JP7251996B2 - Al-containing ferritic stainless steel sheet and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an Al-containing ferritic stainless steel sheet and a method for producing the same. Specifically, the present invention relates to a ferritic stainless steel sheet suitable for use in members exposed to high temperatures.

When the Al-containing ferritic stainless steel sheet is heated to a high temperature, a uniform layer of alumina is formed on the surface thereof, so that it exhibits excellent high-temperature oxidation resistance. Therefore, Al-containing ferritic stainless steel sheets are used for members that are exposed to high-temperature atmospheres, such as automotive exhaust systems and heaters.
However, when the Al-containing ferritic stainless steel sheet is exposed to a high-temperature atmosphere for a long time, creep deformation may occur.
Therefore, in Patent Document 1, in mass %, Cr: 11.0 to 25.0%, C: 0.001 to 0.030%, Si: 0.01 to 2.00%, Mn: 0.00%. 01 to 2.00%, Al: 0.50 to 4.90%, P: 0.050% or less, S: 0.0100% or less, N: 0.030% or less, Ti: 0.010 to 1.000%, Nb: 0.010 to 1.000% 1 or 2, and B: 0.0005 to 0.0025%, Sn: 0.005 to 0.500% 1 or 2 types, the balance being Fe and unavoidable impurities, and the metal structure of a region of a thickness of 1/4 of the plate thickness in both surface directions from the center of the plate thickness is a ferrite structure, and the ferrite structure is a crystal At least one of recrystallized grains with a grain size number of 8.0 or less or expanded grains, and the minimum creep rate when a constant load test in accordance with JIS Z2271 is performed under the test conditions of 700 ° C. and an initial stress of 25 MPa. There has been proposed an Al-containing ferritic stainless steel sheet having excellent creep properties, characterized by having a creep property of 1.0×10 ⁻² (%/h) or less.

Japanese Patent No. 6113359

In recent years, as the use of Al-containing ferritic stainless steel sheets has expanded, demand has arisen for Al-containing ferritic stainless steel sheets of various thicknesses. When the required thickness of the Al-containing ferritic stainless steel sheet is small, if the creep property of the Al-containing ferritic stainless steel sheet is not sufficient, width shrinkage or breakage may occur due to tension during threading in the production line. In addition, creep deformation is likely to occur when used in a high-temperature environment. Patent Literature 1 does not sufficiently examine the creep properties of Al-containing ferritic stainless steel sheets when the sheet thickness is small, and development of a technique for solving these problems has been desired.

The present invention was made to solve the above problems, and provides an Al-containing ferritic stainless steel sheet that has excellent high-temperature oxidation resistance and good creep properties even if the sheet thickness is reduced, and a method for producing the same. intended to

As a result of intensive research to solve the above problems, the present inventors have found that the steel composition of the Al-containing ferritic stainless steel sheet, the average crystal grain size in the plate thickness direction, and the grains of precipitates existing at the grain boundaries It was found that the boundary coverage rate is closely related to the creep properties of Al-containing ferritic stainless steel sheets. The inventors have completed the present invention by adjusting the grain boundary coverage of the precipitates.

That is, in the present invention, C: 0.025% by mass or less, Si: 0.1 to 1.0% by mass, Mn: 1.0% by mass or less, P: 0.05% by mass or less, S: 0.01 % by mass or less, Ni: 0.6 mass % or less, Cr: 16 to 22 mass %, Nb: 0.05 to 0.50 mass %, Al: 1.0 to 2.4 mass %, N: 0.025 % by mass or less, B: 0.0005 to 0.0060% by mass, the balance being Fe and unavoidable impurities, the average crystal grain size in the plate thickness direction being 25 to 90 μm, and the crystal The Al-containing ferritic stainless steel sheet has a grain boundary coverage of 5% or more of precipitates present at the grain boundaries.

