JPH02254136A - Heat-resistant and oxidation-resistant fe-cr-al series alloy having excellent manufacturability - Google Patents

Abstract

PURPOSE:To prepare the heat-resistant and oxidation-resistant Fe Cr-Al series alloy having excellent manufacturability by preparing an alloy contg. specified ratios of Fe, P, Cr, Ti, Al and rare earth metal and having specified contents of C, N, S, Si, Mn and Ni in impurities. CONSTITUTION:An alloy contg., by weight, 31/233 (REM+0.021) to 0.04% P, 18 to 28% Cr, 0.02 to (0.03+4C+24N/7) Ti, 4.5 to 6.5% Al, >0.06 to 0.15% REM (REM denotes lanthanoid series among rare earth elements), in which, as impurities, <=0.015% C, <=0.015% N as well as <=0.02% C+N, <=0.003% S, <=0.5% Si, <=1.0% Mn and <=0.3% N are regulated and the balance substantial Fe is prepd. In this way, the Fe-Cr-Al series alloy having excellent heat resistance, oxidation resistance and manufacturability can be obtd., which is suitable as foil for exhaust gas purifying apparatus.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides FeCr-
Regarding Aβ alloys, they are suitable for catalyst supports for automobile exhaust gas purification, which require particularly high resistance to abnormal oxidation in high-temperature exhaust gas atmospheres, as well as materials for high-temperature equipment using hydrocarbon-based fuels such as oil and gas. For example, it is useful for parts of various heating appliances such as kerosene stoves and hot air heaters, as well as heating elements such as burners and heating wires.

In addition, the abnormal oxidation referred to here means that the protective properties of the oxide film mainly composed of 41:Aff203 are lost, and oxides mainly composed of Fe develop rapidly, and then the center of the alloy foil is oxidized in a short period of time. This is a phenomenon in which things become objects. Further, hereinafter, the period until abnormal oxidation occurs will be referred to as the abnormal oxidation life.

[Conventional technology] Conventionally, ceramic and
Tsuku honeycomb has been used for some time, but in recent years it has been used in Japanese Patent Application Laid-Open No. 50-92 due to its advantages such as improved engine performance.
As disclosed in JP-A No. 286, JP-A-51-48473, JP-A-56-96726, and JP-A-57-7]898, this honeycomb body is made of FeC.
A technique has been proposed in which an r-ΔC-based heat-resistant alloy foil is used.

At this time, attention was focused on oxidation resistance and oxide film adhesion as properties required for the alloy foil, and therefore, since the oxidation resistance and oxide film adhesion have been traditionally focused on, electrical Based on the Fe-Cr-Al alloy, which is widely used as hot wires and high-temperature parts of heating appliances, 7-Al2O, which is oxidation-resistant or directly supports the catalyst, is
A foil with improved adhesion to 2 is used. In each of these technologies, the use of Y has been proposed as a means to improve the oxidation resistance of elementary H, but since Y is an extremely expensive element, its range of use is limited, and it has not been widely put into practical use. I haven't reached that point yet. On the other hand, in JP-A-58177437, Fe-C is mainly used to prevent peeling of the film.
0.002 to 0.05% by weight of La in r-AE alloy,
RE with a total amount of up to 0.06% by weight including Ce, Nd, Pr
An alloy containing M is disclosed, but the REM is 0.0.
It is said that if the content exceeds 6% by weight, the alloy cannot be processed at normal processing temperatures.

Furthermore, it is stated that Ti cannot be added because it lowers the oxidation resistance.

Unexamined Japanese Patent Publication 1986-. 15351, the same (Fe-C
In alloys based on the r7B system, since the addition of Y is expensive, REM whose main component is La other than Ce is added in a range of more than 0.05% by weight and less than 0.20% by weight. It is proposed that. The dirt is mainly caused by Ce, which is the cause of the decrease in hot pressability due to the addition of RFM, and
It is based on the new knowledge that e has the effect of lowering oxidation resistance, and that if REM is added mainly of La without Ce, hot working becomes possible and oxidation resistance is also improved.

