Indian Patents. 222901:IRON-CHROMIUM-ALUMINIUM-ALLOY

Title of Invention	IRON-CHROMIUM-ALUMINIUM-ALLOY
Abstract	Components in diesel vehicles comprising (in weight %) Al 2.5 < 5% Cr >17.5-<19% Si 0.05-max. 0.6% Fe remainder and impurities, additional Y >0.01-<0.1%and Hf > 0.01-0.1% and Zr > 0.01-0.2%.

Full Text	FIELD OF THE INVENTION The invention relates to an Iron-chromium-aluminium alloy haying good oxidation resistance. DESCRIPTION OF RELATED ART Although the catalytic converter is the rule in four-stroke-engines today, the development of catalytic converters for Diesel and two-stroke engines is still in its beginnings. In four-stroke-engines, alloys are used which are simitar to those described in EP-A 0387 670: with ( in % by weight) 20-25% cr, 5-8% Al, max.0.01% P, max.0.01% Mg/nax. 0.5% Mn, max. 0.005% S, residual iron and unavoidable impurities and, if required, alloying elements, such as 0.03-0 08% Y, 0.004-0.008% N, 0.02-0.04% C, 0.035-0.07% Ti, 0.035-0.07% Zr. Since production by traditional methods, namely conventional pouring of the alloy and subsequent hot and cold deformation, is very difficult where aluminium contents of below 6% by weight are concerned and in cases of higher aluminium contents is no longer workable in large -scale production, alternative production methods have been developed. U.S. Pat. No. 5,366,139, for instance, discloses a method whereby foils of iron-chromium aluminium alloys are produced by way of suitable iron-chromium steel being coated on both sides with aluminium or aluminium alloys by way of roll cladding. This composite metal is processed exclusively by cold deformation and is subjected to diffusion annealing to produce a homogeneous structure. A further method whereby the coating is achieved by way of hot dip aluminizing is disclosed in DE-A 198 34 552. The latter foil has the following chemical composition (all details in % by weight): 18-25% Cr, 4-10% Al, 0.03- 0.08% Y, max 0.01% Ti, 0.01-0.05% Zr, 0.01-0.05% Hf, 0.5-1.5% Si, residual iron and method-associated Impurities. Foils fabricated with this alloy were to date used in four-stroke-combustion engines. BRIEF SUMMARY OF THE INVENTION It is the object of the present invention to produce an alloy for applications in the temperature range of 250°C to 1000°C having an adequate oxidation resistance which is also achievable in targe scale productions. The solution to the task set is provided by an iron-chromium -aluminium alloy having good oxidation resistance, with (in % by weight) 2.5 to 5.0% Al and 10 to 25% Cr and 0.05-0.8% Si as welt as additions of >0.01 to 0.1% Y and/or > 0.01 to 0.1% Hf and/or >0.01 to 0.2% Zr and/or >0.01 to 0.2% Cerium mischmetai (Ce, La, Nd) (i.e., at least two of Ce, La, or Nd) as well as production-associated impurities. A preferred iron-chromium -aluminium alloy having good oxidation resistance has the following composition (in % by weight): 2.5-5% Al and 13 to 2i% Cr as well as alternative additions of: >0.0l to 0.1% Y and >0.01 to 0.1% Hf; >0.Ql% to 0.1% Y and >0.01 to 0.1% Hf and >0.01% to 0.2% Zr; >0.01 to 0.2% Cerium mischmetal (Ce, La, Nd); >0.01 to 0.2% Zr and >0.01 to 0.2% Cerium mischmetal (Ce, La, Nd) as well as production-associated impurities. Surprisingly, it has been found that, in Diesel engines and two-stroke engines, aluminium contents above 5% are not required 2.5 to 5.0% by weight are quite sufficient to guarantee an adequate oxidation resistance in the temperature range of 250° C. to 1000° C which is of interest in this regard, as the examples presented below will show. Indispensable in this situation are the additions of reactive elements to guarantee the oxidation resistance. Particularly proven are 0.01 -0.1% Y and/or 0.01-0.1% Hf, where, in the presence of both elements, the sum of both these elements must not exceed 0.15% by weight, because at this level the positive effect of the oxidation resistance will be reversed to a negative. However, also by adding other oxygen-affine reactive elements, such as for instance Zr, Cerium mischmetal and la, positive effects can be achieved in relation to the oxidation resistance of the alloy. One method for the fabrication of semi-finished articles from this alloy is characterized in that the semi-finished article follow ing melting of the alloy by way of ingot casting or continuous- casting as well as hot and cold deformation may be required to undergo one (or more) intermediate annealing processes. Advantageous embodiments of the method are described in the disclosure. The production of a foil of 50µm or even 20 µm thickness is possible in the conventional manner in such compositions. The slabs can even be produced by way of the particularly inexpensive continuous casting process which in the presence of