JP2021110020A - Ferritic stainless steel material and damping member - Google Patents

Abstract

To provide a ferritic stainless steel that can enhance the vibration damping by recrystallization treatment while suppressing thermal deformation.SOLUTION: Provided is a ferritic stainless steel material that contains C: 0.05 mass% or less, Mn: 1.0 mass% or less, Ni: 0.60 mass% or less, P: 0.05 mass% or less, S: 0.03 mass% or less, Cr: 10.5 to 24.0 mass%, N: 0.03 mass% or less, Cu: 0.60% by mass or less, Mo: 2.5% by mass or less, Si: 3.0 mass% or less, Al: 5.0 mass% or less and the balance consisting of Fe and unavoidable impurities. The ferritic stainless steel material has an average grain boundary distortion rate of 1% or more and less than 15%.SELECTED DRAWING: None

Description

The present invention relates to ferritic stainless steel materials and vibration damping members.

With the electrification of automobiles, the noise and vibration caused by the engine are eliminated, and the quietness of the passenger compartment is improved. As a result, noise that was previously buried in engine noise and high-frequency noise that is peculiar to electrification are more likely to be perceived by passengers as abnormal noise, and the level of vibration damping for materials used in automobiles is high. It has become.
Further, in electronic devices such as hard disks, vibration causes malfunctions and failures, so that materials used for electronic device parts are also required to have vibration damping properties.

Resin is a typical example of a material having vibration damping properties, but it is often difficult to use from the viewpoints of strength, environmental resistance (corrosion resistance and heat resistance), heat dissipation, and the like. Therefore, a metal material having vibration damping properties is required.
The metal material having vibration damping properties is roughly classified into a composite type, a ferromagnetic type, a dislocation type and a twin type according to the damping mechanism of vibration energy. Among them, the ferritic stainless steel material is a ferromagnet and has a ferromagnetic damping mechanism. In the ferromagnetic type, the magnetic domains are rearranged in one direction when an external force such as vibration is applied, and the magnetic domains are randomly rearranged when the load is removed. The residual strain at this time absorbs the vibration energy and attenuates the vibration.

As the ferrite-based stainless steel material having excellent vibration damping properties, C: 0.001 to 0.03% by mass, Si: 0.1 to 1.0% by mass, Mn: 0.1 to 2.0% by mass, Ni: 0.01 to 0.6% by mass, Cr: 10.5 to 24.0% by mass, N: 0.001 to 0.03% by mass, Nb: 0 to 0.8% by mass, Ti: 0 to 0. 5% by mass, Cu: 0 to 2.0% by mass, Mo: 0 to 2.5% by mass, V: 0 to 1.0% by mass, Al: 0 to 0.3% by mass, Zr: 0 to 0. The matrix has a chemical composition of 3% by mass, Co: 0 to 0.6% by mass, REM: 0 to 0.1% by mass, Ca: 0 to 0.1% by mass, the balance Fe and unavoidable impurities. A vibration-damping ferrite-based stainless steel material which is a ferrite single phase, has a metal structure in which the average crystal grain size of ferrite crystal grains is 0.3 to 3.0 mm, and has a residual magnetic flux density of 45 mT or less has been proposed. (Patent Document 1).

JP-A-2017-39955

However, the ferrite-based stainless steel material described in Patent Document 1 needs to be recrystallized at a high temperature for a long time (final annealing at 1200 ° C. for 120 minutes or 950 ° C. for 120 minutes) in order to improve vibration damping properties. Therefore, there is a problem that deformation is likely to occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a ferritic stainless steel material capable of improving vibration damping by recrystallization treatment while suppressing thermal deformation. do.
Another object of the present invention is to provide a vibration damping member having less thermal deformation and excellent vibration damping property.

As a result of diligent research to solve the above problems, the present inventors shortened the recrystallization treatment by controlling the composition and average grain boundary strain ratio of the ferritic stainless steel material within a predetermined range. The present invention has been completed by finding that both improvement of vibration damping property and suppression of thermal deformation can be achieved at the same time.