The present invention also provides a method for producing the Al-containing ferritic stainless steel sheet, comprising C: 0.025% by mass or less, Si: 0.1 to 1.0% by mass, Mn: 1.0% by mass or less, P: 0.05% by mass or less, S: 0.01% by mass or less, Ni: 0.6% by mass or less, Cr: 16 to 22% by mass, Nb: 0.05 to 0.50% by mass, Al: 1 .0 to 2.4% by mass, N: 0.025% by mass or less, B: 0.0005 to 0.0060% by mass, and the balance being Fe and unavoidable impurities. After cold rolling the rolled annealed sheet, it is annealed at an annealing temperature of 950 to 1050°C with a heating rate of 5°C/second or more and a soaking time of 0 to 60 seconds , and the temperature from the annealing temperature to 550°C. A method for producing an Al-containing ferritic stainless steel sheet, wherein the cooling rate is set to 20° C./second or higher .

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide an Al-containing ferritic stainless steel sheet which is excellent in high-temperature oxidation resistance and has good creep properties even when the sheet thickness is reduced, and a method for producing the same.

It is a figure for demonstrating the calculation method of the grain-boundary coverage of the precipitate which exists in a grain boundary.

Hereinafter, embodiments of the present invention will be specifically described. The present invention is not limited to the following embodiments, and modifications and improvements can be made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. are also within the scope of the present invention.

The Al-containing ferritic stainless steel sheet according to the embodiment of the present invention has C: 0.025% by mass or less, Si: 0.1 to 1.0% by mass, Mn: 1.0% by mass or less, P: 0.05 mass % or less, S: 0.01 mass % or less, Ni: 0.6 mass % or less, Cr: 16-22 mass %, Nb: 0.05-0.50 mass %, Al: 1.0-2. 4% by mass, N: 0.025% by mass or less, B: 0.0005 to 0.0060% by mass, and the balance being Fe and unavoidable impurities.
Here, the term "steel sheet" as used herein is a concept including a steel strip. In addition, "inevitable impurities" mean components such as O that are difficult to remove. Unavoidable impurities are inevitably mixed in at the stage of smelting raw materials.

C is an element that affects the creep properties and high-temperature oxidation resistance of the Al-containing ferritic stainless steel sheet. If the C content is too high, abnormal oxidation is likely to occur, and the creep properties tend to deteriorate. Therefore, the upper limit of the C content is 0.025% by mass, preferably 0.024% by mass, more preferably 0.023% by mass. On the other hand, the lower limit of the C content is not particularly limited, but is preferably 0.001% by mass, more preferably 0.002% by mass.

Si is an effective element for improving the high-temperature oxidation resistance of the Al-containing ferritic stainless steel sheet. From the viewpoint of obtaining this effect, the lower limit of the Si content is 0.1% by mass, preferably 0.12% by mass. On the other hand, if the Si content is too high, the steel may be hardened and the toughness may be lowered. Therefore, the upper limit of the Si content is 1.0% by mass, preferably 0.95% by mass, and more preferably 0.93% by mass.

Mn is an effective element for improving the hot workability of the Al-containing ferritic stainless steel sheet, but if the Mn content is too high, the high-temperature oxidation resistance is lowered. Therefore, the upper limit of the Mn content is 1.0% by mass, preferably 0.9% by mass, more preferably 0.8% by mass. On the other hand, the lower limit of the Mn content is not particularly limited, but is preferably 0.01% by mass, more preferably 0.1% by mass, and still more preferably 0.2% by mass.

P is an element that may reduce the high-temperature oxidation resistance and toughness of the Al-containing ferritic stainless steel sheet. Therefore, the upper limit of the P content is 0.05% by mass, preferably 0.04% by mass, and more preferably 0.035% by mass. On the other hand, the lower limit of the P content is not particularly limited, but is preferably 0.001% by mass, more preferably 0.010% by mass, and still more preferably 0.020% by mass.