[Problems to be Solved by the Invention] However, REM (rare earth elements) are generally difficult to separate from each other and are therefore substantially pure metals], a is Y
Although it is cheap compared to REM, it is still very expensive compared to so-called Minoshi J7 metal, which is a mixture of REM. Furthermore, similarly, removing only Ce will also result in an increase in price. Furthermore, Tetsu-to-Hagane Vo), 72 (1986), 31482 describes the oxidation behavior of Fe-CrAl alloy foil with a thickness of about 50 mm, and shows that a rapid reaction occurs after a certain time and that up to 6 parts of Rakuchu oxides and The occurrence of so-called abnormal oxidation corresponds to the time when the total amount of AP in the air is consumed as 0.0
The addition of about 15% by weight of (La + Ce) is A ff
It has been reported that the internal protection of 203 is improved.

However, the above report is about the oxidation behavior of the foil in the atmosphere, and the inventors have found that the oxidation behavior of the foil in the combustion exhaust gas, which is the subject of the present invention, is completely different. This became clear.

In other words, the occurrence of abnormal oxidation in exhaust gas does not necessarily mean total Aβ.
Abnormal oxidation has already occurred before the entire Δp is consumed.

Furthermore, in exhaust gas, the peeling resistance of the oxide film is improved by adding about 0.03% by weight of REM, as in the air, but the peeling resistance of the oxide film is improved, especially when observed over a long period of time. The generation of scattered particulate oxides mainly composed of Fe + Cr cannot be suppressed.

In addition, in the atmosphere for a long time, an oxide film mainly composed of Cr, which has some protective properties, may be formed under the A (220:l film), and in this case, the occurrence of abnormal oxidation can be suppressed over time. In some cases, a period of time can be recognized, but in exhaust gas, this period is only a short period of time, and in addition, the elasticity of the foil in this state has already deteriorated, and the dimensional change of the foil itself has become large. In fact, when used as an exhaust gas purification device, the foil that makes up the foil body has reached the end of its service life.The dimensional change of the foil observed over this long period is approximately 50 μm. This phenomenon occurs because the foil is thin, and is caused by the stress that occurs between the film and the metal as the surface oxide film grows.

Therefore, the present invention provides Fe-Cr-AI which has excellent resistance to abnormal oxidation in combustion exhaust gas and excellent manufacturability especially when used as a catalyst support! Its main purpose is to produce alloy foil.

[Means to solve the problem]

In order to achieve the purpose stated in "-", the present inventors have discovered that Fe-
As a result of various studies on Cr-AN alloys, we found that they can be used particularly as alloy foils for combustion exhaust gas purification devices, with excellent hot workability while suppressing price increases, and excellent toughness of hot-rolled sheets. FeCr-Aj has excellent oxidation resistance as a foil required from above, that is, resistance to abnormal oxidation in exhaust gas! They succeeded in obtaining a system alloy.

That is, in the present invention, Cr: 1B or more and 228 or less, and Ti: 0.02 or more (0,03+4C-N
) or less, Al: 4.5 or more and 6.5 or less, REM: more than 0.06 and 0.15 or less (However, I'l
EM contains impurities (C: 0.015 or less, N: 0.015 or less, C-1-N: 0.02 or less, S: 0.003 or less, Si). : 0.5 or less, Mn: ], O or less, Ni: 0.3 or less, and the remainder is essentially Fe. Heat-resistant and oxidation-resistant Fe-Cr-Aff with excellent manufacturability. The toughness and oxidation resistance of the hot-rolled coil can be further improved by adding Nb, if necessary, to the alloy.

Here, R and EM as used in the present invention refer to a mixture of lanthanoids among rare earth elements, and the ratio of the contained elements is approximately Ce=6 to 4.1-a-3-2, Pr
= 1-2, Nd = about 1 to 2, and Ce is contained in the largest amount, although this ratio varies slightly depending on compositional fluctuations in so-called Mi-Noche metal, which is a raw material added to steel, steel manufacturing yield, etc. Furthermore, the total amount of other rare earth elements is very small, and in fact only the above four elements can be detected as an analysis result.

