JPH06104879B2 - Heat-resistant stainless steel foil for combustion exhaust gas purification catalyst carrier - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat resistant stainless steel foil used as a catalyst carrier for a combustion exhaust gas purification apparatus. More specifically, it relates to a heat-resistant stainless steel foil, which is not only excellent in oxidation resistance and manufacturability but also excellent in strength at high temperatures, and therefore has a large effect of improving structural durability when used in a honeycomb body of a catalyst. .

[Conventional technology]

Conventionally, ceramic honeycomb has been used in combustion exhaust gas purification equipment for automobiles, etc., but by replacing it with heat-resistant stainless steel foil, it is possible to reduce the wall thickness of the honeycomb wall and reduce the ventilation resistance and heat capacity of the engine. Since it is possible to improve performance and save expensive catalyst precious metals, for example, JP-A-50-92286, JP-A-51-48473 and JP-A-57-7189.
As disclosed in each publication of No. 8, this honeycomb body is
Techniques for constructing e-Cr-Al heat-resistant metal foil have been proposed.

In this case, as the properties required for the alloy, attention is paid to the oxidation resistance and the adhesion of the film. Therefore, since the material is generally excellent in the oxidation resistance and the adhesion of the film, the heating wire and the Based on the Fe-Cr-Al alloy that has been widely used as high-temperature parts for heating appliances, its oxidation resistance or activated alumina (γ-Al ₂ O ₃ ) that is a direct carrier of the catalyst
A foil having improved adhesion to the coat layer is used. All of the techniques disclosed in the above publications use Y as a means for improving the oxidation resistance of the material, but since Y is an extremely expensive element, its range of use is limited.

On the other hand, JP-A-58-177437 discloses 0.002-0.05 in order to prevent mainly the peeling of the oxide film of Fe-Cr-Al alloy.
Containing wt% of La, Ce, Pr, Nd rare earth element,
Alloys with a total amount of up to 0.06% by weight of rare earth elements, and Zr to stabilize the alloy and Nb to secure the creep strength at high temperature are added within the range of specific relationship with C and N contents, respectively. Alloys have been proposed. In this patent, alloys containing less than 0.06% by weight of rare earth elements show almost no improvement in oxidation resistance as compared with the alloys having a total content of less than 0.06% by weight, and they cannot be processed at normal hot working temperatures. It has said.

Japanese Patent Laid-Open No. 63-45351 discloses that the addition of Y is expensive in an alloy based on the Fe-Cr-Al system, and only 0.05 to 0.2% by weight of Ln or La excluding Ce is considered.
It is proposed to add in the range of. This is because the cause of the decrease in hot workability due to the addition of Ln is the presence of Ce, and further Ce has the effect of reducing the oxidation resistance as well. Therefore, if Ln that excludes only Ce is added, the heat It is said that it is based on the finding that hot working becomes possible and oxidation resistance is also improved. However, because Ln is a chemically active element and its chemical properties are similar to each other, individual separation is not easy, and thus substantially pure La is cheaper than Y. However, it is still very expensive for misch metal, which is a common mixture of Ln. Similarly, separating and removing only Ce inevitably raises prices. Further, in the Japanese Patent Laid-Open No. 63-42356 by the same applicant as this, La, C as an Fe-Cr-Al-based alloy excellent in oxidation resistance and oxide scale delamination resistance is disclosed.
Although an alloy containing 0.01% or more and 0.30% or less in total of e, Pr and Nd is disclosed, hot workability of this alloy has not been examined at all.

In addition, although these conventional techniques have been mainly studied for the adhesion and oxidation resistance of the oxide film, the structural durability of the honeycomb body, which is a practically important required property as a foil forming the honeycomb body of the catalyst, is considered. The effect of the foil material on the properties has not been sufficiently investigated.

[Problems to be Solved by the Invention]

However, for example, in the case of automobile catalyst carriers, the life of the catalyst carrier rarely reaches the end of its life due to the lack of oxidation resistance of the foil under normal operating conditions. In most cases, thermal fatigue causes damage and reaches the end of life. That is, at the time of acceleration, the honeycomb body is rapidly heated from the inside by the high-temperature and high-speed exhaust gas flow, but is forcibly cooled from the outside by the traveling wind, so that a rapid temperature gradient occurs in the honeycomb and large thermal strain occurs. Occurs. This thermal strain is not uniformly distributed in the radial direction of the honeycomb body, but is concentrated from the outermost periphery to the inside of several layers. This is because the material temperature is lower on the outer peripheral side and the yield strength of the foil at that time is higher, and it is because the inner layer side is hot but the temperature gradient is small, and the yield strength of the ferrite-based stainless steel foil forming the honeycomb is remarkably high. This is because the temperature region where the temperature starts to decrease and the region where the steepest temperature gradient occurs are coincident with each other in a few layers from the outermost circumference. Further, even when traveling at a constant speed, since the cooling by the traveling wind is applied from the outside, the degree thereof is moderated, but the strain continues to be concentrated in the region of several layers from the outermost periphery. Further, when decelerating or idling, a relatively low temperature gas flows, so the honeycomb body is cooled from the outside as well as from the inside. Distortion concentrates.

