apparatuses, heating apparatuses and the like.
  • Al-containing ferritic stainless steels have excellent high temperature oxidation resistance and thus are widely used for parts of heating apparatuses such as stove chimneys, electric heating means, etc.
  • the substrate of metallic catalytic converters is formed of metal foil having a thickness of around 50 micrometers.
  • This substrate is used in an exhaust gas atmosphere, in which catalytic reaction takes place and, therefore, has to have excellent high temperature oxidation resistance.
  • high-Al ferritic stainless steels essentially comprising 20Cr-5Al and containing rare earth metals (REM), yttrium (Y), etc. are used for this purpose.
  • REM rare earth metals
  • Y yttrium
  • the present invention is intended to provide a Fe-Cr-Al-REM, Y ferritic stainless steel for metallic catalytic converters having sufficient high temperature oxidation resistance, excellent toughness and good manufacturability, wherein the Al2O3 formed on the surface thereof does not suffer abnormal oxidation.
  • manganese (Mn) oxide compounds penetrate into the Al2O3 formed on the surface of the steel immediately before the abnormal oxidation occurs.
  • the present invention provides a ferritic stainless steel which comprises by weight: C: not more than 0.03 % Si: less than 0.25 % Mn: less than 0.25 % P: not more than 0.03 % S: less than 0.001 % N: not more than 0.03 % Cr: 15 - 25 % Al: 3 - 6 % at least one of REM, Y and alkaline earth metals: 0 01 - 0.2 % and optionally at least one of Nb, V and Ti: 0.05 - 1 %, balance of FE and inevitable incidental impurities.
  • the Mn content is preferably 0.21 % or less and more preferably 0.13 % or less.
  • the Si content is preferably 0.22 % or less and more preferably 0.17 % or less.
  • the reason for defining the composition of the steel of the present invention as above is generally as follows.
  • Si content is the most significant factor in the steel of the present invention. Generally, it is considered that Si is effective for high temperature oxidation resistance. In the case of high-Al-containing ferritic steels, however, the high temperature oxidation resistance thereof is markedly improved by reducing the Si content. We found that the high temperature oxidation resistance of high-Al-containing ferritic stainless steels is markedly improved by reducing both the Si content and the Mn content simultaneously. Also, the toughness of the high-Al-containing ferritic stainless steel can be markedly improved by reducing the Si content. We found that the above-described effects are brought about if the Si content is reduced to less than 0.25 %.
  • Mn In the present invention, the Mn content is significant. Generally Mn is effective for improving hot-workability. In the case of the present invention, however, Mn has a deleterious effect on high temperature oxidation resistance. We found that the high temperature oxidation resistance of high-Al-containing ferritic stainless steels is markedly improved by reducing the Mn content and further by increased addition of Cr, Al, REM, Y, etc. The toughness of the steel of the present invention is also remarkably improved by reduction of the Mn content and the effect is achieved by reducing the Mn content to less than 0.25 %. That is, the lower the Mn content, the better the effect and thus the Mn content is defined as less than 0.25 %.
  • P is an element which is deleterious to high temperature oxidation resistance as well as toughness of steels and, therefore, the lower the P content, the better the steel properties in general. In the case of the present invention, the P content should be not more than 0.03 %.
  • S forms compounds with REM, Y, etc. which degrade the surface properties as non-metallic inclusions. Also S consumes metallic REM, Y etc., which are effective for high temperature oxidation resistance. These adverse effects are great when the content is 0.001% or more. That is, the high temperature oxidation resistance is improved by reducing the S content to less than 0.001 %. In the present invention, the S content is defined as less than 0.001 %.
  • N reduces toughness of steels of the kind contemplated by the present invention. Also, it forms AlN consuming Al, which is effective for providing the steel with high temperature oxidation resistance, and thus inducing abnormal oxidation.
  • the N content is defined as not more than 0.03 %.
  • Cr is a fundamental element that provides the steel with high temperature oxidation resistance. At least 15 % of Cr is required in order to exhibit its effect. On the other hand, Cr in excess of 25 % deteriorates the toughness of slabs and hot coils, causing difficulty in manufacturing. Thus the Cr content is defined as 15 - 25 %.
  • Al is an essential element as well as Cr for providing the steel with high temperature oxidation resistance.
  • Cr Cr
  • abnormal oxidation readily occurs.
  • addition of not less than 3 % of Al is necessary.
  • the Al content need not be excessively high. Rather, Al in excess of 6 % deteriorates the toughness of slabs and hot coils. Thus the Al content is defined as 3 - 6 %.
  • REM, Y and alkaline earth metals are important elements which improve the high temperature oxidation resistance of Fe-Cr-Al alloys. They greatly improve the protecting effect of the formed oxide film, well inhibit abnormal oxidation, which easily develops in very thin materials, and improve adherence of the produced oxide film to the substrate. With a content of less than 0.01 %, the effect is not exhibited. To the contrary, at a content in excess of 0.2 %, they adversely affect hot-workability, making manufacture difficult, and form non-metallic inclusions impairing the surface properties. Thus the content of these elements is defined as 0.01 - 0.2 %.
  • Nb, V and Ti When contained in suitable amounts, these elements combine with C and N in the steel and greatly improve the toughness of the steel.
  • the steel of the present invention is used in severe high temperature environments and thus is required to be provided with excellent high temperature strength. Addition of these elements is very effective for this purpose. Addition of 0.05 % or more is required. The maximum amount is limited to 1 % since addition of excessive amount hardens the steel.
  • the high temperature oxidation resistance of high-Al-containing ferritic steels is provided by the Al2O3 which forms on the surface of the steel. Therefore, it is considered that the high temperature oxidation resistance will be improved as the Al content is increased.
  • Test specimens of the compositions indicated in Table 1 respectively having a thickness of 50 micrometers were subjected to an oxidation test at 1150 °C and the time until abnormal oxidation occurred was measured. The results are also indicated in Table 1. From these results, it is apparent that with increase in the contents of Cr and Al and addition of REM, high temperature oxidation resistance is improved and the steel becomes less susceptible to abnormal oxidation.
  • Respectively 30 kg heats of the steels of the compositions indicated in Table 4 were melted and casted and the ingots were forged, machined, hot-rolled and, thereafter, made into 30 micrometers thick sheets by repeating annealing and cold rolling. These samples were subjected to an oxidation test at 1150 °C and the time upto the occurrence of the abnormal oxidation was measured. The results are also shown in Table 4. The results show that for the steels of the present invention the time required for the occurrence of abnormal oxidation was remarkably prolonged in comparison with conventional steels, that is, the oxidation resistance of the steel of the present invention is greatly improved.
  • the present invention provides an inexpensive steel material having excellent high temperature oxidation resistance and excellent toughness without adding unnecessarily large amounts of Cr, Al, REM and Y.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Claims (5)