By containing REM exceeding 0.06%, the Fe-CrAl alloy of the present invention having such a structure can suppress the generation of particulate oxides mainly composed of Fe and Cr, and in addition, can suppress the generation of particulate oxides mainly composed of Fe and Cr. Even greater effects can be obtained when combined with Ti. At this time, the effect lasts for a longer time when so-called minosmetal, which is a mixture of these REMs, is added than when Ce alone or La is added alone.

Furthermore, by containing more than 0.06% of REM, the plasticity of the oxide is mainly improved compared to when the amount of REM is small, so that the amount of deformation of the foil described above can be reduced.

Furthermore, by adjusting the amount of P in relation to the amount of REM, hot machining can be made easier, resulting in REM.
By making it possible to add a mixture of C and N, the increase in component element costs can be suppressed, and by significantly lowering C and N and using TiN that has a specific relationship with the amounts of both, the toughness of the hot rolled coil can be improved. By simplifying the manufacturing process, it is possible to suppress the increase in costs due to additional steps.

Furthermore, when Nl) is also added, the toughness of the hot rolled coil is further improved.

[For production]

Next, the reasons for limiting the ingredients used in the present invention and their effects will be explained. In addition, all the contents mentioned here are weight %.

(1,)C,N: Both are elements that significantly reduce the toughness of hot rolled coils.

In the present invention, this effect can be suppressed as much as possible depending on the relationship with T1, which will be described later.
If T1 is present in an amount exceeding 0.02% or C+N exceeds 0.02%, the toughness of the hot-rolled coil at around room temperature will not recover to a satisfactory value even if T1 is added, and for example, when unwinding the hot-rolled coil, Reheating to a high temperature is required, which increases the cost. Therefore, each of C and N must be at most 0.015%, and the total amount of C+N must be at least 0.02%.

(2) Ti In the present invention, Ti is a useful element that prevents the above-mentioned adverse effects of C and N on the toughness of the hot rolled coil, and also particularly improves the oxidation resistance in exhaust gas. . In order to improve hot rolled sheet toughness, it is necessary to add at least 0.602% or more. On the other hand, according to the inspection conducted by the present inventors, 1゛i
Once the toughness is significantly decreased with the addition of C, on the contrary, the toughness
If an excess of 1゛ is contained in relation to the amount of N, the toughness will actually become extremely low. Upon further examination, it was found that when Ti is included in excess, 10
A large number of coarse square-shaped TiN exceeding the side (- part T
i (C,N)) precipitates or inclusions are already formed during casting or at subsequent high temperatures exceeding < 1350°C, and these precipitates or inclusions are likely to remain in the material even after hot rolling. It has become clear that this is due to the fact that the sensitivity of Therefore, in this sense, there is an upper limit to the amount of Ti, and according to the studies of the present inventors,
Its value is (0,03-1-4C-+N)%. That is, when ζTi is contained in excess of this amount, T
The toughness of the hot-rolled sheet deteriorates by one level for a different reason than when the l content is less than 0.02%. Therefore, in the present invention, Ti is added to improve the toughness of hot rolled sheets.
is 0.02% or more (0.03+4 C+ -----・N
)%, which is a relatively small amount.

Furthermore, in the present invention, even when added in such a relatively small amount, Ti has the effect of improving oxidation resistance, particularly resistance to abnormal oxidation in exhaust gas.

In this case, the effect becomes greater when Ti is added in an amount of (4c+--N)% or more, but even if Ti is added in excess, the oxidation resistance improvement effect due to Ti quickly saturates, so the toughness of the hot-rolled coil was taken into account. This range corresponds to the addition range of Ti. Therefore, the Ti content of the present invention is 0.02% or more (0,03+4 C + - N
)% or less.

Si: Although Si is useful for improving oxidation resistance, it significantly reduces the toughness of hot-rolled coils. shall be 0.5% or less.

