EP1381701A2

EP1381701A2 - Iron-chrome-aluminium-alloy

Info

Publication number: EP1381701A2
Application number: EP02730208A
Authority: EP
Inventors: Heike Hattendorf; Jürgen WEBELSIEP; Hans-Joachim Balke; Michael Eckhardt
Original assignee: ThyssenKrupp VDM GmbH
Current assignee: VDM Metals GmbH
Priority date: 2001-04-26
Filing date: 2002-04-25
Publication date: 2004-01-21
Anticipated expiration: 2022-04-25
Also published as: BR0209166B1; CN1537177A; AU2002302575A1; WO2002088404A3; WO2002088404A2; EP1381701B1; ATE274605T1; CN1226439C; BR0209166A

Abstract

The invention relates to an iron-chrome-aluminium-alloy with a high service life, comprising (in mass %) >2 3.6 % aluminium and >10 - 20 % chrome and other added materials, 0.1 -1 % Si, max. 0.5 % Mn, 0.01 0.2 % Yttrium and/or 0.01 0.2 % Hf and/or 0.01 0.3 % Zr, max. 0.01 % Mg, max. 0.01 % Ca, max. 0.08 % carbon, max. 0.04 % nitrogen, max. 0.04 % phosphorus max. 0.01 % sulphur, max. 0.05 % copper and respectively max. 0.1 % molybdenum and/or wolfram and the usual manufacture-related impurities, the remainder being iron.

Description

Iron-chromium-aluminum alloy

The invention relates to a deformable, ferritic steel alloy.

Alloys of this type are used, inter alia, for the production of electrical heating elements and catalyst supports. These materials form a dense, firmly adhering aluminum oxide layer, which protects them from destruction. This protection is improved by the addition of so-called reactive elements such as Ca, Ce, La, Y, Zr, Hf, Ti, Nb, which improve the adhesiveness and / or reduce the layer growth, as described in the “Handbook of High-Temperature Materials Technology, Ralf Bürgel, Vieweg Verlag, Braunschweig 1998 ", from page 274.

The aluminum oxide layer protects the metallic material from rapid oxidation. It grows itself, albeit very slowly. This growth takes place with the consumption of the aluminum content of the material. If there is no more aluminum, other oxides (chromium and iron oxides) grow. The metal content of the material is consumed very quickly and the material fails. The time to failure is called lifespan. Increasing the aluminum content therefore extends the service life.

In DE-A 19928842 an alloy with (in mass%) 16 to 22% Cr, 6 to 10% Al and additions of 0.02 to 1.0% Si, max. 0.5% Mn, 0.02 to 0.1% Hf, 0.02 to 0.1% Y, 0.001 to 0.01% Mg, max. 0.02% Ti, max. 0.03% Zr, max. 0.02% SE, max. 0.1% Sr, max. 0.1, max. 0.5% Cu, max. 0.1% V, max. 0.1% Ta, max. 0.1% Nb, max. 0.03% C, max. 0.01% N, max. 0.01% B, remainder iron and melting-related impurities for use as a carrier film for exhaust gas catalysts, as a heating conductor, as a component in industrial furnace construction and in gas burners.

In EP-B 0387670 an alloy with (in mass%) 20 to 25% Cr, 5 to 8% Al and additions of 0.03 to 0.08% yttrium 0.004 to 0.008% nitrogen, 0.020 up to 0.040% carbon, and approximately equal parts 0.035 to 0.07% Ti and 0.035 to 0.07% zirconium, and max. 0.01% phosphorus, max. 0.01% magnesium, max. 0.5% manganese, max. 0.005% sulfur, remainder iron addressed, whereby the sum of the contents of Ti and Zr in% is 1.75 to 3.5 times as large as the sum of the contents of C and N in mass% as well as impurities due to melting. All or part of Ti and Zr can be replaced by hafnium and / or tantalum or vanadium.