That is, in the present invention, C: 0.05% by mass or less, Mn: 1.0% by mass or less, Ni: 0.60% by mass or less, P: 0.05% by mass or less, S: 0.03% by mass or less. , Cr: 10.5 to 24.0% by mass, N: 0.03% by mass or less, Cu: 0.60% by mass or less, Mo: 2.5% by mass or less, Si: 3.0% by mass or less, Al : A ferrite-based stainless steel material containing 5.0% by mass or less, the balance being Fe and unavoidable impurities, and having an average grain boundary strain ratio of 1% or more and less than 15%.

Further, the present invention is a vibration damping member formed of the above-mentioned ferritic stainless steel material.

According to the present invention, it is possible to provide a ferrite-based stainless steel material and a vibration damping member capable of improving vibration damping properties by recrystallization treatment while suppressing thermal deformation.

Hereinafter, embodiments of the present invention will be specifically described. The present invention is not limited to the following embodiments, and changes, improvements, etc. have been appropriately added to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that things also fall within the scope of the present invention.

The ferrite-based stainless steel material according to the embodiment of the present invention has C: 0.05% by mass or less, Mn: 1.0% by mass or less, Ni: 0.60% by mass or less, P: 0.05% by mass or less, S. : 0.03% by mass or less, Cr: 10.5 to 24.0% by mass, N: 0.03% by mass or less, Cu: 0.60% by mass or less, Mo: 2.5% by mass or less, Si: 3 It contains 0.0% by mass or less and Al: 5.0% by mass or less, and the balance is composed of Fe and unavoidable impurities.
Here, the term "unavoidable impurities" as used herein means components such as O that are difficult to remove. Such components are inevitably mixed in at the stage of melting the raw material.
Further, the ferrite-based stainless steel material according to the embodiment of the present invention has Nb: 0.50% by mass or less, Ti: 0.50% by mass or less, Zr: 1.0% by mass or less, Co: 1.0% by mass or less. , V: 1.0% by mass or less, W: 1.0% by mass or less, REM: 0.10% by mass or less, Ca: 0.10% by mass or less, Sn: 0.10% by mass or less, B: 0. It may further contain at least one selected from 01% by mass or less.

C is an element that affects the properties such as intergranular corrosion resistance (sensitization suppressing action) and workability of ferritic stainless steel materials. If the C content is too large, the processability and intergranular corrosion resistance of the ferritic stainless steel material will deteriorate. Therefore, the upper limit of the C content is controlled to 0.05% by mass, preferably 0.045% by mass, and more preferably 0.04% by mass. On the other hand, the lower limit of the C content is not particularly limited, but reducing the C content leads to an increase in the refining cost. Therefore, the lower limit of the C content is preferably 0.0005% by mass, preferably 0.001% by mass.

Mn is useful as a deoxidizing element. If the Mn content is too large, MnS, which is the starting point of corrosion, is likely to be generated, and the ferrite phase is destabilized. Therefore, the upper limit of the Mn content is controlled to 1.0% by mass, preferably 0.9% by mass, and 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 0.05% by mass.

Ni is an element effective for improving the corrosion resistance of ferritic stainless steel and the toughness of welded parts. If the Ni content is too high, the ferrite phase becomes unstable and the manufacturing cost increases. Therefore, the upper limit of the Ni content is controlled to 0.60% by mass, preferably 0.58% by mass, and more preferably 0.55% 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 from the viewpoint of obtaining the above effects.

P is an element that affects the properties such as weldability and workability of ferritic stainless steel. If the content of P is too high, the above characteristics may be deteriorated. Therefore, the upper limit of the P content is controlled to 0.05% by mass, preferably 0.045% by mass, and more preferably 0.04% by mass. On the other hand, the lower limit of the P content is not particularly limited, but reducing the P content leads to an increase in the refining cost. Therefore, the lower limit of the P content is preferably 0.001% by mass, more preferably 0.01% by mass.

S is an element that produces MnS, which is the starting point of corrosion, and affects the toughness and other characteristics of the welded portion of the ferritic stainless steel material. If the S content is too high, the above characteristics may deteriorate. Therefore, the upper limit of the S content is controlled to 0.03% by mass, preferably 0.025% by mass, and more preferably 0.02% by mass. On the other hand, the lower limit of the S content is not particularly limited, but reducing the S content leads to an increase in the refining cost. Therefore, the lower limit of the S content is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more.