Mn: In the present invention, Mn tends to lower the oxidation resistance slightly, so it is set to 1.0% or less.

In the present invention, P is an element that has an important meaning in improving hot workability in relation to REL and A.

That is, studies by the present inventors have revealed that when a relatively large amount of REM exceeding 0.06% is added, processing (that is, rolling) can be performed without any problem during hot rolling. At this time, for example, C, which is contained in the largest amount in REM,
A part of e exists in steel as relatively fine granular phosphides of around 3I1m, so F
This makes it possible to prevent deterioration in hot workability due to the formation of compounds with e.

Therefore, P has such a useful effect when a large amount of REM is added, but on the other hand, Fe-Cr-
A7! In order to promote the embrittlement of the alloy, especially in the temperature range of about 450 to 520°C, its upper limit is limited to 0.04%.

% or less.

S decreases oxidation resistance, so in the present invention it is 0.0
03% or less.

Cr Cr is the most basic additive element that ensures corrosion resistance and heat resistance of stainless steel. In the present invention, if it is less than 18%, oxidation resistance and film adhesion cannot be sufficiently ensured, while if it exceeds 28%, the toughness and cold workability (rollability) of the hot rolled coil will be significantly deteriorated. Since it begins to decrease, the range becomes 18% or more and 28% or less.

/l is a basic element that ensures oxidation resistance in the present invention. If it is less than 4.5%, the protective properties of the oxide film in exhaust gas will be extremely poor, especially in the case of foil, and it will not be able to withstand use as an exhaust gas purification device. On the other hand, if it is added in excess of 6.5%, fine cracks will occur in the film when the foil is repeatedly heated in the exhaust gas, and this cannot be sufficiently suppressed within the scope of the present invention even by adding REM and Ti. .

In addition, excessive AN extremely reduces the toughness of the hot-rolled sheet, and on the other hand, the appropriate tension range for preventing wrinkles during foil rolling becomes narrow.

Therefore, in the present invention, AN is 4.5% or more and 6.5%.
% or less.

N1: Ni is an element with strong bonding force with 11, and FeCr-
In the present invention, it is set to 0.3 or less because it significantly embrittles the Aβ alloy.

RBM: In the present invention, REM significantly improves the foil's resistance to abnormal oxidation, especially in exhaust gas. It has been known that the addition of about 0.03% REM improves the peeling resistance of the Ae ZO:1 film when heating and cooling are repeated, but this is noticeable in combustion exhaust gas as in the present invention. Even if no peeling of the film is observed, very fine cracks occur on the surface film of the foil during long-term use, and in some cases, fine oxide particles mainly composed of Fe are observed in the cracks and around the edges, causing the film to deteriorate. It was revealed that the protective properties of In addition, even if such cracks do not occur, oxide particles mainly composed of Fe and Cr are found in the oxide film mainly composed of A 1 zO3 by microscopic observation from the surface during long-term use in exhaust gas. The film becomes scattered, and the protective properties of the film decrease in these areas. These phenomena are observed even before the total ρ in the flute is consumed.

However, when REV is added in an amount exceeding 0.06%, this phenomenon is significantly suppressed and the life of abnormal oxidation in exhaust gas is significantly improved.

Furthermore, it has been found that the effect of REM addition is greater when the mixture is added than when Ce is added alone or when La is added alone.

On the other hand, the REM
Although it prevents the film from peeling off, it is said that if added in large quantities, hot processing becomes impossible.

Furthermore, in the above-mentioned Japanese Patent Application Laid-Open No. 63-45351, REM
As a result of examining each element separately, it was found that hot processing is possible with the exception of Ce when a large amount of REM is added.

In the present invention, the relationship with P is important as a technique that makes it possible to add a large amount of REM to the mixture due to the effect of REM on the oxidation properties of the foil in exhaust gas as described above. It has become clear that it is possible to sufficiently manufacture the film by a normal hot rolling process if the above-mentioned specific quantitative relationship is maintained.

