EP2162558A1

EP2162558A1 - Iron-nickel-chromium-silicon alloy

Info

Publication number: EP2162558A1
Application number: EP08773262A
Authority: EP
Inventors: Heike Hattendorf; Jürgen WEBELSIEP
Original assignee: ThyssenKrupp VDM GmbH
Current assignee: VDM Metals International GmbH
Priority date: 2007-06-26
Filing date: 2008-06-12
Publication date: 2010-03-17
Anticipated expiration: 2028-06-12
Also published as: CN101707948B; JP5626815B2; BRPI0813917A2; KR101335009B1; KR20100022488A; CA2690637A1; PL2162558T3; JP5447864B2; DE102007029400A1; ES2643635T3; CA2690637C; JP2010532425A; CN101707948A; MX2009013253A; BRPI0813917A8; DE102007029400B4; SI2162558T1; US20100172790A1; WO2009000230A1; US20130200068A1

Abstract

The invention relates to an iron-nickel-chromium-silicon alloy comprising (in wt.-%) 19 to 34% or 42 to 87% nickel, 12 to 26% chromium, 0.75 to 2.5% silicon, and additives of 0.05% to 1% Al, 0.01 to 1% Mn, 0.01 to 0.26% lanthanum, 0.0005 to 0.05% magnesium, 0.04 to 0.14% carbon, 0.02 to 0.14% nitrogen, and further comprising 0.0005 to 0.07% Ca, 0.002 to 0.020% P, a maximum of 0.01% sulfur, a maximum of 0.005% B, the remainder comprising iron and the usual process-related impurities.

Description

Iron-nickel-chromium-silicon alloy

The invention relates to iron-nickel-chromium-silicon alloys with improved life and dimensional stability.

Austenitic iron-nickel-chromium-silicon alloys with different nickel, chromium and silicon contents have long been used as heating conductors in the temperature range up to 1100 ^° C. For use as a heating conductor alloy, this alloy group is standardized in DIN 17470 (Table 1) and ASTM B344-83 (Table 2). There are a number of commercially available alloys listed in Table 3 for this standard.

The sharp increase in the price of nickel in recent years gives rise to the desire to use Heizleiterlegierungen with the lowest possible nickel content or significantly increase the life of the alloys used. This allows the heater manufacturer either to switch to a lower nickel alloy or to explain the higher price to the customer with a longer shelf life.

In general, it should be noted that the service life and service temperature of the alloys indicated in Tables 1 and 2 increase with increasing nickel content. All these alloys form a chromium oxide layer (Cr ₂ O ₃ ), with an underlying, more or less closed, SiO ₂ layer. Small additions of strongly oxygen affine elements such as Ce, Zr, Th, Ca, Ta (Pfeifer / Thomas, Zunderfeste alloys 2nd edition, Springer Verlag 1963, pages 258 and 259) increase the life, in the cited case, only the influence of a investigated individual oxygen affinity element, but no information on the effect of a combination of such elements were made. The chromium content is slowly consumed in the course of using a heat conductor to build up the protective layer. Therefore, the lifetime is increased by a higher chromium content, since a higher content of the protective layer forming element chromium Time delays at which the Cr content is below the critical limit and form other oxides than Cr ₂ O ₃ , which are, for example, iron-containing oxides.

By EP-A 0 531 775 is a heat-resistant austenitic heat-deformable

Nickel alloy of the following composition (in% by weight):

C 0.05-0.15%

Si 2.5-3.0%

Mn 0.2-0.5%

P max. 0.015%

S max. 0.005%

Cr 25-30%

Fe 20-27%

Al 0.05-0.15%

Cr 0.001-0.005%

SE 0.05-0.15%

N 0.05-0.20%

Balance Ni and impurities caused by melting.

EP-A-0 386 730 describes a nickel-chromium-iron alloy with very good oxidation resistance and high temperature resistance, as desired for advanced heat conductor applications, starting from the known NiCr6015 heating conductor alloy and making significant modifications to the composition Improvements in performance could be achieved. The alloy differs from the known material NiCr6015 in particular in that the rare earth metals are replaced by yttrium, that it additionally contains zirconium and titanium, and that the nitrogen content is specially adapted to the contents of zirconium and titanium.