Cr is an element effective for improving the corrosion resistance and oxidation resistance of ferritic stainless steel materials. If the Cr content is too high, the toughness of the ferritic stainless steel material will decrease, and the manufacturing cost will increase. Therefore, the upper limit of the Cr content is 24.0% by mass, preferably 23.5% by mass, and more preferably 23.0% by mass. On the other hand, if the Cr content is too small, the above effect may not be sufficiently obtained. Therefore, the lower limit of the Cr content is 10.5% by mass, preferably 11.0% by mass.

N is an element that affects properties such as intergranular corrosion resistance (sensitization inhibitory action) and workability. If the N content is too large, the processability and intergranular corrosion resistance of the ferritic stainless steel material will deteriorate. Therefore, the upper limit of the N content is controlled to 0.03% by mass, preferably 0.028% by mass, and more preferably 0.025% by mass. On the other hand, the lower limit of the N content is not particularly limited, but reducing the N content leads to an increase in the refining cost. Therefore, the lower limit of the N content is preferably 0.0005% by mass, preferably 0.001% by mass.

Cu is an element effective for improving the corrosion resistance of ferritic stainless steel materials. If the Cu content is too high, the ferrite phase becomes unstable and the manufacturing cost increases. Therefore, the upper limit of the Cu content is controlled to 0.60% by mass, preferably 0.55% by mass, and more preferably 0.50% by mass. On the other hand, the lower limit of the Cu content is not particularly limited, but is preferably 0.001% by mass, preferably 0.01% by mass.

Mo is an element effective for improving the corrosion resistance and oxidation resistance of ferritic stainless steel materials. If the Mo content is too high, the processability of the ferritic stainless steel material will decrease and the manufacturing cost will increase. Therefore, the upper limit of the Mo content is controlled to 2.5% by mass, preferably 2.3% by mass, and more preferably 2.0% by mass. On the other hand, the lower limit of the Mo content is not particularly limited, but is preferably 0.001% by mass, preferably 0.01% by mass.

Si and Al are elements effective for improving the vibration damping property of ferritic stainless steel materials. If the Si content is too high, the workability of the ferritic stainless steel material and the toughness of the welded portion will decrease. Therefore, the upper limit of the Si content is controlled to 3.0% by mass, preferably 2.8% by mass, and more preferably 2.5% by mass. Further, if the Al content is too large, the toughness of the ferritic stainless steel material is lowered. Therefore, the upper limit of the Al content is controlled to 5.0% by mass, preferably 4.5% by mass, and more preferably 4.0% by mass. The contents of Si and Al are not particularly limited, but the total content of Al and Si is preferably 1.0% by mass or more, more preferably 1.0% by mass or more, from the viewpoint of stably improving the vibration damping property of the ferritic stainless steel material. It is 1.2% by mass or more, more preferably 1.5% by mass or more.

Nb and Ti are elements that affect properties such as intergranular corrosion resistance (sensitization inhibitory action). If the Nb content is too high, the workability and toughness of the ferritic stainless steel material will decrease. Therefore, the upper limit of the Nb content is controlled to 0.50% by mass, preferably 0.48% by mass, and more preferably 0.45% by mass. Further, if the Ti content is too large, the processability and surface quality of the ferritic stainless steel material deteriorate. Therefore, the upper limit of the Ti content is controlled to 0.50% by mass, preferably 0.48% by mass, and more preferably 0.45% by mass. On the other hand, the lower limit of the contents of Nb and Ti is controlled from the relationship with the contents of C and N, which lower the intergranular corrosion resistance. Specifically, the lower limit of the total content of Nb and Ti is controlled to 6 (C + N), preferably 7 (C + N). Here, C and N represent the contents of C and N, respectively.

Zr, Co, V and W are elements effective for improving the oxidation resistance of ferritic stainless steel materials. If the contents of Zr, Co, V and W are too large, the processability and toughness of the ferritic stainless steel material will decrease, and the manufacturing cost will increase. Therefore, the upper limit of the contents of Zr, Co, V and W is controlled to 1.0% by mass, preferably 0.8% by mass, and more preferably 0.5% by mass. On the other hand, the lower limit of the contents of Zr, Co, V and W is not particularly limited, but is preferably 0.001% by mass and more preferably 0.01% by mass, respectively.