S is an element that may form sulfide-based inclusions and degrade the surface properties. Therefore, the upper limit of the S content is 0.01% by mass, preferably 0.008% by mass, and more preferably 0.006% by mass. On the other hand, the lower limit of the S content is not particularly limited, but is preferably 0.0001% by mass, more preferably 0.0005% by mass.

Ni is an element effective in improving low-temperature toughness. However, if the Ni content is too high, it is an austenite phase stabilizing element, so it forms a martensite phase and deteriorates workability. Moreover, when there is too much Ni content, a cost rise will be caused. Therefore, the upper limit of the Ni content is 0.6% by mass, preferably 0.5% by mass, and more preferably 0.4% by mass. On the other hand, the lower limit of the Ni content is not particularly limited, but is preferably 0.01% by mass, more preferably 0.05% by mass, and still more preferably 0.1% by mass.

Cr is an effective element for improving the creep property and high-temperature oxidation resistance of the Al-containing ferritic stainless steel sheet. From the viewpoint of obtaining this effect, the lower limit of the Cr content is 16% by mass, preferably 16.3% by mass, more preferably 16.5% by mass. On the other hand, if the Cr content is too high, the toughness of the Al-containing ferritic stainless steel sheet is lowered. Therefore, the upper limit of the Cr content is 22% by mass, preferably 21.5% by mass, more preferably 21% by mass.

Nb is an effective element for improving creep properties and high-temperature oxidation resistance of Al-containing ferritic stainless steel sheets. From the viewpoint of obtaining this effect, the lower limit of the Nb content is 0.05% by mass, preferably 0.06% by mass, more preferably 0.08% by mass. On the other hand, if the Nb content is too high, the Al-containing ferritic stainless steel sheet will be hardened and the toughness will be lowered. Therefore, the upper limit of the Nb content is 0.50% by mass, preferably 0.48% by mass, more preferably 0.46% by mass.

Al is an effective element for improving the high-temperature oxidation resistance of the Al-containing ferritic stainless steel sheet. From the viewpoint of obtaining this effect, the lower limit of the Al content is 1.0% by mass, preferably 1.1% by mass, more preferably 1.2% by mass. On the other hand, if the Al content is too high, the Al-containing ferritic stainless steel sheet will be hardened and the toughness will be lowered. Therefore, the upper limit of the Al content is 2.4% by mass, preferably 2.2% by mass, more preferably 2.0% by mass.

N is an element that combines with Al to form AlN, which is the starting point of abnormal oxidation, and may reduce the toughness of the Al-containing ferritic stainless steel sheet. Therefore, the upper limit of the N content is 0.025% by mass, preferably 0.020% by mass, more preferably 0.015% by mass. On the other hand, the lower limit of the N content is not particularly limited, but is preferably 0.001% by mass, more preferably 0.003% by mass, and still more preferably 0.005% by mass.

B is an element effective in improving creep properties. From the viewpoint of obtaining this effect, the lower limit of the B content is 0.0005% by mass, preferably 0.0006% by mass, more preferably 0.0007% by mass. On the other hand, if the B content is too high, the secondary workability and oxidation resistance are lowered. Therefore, the upper limit of the B content is 0.0060% by mass, preferably 0.0055% by mass, more preferably 0.0053% by mass.

In addition to the above elements, the Al-containing ferritic stainless steel sheet according to the embodiment of the present invention has Ti: 0.01 to 0.50 mass%, V: 0.01 to 0.50 mass%, and Mo: 0.01. ~0.50% by mass, Co: 0.01-0.50% by mass, Zr: 0.01-0.50% by mass, Cu: 0.01-0.50% by mass, Mg: 0.0005-0 .0030% by mass, and rare earth element (REM): 0.001 to 0.050% by mass or less.