WO-A 2005/031018 discloses an austenitic Fe-Cr-Ni alloy for use in the high-temperature range, which has essentially the following chemical composition (in% by weight): Ni 38-48%

Cr 18-24%

Si 1, 0-1, 9%

C <0.1%

Fe rest.

In free-hanging heating elements in addition to the demand for a long life and the requirement for good dimensional stability at the application temperature. Too much sagging during operation results in uneven spacing of the turns with uneven temperature distribution, thereby shortening the life. To compensate this would require more support points for the heating coil, which increases the cost. This means that the heating conductor material must have a sufficiently good dimensional stability or creep resistance.

The creeping mechanisms affecting the dimensional stability in the area of the application temperature (dislocation creeping, grain boundary slipping or

Diffusion creep) are all influenced by the creep, except for the dislocation creeping by a large grain size in the direction of greater creep resistance. The dislocation creep does not depend on the grain size. The production of a wire with a large grain size increases the creep resistance and thus the dimensional stability. For all considerations, grain size should therefore also be taken into account as an important influencing factor.

Another important factor for a heat conductor material is the highest possible specific electrical resistance and the smallest possible change in the ratio of the thermal resistance / cold resistance to the temperature (temperature coefficient et).

The object underlying the invention is to design alloys which, at similar nickel, chromium and Si contents, as the prior art alloys in Tables 1 and 2, however a) a significantly improved oxidation resistance and a concomitant long life

b) a significantly improved dimensional stability at the application temperature

c) have a high electrical resistivity in conjunction with the smallest possible change in the ratio of heat resistance / cold resistance with the temperature (temperature coefficient et).

This object is achieved by an iron-nickel-chromium-silicon alloy, with (in wt .-%) 19 to 34% or 42 to 87% nickel, 12 to 26% chromium, 0.75 to 2.5% silicon and additions of 0.05 to 1% Al, 0.01 to 1% Mn, 0.01 to 0.26% lanthanum, 0.0005 to 0.05% magnesium, 0.04 to 0.14% carbon, 0.02 to 0.14% nitrogen, further including 0.0005 to 0.07% Ca, 0.002 to 0.020% P, max. 0.01% sulfur, max. 0.005% B, balance iron and the usual process-related impurities.

Advantageous developments of the subject invention can be found in the associated dependent claims.

Due to their special composition, these alloys have a longer service life than the alloys of the prior art with comparable nickel and chromium contents. In addition, an increased dimensional stability or a lower sagging can be achieved than the alloys according to the prior art.

The spreading range for the element nickel is either between 19 to 34% or 42 to 87%, depending on the application, nickel contents can be given as follows and be adjusted depending on the application in the alloy.

Preferred Ni ranges between 19 and 34% are given as follows:

19 to 25% 19 to 22% 23 to 25% 25 to 34% 25 to 28% 28 to 31% 31 to 34%

Preferred Ni ranges between 42 and 87% are given as follows:

42 to 44% 44 to 52% 44 to 48% 48 to 52% 52 to 57% 57 to 65% 57 to 61% 61 to 65% 65 to 75% 65 to 70% 70 to 75% 75 to 83% 75 to 79% 79 to 83%.

The chromium content is between 12 and 26%, whereby also here, depending on the area of use of the alloy, chromium contents can be given as follows:

14 to 26% 14 to 18% 18 to 21%

20 to 26%

21 to 24% 20 to 23% 23 to 26%.

The silicon content is between 0.75 and 2.5%, whereby, depending on the field of application, defined contents within the spread range can be set:

1.0-2.5%

1.5-2.5%

1.0-1.5%

1.5-2.0%

1.7-2.5%

1, 2 - 1, 7%

1.7-2.2%

2,0 - 2,5%.

The element aluminum is provided as an addition and in amounts of 0.05 to 1%. Preferably, it may be adjusted in the alloy as follows:

0.1-0.7%.

The same applies to the element manganese, which is added with 0.01 to 1% of the alloy. Alternatively, the following spread range is conceivable:

0.1-0.7%.

The subject of the invention preferably assumes that the material properties specified in the examples are essentially set with the addition of the element lanthanum in contents of 0.01 to 0.26%. Depending on the field of application, defined values in the alloy can also be set here:

0.02 - 0.26% 0.02 - 0.20% 0.02-0.15% 0.04-0.15%.