REM and Ca are elements effective for improving the oxidation resistance of ferritic stainless steel materials. If the contents of REM and Ca are too high, the production cost of the ferritic stainless steel material will increase. Therefore, the upper limit of the contents of REM and Ca is controlled to 0.10% by mass, preferably 0.08% by mass, and more preferably 0.05% by mass. On the other hand, the lower limit values of REM and Ca are not particularly limited, but are preferably 0.0001% by mass and more preferably 0.003% by mass, respectively.

Sn is an element effective for improving the oxidation resistance of ferritic stainless steel materials. If the Sn content is too high, Sn will segregate and the manufacturability will decrease. Therefore, the upper limit of the Sn content is controlled to 0.10% by mass, preferably 0.08% by mass, and more preferably 0.05% by mass. On the other hand, the lower limit of the Sn content is not particularly limited, but is preferably 0.001% by mass, more preferably 0.005% by mass.

B is an element effective for improving the secondary workability of the ferritic stainless steel material. If the B content is too high, the fatigue strength of the ferritic stainless steel material will decrease. Therefore, the upper limit of the B content is controlled to 0.01% by mass, preferably 0.008% by mass, and more preferably 0.005% by mass. On the other hand, the lower limit of the B content is not particularly limited, but is preferably 0.0001% by mass, more preferably 0.0005% by mass.

The ferrite-based stainless steel material according to the embodiment of the present invention has an average grain boundary distortion rate of 1% or more and less than 15%, preferably 3 to 10%. By controlling the average grain boundary distortion rate in such a range, it is possible to grow coarse crystal grains by heat treatment (recrystallization treatment) for a short time. Since the movement of magnetic domains effective for the development of vibration damping properties is hindered as the number of crystal grain boundaries increases, the vibration damping properties can be improved by coarsening the crystal grains and reducing the grain boundaries.
It is generally known that strain acts as a driving force for recrystallization, but when the average grain boundary distortion rate is high, fine crystal grains grow and then grow while taking in surrounding crystal grains. Time heat treatment is required.

The ferritic stainless steel material according to the embodiment of the present invention can be produced by melting stainless steel having the above composition, forming a steel sheet by a conventional method, and then imparting strain to the steel sheet. Specifically, first, stainless steel having the above composition is melted, forged or cast, and then hot-rolled to obtain a hot-rolled plate. Next, the hot-rolled plate is annealed, pickled, and cold-rolled in that order to obtain a cold-rolled plate. Next, the cold-rolled plate is annealed and pickled in sequence to obtain a cold-rolled annealed plate. Next, strain may be introduced into the cold-rolled annealed plate by a light reduction applying means such as a tension leveler or a skin pass so as to have a predetermined average grain boundary distortion factor. Although the strain can be introduced by cold rolling, it is difficult to control it to a predetermined average grain boundary distortion factor because the average grain boundary distortion factor becomes high.
The conditions in each step may be appropriately adjusted according to the composition of the stainless steel and the like, and are not particularly limited.

The ferrite-based stainless steel material according to the embodiment of the present invention preferably has an average crystal grain size of 150 μm or more after the recrystallization treatment. By setting the average crystal grain size in such a range, the grain boundaries can be reduced, and the vibration damping property can be improved.
Here, the conditions of the recrystallization treatment are not particularly limited, but heat treatment at 900 to 1100 ° C. for 5 to 30 minutes is preferable. Further, the heat treatment atmosphere may be an atmospheric atmosphere or a non-oxidizing atmosphere.

The ferrite-based stainless steel material according to the embodiment of the present invention preferably has a loss coefficient η after recrystallization treatment of 5 × 10 ^-4 or more, and more preferably 1 × 10 ^-3 or more. By setting the loss coefficient η in such a range, the vibration damping property can be improved.

In the ferrite-based stainless steel material according to the embodiment of the present invention, since the composition and the average grain boundary strain ratio of the ferrite-based stainless steel material are controlled within a predetermined range, vibration damping is achieved by recrystallization treatment while suppressing thermal deformation. Can be enhanced. Therefore, this ferritic stainless steel material is suitable for use as a vibration damping member. The vibration damping member is not particularly limited, and can be used for various members that require vibration damping in automobiles, electronic devices, and the like.