In EP-B 0290719 an alloy with (in mass%) 12 to 30% Cr, 3.5 to 8% Al, 0.008 to 0.10% carbon, max. 0.8% silicon, 0.10 to 0.1% manganese, max. 0.035% phosphorus, max. 0.020% sulfur, 0.1 to 1.0% molybdenum, max. 1% nickel, and the additives 0.010 to 1.0% zirconium, 0.003 to 0.3% titanium and 0.003 to 0.3% nitrogen, calcium plus magnesium 0.005 to 0.05%, and rare earth metals from 0.003 to 0.80 %, Niobium of 0.5%, rest of iron described with usual accompanying elements, which is used for example as wire for heating elements for electrically heated furnaces and as a construction material for thermally stressed parts and as a film for the production of catalyst supports.

In US-A 4277374 an alloy with (in mass%) up to 26% chromium, 1 to 8% aluminum, 0.02 to 2% hafnium, up to 0.3% yttrium, up to 0.1% Carbon, up to 2% silicon, balance iron, with a preferred range of 12 to 22% chromium and 3 to 6% aluminum, which is used as a film for the production of catalyst supports.

The above documents are based on traditional manufacturing processes, namely the conventional casting of the alloy and the subsequent hot and cold working. Since these processes are associated with high failures due to embrittlement phenomena during hot rolling, alternatives have been developed in recent years in which a chromium steel containing reactive elements is coated with aluminum or aluminum alloys. Such composites are then rolled to final thickness and then diffusion annealed, whereby a homogeneous material is produced when suitable annealing parameters are set.

Such processes have been described, for example, in the publications EP-B 0640390, EP-B 0204423 and WO 99/18251 and are outstandingly suitable for the processing problems for the applications where a high aluminum content is technically required and for use in the form of foil or Band is made to decrease.

Another possibility of reducing the failures and the costs due to the embrittlement phenomena is the use of iron-chromium-aluminum alloys for household appliances such as. B. toaster, hairdryer, u. Ä., practiced, which are generally used at lower temperatures below 800 ° C and are produced very strongly from a cost perspective. Since the application is usually in the form of wire, the solutions described cannot be obtained by coating. Because of the lower temperature loads, alloys with (in mass%) a reduced aluminum content of less than 5% are used, e.g. B. an alloy with approx. 14.5% Cr, approx. 4.5% Al, addition of reactive elements, rest of iron, as described in DIN standard 17470 in Table 3 with 14% chromium and 4% aluminum, rest of iron (Cr AI 14 4) is described and produced, as from "Wires from Krupp VDM for the electrical industry", publication N563, November 1998 edition on page 24, material Aluchrom W, with 14 to 16% chromium, 3.5 to 5 , 0% aluminum, max. 0.08% carbon, max. 0.6% manganese, max. 0.5% silicon, max. 0.3% zirconium, other melting-related impurities, the rest iron is known following as a comparison alloy and is briefly referred to as Cr AI 14 4.

The iron-chromium-aluminum alloy Cr AI 14 4 can be manufactured more easily by the aluminum content lowered to approx. 4 to 4.5 mass% than the alloys described above with more than 5 mass% aluminum. But it shows still embrittlement phenomena, which lead to increased production costs for hot forming.

Up to now it was state of the art that in Fe Cr AI alloys with approximately 14 to 15 mass% chromium a minimum content of approximately 4 mass% AI is required in order to build up a protective aluminum oxide layer, as described, for example, in “Handbook of High Temperature Material Technology” , Ralf Bürgel, Vieweg Verlag, Braunschweig 1998 "on page 272 in Figure 5.13.

GB-A 476,115 shows an iron alloy, particularly suitable as electrical resistance, which contains the following elements: 6.1 - 30% Cr, 3 - 12% Al, 0.07 - 0.2% C, 4% Ti , Rest of Fe as well as contamination due to melting. The Ti content is bound to the C content in such a way that it should not be less than 3 times the C content. Preferred ranges for Cr are> 8%, for AI> 5%, for C> 0.085%.