However, when REM is added in an amount exceeding 0.15%, both the amount and size of phosphides increase, making it difficult to roll the foil into a foil of about 50 nm.

Furthermore, defects such as cracks frequently occur on the surface of the steel ingot after casting, resulting in extremely low productivity.

Therefore, the addition range of REM is 0.0 in the present invention.
It exceeds 6% and becomes 0.15% or less.

Further, it is desirable to add REM at the final stage of melting, that is, immediately before casting.

Nb: Nb can be added selectively in the present invention.

In the present invention, the purpose of adding Nb is mainly to improve the toughness of the hot-rolled coil, but coexistence with REM also improves the adhesion of the coating.

From the viewpoint of ensuring toughness, at least 0.05% or more is required, but if it is contained in a large amount, the steel ingot after casting is likely to crack during cooling. In terms of the direction of toughness, the upper limit for the amount of Nb added is that even if it is added in excess of C and N%, the toughness improvement effect will be saturated.

Furthermore, when Nb is added in combination with REV, it has the effect of particularly improving the adhesion of the film, but in the present invention, this is only an auxiliary effect.

Therefore, the addition range depending on the selection of Nb is as follows.

In addition, this selectively added Nb is added to Ti during melting.
It is desirable to add it earlier.

〔Example〕

Next, the present invention will be further explained in detail with reference to Examples.

(Example-1) Table 1 shows the chemical composition of the alloy foil of the example of the present invention and the chemical composition of the alloy of the comparative example.

Both of these steels are processed to 25k in a vacuum high frequency induction furnace.
After g melting and ingot casting, l] at 80'c.
Immediately after the hr holding time, hot rolling was started and the plate was rolled to a thickness of 4 mm. After that, it was allowed to cool naturally, and when the surface temperature of the plate reached 550"C, it was charged into a heating furnace at 500°C and rolled for 1hr. After inspection, the furnace was cooled.At this time, cracks occurred in Y2, but the steel ingot did not break apart, so the thickness was 4Ill.
He even made it to the board of I11.

In addition, some cracking occurred in Yll during rolling, and when the finished plate was observed, edge cracking and surface cracking were observed, although they were relatively minor. No particular problem occurred during hot rolling for the other steels, neither the X series nor the Y series. These results are summarized in Table 2 in the column of hot-rolling property with X marks for those in which cracks occurred in the hot-rolled sheets, and O marks for those without any problems.

Next, the toughness of these hot rolled sheets was examined using sub-sized Charpy test pieces.

For Y3, Y7, and Y8, cracks occurred in the sub-size Charpy test specimens during processing, or
A phenomenon in which part of the test piece fell off occurred frequently. From this, it was determined that these three steel types had extremely poor toughness, so Charpy impact tests were not conducted.

Table 2 shows the results of the hot rolled sheet toughness investigation.

As a judgment indicator, the average value of the absorbed energy of a 2mm V notch 1/3 sub-size Charpy impact test piece at three points at each temperature exceeds 5.5 kg・rn/c+a, and this temperature is 60°C or less. Mark things with ◎,
Over 60°C and under 90°C marked with ○, over 90'C with 12
Those below 0°C were marked with an X, and those above 20°C were marked with an XX mark. In addition, those marked with ◎ can be manufactured without any special treatment even during mass production at a factory, and O
The mark may require some heat treatment, but basically it can be mass-produced. On the other hand, the ones marked with an "X" are completely passed through the factory (although it is not impossible, care must always be taken to control the temperature of the board at that time, resulting in an extremely low productivity and a significant increase in costs. It is judged that it is practically impossible to manufacture this product using the normal factory production process for stainless steel sheets using hot-rolled coils.