The vibration damping member according to the embodiment of the present invention includes the recrystallized material of the above-mentioned ferritic stainless steel material. Since this vibration damping member uses the above-mentioned ferritic stainless steel material, it has little thermal deformation and is excellent in vibration damping property.

Hereinafter, the contents of the present invention will be described in detail with reference to examples, but the present invention is not construed as being limited thereto.

(Examples 1 to 11 and Comparative Examples 1 to 9)
A ferritic stainless steel material was produced according to the following procedure.
Stainless steel having the composition shown in Table 1 is melted and hot-rolled to obtain a hot-rolled plate with a thickness of 3.0 mm, which is then annealed at 1050 ° C and pickled to be hot-rolled. An annealed plate was obtained. Next, the hot-rolled annealed plate is cold-rolled to obtain a cold-rolled plate having a thickness of 1.0 mm, and then the cold-rolled annealed plate is finished-annealed at 950 to 1050 ° C. and pickled to obtain the cold-rolled annealed plate. Obtained. Next, with respect to Examples 1 to 11 and Comparative Examples 3, 4, 7 and 8, a tensile test piece having a rolling direction (L direction) of 300 mm × a width direction (C direction) of 40 mm was cut out by cutting, and a tensile tester was used. The strain was applied by the tensile force shown in Table 2. The tensile direction was the rolling direction. No distortion was applied to Comparative Examples 1, 2, 5, 6 and 9.

The following evaluations were made on the ferritic stainless steel materials obtained above.

(Average grain boundary distortion rate)
A 10 mm × 10 mm test piece was cut out from the ferritic stainless steel material obtained above by cutting, and then resin-filled so that the cross section in the plate thickness direction parallel to the rolling direction became the observation surface. Next, the resin-filled test piece was mirror-treated by wet polishing using SiC abrasive paper and diamond paste, and then polished with a colloidal silica abrasive. The crystal orientation of the test piece treated in this manner was measured by the EBSD method. An FE-SEM equipped with an OIM (Orientation Imaging Microscopy) system was used for crystal orientation measurement. The evaluation area was a field of view of 100 μm square or more, and the strain area ratio was calculated using the KAM map (Kernel Average Misorientation Map) for the measurement results. The strain area factor was calculated in any of the five fields of view, and the average value thereof was taken as the average grain boundary strain factor.

(Heat treatment: recrystallization treatment)
A test piece having a width direction of 20 mm and a rolling direction of 270 mm was cut out from the ferritic stainless steel material obtained above by cutting, and then heat-treated (recrystallized) under the conditions shown in Table 2 under an atmospheric atmosphere. After the heat treatment, it was cooled by air cooling.

(Amount of thermal deformation)
The heat-treated test piece is placed on a flat table, and a range of 30 mm from one end of the test piece (one end in the rolling direction) is brought into contact with the table and fixed with a clamp, and the other end (the other end in the rolling direction). The height (warp height) of the part) floating from the table was measured. The warp height was measured at both ends of the test piece in the rolling direction, and the average value thereof was taken as the warp height. In this evaluation, the case where the warp height was 5 mm or less was evaluated as 〇 (the amount of thermal deformation was small), and the case where the warp height exceeded 5 mm was evaluated as x (the amount of thermal deformation was large).

(Average crystal grain size after heat treatment (recrystallization treatment))
A 10 mm × 10 mm test piece was cut out from the heat-treated test piece by cutting, and then resin-filled so that the cross section in the plate thickness direction parallel to the rolling direction became the observation surface. Next, the resin-embedded test piece was mirror-treated by wet polishing, and then the metallographic structure exposed by etching with fluorinated nitric acid was observed with an optical microscope. For observation with an optical microscope, a straight line was drawn at an arbitrary position on the optical microscope image, the number of intersections between the straight line and the grain boundary was measured, and the average intercept length was taken as the crystal grain size according to JIS G0551: 2013. .. The crystal grain size was measured by drawing 20 or more straight lines in a plurality of fields of view, and the average value thereof was taken as the average crystal grain size. In this evaluation, a case where the average crystal grain size was 150 μm or more was evaluated as 〇 (sufficient coarsening of crystal grains), and a case where the average crystal grain size was less than 150 μm was evaluated as × (sufficient coarsening of crystal grains).