Ti and V are elements that combine with C and/or N to improve toughness. From the viewpoint of obtaining this effect, the lower limits of the Ti and V contents are preferably 0.01 mass %, more preferably 0.03 mass %, and still more preferably 0.05 mass %. On the other hand, if the contents of Ti and V are too high, the Al-containing ferritic stainless steel sheet may be hardened and the toughness may be lowered. Therefore, the upper limits of the contents of Ti and V are set to 0.50% by mass, preferably 0.45% by mass, and more preferably 0.40% by mass.

Mo is an element effective in improving high-temperature oxidation resistance and high-temperature strength of an Al-containing ferritic stainless steel sheet. From the viewpoint of obtaining this effect, the lower limit of the Mo content is preferably 0.01% by mass, more preferably 0.02% by mass, and still more preferably 0.03% by mass. On the other hand, if the Mo content is too high, the Al-containing ferritic stainless steel sheet may be hardened and the toughness may be lowered. Therefore, the upper limit of the Mo content is preferably 0.50% by mass, more preferably 0.48% by mass, and still more preferably 0.45% by mass.

Zr is an element effective in improving toughness and oxidation resistance by combining with C and N in steel. Also, Co and Cu are effective elements for improving the high-temperature strength of steel. In order to obtain the effect of adding these elements, the lower limit of the content is set to 0.01% by mass, more preferably 0.05% by mass, and still more preferably 0.1% by mass. On the other hand, if the content of these elements is too high, the toughness of steel deteriorates. Therefore, the upper limit of their content is 0.50% by mass, preferably 0.45% by mass, and more preferably 0.40% by mass.

Mg is an element that promotes the formation of carbonitrides of Nb and can be finely precipitated. From the viewpoint of obtaining this effect, the lower limit of the Mg content is preferably 0.0005% by mass, more preferably 0.0008% by mass, and still more preferably 0.0010% by mass. On the other hand, if the Mg content is too high, the creep resistance may deteriorate. Therefore, the upper limit of the Mg content is preferably 0.0030% by mass, more preferably 0.0025% by mass, and still more preferably 0.0020% by mass.

A rare earth element (REM) is an effective element for improving the high-temperature oxidation resistance of an Al-containing ferritic stainless steel sheet. From the viewpoint of obtaining this effect, the lower limit of the rare earth element is preferably 0.001% by mass, more preferably 0.005% by mass, and still more preferably 0.01% by mass. On the other hand, if the rare earth element content is too high, the hot workability and toughness may deteriorate. Therefore, the upper limit of the rare earth element content is preferably 0.050% by mass, more preferably 0.045% by mass, and still more preferably 0.040% by mass.

The Al-containing ferritic stainless steel sheet according to the embodiment of the present invention has an average crystal grain size in the plate thickness direction of 25 to 90 μm, preferably 26 to 85 μm, more preferably 27 to 80 μm, still more preferably 28 to 75 μm, most preferably 28 to 75 μm. is 30-70 μm. If the average crystal grain size is less than 25 μm, the creep properties are degraded. On the other hand, if the average crystal grain size exceeds 90 μm, the surface becomes rough and workability is lowered.
Here, the term "average crystal grain size in the plate thickness direction" as used herein refers to the observation surface obtained by polishing the cross section of the Al-containing ferritic stainless steel sheet in the plate thickness direction, and is specified in Appendix C of JIS G0551:2003. Means the average grain size obtained according to the cutting method by a straight line test line. A linear test line is randomly drawn at eight locations, and the average value of each location is taken as the average crystal grain size. Moreover, the cross section of the viewing surface is preferably an L cross section parallel to the rolling direction.

In the Al-containing ferritic stainless steel sheet according to the embodiment of the present invention, the grain boundary coverage of precipitates present at grain boundaries is 5% or more, preferably 6% or more. If the grain boundary coverage of the precipitates is less than 5%, the creep properties are degraded. On the other hand, the upper limit of the grain boundary coverage of precipitates is not particularly limited, but is preferably 50%, more preferably 40%, and still more preferably 35%.
Here, in this specification, the term “grain boundary coverage of precipitates existing at grain boundaries” means that the grain boundary coverage of the Al-containing ferritic stainless steel sheet is between two grains on the observation surface obtained by polishing the cross section in the plate thickness direction. It means the ratio of the length d of the portion covered by the precipitate existing at the grain boundary to the length L of the grain boundary. FIG. 1 shows a schematic diagram of the length L of the grain boundary and the length d of the portion covered by the precipitate. Five crystal grain boundaries between two crystal grains are randomly selected, and the average value at each location is taken as the grain boundary coverage of precipitates.