higher aluminium contents is, as a rule, connected with high tosses. Preferred applications for this alloy are: components in exhaust systems of Diesel engines in vessels, Diesels engines and two-stroke engines of motor vehicles (cars, trucks) or motorbikes; substrate foils in metallic catalytic converters of Diesel engines and two- strokes engines; components in Diesel engine glow plugs; knitted metal fabrics and mats for exhaust cleaning systems used in for instance motorcycles, brush cutters, lawn mowers and power saws; components for exhaust cleaning systems for fuel cells; spraying wires for surface coatings of components employed in exhaust systems of diesel and two-stroke systems; heating conductors or resistance materials for electrical preheating of exhaust cleaning systems in Diesel and two-stroke systems. The subject of the invention is described in greater detail in the following examples. DETAILED DESCRIPTION (Aluchrom ISE, Hf3 and Hf4 represent comparative alloys and Aluchrom Hf1 and Hf2 are the subject of the present invention). Chemical Compostions The examples in accordance with the invention were produced by melting in the electric arc furnace, continuous casting or ingot casting, hot roiling to a thickness of about 3 mm, with intermediate annealing at end thicknesses of 0.02 to 0.05 and cold rolling on a 20 roller scaffold. Oxidation Test As the examples show, besides the Al content, the exact tuning of the oxygen affine reactive elements is of predominant importance. For instance, the alloys according to the present invention. Aluchrom Hf1 and Aiuchrom Hf2, in spite of their comparatively low Al-content of around 3% show an extremely good oxidation resistance, which is simitar to the comparative alloys Aluciirom ISE and Aluchrom Hf4. By comparison, Aiuchrom, Hf3, in spite of its high Al- content of 5.36% has lower values which can be attributed to the Y content being too low. In this instance therefore additions of Y or Cerium mischmetai result in a markedly Improved oxidation resistance ( compare Aluchrom ISE and Aluchrom Rf4). A further important aspect for the construction of metallic catalytic converter substrates for Diesel engines and two - stroke engines is the dimensional stability of the foil during the useful life of the foil. A respective characteristic feature in this regard is the linear deformation which should, if possible, not exceed 4%. Dimensional Stability This also shows that the alloys in accordance with the present Invention, Aluchrom Hf1 and Aluchrom Hf2, having an at content of around 3%, achieve a dimensional stability of and Aluchrom Hf4 having an al content of >5%. Also in this case, in spite of their comparatively high Al content of 5.36% but too low a Y content, the comparative alloy Aiuchrom Hf3 does not meet the requirements, since the linear deformation after 400 h, being about 5% is clearly too great. Thus it is surprisingly found that with a suitable tuning of the oxygen-affine rective elements, even where Al contents clearly below 5% are present, a dimensional stability necessary for the production of metallic catalytic converters can be achieved. A cost-effective production, based on the comparatively low Al contents, by way of ingot casting, continuous casting or even strip casting whilst observing the application-specific parameters is thus achieved. We Claim: 1. Components in diesel vehicles comprising (in weight %) Al 2.5 Cr >17.5- Si 0.05 - max. 0.6% Fe remainder and impurities, additional Y > 0.01- Hf > 0.01-0.1% and Zr > 0.01-0.2%. 2. Components in two stroke devices comprising (in weight %) Al 2.5 - Cr 17.5- Si 0.05 - max. 0.6% Fe remainder and impurities, additional Y > 0.001 - Hf > 0.01-0.1% and Zr > 0.01-0.2%. 3. The component as claimed in claim 1 or 2, wherein said diesel vehicles and two-stroke devices comprise diesel and two-stroke engines. 4. The component as clamed in claim 3, wherein said component is a substrate foil in metallic catalytic exhaust converters. 5. Diesel engine glow cells comprising the component as claimed in claim 1 or 2. 6. Components employed in exhaust systems of diesel or two-stroke engines comprising a surface coating formed by applying said surface coating from a spraying wire comprising the alloy as claimed in claim 1 or 2. 7. The component as claimed in claim 3, wherein said component is a heating conductor or resistance material for electrical preheating of exhaust cleaning systems of diesel or two-stroke engines. 8. Exhaust cleaning systems of fuel cells comprising a component comprising the alloy as claimed in claim 1 or 2. Components in diesel vehicles comprising (in weight %) Al 2.5 Cr >17.5- Si 0.05-max. 0.6% Fe remainder and impurities, additional Y >0.01- Hf > 0.01-0.1% and Zr > 0.01-0.2%.