This applies equally to the element nitrogen, which is added in amounts between 0.02 and 0.14%. Defined contents can be given as follows:

0.02-0.10% 0.03-0.09% 0.05-0.09%.

Carbon is added to the alloy in the same manner, at levels between 0.04 and 0.14%. Specifically, contents can be adjusted in the alloy as follows:

0.04 - 0.10%.

Also, magnesium is one of the addition elements in levels of 0.0005 to 0.05%. Specifically, it is possible to adjust this element in the alloy as follows:

0.001-0.05% 0.008-0.05%.

The alloy may further include calcium at levels between 0.0005 and 0.07%, especially 0.001 to 0.05% or 0.01 to 0.05%.

The alloy may further include phosphorus at levels of between 0.002 and 0.020%, especially 0.005 to 0.02%.

The elements sulfur and boron may be given in the alloy as follows:

Sulfur max. 0.005% boron max. 0.003%. If the effectiveness of the reactive element lanthanum alone should not be sufficient to produce the material properties set out in the task, the alloy may further comprise at least one of the elements Ce, Y, Zr, Hf, Ti with a content of 0.01 to 0, 3%, where necessary, the elements can also be defined additions.

Additions of oxygen affinity elements, such as preferred La and, if necessary, Ce, Y, Zr, Hf, Ti, improve the lifetime. They do this by incorporating them into the oxide layer and blocking the diffusion paths of the oxygen there on the grain boundaries. The amount of elements available for this mechanism must therefore be normalized to the atomic weight in order to be able to compare the amounts of different elements among each other.

The potential of the active elements (PwE) therefore becomes too high

PwE = 200 • Σ (X _E / atomic weight of E)

where E is the element in question and XE is the content of that element in percent.

As already mentioned, the alloy may contain 0.01 to 0.3% of one or more of the elements La, Ce, Y, Zr, Hf, Ti, respectively

Σ PwE = 1, 43 - Xc ₈ + 1, 49 ^• Xi ₃ + 2.25 ^« X _Y + 2.19 - Xz _r + 1, 12 ^• X _Hf + 4.18 ^• X _Ti <0.38, in particular <0.36 (at 0.01 to 0.2% of the total element), where PwE corresponds to the potential of the active elements.

Alternatively, in the presence of at least one of the elements La, Ce, Y, Zr, Hf, Ti in contents of 0.02 to 0.10%, there is the possibility that the sum PwE =

1, 43 • X _Ce + 1, 49 • X _La + 2.25 • X _γ + 2.19 • X _zr +1, 12 • X _Hf + 4.18 ^• X _{Ti is} less than or equal to 0.36, where PwE corresponds to the potential of the active elements. Furthermore, the alloy may contain between 0.01 to 1.0% of one or more of the elements Mo, W, V, Nb, Ta, Co, which may be further limited as follows:

0.01 to 0.06% 0.01 to 0.2%.

Finally, impurities may still contain the elements copper, lead, zinc and tin in amounts as follows:

Cu max. 1, 0%

Pb max. 0.002%

Zn max. 0.002%

Sn max. 0.002%.

The alloy according to the invention should preferably be used for use in electrical heating elements, in particular in electrical heating elements which require high dimensional stability and low sagging.

However, use in heating elements of tubular heaters is also conceivable.

Another concrete application for the alloy according to the invention is the use in furnace construction.

Based on the following examples, the subject invention will be explained in more detail.

Examples:

Tables 1 to 3 reflect - as already mentioned at the beginning - the state of the art.

For the alloys melted on an industrial scale in the following examples, an industrially manufactured and soft annealed from industrial production Pattern taken with the diameter 1, 29 mm. For the life test, a smaller subset of the wire was drawn on a laboratory scale up to 0.4 mm.

For heating elements, in particular heating conductors in the form of wire, accelerated life tests for comparing materials with one another are possible and customary, for example with the following conditions:

The heat conductor life test is carried out on wires with a diameter of 0.40 mm. The wire is clamped between 2 power supply lines at a distance of 150 mm and heated by applying a voltage up to 1150 ⁰ C. The heating at 1150 ⁰ C takes place in each case for 2 minutes, then the power supply is interrupted for 15 seconds. At the end of its life, the wire fails because the remaining cross section melts. The burning time is the addition of the "on" times during the life of the wire The relative burning time tb is the indication in% related to the burning time of a reference batch.