That is, in many cases, the honeycomb body of the catalyst carrier reaches the structural life such as crushing or extreme deformation of cells due to the accumulation of thermal strain generated therein by the repeated heating and cooling. In such a case, the proof stress at high temperature of the foil is important, especially where it matches the steep temperature gradient region in the honeycomb body as described above, that is, the temperature of 600 to 850 ° C. according to the measurement by the inventors. It is clear that it is effective for improving the structural life of the honeycomb body that the foil material in the region has a high yield strength and that the degree of decrease in the yield strength due to the temperature at 600 ° C or higher is as small as possible. It was

Further, when widely used for general use such as passenger cars, first of all, it is desirable that the material cost is low and stable supply is possible. Therefore, the material cost is low and the conventional stainless steel is used. It is important to keep the manufacturing cost low because it can be manufactured relatively easily in the mass production process.

Further, since it is exposed to high-temperature exhaust gas in the state of a foil having a remarkably large surface area with respect to volume, it must naturally also have excellent oxidation resistance.

The present inventors have made various studies to develop a constituent foil of a catalyst carrier having all of the above-mentioned characteristics in view of the problems of the present situation, and arrived at the present invention.

[Means for Solving the Problems]

That is, first, in order to improve the oxidation resistance while suppressing the component cost of the foil as low as possible, it is effective to add Ln in excess of 0.06%, and the oxidation resistance is dramatically improved compared to the case of 0.06% or less. Improved and in this case the previously mentioned JP-A-58-177437
The deterioration of hot workability as described in Japanese Patent No. 63-45351 and No. 63-45351 does not occur at all if P is contained in combination with Ln.

Further, as described above, in order to improve the structural durability of the catalyst carrier due to heating / cooling, 60% of the foil constituting the honeycomb body is used.
It is important to improve the proof stress at 0 to 850 ° C, and as a result of various studies for this purpose, the addition of Ta is particularly effective, and when Mo and / or W is further added, especially at a high temperature side exceeding 800 ° C. It has been found that the yield strength is further improved.

Furthermore, as a result of investigating the toughness of hot-rolled sheet, which is a problem in manufacturing this type of ferritic stainless steel, Nb similar to Ta
It has been revealed that the addition can be remarkably improved, and can be raised to a level at which mass production can be sufficiently performed in a normal stainless steel manufacturing process.

In addition, during such various investigations, the effects of Ti, Zr and V were also investigated, but it was revealed that Ti hardly increases the high temperature proof stress, and excessive addition rather reduces the toughness of the hot rolled sheet, It has been found that Zr slightly increases the proof stress at high temperature when added in a relatively small amount, but it significantly reduces the oxidation resistance of the foil and also impairs the toughness of the hot rolled sheet. Further, it has been clarified that V has neither an effect of improving the proof stress at high temperature nor an effect of improving the toughness of the hot rolled sheet.

That is, according to the present invention, based on the above-described examination results, it is natural that the foil is excellent in oxidation resistance and film adhesion even in high-temperature exhaust gas. It was achieved for the purpose of providing a heat-resistant stainless steel foil that can be supplied at low cost, which is also effective in improving the structural durability of the product, and is also excellent in manufacturability such as hot workability and toughness of hot-rolled sheet. It is a thing. Then, the specific means is as follows.

% By weight, Ln: more than 0.06%, 0.15% or less (however, Ln is La, Ce, Pr, Nd) P: 8 x (Ln% + 0.015) / 45 or more, 0.1% or less Al: 4.5% or more, 6.5% or less Cr: 13% or more, 25% or less Ta: (181 ・ C% / 12 ＋ 181 ・ N% / 14) × 1.5 or more, 3% or less C: 0.025% or less N: 0.02% or less C + N: 0.03% or less Remainder A heat resistant stainless steel foil for a combustion exhaust gas purifying catalyst carrier, characterized by comprising Fe and inevitable impurities, and further by containing Nb in an amount of% by weight and Ta + Nb of 3% or less, particularly the hot rolled sheet. Toughness can be improved.