Full Text

FIELD OF THE INVENTION
The invention relates to an Iron-chromium-aluminium alloy haying good
oxidation resistance.
DESCRIPTION OF RELATED ART
Although the catalytic converter is the rule in four-stroke-engines today, the
development of catalytic converters for Diesel and two-stroke engines is still in
its beginnings. In four-stroke-engines, alloys are used which are simitar to those
described in EP-A 0387 670: with ( in % by weight) 20-25% cr, 5-8% Al,
max.0.01% P, max.0.01% Mg/nax. 0.5% Mn, max. 0.005% S, residual iron and
unavoidable impurities and, if required, alloying elements, such as 0.03-0 08% Y,
0.004-0.008% N, 0.02-0.04% C, 0.035-0.07% Ti, 0.035-0.07% Zr. Since
production by traditional methods, namely conventional pouring of the alloy and
subsequent hot and cold deformation, is very difficult where aluminium contents
of below 6% by weight are concerned and in cases of higher aluminium
contents is no longer workable in large -scale production, alternative production
methods have been developed.
U.S. Pat. No. 5,366,139, for instance, discloses a method whereby foils of
iron-chromium aluminium alloys are produced by way of suitable iron-chromium
steel being coated on both sides with aluminium or aluminium alloys by way of
roll cladding. This composite metal is processed exclusively by cold deformation
and is subjected to diffusion annealing to produce a homogeneous structure.
A further method whereby the coating is achieved by way of hot dip
aluminizing is disclosed in DE-A 198 34 552. The latter foil has the following
chemical composition (all details in % by weight): 18-25% Cr, 4-10% Al, 0.03-
0.08% Y, max 0.01% Ti, 0.01-0.05% Zr, 0.01-0.05% Hf, 0.5-1.5% Si, residual
iron and method-associated Impurities. Foils fabricated with this alloy were to
date used in four-stroke-combustion engines.
BRIEF SUMMARY OF THE INVENTION
It is the object of the present invention to produce an alloy for applications in
the temperature range of 250°C to 1000°C having an adequate oxidation
resistance which is also achievable in targe scale productions.
The solution to the task set is provided by an iron-chromium -aluminium alloy
having good oxidation resistance, with (in % by weight) 2.5 to 5.0% Al and 10
to 25% Cr and 0.05-0.8% Si as welt as additions of >0.01 to 0.1% Y and/or >
0.01 to 0.1% Hf and/or >0.01 to 0.2% Zr and/or >0.01 to 0.2% Cerium
mischmetai (Ce, La, Nd) (i.e., at least two of Ce, La, or Nd) as well as
production-associated impurities.
A preferred iron-chromium -aluminium alloy having good oxidation resistance
has the following composition (in % by weight): 2.5-5% Al and 13 to 2i% Cr as
well as alternative additions of:
>0.0l to 0.1% Y and >0.01 to 0.1% Hf;
>0.Ql% to 0.1% Y and >0.01 to 0.1% Hf and >0.01% to 0.2% Zr;
>0.01 to 0.2% Cerium mischmetal (Ce, La, Nd);
>0.01 to 0.2% Zr and >0.01 to 0.2% Cerium mischmetal (Ce, La, Nd)
as well as production-associated impurities.
Surprisingly, it has been found that, in Diesel engines and two-stroke
engines, aluminium contents above 5% are not required 2.5 to 5.0% by weight
are quite sufficient to guarantee an adequate oxidation resistance in the
temperature range of 250° C. to 1000° C which is of interest in this regard, as
the examples presented below will show. Indispensable in this situation are the
additions of reactive elements to guarantee the oxidation resistance. Particularly
proven are 0.01 -0.1% Y and/or 0.01-0.1% Hf, where, in the presence of both
elements, the sum of both these elements must not exceed 0.15% by weight,
because at this level the positive effect of the oxidation resistance will be
reversed to a negative. However, also by adding other oxygen-affine reactive
elements, such as for instance Zr, Cerium mischmetal and la, positive effects
can be achieved in relation to the oxidation resistance of the alloy.
One method for the fabrication of semi-finished articles from this alloy is
characterized in that the semi-finished article follow ing melting of the alloy by
way of ingot casting or continuous- casting as well as hot and cold deformation
may be required to undergo one (or more) intermediate annealing processes.
Advantageous embodiments of the method are described in the disclosure.
The production of a foil of 50µm or even 20 µm thickness is possible in the
conventional manner in such compositions. The slabs can even be produced by
way of the particularly inexpensive continuous casting process which in the
presence of higher aluminium contents is, as a rule, connected with high tosses.
Preferred applications for this alloy are:
components in exhaust systems of Diesel engines in vessels, Diesels engines