DE-A 196 52 399 describes a process for producing a multilayer metal composite film and the use thereof. The metal composite foil contains a carrier layer made of ferritic steel strip, which is provided on both sides with an outer layer made of aluminum or an aluminum alloy. The carrier layer is formed from an alloy, with (in mass%) 16-25% Cr, rare earths, Y or Zr in contents between 0.01-0.1%, Fe rest. Furthermore, AI in contents between 2 and 6% can be added. Preferred Cr contents are above 20%.

Finally, EP-A 0402 640 discloses a stainless steel foil as a carrier element for catalysts and their production. The foil is formed from an alloy of the following composition (in mass%): 1.0-20% Al, 5-30% Cr, up to 2% Mn, up to 3% Si, up to 1% C, balance Fe and manufacturing-related impurities. Preferred ranges for AI are between 5.5 and 20%. Furthermore, Y, Sc or rare earths can be added in limits up to 0.3% are, wherein at least one of the elements Ti, Nb, Zr, Hf, V, Ta, Mo, W can be provided in contents up to 2%. Levels <4% AI require Cr contents> 25%.

The invention has for its object to provide an inexpensive iron-chromium-aluminum alloy that has a similar or better life than Cr AI 14 4, but has an even lower brittleness and thus improved formability, but at the same time the same technical functionality as Cr AI 14 4 has.

This object is achieved by an iron-chromium-aluminum alloy with a long service life with (in mass%)> 2 to 3.6 mass% aluminum and> 10 to 20% chromium and additions of 0.1 to 1% Si, Max. 0.5% Mn, 0.01 to 0.2% yttrium and / or 0.01 to 0.2% Hf and / or 0.01 to 0.3% Zr, max. 0.01% Mg, max. 0.01% Ca, max. 0.08% carbon, max. 0.04% nitrogen, max. 0.04% phosphorus, max. 0.01% sulfur, max. 0.05% copper, and max. 0.1% molybdenum and / or tungsten and manufacturing-related impurities, the rest iron

Advantageous developments of the alloy according to the invention can be found in the subclaims.

The Al content can preferably be set within limits of 2.5-3.55% and the Cr content within limits of 13-17%.

The most effective way to reduce brittleness is to reduce the aluminum content. However, this has the disadvantage that the specific electrical resistance also decreases and the service life decreases. The brittleness is also increased by chromium, silicon, carbon and nitrogen, which is why these elements should also be kept as low as possible.

The same technical functionality for a heating conductor, which is used for the electrical generation of heat, can be achieved if the surface power, the power on the heating element, the total resistance of the heating element and the service life of the heating element remain constant with any change in the material.

If the specific electrical resistance is now reduced with constant surface power, constant power and constant resistance, in order to be able to comply with the above conditions, the diameter of the wire must be reduced and the wire length increased by the same percentage as the diameter. Overall, the volume is reduced by this percentage. This means that material is saved by reducing the specific electrical resistance. This can also be found in H. Pfeifer, H. Thomas, Tinder-resistant alloys, Springer Verlag, Berlin 1963, on page 387.

The following calculation demonstrates this:

For wires, the change in diameter, length and weight when material A is replaced by B are calculated, while surface performance, power and resistance are kept constant.

The following formulas apply with the above boundary conditions

Diameter D _B / D _A

Length _LB / L _{A =} ^ ^

Weight M _B / M _A = * jp _B lp _A • γ _B lγ _A When using the alloy according to the invention as a wire z. B. for a heating element with a

D _B / D _A = \ I _PB / _PA

changed diameter DB and one after

L _B IL _A = fp p _B

changed lengths LB, the wire with the specific electrical resistance p _B , which has the same functionality compared to that of an alloy A with the specific electrical resistance PA, the diameter D _A and the length L _A , however, if ps is smaller than PA and approximately γ _A = γβ, one around

M _B IM _A = ljp _B lp _Λ • γ _B lγ _A

less material quantity of an alloy B is required.