In addition, the total amount of at least one of Mo and W is 4% by weight.
By adding in the following range, the proof stress can be further improved especially on the high temperature side.

[Action]

Next, the reasons for limiting the components in the present invention and their effects will be described in detail. All chemical compositions in the present specification are% by weight.

(1) Ln (Lanthanoide): First, Ln (Lanthanoide) means La and Lu in the periodic table, and Lu
In the case of the present invention, a cheaper so-called misch metal can be used as the actual addition raw material. At this time, four elements of La, Ce, Pr, and Nd are detected as a result of the analysis, and the other elements are negligible because they are extremely small amounts. Therefore, the Ln of the present invention refers to the above 4
It is a mixture of elements, and misch metal is used as an additive raw material.

As mentioned above, Ln has the effect of improving the resistance to the abnormal oxidation of the foil in the exhaust gas, and the life until the abnormal oxidation of the foil in the exhaust gas is such that Ln exceeds 0.06%. And significantly less than that, but 0.
When it exceeds 15%, it begins to decline again. Therefore, the range is
It is limited to more than 0.06% and 0.15% or less.

(2) P: In the present invention, P is an important element for the purpose of improving the hot workability in relation to Ln.

That is, the present invention makes it possible to remarkably improve the oxidation resistance of the foil by adding Ln in the above-mentioned range, but conventionally the addition of such a relatively large amount of Ln improves the workability during hot working. It has been considered difficult to manufacture in the usual mass production process of the stainless steel sheet using the hot rolled coil. It has been considered that the cause is that Ce, which is the main component when misch metal is added, easily forms an intermetallic compound with Fe having a low melting point. However, if a large amount of Ln is added in combination with P, for example, Ce and La
A part of them is present in the steel as a relatively fine and granular high melting point phosphide having a particle size of 3 μm or less, and the hot workability is not deteriorated at all. According to the study of the present inventors, the content of P necessary for this is based on the premise of a large-scale steel ingot in a factory with large segregation in the range of Ln exceeding 0.06% and 0.15% or less. Has a lower limit of 8 × (Ln% +
It becomes 0.015) / 45.

On the other hand, since P has an action of lowering the toughness of ferritic stainless steel, the addition amount is limited from this point in Fe-Cr-Al stainless steel which is originally inferior in toughness, and in the present invention, The amount is 0.1%. Further, addition of P in such a range does not adversely affect the oxidation resistance.

(3) Al: Al is a basic element for ensuring the oxidation resistance in the present invention, and if it is less than 4.5%, the protection of the oxide film in the exhaust gas is poor in the case of foil, and abnormal oxidation easily occurs. Since it is generated, it cannot be used as a carrier for the catalyst. On the other hand, when the content exceeds 6.5%, the toughness of the hot-rolled sheet is extremely lowered, the productivity is impaired, and the thermal expansion coefficient of the foil becomes large,
When used as a catalyst carrier, thermal fatigue increases due to repeated heating and cooling. Therefore, in the present invention, Al
Is 4.5% or more and 6.5% or less.

(4) Cr: Cr is a basic element that ensures the corrosion resistance of stainless steel.
In the present invention, the main component of oxidation resistance is the Al ₂ O ₃ film, but if Cr is insufficient, its adhesion and protection properties will deteriorate. On the other hand, if Cr is excessive, the toughness of the hot-rolled sheet decreases, so the range is 13% or more and 25% or less.

(5) Ta: In the present invention, Ta is an important additive element for improving the yield strength of the foil at high temperature and improving the structural durability of the catalyst carrier. The action of Ta combines with C and N in the steel to form carbonitrides, which in addition to exerting a so-called precipitation strengthening action, and in addition, the surplus amount of which forms a solid solution in the matrix to exert a solid solution strengthening action. The high temperature yield strength is improved. At this time, the precipitation strengthening action has a great effect, but for example, the precipitate may become coarser gradually during use for a long time in a temperature range exceeding 750 ° C., and the effect may be reduced. On the other hand, the solid solution strengthening action is not so effective as the precipitation strengthening action, but there is almost no decrease in the action and effect even after long-term use. Therefore
Even if the precipitation strengthening effect of Ta is lost due to the above-mentioned phenomenon, Ta still has the effect of maintaining C, C
It is necessary to add some excess with respect to the amount of N. From the above viewpoint, the present inventors have examined (181
・ C% / 12 + 181 ・ N% / 14) × 1.5 or more is required.