  1. Ferritischer nichtrostender Stahl, der folgende Elemente (in Gew.-%) umfaßt:
       C: höchstens 0,03%,
       Si: unter 0,25%,
       Mn: unter 0,25%,
       P: höchstens 0,03%,
       S: unter 0,001%,
       N: höchstens 0,03%,
       Cr: 15 - 25%,
       Al: 3 - 6%,
       wenigstens ein Element aus der Gruppe, bestehend aus SEM, Y und Erdalkalimetallen: 0,01 - 0,2%,
       und gegebenenfalls wenigstens ein Element aus der Gruppe, bestehend aus Nb, V und Ti: 0,05 - 1%,
       wobei der Rest auf Fe und unvermeidliche Verunreinigungen entfällt.
  2. Stahl nach Anspruch 1, bei dem der Mn-Gehalt höchstens 0,21% beträgt.
  3. Stahl nach Anspruch 2, bei dem der Mn-Gehalt höchstens 0,13% beträgt.
  4. Stahl nach Anspruch 1, bei dem der Si-Gehalt höchstens 0,21% beträgt.
  5. Stahl nach Anspruch 4, bei dem der Si-Gehalt höchstens 0,17% beträgt.
EP91117384A 1990-10-11 1991-10-11 Aluminium enthaltender rostfreier ferritischer Stahl mit hoher Beständigkeit gegen Hochtemperatursoxydation und hoher Zähigkeit Revoked EP0480461B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP270521/90 1990-10-11
JP2270521A JPH04147945A (ja) 1990-10-11 1990-10-11 耐高温酸化性および靭性に優れた高Ａｌ含有フェライト系ステンレス鋼

Publications (2)

Publication Number Publication Date
EP0480461A1 EP0480461A1 (de) 1992-04-15
EP0480461B1 true EP0480461B1 (de) 1995-08-16

Family

ID=17487384

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91117384A Revoked EP0480461B1 (de) 1990-10-11 1991-10-11 Aluminium enthaltender rostfreier ferritischer Stahl mit hoher Beständigkeit gegen Hochtemperatursoxydation und hoher Zähigkeit

Country Status (5)

Country Link
EP (1) EP0480461B1 (de)
JP (1) JPH04147945A (de)
KR (1) KR100196984B1 (de)
CA (1) CA2053175A1 (de)
DE (1) DE69112165T2 (de)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3176403B2 (ja) * 1991-12-20 2001-06-18 新日本製鐵株式会社 波付け加工用高強度ステンレス鋼箔およびその製造方法
JP2689208B2 (ja) * 1992-12-11 1997-12-10 新日本製鐵株式会社 湿潤耐食性および加工性の優れた内燃機関排気系用鋼
DE646657T1 (de) * 1993-03-19 1995-09-28 Nippon Yakin Kogyo Co Ltd Rostfreier, ferritischer stahl mit herverrogendem oxidationswiderstand.
JPH08117614A (ja) * 1994-10-20 1996-05-14 Matsushita Electric Ind Co Ltd 触媒体およびその製造方法
FR2732360B1 (fr) * 1995-03-29 1998-03-20 Ugine Savoie Sa Acier inoxydable ferritique utilisable, notamment pour des supports de catalyseurs
US6652830B2 (en) * 2001-02-16 2003-11-25 Battelle Memorial Institute Catalysts reactors and methods of producing hydrogen via the water-gas shift reaction
DE10261207A1 (de) * 2002-12-20 2004-07-15 Mk Metallfolien Gmbh Eisenlegierung, insbesondere zur Verwendung in einer Abgasreinigungseinheit