Example: Material A: PA = 1, 25 Ωmm ² / m

Material B: pe = 1.05 Ωmm ² / m

D _B / D _A = 0.94; ie reduction of the diameter by 6 mass%

L _B / L _A = 1.06; ie increase in length by 6 mass%

M _B / M _A = 0.94; ie weight reduction by 6 mass%

where γ _A = s is assumed for this exemplary preliminary consideration for the densities. The validity of this assumption must be checked in the specific case. So far, this path has not been labeled because the reduction in diameter is accompanied by a reduction in the service life.

In the following, the service life reduction is estimated by reducing the wire diameter:

According to I. Gurrappa, S. Weinbruch, D. Naumenko, W. J. Quadakkers, Materials and Corrosion 51 (2000), pages 224 to 235, the service life t of a wire can be calculated

4.4xl (r χ (C ₀ -) xr * f with / = - for wire with the

2

Diameter D γ = density of the alloy

Co = aluminum concentration of the alloy before the start of oxidation or the use of a heating coil CK = critical aluminum concentration at which the "break away" oxidation, ie the formation of oxides other than aluminum oxides, starts. This indicates the end of the functionality of a heating conductor and leads to rapid melting of the heating conductor and is therefore to be regarded as the end of the service life. k = oxidation constant n = oxidation rate exponent, with a size of approximately 0.5 The oxidation constant k is a measure of the quality of the oxide layer k smaller than with a poorer oxide layer, the smaller k is, the longer the life.

If, as in the above considerations, the wire diameter is reduced by a factor of 0.94 for an alloy, the service life is reduced since the oxidation constant k, the density γ, C ₀ and CK remain unchanged as follows:

with ti = service life with larger wire diameter Di. and t ₂ = service life with smaller wire diameter D ₂ .

This means that an alloy with the same functionality would have to have at least a 12% longer service life in order to compensate for the disadvantage of the smaller wire diameter. Longer lifetimes also offer the advantage of a longer lifespan, that is, improved functionality.

Surprisingly, it was found that alloys with (in mass%)> 2 to 3.6% aluminum and> 10 to 20% chromium, and additions of 0.1 to 1% Si, max. 0.5% Mn, 0.01 to 0.2% yttrium, and / or 0.01 to 0.2% Hf and / or 0.01 to 0.3% Zr, max. 0.01% Mg, max. 0.01% Ca, max. 0.08% carbon, remainder iron and the usual process-related impurities have a much better lifespan than the previously used alloy with approx. 14.5% Cr, approx. 4.5% Al, and additions of max. 0.3% zirconium, max. 0.08% carbon, max. 0.6% manganese, max. 0.5% silicon, the rest iron and other melting-related impurities.

The subject of the invention is in addition to heating conductors for heating elements, for. B. a household appliance, or as a construction material in furnace construction can also be used as a film, for example as a carrier film for catalysts.

The advantages of the invention are explained in more detail in the following examples:

Examples: Table 1 shows various iron-chromium-aluminum alloys, the table containing batches that have been melted on an industrial scale as well as in a laboratory.

For heating elements (heating conductors) in the form of wire, accelerated life tests for comparing materials with each other are possible, for example under the following conditions: The test is carried out on wires with a diameter of 0.40 mm, from which wire coils with 12 turns, a coil diameter of 4 mm and a coil length of 50 mm are produced. The wire coils are clamped between two power supplies and heated up to 1200 ° C by applying a voltage. The heating takes place for 2 minutes each, then the power supply is interrupted for 15 seconds. At the end of the service life, the wire fails because the remaining cross-section melts. The total time that the wire was heated, without the interruption times, is given as the service life in the following.

The large-scale batch T1 and the laboratory batches T2 and T3 represent the state of the art for Cr AI 14 4, with (in mass%) approx. 14.5% chromium, 4.5% aluminum, approx. 0.3% manganese , approx. 0.2% silicon and as a reactive element 0.17 to 0.18% zircon. They have lifetimes of 49 hours for the T3 laboratory batch, 63 hours for the T2 laboratory batch and 77 hours for the T1 industrial batch. Batches H1 to H6 are batches with an aluminum content of more than 5% by mass and various additions of silicon, manganese, zirconium, titanium, hafnium and yttrium and other additives such as calcium, magnesium, carbon and nitrogen. As was to be expected, they all show a significantly longer service life compared to batches T1 to T3 due to the increased aluminum content. Differences in the service life of H1 to H6 are due in particular to the different levels of aluminum, silicon, zirconium, titanium, hafnium and yttrium.