Next, among the hot-rolled sheets obtained in this way, Y2 and Yll, which had cracks during hot rolling, and Yl, Y3, and Y7, whose hot-rolled sheets had extremely low toughness. After cold rolling each material except Y8 and YIO (some were warm rolled) 950
After annealing at 'C, the thickness is 1.5 mm, the width is 2 On+m,
It was attached to a coupon-shaped oxidation test piece with a length of 25 mm, and the surface was wet-polished with No. 1500 emery paper. These test pieces were heated to 1200°C for 20 hours, then immediately placed in a metal petri dish, allowed to cool naturally, and the test was repeated 5 times to collect the resulting peeled off oxide film. The weight of the fallen oxide scale collected at this temperature was measured, and the scale resistance and releasability of each sample were examined.

The results are summarized in the column of atmospheric peeling resistance in Table 2.

The ◎ mark in the table indicates the total weight of peeled scale is 0 after heating 5 times.
．． 5 mg or less, ○ mark is 0.5 mgl 2.0
mg or less, and X marks exceed 2.0 mg. Among the tested ropes, Yl and 4, which have no 'Fi added and a small amount of REM added, had a slightly higher amount of peeling, but the other ropes were based on this test! , 11 distance is very small, less than 2.0 mg.

Next, the cold-rolled annealed sheet was further rolled to a foil of 50 IITn, cut into Tl]3Q mm lengths of 50 mm, heated in gasoline engine exhaust gas at 1150°C for 7 hours, and then allowed to cool. The process was continued until abnormal oxidation occurred on each foil.

In addition, the sample foil at this time was 501! Three specimens were tested for each component with m-L of 1 μm, and the average value was taken as the abnormal oxidation life of the component foil.

In addition, the engine exhaust gas is a 4-cylinder gasoline engine with an exhaust of 1800 cc at a rotation speed of 1500 rpm and a load of 5 kg.
- Occurs at an air-fuel ratio of 13 under operating conditions of 150
It was introduced into the heating furnace through a conduit kept at a temperature of 'C.

These results are summarized in the column of exhaust gas life in Table 2. Each of the steel foils of X1 to X10 of the present invention examples was used for 370 h.
It shows a long life of more than r.

(Example-2) In Table 1, xl and X3 are examples of the present invention, and Y9 is a comparative example. A total of 5 types of Yl3 and Yl6, thickness 50 μm
The foil [1] is a 65 mm copper strip, and a period of 3 and 5 is attached to this.
A piece of corrugated material (corrugated sheet) with a sinusoidal waveform of 3.2 mm in width and amplitude of 3.2 mm is rolled up by overlapping this unprocessed foil (flat plate) band to an apparent diameter of about 42 mm and a length of 65 m.
A honeycomb-shaped cylindrical body of 3 m was prepared, and a commercially available Ni-based brazing material powder was appropriately adhered to the corrugated plate/flat plate contact part.
It was heated in a vacuum of about Xl0-'Torr and subjected to brazing treatment.

The honeycomb structure thus obtained was placed in a horizontal tubular heating furnace with an inner diameter of 45 mm in the furnace core tube, and the same engine exhaust gas as described above was introduced from one end of the furnace core tube at an inflow rate of 10 E / min (at 150°C)]
Heated at 100°C and 300 br.

Furthermore, these honeycomb structures are then cut and disassembled,
While observing the oxidation status of the foil surface using SEM,
The Aβ concentration in Kyoto was measured at -A.

At this time, when the vertically split cross section of the honeycomb body was visually observed, Yl3 had turned green, and abnormal oxidation was observed in some parts. In addition, a patchy green area was observed in Y9, and a green area was observed in Yl6 near the wax phase. On the other hand, Xl and X3 exhibited a grayish white color overall.

-] Duplicate SBM and EPMΔ results are shown in Table 3.

According to the observation results by SEM, Yl3 with a small amount of REM
There were many cracks in the Ae 203 film on the surface of the foil, and Fe-based oxide particles were observed in some of the cracks. In addition, cracks in the film were also observed in Y9 and Yl6, although it was milder than Yl3, and some cracks were observed in Y9 and Yl6.
Similar to 13, generation of Fe-based oxides was also confirmed. On the other hand, in Xl and χ3, steps corresponding to the crystal grain boundaries of the substrate were observed on the coating surface, but no cracks were observed in the coating.