Although the type of the Al-containing ferritic stainless steel sheet according to the embodiment of the present invention is not particularly limited, it is preferably a cold-rolled annealed sheet.
In addition, the thickness of the Al-containing ferritic stainless steel sheet according to the embodiment of the present invention is not particularly limited, but is preferably 0.1 mm or more and less than 0.8 mm, more preferably 0.1 to 0.6 mm, further preferably 0.1 to 0.5 mm.

The Al-containing ferritic stainless steel sheet according to the embodiment of the present invention preferably has an arithmetic mean roughness Ra of 5.0 μm or less, more preferably 4.5 μm or less after applying a tensile strain of 20%. If this arithmetic mean roughness Ra exceeds 5.0 μm, the workability is deteriorated.

The Al-containing ferritic stainless steel sheet according to the embodiment of the present invention having the characteristics as described above can be manufactured according to a known method using a slab having the composition described above. Specifically, hot rolling, annealing, cold rolling and annealing may be sequentially performed on the slab having the above composition. In a preferred embodiment, the hot rolled sheet or hot rolled annealed sheet having the above composition is cold rolled and then annealed at a temperature of 950 to 1050°C. If the annealing temperature after cold rolling is less than 950°C, there is a risk of non-recrystallization. On the other hand, if the annealing temperature after cold rolling exceeds 1050° C., the surface roughness decreases, resulting in poor workability. Further, annealing after cold rolling is preferably performed at a heating rate of 5° C./second or more and a soaking time of 0 to 60 seconds. Further, the cooling rate is preferably 20°C/second or more in the temperature range from the annealing temperature to 550°C. By performing annealing after hot rolling under such conditions, it is possible to control the average crystal grain size in the sheet thickness direction and the grain boundary coverage of precipitates present at the grain boundaries within a predetermined range. .

Hot rolling is generally carried out in a temperature range of 1150 to 1250° C., although it is not particularly limited. Annealing after hot rolling is performed at a temperature corresponding to the alloy composition for the purpose of recrystallization, preferably in a temperature range of 950 to 1050°C. In addition, cold rolling can be performed multiple times, and annealing may be performed after each cold rolling. The annealing temperature at this time is preferably 950 to 1050°C.

The Al-containing ferritic stainless steel sheet according to the embodiment of the present invention manufactured as described above has excellent creep properties and high-temperature oxidation resistance. Therefore, the Al-containing ferritic stainless steel sheet according to the embodiment of the present invention can be used for fuel cell reformers, various pipes exposed to high temperature conditions, automobile exhaust gas components, burner combustion cylinders, chimneys, heating equipment, heating elements, etc. It is suitable for use in heat-resistant members that require toughness (workability) and high-temperature oxidation resistance.

EXAMPLES The content of the present invention will be described in detail below with reference to Examples, but the present invention is not construed as being limited thereto.

The stainless steels shown in Table 1 were vacuum melted and cast to obtain slabs. This slab was hot-rolled at 1200° C. to obtain a hot-rolled sheet with a thickness of 3.0 mm. Next, this hot-rolled sheet was annealed at the temperature shown in Table 2 to obtain a hot-rolled annealed sheet. Next, after cold rolling to a plate thickness of 1.0 mm and annealing at the temperature shown in Table 2, cold rolling to a plate thickness of 0.2 mm and annealing at the temperature shown in Table 2, a cold rolled annealed plate (Al-containing ferritic stainless steel sheet) was obtained. Annealing after cold rolling was performed at a heating rate of 10°C/second or more, a soaking time of 30 seconds, and a cooling rate of 20°C/second in the temperature range from the annealing temperature to 550°C.