For the investigation of dimensional stability, the sagging behavior of heating coils at the application temperature is investigated in a sagging test. In this case, the sagging of the coils from the horizontal is recorded after a certain time on heating coils. The lower the sag, the greater the dimensional stability or creep resistance of the material.

For this experiment, a soft annealed wire with a diameter of 1.29 mm is wound into spirals with an internal diameter of 14 mm. In total, 6 heating coils with 31 turns each are produced for each batch. All heating coils are controlled at the beginning of the experiment to a uniform outlet temperature of 1000 ⁰ C. The temperature is determined with a pyrometer. The test is carried out with a switching cycle of 30 s "on" / 30 s "off" at constant voltage. After 4 hours, the experiment is terminated. After the heating coils have cooled, the sagging of the individual turns (sagging) from the horizontal is measured and the mean value of the 6 values of the heating coils is formed. There have been various exemplary alloys having nickel contents of 30 to 34%, or 50 to 60% Ni, 16 to 22% Cr, 1 to 3 to 2.2% Si, and additions of 0.2 to 0.5% Al, 0.3 to 0.5% Mn, 0.01 to 0.09% La, 0.005 to 0.014% Mg, 0.01 to 0.065% C, 0.03 to 0.065% N, further including 0.001 to 0.04 Ca, 0.005 to 0.013% P, 0.0005 to 0.002% S, 0.003 B max, 0.01 to 0.08% Mo, 0.01 to 0.1% Co, 0.02 to 0.08% Nb, 0.01 to 0.06% V, 0.01 to 0.02% W, 0.01 to 0.1% Cu, balance iron and a PwE of 0.09 to 0.19 made industrially and as above described examined.

The results were evaluated by means of a multiple linear regression.

FIG. 1 shows the dependence of the relative burning time on the La content, the influences of the Ni, Cr, Si content being excluded. It turns out that the relative burning time greatly increases with increasing La content. In particular, a La content of 0.04 to 0.15% is particularly advantageous.

In the evaluation of the sagging (sagging of the coils), only samples with a grain size of 20 to 25 μm were included, so that no regression had to be made according to this parameter.

FIG. 2 shows the dependence of the sagging on the N content, the influences of the Ni, Cr, Si and C contents having been calculated out. It can be seen that sagging decreases strongly with increasing N content. In particular, an N content of 0.05 to 0.09% is advantageous.

FIG. 3 shows the dependence of the sagging on the C content, the influences of the Ni, Cr, Si and N contents being excluded. It can be seen that sagging decreases significantly with increasing C content. In particular, a C content of 0.04 to 0.10% is advantageous.

Alloys with lower nickel contents (variant 1) are particularly cost-effective. Therefore, the alloys in the range of 19% to 34% Ni are of great interest, despite compared to alloys with higher nickel contents worse temperature coefficients and lower specific electrical resistances. Below 19% nickel, there is an increasing risk of sigma phase formation, which causes the alloy to become brittle. Therefore, 19% is the lower limit for the nickel content.

The cost of the alloy increases with the nickel content. Therefore, 34% should be the upper limit of the low-nickel alloys (variant 1).

Above 42% Ni, the temperature coefficient improves progressively. Also, the specific electrical resistance is higher. At the same time, the proportion of nickel is comparatively low at about 80% compared with alloys containing high nickel content. Therefore, 42% is a reasonable lower limit for the alloys with higher nickel content (variant 2).

Alloys above 87% nickel no longer contain enough Cr and Si to be sufficiently resistant to oxidation. Therefore, 87% is the upper limit for the nickel content.

Too low Cr contents mean that the Cr concentration drops very quickly below the critical limit. That's why 12% Cr is the lower limit for chromium. Too high Cr contents deteriorate the workability of the alloy. Therefore, 26% Cr is considered the upper limit.