In the laboratory batch K1, the aluminum content has been reduced from 4.5 to 3.55 mass% compared to the laboratory batch according to the prior art T2. As expected, the service life was reduced from 63 hours to 34 hours.

This is different with the batches L2, L3, M1, M2 and M4 labeled with “E” according to the invention. In comparison to the laboratory batches T3 and T2 according to the prior art, they have a life span that is increased by a factor of 1.5 to 2, although they significantly reduced aluminum contents from 2.5 to 3.6 mass% contain. Their common characteristic is that they contain yttrium and / or hafnium in addition to zirconium. Charge L2 with an aluminum content of (in mass%) 2.55% and a zirconium content of 0.05% and a hafnium content of 0.04% and an yttrium content of 0.02% achieved a service life of 109 hours. Batch L3 with an aluminum content of 3.55% and a zirconium content of 0.053% and a hafnium content of 0.042% and an yttrium content of 0.02% has a service life of 90 hours. Batch M1 has a lifetime of 92 hours with an aluminum content of 2.78% and a zircon content of 0.05% and a hafnium content of 0.03% and an yttrium content of 0.02%. Charge M2 has a life of 126 hours with an aluminum content of 2.71% and a zirconium content of 0.05% and a hafnium content of 0.03% and an yttrium content of 0.04%. Batch M4 has a lifetime of 85 hours with an aluminum content of 2.8% and a zircon content of 0.03% and a hafnium content of 0.03% and an yttrium content of 0.03%.

These examples show that with very small additions of zirconium, hafnium and yttrium to the iron - chromium - aluminum alloy, even at low aluminum contents of 2.5%, very long lifetimes, compared to those of iron - chromium - aluminum alloys with more than 5% % Aluminum, can be achieved.

In summary, it can be said that the alloy according to the invention must contain additions of 0.01 to 0.2% yttrium, and / or 0.01 to 0.2% Hf and / or 0.01 to 0.3% Zr.

Batch L1 shows that even with the addition of zirconium, hafnium and yttrium with an aluminum content of 1.55%, only a service life of 9.3 hours is achieved. Even with the addition of zirconium, hafnium and yttrium and an aluminum content of only 2.24%, Charge M3 only has a lifespan of 72 hours, which is in the range of the batches according to the prior art. The Alloy according to the invention should therefore have an aluminum content of more than 2%.

Chromium contents between 14 and 17% have no decisive influence on the service life like the comparison of the batches M1 containing zirconium, hafnium and yttrium with 14.85% chromium and 2.78% aluminum and batch L2 with 16.86% chromium and 2.55 % Aluminum shows. However, a certain chromium content is necessary, since chromium promotes the formation of the particularly stable and protective α - A 0 ₃ layer. According to HM Herbelin, M Mantel, Colloque C7, Suppleement au Journal de Physique III, Vol. 5, Novembre 1995, pages C7-365 to 374, this still happens with a chromium content of 13%, but a chromium content of 6% is no longer sufficient ,

According to J. Klöwer, Materials and Corrosion 51 (2000), pages 373 to 385, additions of silicon of approximately 0.3 mass% and more increase the service life by improving the adhesion of the top layer. A content of at least 0.1% by mass of silicon is therefore required.