The cold-rolled annealed sheets obtained above were evaluated as follows.
<Average grain size>
After mirror-polishing the L cross section in the plate thickness direction of the cold-rolled annealed sheet, the surface was polished with a mixed solution of hydrofluoric acid, nitric acid and glycerin (hydrofluoric acid:nitric acid:glycerin mass ratio is 3:1:2). etched. On this etched surface, the average crystal grain size was determined according to the straight test line cutting method specified in Appendix C of JIS G0551:2003. Eight straight test lines were drawn at random, and the average value of each point was taken as the average crystal grain size.

<Grain Boundary Coverage of Precipitates Present at Grain Boundaries>
After mirror-polishing the L cross section in the thickness direction of the cold-rolled annealed sheet, etching was performed for 3 seconds using a solution containing 10% by mass of oxalic acid under the conditions of a voltage of 6 V and a current of 1 A. The etched surface was subjected to mapping analysis using FE-EPMA to determine the grain boundary coverage of precipitates present at the grain boundaries.

<Arithmetic mean roughness Ra>
A JIS No. 5 test piece was prepared from the cold-rolled annealed sheet, and a tensile strain of 20% was applied with a gauge length of 50 mm. manufactured by SURFCOM2900DX). The measurement distance was 20 mm in the direction perpendicular to the rolling direction in the central part between gauge points.

<Creep characteristics>
A test piece having a length of 200 mm in the rolling direction, a length of 15 mm in the width direction, and a gauge length of 50 mm was cut out from the cold-rolled and annealed sheet. A constant load test was carried out in accordance with JIS Z2271:2010 for the heating of the test piece and the load of the test piece force. In the constant load test, the shrinkage rate of the sheet width after applying 7 MPa at 900 ° C. for 180 seconds to the test piece was obtained, and when the shrinkage rate of the sheet width was 1.0% or less, the creep property was considered to be good. It was judged.

<High temperature oxidation resistance>
A test piece with a length of 35 mm in the rolling direction and a length of 25 mm in the width direction is cut from the cold-rolled annealed sheet, and the surface of the test piece is dry-polished with #400 grit and the cross section with #600 grit, respectively. Evaluation was performed after immersion and ultrasonic cleaning. The high-temperature oxidation resistance was evaluated by heating a test piece at 900° C. for 100 hours in an air atmosphere and measuring the change in mass of the test piece before and after heating. When the amount of change in mass was 0.6 mg/cm ² or less, it was judged that the high-temperature oxidation resistance was good.

Table 2 shows the above evaluation results.

As shown in Table 2, the cold-rolled annealed sheets of test numbers 1 to 14 (examples of the present invention) having a predetermined composition and satisfying a predetermined range of average crystal grain size and grain boundary coverage of precipitates were: Good creep properties and high temperature oxidation resistance were obtained.
On the other hand, the cold-rolled annealed sheet of Test No. 15 (comparative example) had an insufficient creep property because the average grain size was too small.
Since the cold-rolled annealed sheets of test numbers 16 and 20 (comparative examples) did not contain Nb and B, no precipitate was formed at the grain boundaries. Therefore, this cold-rolled and annealed sheet was insufficient in creep properties and had a low high-temperature oxidation resistance.
In the cold-rolled annealed sheet of Test No. 17 (comparative example), since the Nb content was too small, the grain boundary coverage of the precipitates was lowered and the creep property was insufficient.