The formation of a silicon oxide layer below the chromium oxide layer reduces the oxidation rate. Below 0.75%, the silicon oxide layer is too patchy to fully develop its effect. Too high Si contents impair the processability of the alloy. Therefore, an Si content of 2.5% is the upper limit.

As already mentioned, additions of oxygen-affine elements improve the lifetime. They do this by incorporating them into the oxide layer and blocking the diffusion paths of the oxygen there on the grain boundaries. The amount of elements available for this mechanism must therefore be based on the Atomic weight can be normalized to compare the amounts of different elements with each other.

The potential of the active elements PwE therefore becomes too high

PwE = 200 • Σ (X _E / atomic weight of E), where E is the element concerned and X _{E is} the content of the relevant element

Element is in%.

In the presence of La or Ce or SE, Ca and Mg no longer appear to belong to the active elements.

The addition for the potential of the active elements PwE has therefore been carried out via La, Ce, Y, Zr, Hf and Ti. If no information is given for La and Ce, but due to the addition of cerium mischmetal only the blanket statement SE given, it is assumed for the calculation of PwE Ce = 0.6 SE and La = 0.35 SE.

PwE = 1, 49 • X _La , 1, 43 • X _Ce + 2.25 • X _γ + 2.19 • X _zr +1, 12 • X _Hf + 4.18 • X _Ti

A minimum content of 0.01% La is necessary to obtain the oxidation resistance-enhancing effect of La. The upper limit is set at 0.26%, which corresponds to a PwE of 0.38. Larger values of PwE are not useful here.

AI is needed to improve the processability of the alloy. It is therefore necessary a minimum content of 0.05%. Too high contents in turn affect the processability. The Al content is therefore limited to 1%.

It is a minimum content of 0.04% C for good dimensional stability and low Sagging necessary. C is limited to 0.14% because this element reduces oxidation resistance and processability.

A minimum content of 0.02% N is required for good dimensional stability or low sagging. N is limited to 0.14% because this element reduces oxidation resistance and processability. For Mg, a minimum content of 0.0005% is required, which improves the processability of the material. The limit is set at 0.05% because too much Mg has proved negative.

For Ca, a minimum content of 0.0005% is required, as this improves the processability of the material. The limit is set at 0.07% because too much Ca has proved negative.

The levels of sulfur and boron should be adjusted as low as possible, as these surfactants impair oxidation resistance. It will therefore max. 0.01% S and max. 0.005% B is set.

Copper is heated to max. 1% limited as this element reduces the oxidation resistance.

Pb is set to max. 0.002% limited because this element reduces the oxidation resistance. The same applies to Sn.

A minimum content of 0.01% Mn is required to improve processability. Manganese is limited to 1% because this element also reduces oxidation resistance.

Table 1 Alloys according to DIN 17470 and 17742 (composition of NiCr8020, NiCr7030, NiCr6015). All data in% by weight

*)Max. Co 1.5%

Table 2: Alloys according to ASTM B 344-83. All data in% by weight

Cr Ni + Co ^*) Fe Si Mn CSP (μΩm) Ct (at 871 ⁰ C)

80Ni, 20Cr 19-21 radical <1.0 0.75-1.75 <1, 0 <o, 15 <0, 01 1, 081 1, 008

60Ni, 16Cr 14-18> 57 0.75-1.75 <1, 0 <o, 15 <0, 01 1, 122 1, 073

35Ni, 20Cr 18-21 34- 37 radical 1.0-3.0 <1, 0 <o, 15 <0, 01 1, 014 1, 214

Table 3: Commercially available alloys. All data in% by weight

c \

LIST OF REFERENCE NUMBERS

Figure 1 Graphical representation of the dependence of the relative burning time tb of

La content shown, the influences of the Ni, Cr, Si content were calculated using a multiple linear regression analysis.

FIG. 2 dependency of the sagging (sagging of the helices) on the N content, the influences of the Ni, Cr, Si and C contents having been calculated out with the aid of a multiple linear regression analysis. It can be seen that sagging is greatly reduced with increasing N content. In particular, an N content of 0.03 to 0.09% is advantageous.

FIG. 3 dependency of the sagging (sagging of the helixes) on the C content, wherein the influences of the Ni, Cr, Si and N contents were calculated out with the aid of a multiple linear regression analysis. It can be seen that sagging is greatly reduced with increasing N content. In particular, an N content of 0.04 to 0.10% is advantageous.