Furthermore, the remaining amount of Aβ by EPMA is 0.7 for Yl3.
% of All remains. In addition, 09% of Y9 was further Yl6. 1.1% and 1.0 for Xl and X3, respectively
%, ], 4% remain.

From this, it is clear that the honeycomb structure using the foil according to the present invention has high resistance to minute cracks in the film even in exhaust gas, and is also excellent in resistance to abnormal oxidation.

(Example-3) 100 kg of steel having the composition shown in Table 4 was melted and cast in a vacuum high-frequency furnace, heated to 1200°C, hot rolled to 30%, air cooled, and further heated to ζ1150. A hot-rolled sheet with a thickness of 2.5 n+m was obtained by hot rolling at °C.

Furthermore, this was processed into a 7821 (7821) with a thickness of 50 cm and a medium size of 65 mm by the steps of John de blasting, pickling, cold rolling, annealing, degreasing, pickling, foil rolling, degreasing, slitting, foil rolling, and vacuum annealing.
A file was created.

The diameter of this foil was 42 m111 by using the same method as described above.
A brazed cylindrical honeycomb structure with a length of 65 mm was prepared and installed in a horizontal tubular heating furnace with a core tube inner diameter of 45 mm. From one end of this heating furnace, a mixed gas of about 0.2 Vo, 1% and the balance N2 is fed as a simulated coagulation exhaust gas at room temperature.
The honeycomb-shaped test specimen was heated to 1070°C and taken out every 50 hours, and after cooling, the mold amount changed and the distance between the center portions of both end faces was measured. 12 times to measure the change in length (copper 600
(equivalent to heating time) was repeated.

The results are shown in Figure 1 and the second round.

Both the weight increase and dimensional change after 600 hours were significantly smaller in Xll according to the present invention than in Comparative Example YIB, and it is clear that it has excellent durability when used as a constituent foil of an exhaust gas purification device.

Table 2 Table 3 Table 2 Continued 2541.36 (12) [Effects of the invention] As is clear from the examples, FeCr-- according to the present invention
Ae-based alloys allow the selection of additive elements at a lower cost, have good hot cutability and hot rolled sheet toughness, and are excellent in the manufacture of foils, etc., so manufacturing costs can be reduced. In addition to the peeling resistance of the oxide film, it also has excellent resistance to abnormal oxidation in exhaust gas as an alloy foil, and even as a honeycomb structure made of brazed alloy foil, it has excellent peeling resistance in exhaust gas. It also has excellent oxidation resistance and resistance to shape change.

Therefore, the Fe-Cr-Aji alloy of the present invention is suitable as a foil for an exhaust gas purification device, and is particularly suitable as a catalyst support for an automobile exhaust gas purification device.

[Brief explanation of drawings]

FIG. 1 shows a honeycomb 1 brazed with alloy foil according to the present invention.
FIG. 2 is a graph showing the change in weight over time of the structure due to heating at 1070° C. in simulated exhaust gas, and FIG. 2 is a graph showing the change in length over time. (5) 10r (& woki 11 (Tayama) Kishudan 2 vows

Claims (1)

[Claims] 1. P in weight%: 31/233 (REM+0.021) or more 0.04
% or less, Cr: 18 or more and 28 or less, Ti: 0.02 or more (0.03+4C+24/7N) or less, Al: 4.5 or more and 6.5 or less, REM: more than 0.06 and 0.15 or less (however, R.E.M.
is a lanthanoid among rare earth elements), and contains C: 0.015 or less, N: 0.015 or less as impurities, and C+N: 0.02 or less, S: 0.003 or less, Si: 0.5 or less. A heat-resistant and oxidation-resistant Fe-Cr-Al alloy with excellent manufacturability, characterized in that Mn: 1.0 or less, Ni: 0.3 or less, and the remainder substantially consists of Fe. 2. Furthermore, Nb: 0.05 or more [0.1+(93/12)・C+(
93/14).N] or less.