However, when the Ta content is extremely excessive, the Laves phase precipitates, the steel ingot after casting is easily cracked, and the hot workability,
The toughness and high temperature proof stress of the hot-rolled sheet also start to decrease. Of the present invention
In the range of C and N amounts, the amount is 3%. For these reasons, the Ta addition range is as follows.

Ta: (181 · C% / 12 + 181 · N% / 14) × 1.5 or more, 3% or less Furthermore, Ta has the effect of improving the toughness of the hot-rolled sheet because it fixes C and N, but within the above addition range. If so, this effect is sufficiently brought about, and excessive addition rather reduces toughness.

(6) C, N: In the present invention, both C and N significantly reduce the toughness of the hot rolled sheet. This adverse effect can be suppressed by the action of Ta or Nb described later, but recovers the toughness when C exceeds 0.025%, N exceeds 0.02%, or the total amount of C + N exceeds 0.03%. It will be difficult to make them. Therefore, from this point, C: 0.025% or less, N: 0.02% or less, and C + N: 0.03% or less are in that range.

C and N also precipitate as carbonitrides, which also has the desirable effect of improving the high-temperature yield strength by precipitation strengthening, but as mentioned above, this is effective when the precipitates become coarse. Is reduced. When a large amount of C and N is contained, even if Ta is added in an amount not less than the above lower limit, coarsening of this precipitate is promoted and the rate of reduction of the strengthening action becomes large. That is, when a large amount of C and N is contained, the size of each carbonitride increases, and it is difficult to form a fine and uniform precipitation morphology effective for precipitation strengthening.
From this point as well, the C and N contents are limited, but in the present invention, such inconvenience does not occur as long as it is within the range determined from the toughness point described above. For the above reasons, C, N
The range of C is 0.025% or less, N: 0.02% or less, and C + N: 0.03% or less.

(7) Nb: In the present invention, Nb can be selectively added to improve the toughness of the hot-rolled sheet, but Nb, like Ta, forms a Laves phase when it is added excessively excessively. Causes the same damage as in. Therefore, the upper limit is limited from this point, and according to the study of the present inventors, Ta + Nb is 3% or less.

(8) Mo, W: In the present invention, Mo and W can be selectively added in order to further improve the proof stress particularly at high temperature. In the present invention, the proof stress at high temperature can be improved by the proper addition of Ta, but as described above, the part of the action of Ta due to precipitation strengthening may gradually decrease during use at high temperature. On the contrary, excessive addition lowers the high temperature yield strength. However, Mo
Most of W and W are dissolved in a considerable amount without forming a harmful precipitation phase, and a relatively large strengthening effect is obtained, and Ta, N
Even in the presence of b, its effect is not affected at all, and at the same time, there is almost no decrease in the strengthening action with time.
That is, by adding Mo and W, the high temperature proof stress can be stably improved further.

On the other hand, since most of Mo and W both form a solid solution, the metal base is strengthened with the addition amount, but at the same time, the hot workability and toughness decrease. Therefore, the addition amounts of Mo and W are restricted from this point, and the upper limit values are both 4%. The same effect can be obtained by adding Mo and W together, but the upper limit in this case is 4% or less for Mo + W.

(9) Other impurities: In the present invention, Mn: Mn is particularly concentrated in the oxide film at the very initial stage, which adversely affects the subsequent formation of Al ₂ O ₃ film and leaves structural defects in the film. It is desirable to limit it to 0.3% or less because it will contribute.

Si: Si is an element that improves the oxidation resistance, but at the same time greatly reduces the toughness of the hot rolled sheet. High Al ferritic stainless steels such as those of the present invention are originally superior in oxidation resistance, so Si
From the viewpoint of toughness, it is desirable to control the amount to be a small amount, and the range is 0.5% or less. Like S, S: S easily forms a high melting point compound with Ln, but at the same time reduces oxidation resistance,
In the present invention, it is desirable to suppress the content to 0.003% or less.

The Fe-Cr-Al alloy of the present invention having such a configuration is combined with a melting process, a hot rolling process, and a cold rolling process, which are similar to the mass production process of a normal ferritic stainless steel, and an annealing process as needed. By doing so, it is possible to manufacture foil with a thickness of about 50 μm. Further, the foil thus produced, and the exhaust gas purifying catalyst carrier and the catalyst device configured by using the foil not only have a significantly high resistance to the occurrence of abnormal oxidation even in a high temperature combustion exhaust gas atmosphere, but also at a high temperature of the foil. Since the honeycomb body has a high yield strength, it has a large resistance to thermal fatigue as a honeycomb body, and has excellent structural durability even under a use condition in which heating and cooling are repeated.