Claims

claims

1. iron-nickel-chromium-silicon alloy, with (in wt .-%) 19 to 34% or 42 to 87% nickel, 12 to 26% chromium, 0.75 to 2.5% silicon, and additions of 0.05 to 1% Al, 0.01 to 1% Mn, 0.01 to 0.26% lanthanum, 0.0005 to 0.05% magnesium, 0.04 to 0.14% carbon, 0.02 to 0.14% nitrogen, further including 0.0005 to 0.07% Ca, 0.002 to 0.020% P, max. 0.01% sulfur, max. 0.005% B, balance iron and the usual process-related impurities.

2. iron-nickel-chromium-silicon alloy according to claim 1, with (in wt .-%) 19 to 34% or 42 to 83% nickel, 14 to 26% chromium, 1, 0 to 2.5% silicon and from 0.05 to 1% Al, 0.01 to 1% Mn, 0.02 to 0.26% lanthanum, 0.0005 to 0.05% magnesium, 0.04 to 0.14% carbon, 0, 02 to 0.14% nitrogen, further including 0.0005 to 0.07% Ca, 0.002 to 0.020% P, max. 0.01% sulfur, max. 0.005% B, balance iron and the usual process-related impurities.

3. Alloy according to claim 1 or 2, with a nickel content of 19 to 25

%.

4. The alloy of claim 1 or 2, with a nickel content of 25 to 34%.

5. An alloy according to claim 1 or 2, having a nickel content of 42 to 44

%.

6. The alloy of claim 1 or 2, with a nickel content of 44 to 52%.

7. An alloy according to claim 1 or 2, having a nickel content of 52 to 57

%.

8. The alloy of claim 1 or 2, having a nickel content of 57 to 65

%

9. An alloy according to claim 1 or 2, having a nickel content of 65 to 75

%.

10. An alloy according to claim 1 or 2, having a nickel content of 75 to 83

%

11. An alloy according to claim 1 or 2, having a nickel content of 19 to 22

%.

12. An alloy according to claim 1 or 2, having a nickel content of 23 to 25

%.

13. An alloy according to claim 1 or 2, having a nickel content of 25 to 28

%.

14. An alloy according to claim 1 or 2, having a nickel content of 28 to 31

%.

15. An alloy according to claim 1 or 2, having a nickel content of 31 to 34

%.

16. An alloy according to claim 1 or 2, with a nickel content of 44 to 48%.

17. An alloy according to claim 1 or 2, having a nickel content of 48 to 52%.

18. An alloy according to claim 1 or 2, having a nickel content of 57 to 61

%.

19. An alloy according to claim 1 or 2, having a nickel content of 61 to 65

%.

20. An alloy according to claim 1 or 2, having a nickel content of 65 to 70%.

21. The alloy of claim 1 or 2, having a nickel content of 70 to 75

%.

22. An alloy according to claim 1 or 2, having a nickel content of 75 to 79%.

23. Alloy according to claim 1 or 2, with a nickel content of 79 to 83

%.

24. An alloy according to any one of claims 1 to 23, having a chromium content of 14 to 18%.

25. Alloy according to one of claims 1 to 23, having a chromium content of 18 to 21%.

26. An alloy according to any one of claims 1 to 23, having a chromium content of 20 to 26%.

27. An alloy according to any one of claims 1 to 23, having a chromium content of 21 to 24%.

An alloy according to any one of claims 1 to 23, having a chromium content of 20 to 23%.

29. An alloy according to any one of claims 1 to 23, having a chromium content of 23 to 26%.

30. The alloy of any one of claims 1 to 29, having a silicon content of 1, 5 to 2.5%.

31. An alloy according to any one of claims 1 to 29, having a silicon content of 1, 0 to 1, 5%.

An alloy according to any one of claims 1 to 29, having a silicon content of 1.5 to 2.0%.