Since the cold-rolled annealed sheet of test number 18 (comparative example) did not contain Nb and B, no precipitate was formed at the grain boundary, and the creep property was insufficient. In addition, since the cold-rolled annealed sheet had an excessively low Al content, the high-temperature oxidation resistance was also lowered.
The cold-rolled annealed sheet of Test No. 19 (comparative example) had too high a Mn content, so the high-temperature oxidation resistance was lowered.
In the cold-rolled annealed sheet of test number 21 (comparative example), the Si content and the Nb content were too small, so the grain boundary coverage of precipitates decreased, the creep property was insufficient, and the high-temperature oxidation resistance decreased. bottom.
The cold-rolled annealed sheet of test number 22 (comparative example) had a low high-temperature oxidation resistance because the Cr content was too low.
The cold-rolled annealed sheet of Test No. 23 (comparative example) did not contain Nb, and therefore had insufficient creep properties.

As can be seen from the above results, according to the present invention, it is possible to provide an Al-containing ferritic stainless steel sheet that has excellent high-temperature oxidation resistance and good creep properties even if the sheet thickness is reduced, and a method for producing the same.

Claims (7)

C: 0.025% by mass or less, Si: 0.1 to 1.0% by mass, Mn: 1.0% by mass or less, P: 0.05% by mass or less, S: 0.01% by mass or less, Ni: 0.6% by mass or less, Cr: 16 to 22% by mass, Nb: 0.05 to 0.50% by mass, Al: 1.0 to 2.4% by mass, N: 0.025% by mass or less, B: containing 0.0005 to 0.0060% by mass, the balance being composed of Fe and unavoidable impurities, having an average crystal grain size in the thickness direction of 25 to 90 μm, and precipitates present at grain boundaries An Al-containing ferritic stainless steel sheet having a grain boundary coverage of 5% or more. Ti: 0.01 to 0.50% by mass, V: 0.01 to 0.50% by mass, Mo: 0.01 to 0.50% by mass, Co: 0.01 to 0.50% by mass, Zr: One or more of 0.01 to 0.50% by mass, Cu: 0.01 to 0.50% by mass, Mg: 0.0005 to 0.0030% by mass, rare earth element: 0.001 to 0.050% by mass The Al-containing ferritic stainless steel sheet according to claim 1, further comprising: The Al-containing ferritic stainless steel sheet according to claim 1 or 2, having a thickness of 0.1 mm or more and less than 0.8 mm. The Al-containing ferritic stainless steel sheet according to any one of claims 1 to 3, having an arithmetic mean roughness Ra of 5.0 µm or less after applying a tensile strain of 20%. A method for producing an Al-containing ferritic stainless steel sheet according to any one of claims 1 to 4,
C: 0.025% by mass or less, Si: 0.1 to 1.0% by mass, Mn: 1.0% by mass or less, P: 0.05% by mass or less, S: 0.01% by mass or less, Ni: 0.6% by mass or less, Cr: 16 to 22% by mass, Nb: 0.05 to 0.50% by mass, Al: 1.0 to 2.4% by mass, N: 0.025% by mass or less, B: After cold-rolling a hot-rolled sheet or hot-rolled and annealed sheet having a composition containing 0.0005 to 0.0060% by mass and the balance being Fe and unavoidable impurities, the heating rate is 5 ° C./sec or more, uniform An Al-containing ferritic stainless steel plate, which is annealed at an annealing temperature of 950 to 1050°C with a heating time of 0 to 60 seconds , and cooled at a cooling rate of 20°C/second or more in the temperature range from the annealing temperature to 550°C. manufacturing method. The hot-rolled sheet or the hot-rolled annealed sheet contains Ti: 0.01 to 0.50% by mass, V: 0.01 to 0.50% by mass, Mo: 0.01 to 0.50% by mass, Co: 0.01 to 0.50% by mass, Zr: 0.01 to 0.50% by mass, Cu: 0.01 to 0.50% by mass, Mg: 0.0005 to 0.0030% by mass, rare earth element: 0 The method for producing an Al-containing ferritic stainless steel sheet according to claim 5, further comprising one or more of 0.001 to 0.050% by mass. A heat-resistant member formed from the Al-containing ferritic stainless steel sheet according to any one of claims 1 to 4.

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