〔Example〕

Next, the effects of the present invention will be described in more detail with reference to examples.

(Example 1) Table 1 shows the chemical composition of the steel used for evaluating the hot workability and toughness as the manufacturability of the steel according to the present invention, the oxidation resistance of the foil, and the proof stress at high temperature. . At this time, Si was 0.3% or less in any steel and S was 0.003% or less. The chemical composition of the misch metal, which is the raw material for the addition of Ln used for melting, is Ce: 49-54%, La: 19-27%, Nd: 16-24%.
%, Pr: 5 to 8%, Sm: 0.2% or less, and all other Ln were below the detection limit.

Each of these steels was vacuum melted, cast into a 25 kg ingot, and then hot rolled immediately after being held at 1180 ° C for 1 hour. The final pass was set to a temperature range of 880 to 900 ° C to a thickness of 4 mm and allowed to cool. did. Observation of the state of cracking in this hot rolling revealed that in Comparative Example B3, many severe lateral cracks had already occurred in the ears and the surface in the first pass, so the rolling was stopped halfway. Further, cracking was observed in the ears of B6, B8, B9 and B10 after hot rolling. On the other hand, the hot rolled sheet having a good shape was obtained from all the others. The results are shown in the hot workability column of Table 1 with XX mark for B3, X mark for B6, B8, B9 and B10, and ◯ mark for other hot workability.

Next, 1/3 subsize v-notch Charby test pieces were taken from each hot-rolled sheet except B3, and the toughness was investigated. The results are shown in the column of hot-rolled sheet toughness in Table 2. As a judgment index, the average value of 3 points of impact absorption energy at one test temperature is 3k.
Temperatures exceeding g · m / cm ² were marked with a mark of ◎ when the temperature was 50 ° C or lower, marked with a mark of more than 50 ° C and 100 ° C or lower, and marked with a mark of 100 ° C or higher. Those marked with ◎ can be used for sheet passing in the same way as ordinary ferritic stainless steel without any special measures during mass production in the factory, and those marked with ○ are those requiring a slight heat treatment. Basically, it is possible to mass-produce it. On the other hand, the X mark indicates that factory production is not impossible at all, but in that case, it is necessary to always pay attention to the temperature control and handling of the plate, and it can be judged that the productivity is extremely reduced and the production cost is significantly increased. .

All of the steels of the present invention have excellent toughness in hot-rolled sheets, and it could be determined that mass production in a factory was relatively easy, but comparative examples B6 to B1.
Steel No. 1 had low toughness and had a problem in productivity.

As described above, the steel within the scope of the present invention has excellent manufacturability.

(Example 2) Next, the results of investigating the characteristics of these steel catalyst carriers in terms of performance in use will be described.

After descaling the hot rolled sheet except B3 obtained in Example 1, B6 to B11 were heated to a sheet temperature of 120 ° C, and all others were cold rolled at room temperature to a thickness of 0.8 mm. . After that, it was annealed at 900 ° C. and then rolled at room temperature to a foil of about 50 μm.

The foil thus produced was heated at 1150 ° C. for 25 hours in a heating furnace into which exhaust gas of a gasoline engine was introduced until the foil was abnormally oxidized. Each of the test foils had a thickness of 50 ± 2 μm, three bodies were tested for each component system, and the average value was taken as the abnormal oxidation life of the component foil. The presence or absence of abnormal oxidation was visually determined. The results are shown in the column of oxidation life in Table 2.

Although the foils of the examples of the present invention each have a life of 250 hours or more, B1 of the comparative example is 150 hours or less, and B2, B6 and B8.
Also had a short life of less than 200 hours.

(Example 3) The hot-rolled sheet obtained in Example 1 was processed to the same thickness as in Example 2.
After cold rolling to 1.5 mm, a plate-shaped tensile test piece was taken from the one that was heat-treated at 1200 ° C in vacuum for 10 minutes and then cooled in the furnace.
The yield strength was measured at 0,700 and 800 ° C. The results are shown in the second high temperature proof stress column. The average value of the three bodies and yield strength at that temperature, 600 ° C. in 20 kgf / mm ² or more as a criterion, 700 ° C. in 13 kgf / mm ² or more, the further 800 ° C. 4.5 kgf /
mm ² or more, those that clear these standards are indicated by ◯, and those that do not clear are indicated by X. All of the A series of the present invention have a proof stress higher than the above standard,
The high-temperature yield strength is high, whereas the comparative examples B4 to B8 cannot achieve the high-temperature yield strength improvement.