33. An alloy according to any one of claims 1 to 29, having a silicon content of 1.7 to 2.5%.

34. An alloy according to any one of claims 1 to 29, having a silicon content of 1, 2 to 1, 7%.

35. An alloy according to any one of claims 1 to 29, having a silicon content of 1.7 to 2.2%.

36. An alloy according to any one of claims 1 to 29, having a silicon content of 2.0 to 2.5%.

37. An alloy according to any one of claims 1 to 36, having an aluminum content of 0.1 to 0.7%.

38. An alloy according to any one of claims 1 to 37, having a manganese content of 0.1 to 0.7%.

39. An alloy according to any one of claims 1 to 38, having a lanthanum content of 0.02 to 0.2%.

40. An alloy according to any one of claims 1 to 38, having a lanthanum content of 0.02 to 0.15%.

41. An alloy according to any one of claims 1 to 38, having a lanthanum content of 0.04 to 0.15%.

42. An alloy according to any one of claims 1 to 41, having a nitrogen content of 0.02 to 0.10%.

43. An alloy according to any one of claims 41 to 41, having a nitrogen content of 0.03 to 0.09%.

44. An alloy according to any one of claims 1 to 41, having a nitrogen content of 0.05 to 0.09%.

45. An alloy according to any one of claims 1 to 44, having a carbon content of 0.04 to 0.10%.

46. An alloy according to any one of claims 1 to 45, having a magnesium content of 0.001 to 0.05%.

47. An alloy according to any one of claims 1 to 45, having a magnesium content of 0.008 to 0.05%.

48. An alloy according to any one of claims 1 to 47, with max. 0.005% sulfur and max. 0.003% B.

49. The alloy of any one of claims 1 to 48, further comprising 0.01 to 0.05% Ca.

50. The alloy of any of claims 1 to 48, further comprising 0.001 to 0.05% Ca.

51. An alloy according to any one of claims 1 to 50, further, if necessary, as an addition comprising at least one of the elements Ce, Y, Zr, Hf, Ti, each having a content of 0.01 to 0.3%

52. An alloy according to any one of claims 1 to 51, wherein 0.01 to 0.3% each of one or more of the elements La, Ce, Y, Zr, Hf, Ti, wherein the sum PwE = 1, 43 - Xce + 1 , 49 ^• X _La + 2.25 • X _γ + 2.19 • X _zr +1, 12 • X _Hf + 4.18 - X _T i ≤ 0.38, where PwE corresponds to the potential of the active elements.

53. An alloy according to any one of claims 1 to 51, wherein 0.01 to 0.2% each of one or more of the elements La, Ce, Y, Zr, Hf, Ti, wherein the sum PwE = 1, 43 'XCe ⁺ 1 , 49 ^• X _La + 2.25 • X _γ + 2.19 ^« X _zr +1, 12 • X ^ + 4.18 • Xτι <0.36, where PwE corresponds to the potential of the active elements.

54. An alloy according to any one of claims 1 to 51, wherein 0.02 to 0.15% each of one or more of the elements La, Ce, Y, Zr, Hf, Ti, wherein the sum PwE = 1, 43 - X _C e + 1, 49 • X _La + 2.25 • X _γ + 2.19 • X _zr +1, 12 - X ^ + 4.18 • X _T i ≤ 0.36, where PwE corresponds to the potential of the active elements ,

55. An alloy according to any one of claims 1 to 54, having a phosphorus content of 0.005 to 0.020%.

56. An alloy according to any one of claims 1 to 55, further comprising 0.01 to 1.0% each of one or more of Mo, W, V, Nb, Ta, Co.

57. An alloy according to any one of claims 1 to 55, further comprising 0.01 to 0.2% each of one or more of Mo, W, V, Nb, Ta, Co.

An alloy according to any one of claims 1 to 55, further comprising 0.01 to 0.06% each of one or more of Mo, W, V ₁ Nb, Ta, Co.

59. An alloy according to any one of claims 1 to 58, wherein the impurities are present in levels of max. 1, 0% Cu, max. 0.002% Pb, max. 0.002% Zn, max. 0.002% Sn are set.

60. Use of the alloy according to one of claims 1 to 59 for use in electrical heating elements.

61. Use of the alloy according to one of claims 1 to 59 for use in tubular heaters.

62. Use of the alloy according to one of claims 1 to 59 for use in electrical heating elements that require a high dimensional stability or a low sagging.

63. Use of the alloy according to one of claims 1 to 59 for use in furnace construction.