and two-stroke engines of motor vehicles (cars, trucks) or motorbikes;
substrate foils in metallic catalytic converters of Diesel engines and two-
strokes engines;
components in Diesel engine glow plugs;
knitted metal fabrics and mats for exhaust cleaning systems used in for
instance motorcycles, brush cutters, lawn mowers and power saws;
components for exhaust cleaning systems for fuel cells;
spraying wires for surface coatings of components employed in exhaust
systems of diesel and two-stroke systems;
heating conductors or resistance materials for electrical preheating of
exhaust cleaning systems in Diesel and two-stroke systems.
The subject of the invention is described in greater detail in the
following examples.
DETAILED DESCRIPTION
(Aluchrom ISE, Hf3 and Hf4 represent comparative alloys and Aluchrom Hf1
and Hf2 are the subject of the present invention).
Chemical Compostions
The examples in accordance with the invention were produced by melting in
the electric arc furnace, continuous casting or ingot casting, hot roiling to a
thickness of about 3 mm, with intermediate annealing at end thicknesses of 0.02
to 0.05 and cold rolling on a 20 roller scaffold.
Oxidation Test
As the examples show, besides the Al content, the exact tuning of the oxygen
affine reactive elements is of predominant importance. For instance, the alloys
according to the present invention. Aluchrom Hf1 and Aiuchrom Hf2, in spite of
their comparatively low Al-content of around 3% show an extremely good
oxidation resistance, which is simitar to the comparative alloys Aluciirom ISE and
Aluchrom Hf4. By comparison, Aiuchrom, Hf3, in spite of its high Al- content of
5.36% has lower values which can be attributed to the Y content being too low.
In this instance therefore additions of Y or Cerium mischmetai result in a
markedly Improved oxidation resistance ( compare Aluchrom ISE and Aluchrom
Rf4).
A further important aspect for the construction of metallic catalytic converter
substrates for Diesel engines and two - stroke engines is the dimensional
stability of the foil during the useful life of the foil. A respective characteristic
feature in this regard is the linear deformation which should, if possible, not
exceed 4%.
Dimensional Stability
This also shows that the alloys in accordance with the present Invention,
Aluchrom Hf1 and Aluchrom Hf2, having an at content of around 3%, achieve a
dimensional stability of and Aluchrom Hf4 having an al content of >5%. Also in this case, in spite of their
comparatively high Al content of 5.36% but too low a Y content, the
comparative alloy Aiuchrom Hf3 does not meet the requirements, since the linear
deformation after 400 h, being about 5% is clearly too great.
Thus it is surprisingly found that with a suitable tuning of the oxygen-affine
rective elements, even where Al contents clearly below 5% are present, a
dimensional stability necessary for the production of metallic catalytic converters
can be achieved.
A cost-effective production, based on the comparatively low Al contents, by
way of ingot casting, continuous casting or even strip casting whilst observing
the application-specific parameters is thus achieved.
We Claim:
1. Components in diesel vehicles comprising (in weight %)
Al 2.5 Cr >17.5- Si 0.05 - max. 0.6%
Fe remainder and impurities, additional
Y > 0.01- Hf > 0.01-0.1% and
Zr > 0.01-0.2%.
2. Components in two stroke devices comprising (in weight %)
Al 2.5 - Cr 17.5- Si 0.05 - max. 0.6%
Fe remainder and impurities, additional
Y > 0.001 - Hf > 0.01-0.1% and
Zr > 0.01-0.2%.
3. The component as claimed in claim 1 or 2, wherein said diesel
vehicles and two-stroke devices comprise diesel and two-stroke
engines.
4. The component as clamed in claim 3, wherein said component is a
substrate foil in metallic catalytic exhaust converters.
5. Diesel engine glow cells comprising the component as claimed in
claim 1 or 2.
6. Components employed in exhaust systems of diesel or two-stroke
engines comprising a surface coating formed by applying said
surface coating from a spraying wire comprising the alloy as
claimed in claim 1 or 2.
7. The component as claimed in claim 3, wherein said component is a
heating conductor or resistance material for electrical preheating of
exhaust cleaning systems of diesel or two-stroke engines.
8. Exhaust cleaning systems of fuel cells comprising a component
comprising the alloy as claimed in claim 1 or 2.
Components in diesel vehicles comprising (in weight %)
Al 2.5 Cr >17.5- Si 0.05-max. 0.6%
Fe remainder and impurities, additional
Y >0.01- Hf > 0.01-0.1% and
Zr > 0.01-0.2%.