(Loss coefficient η after heat treatment (recrystallization treatment))
A test piece having a width direction of 10 mm and a rolling direction of 250 mm was cut out from the test piece after the heat treatment by cutting. Using this test piece, the loss factor η was measured according to the “central excitation method” defined in JIS K7391: 2008. Specifically, the test piece with the central portion fixed was vibrated by the impedance head, and the mechanical impedance was derived from the output force signal and acceleration vibration. Then, the loss coefficient η was derived based on the anti-resonance frequency that is the peak of the mechanical impedance and the frequency at which the amplitude drops by 3 dB from the peak. In this evaluation, the case where the loss coefficient η is 5 × 10 ^-4 or more is ◎ (excellent vibration damping property), and the case where the loss coefficient η is 1 × 10 ^-3 or more and less than 5 × 10 ^-4 is 〇 (vibration damping property). Is good), and the case where the loss coefficient η is ^{less than 1 × 10 -3} was evaluated as × (insufficient vibration damping property).
The results of each of the above evaluations are shown in Table 2.

As shown in Table 2, the ferritic stainless steel materials of Examples 1 to 11 having an average grain boundary strain ratio of 1% or more and less than 15% have all the results of the amount of thermal deformation, the average grain size, and the loss coefficient η. It was good.
On the other hand, since the ferritic stainless steel materials of Comparative Examples 1 to 7 have an average grain boundary strain rate outside the above range, the result is one or more of the thermal deformation amount, the average crystal grain size, and the loss coefficient η. Was not enough. Further, the ferrite-based stainless steel material of Comparative Example 8 had an excessively small amount of Cr, so that the result of the amount of thermal deformation was not sufficient. Further, since the ferrite-based stainless steel material of Comparative Example 9 has an excessively low Cr content and an average grain boundary strain rate outside the above range, all of the thermal deformation amount, the average crystal grain size, and the loss coefficient η are all. The result was not enough.

As can be seen from the above results, according to the present invention, it is possible to provide a ferritic stainless steel material and a vibration damping member capable of improving the vibration damping property by recrystallization treatment while suppressing thermal deformation.

Claims (11)

C: 0.05% by mass or less, Mn: 1.0% by mass or less, Ni: 0.60% by mass or less, P: 0.05% by mass or less, S: 0.03% by mass or less, Cr: 10.5 ~ 24.0% by mass, N: 0.03% by mass or less, Cu: 0.60% by mass or less, Mo: 2.5% by mass or less, Si: 3.0% by mass or less, Al: 5.0% by mass A ferrite-based stainless steel material containing the following, the balance consisting of Fe and unavoidable impurities, and an average grain boundary strain ratio of 1% or more and less than 15%. It further contains at least one selected from Nb: 0.50% by mass or less and Ti: 0.50% by mass or less, and the total content of Nb and Ti is 6 (C + N) or more (C and N are C and N). The ferrite-based stainless steel material according to claim 1, which represents the content of each of the above. The ferrite-based stainless steel material according to claim 1 or 2, wherein the total content of Al and Si is 1.0% by mass or more. Claims 1 to further include at least one selected from Zr: 1.0% by mass or less, Co: 1.0% by mass or less, V: 1.0% by mass or less, and W: 1.0% by mass or less. The ferritic stainless steel material according to any one of 3. The ferrite-based stainless steel material according to any one of claims 1 to 4, further comprising at least one selected from REM: 0.10% by mass or less and Ca: 0.10% by mass or less. The ferrite-based stainless steel material according to any one of claims 1 to 5, further comprising at least one selected from Sn: 0.10% by mass or less and B: 0.01% by mass or less. The ferrite-based stainless steel material according to any one of claims 1 to 6, wherein the average crystal grain size after the recrystallization treatment is 150 μm or more. The ferrite-based stainless steel material according to any one of claims 1 to 7, wherein the loss coefficient η after the recrystallization treatment is 5 × 10 ^{-4 or more.} The ferrite-based stainless steel material according to claim 7 or 8, wherein the recrystallization treatment is a heat treatment at 900 to 1100 ° C. for 5 to 30 minutes. The ferrite-based stainless steel material according to any one of claims 1 to 9, which is used for a vibration damping member. A vibration damping member containing a recrystallized material for a ferritic stainless steel material according to any one of claims 1 to 10.