(Example 4) Next, the results of an examination of the structural durability of the catalyst carrier will be described.

The steel with the components shown in Table 3 was vacuum melted, cast into a 300 kg ingot, heated at 1180 ° C. for 2 hours, hot-rolled to 2.5 mm, and then repeatedly descaled, cold-rolled, and annealed to obtain a thickness of 50 μm. A foil was made. At this time, B13 is the second embodiment.
In the same manner as in the above case, a heat retention treatment was performed as necessary. Next, a sine wave-shaped corrugated plate with a period of 3.5 mm and an amplitude of 3.2 mm (corrugated plate) and an unprocessed foil (flat plate) band are overlapped and rolled up, and an apparent outer diameter of 110 mm and a long length are obtained. 110 mm
With a honeycomb-shaped cylindrical body, the inner diameter is 110 mm and the length is 110 mm.
mm, and a plate thickness of 1.7 mm was inserted into a type 434 series ferritic stainless steel cylinder (outer cylinder), and each contact was brazed in a vacuum using a commercially available Ni-based brazing material to prepare a catalyst carrier. Next, these catalyst carriers were installed in the exhaust gas passage of a 2000cc gasoline engine, the gas temperature on the inlet side was set to 865 ° C, the engine was operated for 6 minutes, and then the engine was stopped and forced cooling cooled the temperature inside the catalyst carrier to 50 ° C or below. The cooling operation was repeated 1000 times, and the damage state of the gas-containing side end surface of the honeycomb body at this time was observed. The results are shown in Table 4.

All of the carriers produced in the A series within the scope of the present invention show a relatively good appearance shape although some cell deformation is observed even after the above test, and it can be judged that the damage situation is comparatively low and minor. Those made of low temperature proof material of the comparative example have been greatly damaged such as partial blockage due to cell dipping and foil breakage due to large deformation of the cell wall, and further displacement of the end face in the gas flow direction, It is clear that the foil of the present invention has a great effect of improving the structural durability of the carrier.

[Effects of the Invention] As is clear from the examples, the Fe-Cr-Al-based stainless foil according to the present invention not only has high resistance to abnormal oxidation in engine exhaust gas, but also has hot workability and heat resistance. Due to the excellent toughness of the rolled sheet, it has excellent manufacturability, and since its proof strength at high temperature is very high, it has high resistance to thermal fatigue as a honeycomb body, and therefore the structural durability of the catalyst carrier. The effect of improving it is great. Due to these effects, the stainless foil of the present invention is suitable for constituting a catalyst carrier for automobiles and the like.

Front page continuation (72) Inventor Masuhiro Fukaya 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa Inside the 2nd Technical Research Laboratories, Nippon Steel Corporation (72) Inventor Fumio Saken, 3434, Shimada, Hikari City, Yamaguchi Prefecture Nippon Steel Co., Ltd. Hikari Steel Works (72) Inventor Hidehiko Sumitomo 3434 Shimada, Hikari City, Yamaguchi Prefecture Nippon Steel Co., Ltd. Hikari Steel Works (56) Reference JP-A-3-170642 (JP, A) JP-A-1-287253 (JP, A) JP-A-63-42347 (JP, A)

Claims (4)

[Claims] 1. Ln: more than 0.06% and 0.15% or less by weight% (however, Ln is La, Ce, Pr, Nd) P: 8 × (Ln% + 0.015) / 45 or more, 0.1% or less Al : 4.5% or more, 6.5% or less Cr: 13% or more, 25% or less Ta: (181 ・ C% / 12 ＋ 181 ・ N% / 14) × 1.5 or more, 3% or less C: 0.025% or less N: 0.02% or less C + N : 0.03% or less A heat-resistant stainless steel foil for a combustion exhaust gas purification catalyst carrier, which comprises the balance Fe and unavoidable impurities. 2. The heat-resistant stainless steel foil according to claim 1, further comprising Nb in a range such that Ta + Nb is 3% or less by weight. 3. The heat-resistant stainless steel foil according to claim 1, which contains at least one kind of Mo or W in a total amount of 4% or less by weight. 4. The heat-resistant stainless steel foil according to claim 3, further comprising Nb in a range such that Ta + Nb is 3% or less by weight.