Documents:

2005-KOLNP-2005-CORRESPONDENCE-1.1.pdf

2005-KOLNP-2005-CORRESPONDENCE.pdf

2005-KOLNP-2005-FORM 27-1.1.pdf

2005-KOLNP-2005-FORM 27.pdf

2005-KOLNP-2005-FORM-27.pdf

2005-kolnp-2005-granted-abstract.pdf

2005-kolnp-2005-granted-claims.pdf

2005-kolnp-2005-granted-correspondence.pdf

2005-kolnp-2005-granted-description (complete).pdf

2005-kolnp-2005-granted-examination report.pdf

2005-kolnp-2005-granted-form 1.pdf

2005-kolnp-2005-granted-form 18.pdf

2005-kolnp-2005-granted-form 2.pdf

2005-kolnp-2005-granted-form 26.pdf

2005-kolnp-2005-granted-form 3.pdf

2005-kolnp-2005-granted-form 5.pdf

2005-kolnp-2005-granted-letter patent.pdf

2005-kolnp-2005-granted-priority document.pdf

2005-kolnp-2005-granted-reply to examination report.pdf

2005-kolnp-2005-granted-specification.pdf

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Patent Number

222901

Indian Patent Application Number

2005/KOLNP/2005

PG Journal Number

35/2008

Publication Date

29-Aug-2008

Grant Date

27-Aug-2008

Date of Filing

10-Oct-2005

Name of Patentee

THYSSENKRUPP VDM GMBH

Applicant Address

PLETTENBERGER STRASSE 2, 58791 WERDOHL

Inventors:

#	Inventor's Name	Inventor's Address
1	KOLB-TELIEPS, ANGELIKA	REICHENBERGERSTRASSE 12,5811 LUDENSCHEID
2	HATENDORE, HELKE	FRIEDHOFSTRASSE 49,58791 WERDOHL
3	HOJDA, RALF	BLUMENSTRASSE 1,58762 ALTENA

PCT International Classification Number

C22C 38/18

PCT International Application Number

PCT/DE2004/000454

PCT International Filing date

2004-03-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	103 10 865.3	2003-03-11	Germany