Table 1 lists the impact energy at room temperature, 50 ° C, 100 ° C and 150 ° C on standard DMV samples (see W. Domke, Materials Science and Testing, Verlag W. Gerardet, Essen, 1981, from page 336). The impact energy is low for a ferritic steel in the case of the brittle fracture occurring at low temperatures (low position), in the case of ductile, easily deformable behavior high (high position) with a steep increase within a few degrees from the low position to the high position. In this area, the impact energy can be widely scattered. The temperature at which the transition from the high position to the low position takes place is called the notch impact transition temperature. For example, a material is the more brittle the larger the grain size or, in the case of iron-chromium-aluminum materials, the higher the content of alloying elements such as aluminum, chromium, silicon, nitrogen, carbon, phosphorus and sulfur. Due to your manufacturing route as a laboratory batch, all impact tests in Table 1 have one very large grain size of approximately 200 to 400 μm, which is very unfavorable. Therefore, all samples are in the low position at room temperature, with the samples with the lowest aluminum content, the lowest chromium content and the lowest carbon content having the highest impact energy, as shown by batches M1, M2, M3, M4 and L1. Charge M4 has a slightly lower notch impact energy than Charge M2 with a similar aluminum and chromium content, since it has a higher carbon content. Charge L2 has a slightly lower impact energy than Charge M2 because it has a higher chromium content. Nitrogen, phosphorus and sulfur act similarly to carbon, the contents of which should therefore advantageously be kept low. It turns out that the aluminum content must not exceed 3.6% in order to keep the embrittling effect of the aluminum as low as possible.

The same picture is shown for the notched bar impact tests measured at 50 ° C and 100 ° C, only that the improvement in the notched bar impact work is even more pronounced with the low aluminum contents and also the reduction in the notched bar impact work due to an increased C content in M4 compared to M1 and M2 can be seen even better. It can also be seen here that batch M1, which differs from batch M2 in that it has a higher silicon content, has a slightly lower impact energy. At 150 ° C, all notch impact work is in the ductile high position, with batches M2, M3 and M4 having the highest notch impact work with an aluminum content of 2.2 to 2.8%.

In summary it can be said that the brittle behavior of the iron-chromium-aluminum alloys is significantly reduced by lowering the aluminum content to below 3.6%. This is further supported by low levels of silicon, carbon, nitrogen, phosphorus and sulfur. The carbon content is therefore limited to max. 0.08%, the nitrogen content to max. 0.04%, the phosphorus content to max. 0.04% and the sulfur content to max. 0.01 Mass% limited. Phosphorus and sulfur also have an unfavorable effect on the service life, so that the lowest possible levels of these elements are also advantageous from this point of view.

Because of the embrittling effect, the chromium content should also be as low as possible. Due to the requirements regarding the service life, the silicon and chromium content cannot be reduced to almost zero, but must be at least 0.1% silicon and 10% chromium. However, no more than 20% chromium and 1% silicon should be added in order to achieve the lowest possible brittleness.

When an alloy Cr AI 14 4, as represented in Table 1, for example by batches T1, T2 and T3, is replaced by an alloy according to the invention, such as batches M2 or M4, the specific electrical resistance of 1 is reduced. 21 Ωmm ² / m (Alloy A) to 1.04 Ωmm ² / m. (Alloy B). The same functionality is guaranteed according to what has been said above if the surface power, power and resistance of the heating coil are kept constant.

This gives the diameter ratio D _B / D = 0.95

and for the aspect ratio L _B / L _A = = 1.05

the weight ratio M _B / M _A = • γ _B lϊ _A = 0.95 with

approximately Y _A = γβ

The density of alloy A is YA = 7.12 g / cm ² , the density of alloy B is γ _B = 7.30 g / cm ² . Taking into account the change in density, the weight ratio is only slightly larger

M _B / M _A = lp _B lp _A * γ _B lγ _A = 0.97 This means that the approximate estimate with J = J _B was allowed in this case.

The lifetime assessment according to I. Gurrappa, S. Weinbruch, D. Naumenko, W. J. Quadakkers, Materials and Corrosion 51 (2000), pages 224 to 235 by reducing the wire diameter in alloy B according to the invention shows:

This means that the alloy according to the invention must have an at least 10% longer lifespan in order to compensate for the disadvantage of the smaller wire diameter. However, since the batches according to the invention all have an at least 50% longer lifespan, the use of the alloy according to the invention additionally has the advantage of an increased lifespan.