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171737A (en) * 1961-04-28 1965-03-02 Hoskins Mfg Company Electrical resistance alloy
SU552369A1 (ru) * 1975-12-12 1977-03-30 Предприятие П/Я Р-2120 Жаростойка сталь
CA1170481A (en) * 1980-01-28 1984-07-10 George Aggen Substrate for catalytic system and ferritic stainless steel from which it is formed
GB2079065B (en) * 1980-06-27 1983-09-07 Sharetree Ltd Linear differential transformer
EP0246939B1 (de) * 1986-04-21 1992-07-01 Kawasaki Steel Corporation Rostfreier Chrom-Aluminium-Stahl mit hoher Beständigkeit gegen Oxydation und Abblätterung und Folien aus Chrom-Aluminium-Stahl für Katalysatorträger in katalytischen Konvertern

Also Published As

Publication number Publication date
JPH04147945A (ja) 1992-05-21
KR920008206A (ko) 1992-05-27
DE69112165D1 (de) 1995-09-21
EP0480461A1 (de) 1992-04-15
CA2053175A1 (en) 1992-04-12
KR100196984B1 (ko) 1999-06-15
DE69112165T2 (de) 1996-03-21

Similar Documents

Publication Publication Date Title
US5332544A (en) High-aluminum-containing ferritic stainless steel having improved high-temperature oxidation resistance
EP2557189B1 (de) Ferrit-edelstahlblech mit hoher wärmebeständigkeit und bearbeitbarkeit sowie herstellungsverfahren dafür
JP2011190524A (ja) 耐酸化性、二次加工脆性および溶接部の靭性に優れたフェライト系ステンレス鋼
EP0727502B1 (de) Chromstahlplatte mit hervorragender pressbarkeit
JP4185425B2 (ja) 成形性と高温強度・耐高温酸化性・低温靱性とを同時改善したフェライト系鋼板
EP0480461B1 (de) Aluminium enthaltender rostfreier ferritischer Stahl mit hoher Beständigkeit gegen Hochtemperatursoxydation und hoher Zähigkeit
CA1086538A (en) Ferrite stainless steel having improved weldability and oxidation resistance
US5792285A (en) Hot-rolled ferritic steel for motor vehicle exhaust members
JP3247162B2 (ja) 耐酸化性に優れたＦｅ−Ｃｒ−Ａｌ系合金およびその箔
JP3410139B2 (ja) Ａｌ含有耐酸化性オーステナイト系ステンレス鋼
EP0359085A1 (de) Hitzebeständige Gussstähle
JP2514367B2 (ja) 自動車エンジンのマニホ−ルド用鋼
WO1994021836A1 (en) Ferritic stainless steel excellent in oxidation resistance
JP2001271148A (ja) 耐高温酸化性に優れた高Ａｌ鋼板
US5126107A (en) Iron-, nickel-, chromium base alloy
JP3865452B2 (ja) 耐高温酸化性および耐高温変形性に優れたＦｅ−Ｃｒ−Ａｌフエライト系ステンレス鋼
JP2942073B2 (ja) 高温強度に優れたエキゾースト・マニホールド用フェライト系ステンレス鋼
JPH06271993A (ja) 耐酸化性に優れたオーステナイト系ステンレス鋼
JPH07252608A (ja) 熱間加工性フェライト系ステンレス鋼合金
JP3351837B2 (ja) 製造性及び耐高温酸化性に優れたＡｌ含有フェライト系ステンレス鋼
JPS5864359A (ja) 耐熱鋳鋼
JPS6214626B2 (de)
JP3364322B2 (ja) 製造性、加工性および高温長時間時効後の高温強度に優れた自動車排気マニホールド用ステンレス鋼
JPH08260110A (ja) 耐高温酸化性およびスケール密着性に優れたフエライト系ステンレス鋼の薄板または薄肉管
JP3351836B2 (ja) 耐高温酸化性に優れた高Ａｌ含有フェライト系ステンレス鋼

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT SE

17P Request for examination filed

Effective date: 19921014

17Q First examination report despatched

Effective date: 19940503

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT

Effective date: 19950816

ET Fr: translation filed
REF Corresponds to:

Ref document number: 69112165

Country of ref document: DE

Date of ref document: 19950921

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19951116

Ref country code: GB

Effective date: 19951116

PLBQ Unpublished change to opponent data

Free format text: ORIGINAL CODE: EPIDOS OPPO

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: KRUPP VDM GMBH

Effective date: 19951230

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19951116

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19971009

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19971017

Year of fee payment: 7

RDAH Patent revoked

Free format text: ORIGINAL CODE: EPIDOS REVO

RDAG Patent revoked

Free format text: ORIGINAL CODE: 0009271

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: PATENT REVOKED

27W Patent revoked

Effective date: 19980416