Manganese is limited to 0.5% by mass because this element reduces the resistance to oxidation. The same applies to copper.

Claims

claims

1. Iron-chromium-aluminum alloy with a long service life, with (in mass%)> 2 to 3.6% aluminum and> 10 to 20% chromium and additions of 0.1 to 1% Si, max. 0.5% Mn, 0.01 to 0.2% yttrium and / or 0.01 to 0.2% Hf and / or 0.01 to 0.3% Zr, max. 0.01% Mg, max. 0.01% Ca, max. 0.08% carbon, max. 0.04% nitrogen, max. 0.04% phosphorus max. 0.01% sulfur, max. 0.05% copper and max. 0.1% molybdenum and / or tungsten and manufacturing-related impurities, the rest iron

2. iron-chromium-aluminum alloy according to claim 1 with (in mass%) 2.5 to 3.55% aluminum, 13 to 17 mass% chromium and additions of 0.1 to 0.5% Si, max. 0.5% Mn, 0.01 to 0.1% yttrium, and / or 0.01 to 0.1% Hf and / or 0.01 to 0.2% Zr, max. 0.01% Mg, max. 0.01% Ca, max. 0.08% carbon, max. 0.04% nitrogen, max. 0.04% phosphorus max. 0.01% sulfur, max. 0.05% copper, and max. 0.1% molybdenum and / or tungsten and manufacturing-related impurities, the rest iron.

3. iron-chromium-aluminum alloy according to claim 1 or 2 with (in mass%) 2.5 to 3.0% aluminum and 14 to 17% chromium and additions of 0.1 to 0.5% Si, max , 0.5% Mn, 0.01 to 0.08% yttrium and / or 0.01 to 0.08% Hf and / or 0.01 to 0.08% Zr, max. 0.01% Mg, max. 0.01% Ca, max. 0.08% carbon, max. 0.04% nitrogen, max. 0.04% phosphorus max. 0.01% sulfur, max 0.05% copper, and max. 0.1% molybdenum and / or tungsten and manufacturing-related impurities, the rest iron.

4. Iron-chromium-aluminum alloy according to one of claims 1 to 3, in which one or more of the elements yttrium, hafnium or zircon, wholly or partly by (in mass%) 0.01 to 0.1% of one or several of the elements scandium and / or titanium and / or vanadium, and / or niobium, and / or tantalum and / or rare earth metals, such as in particular lanthanum and / or cerium, can be replaced.

5. iron-chromium-aluminum alloy according to one of claims 1 to 4, characterized in that the contents of carbon are limited to 0.02%, nitrogen to 0.01%, phosphorus to 0.01% and sulfur to 0.005% are.

6. iron-chromium-aluminum alloy according to one of claims 1 to 5, wherein when using the alloy as a wire and keeping the surface performance, performance and resistance and exchange of a material A with a material B following boundary conditions with respect to the diameter, Length and weight changes are given.

Diameter D _B ID _A - \ jp _B / p _A

Length L _B IL _A = ^ p _A l ρ _B

Weight M _B IM _A = jp _B lp _A • γ _B lγ _A

wherein

D the diameter

the specific electrical resistance

L the length

M the weight

Y the density

of the respective wire

7. Use of an iron-chromium-aluminum alloy according to one of claims 1 to 6, as a heating conductor in a heating element.

8. Use of an iron-chromium-aluminum alloy according to one of claims 1 to 6 as an alloy, in particular in the form of a heating element, for use in household appliances.

9. Use of an iron-chromium-aluminum alloy according to one of claims 1 to 6 as an alloy, in particular in the form of a heating element or as a construction material for use in furnace construction.

10. Use of an iron-chromium-aluminum alloy according to one of claims 1 to 5 as an alloy, in particular in the form of a foil, for use as a carrier foil for catalysts.

11. Use of an iron-chromium-aluminum alloy according to one of claims 1 to 6 as an alloy, in particular in the form of wire or tape, for use as a braking and starting resistor.