JP6029662B2 - Austenitic stainless steel sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to an austenitic stainless steel sheet and a method for producing the same, and specifically, for example, suitable for use as a structural member such as an automobile or a train. The present invention relates to an austenitic stainless steel sheet having both ductility in a strain rate region and a method for producing the same.

  In recent years, there has been a demand for improvement in fuel efficiency of automobiles, railways, and the like as a countermeasure to environmental problems, and as a solution to this, a reduction in the weight of the vehicle body is very effective. Furthermore, to reduce the weight of the vehicle body, it is effective to reduce the weight of the material forming the structural member that occupies most of the weight, specifically to reduce the thickness of the material. However, the thinning of the material decreases the rigidity and the shock absorption capacity at the time of collision. Therefore, in recent years, application of high-strength materials to structural members has been progressing.

  For example, a front side member of an automobile needs to absorb impact energy without being greatly deformed. As an index of the impact absorbing ability in such a small strain region, 10% flow stress at a strain rate equivalent to collision of 1000 / s is considered suitable. Further, as an index of press formability, it is considered that uniform elongation at a strain rate of 0.1 / s equivalent to press is suitable. That is, it can be said that a material excellent in 10% flow stress at a strain rate of 1000 / s and uniform elongation at a strain rate of 0.1 / s is suitable as a structural member. Specifically, either the impact absorbing ability and press formability in which the product of 10% flow stress at a strain rate of 1000 / s and uniform elongation at a strain rate of 0.1 / s is 450 MPa or more, or Materials that are both very good are desirable.

  Patent Document 1 discloses an invention related to an austenitic stainless steel in which Mn is added in a large amount and does not cause work-induced martensitic transformation at the time of deformation, and the strength is increased by twin deformation of austenite. However, since the austenitic stainless steel of the present invention does not cause any work-induced martensitic transformation, there may be an insufficient balance of strength and elongation. Specifically, Patent Document 1 describes, as an example, 10% flow stress in a dynamic tensile test and breakage in a static tensile test, but the product of these is only less than 400 MPa.

  Patent Document 2 discloses an invention relating to a low Ni type austenitic stainless steel for automobile structural members. However, since the austenitic stainless steel of the present invention has a coarse crystal grain size of several tens of μm, cracks often occur on the surface of the bent portion when it is molded as an automobile structural member. It is insufficient.

JP 2009-30128 A JP 2010-196103 A

  In order to further reduce the weight of structural members and improve design flexibility, materials are still required to have high strength at high strain rates and to improve ductility at low strain rates. For this reason, even the austenitic stainless steel disclosed in Patent Documents 1 and 2 may not fully satisfy the performance required for the latest products.

  As a result of studying various methods for increasing the strength of steel in order to achieve both high strength and high ductility, which are generally contradictory properties, the present inventors have found (a) solid solution among various methods for increasing strength. C, strengthening by solid solution N, (b) strengthening by transformation-induced plasticity (TRIP effect) during deformation, and (c) strengthening by crystal grain refinement, high strength at high strain rate and low The present invention has been completed by finding that high ductility at a strain rate can be achieved at the same time. The present invention is listed below.

[1] By mass%, C: 0.02 to 0.30%, Cr: 10.0 to 25.0%, Ni: 3.5 to 10.0%, Si: 0.1 to 3.0% , Mn: 0.5% to 5.0%, N: 0.10 to 0.40%, Mo: 0 to 3.0%, Cu: 0 to 3.0%, Ti: 0 to 0.10% , Nb: 0 to 0.50%, V: 0 to 1.0%, C + 3 × N: 0.4% or more, consisting of the balance Fe and impurities, Md defined by the following formula (1) ₃₀ value is at 50 ° C. or less 0 ℃ or more, a volume ratio of Cr carbide and Cr nitrides than 1%, and the average crystal grain size of the matrix phase is Ri der less 10 [mu] m, at a strain rate of 1000 / s An austenitic stainless steel sheet having a product of 10% flow stress and uniform elongation at a strain rate of 0.1 / s of 450 MPa or more .

[2]
The austenitic stainless steel sheet according to [1], which contains at least one of Mo: 0.4 to 3.0% and Cu: 0.4 to 3.0% by mass%.

[3]
One or more selected from the group consisting of Ti: 0.01 to 0.10%, Nb: 0.02 to 0.50%, and V: 0.02 to 1.0% by mass% The austenitic stainless steel sheet according to [1] or [2].

[4] A method for producing an austenitic stainless steel sheet according to [1], wherein, in mass%, C: 0.02 to 0.30%, Cr: 10.0 to 25.0%, Ni: 3 0.5 to 10.0%, Si: 0.1 to 3.0%, Mn: 0.5% to 5.0%, N: 0.10 to 0.40%, Mo: 0 to 3.0% Cu: 0 to 3.0%, Ti: 0 to 0.10%, Nb: 0 to 0.50%, V: 0 to 1.0%, C + 3 × N: 0.4% or more Then, after hot rolling the stainless steel material composed of the remaining Fe and impurities, the obtained hot-rolled steel sheet is hot-rolled at an annealing temperature T (° C.) and an annealing time t (sec) satisfying the following expression (2). A method for producing an austenitic stainless steel sheet, which is subjected to sheet annealing.

  The austenitic stainless steel sheet according to the present invention has a product of 10% flow stress at a strain rate of 1000 / s and a uniform elongation at a strain rate of 0.1 / s of 450 MPa or more. Either or both of these can be greatly improved as compared with conventional steels, and high strength can be achieved at a high strain rate and ductility can be improved at a low strain rate.

FIG. 1 is a graph illustrating equation (2). FIG. 2 is a graph showing the analysis result of the hot-rolled annealed plate by EPMA line analysis, FIG. 2 (a) shows the analysis result of the steel plate 3, FIG. 2 (b) shows the analysis result of the steel plate 43, and FIG. (C) shows the analysis result of the steel plate 44.

  The chemical composition, metal structure and manufacturing method of the austenitic stainless steel sheet according to the present invention will be described. In this specification, “%” relating to chemical composition means “mass%” unless otherwise specified.

1. Chemical composition (C: 0.02-0.30%)
C is a solid solution strengthening element and greatly contributes to high strength at a high strain rate. Solid solution strengthening by C is strengthening utilizing short-range obstacles, and the strain rate dependence of strengthening is large. Therefore, compared to solid solution strengthening with alloy elements, strengthening with dislocations, and other strengthening with precipitates, the deterioration of ductility at a low strain rate is small, and the purpose of the present invention is to increase the strength at a high strain rate. It is extremely effective in achieving both ductility at a low strain rate. For this reason, C content shall be 0.02% or more. However, if the C content is excessive, coarse carbides are produced in the production process, and the balance between strength and ductility deteriorates, so the C content is 0.30% or less. The C content is preferably 0.04% or more and 0.30% or less, and more preferably 0.06% or more and 0.30% or less.

(Cr: 10.0 to 25.0%)
Cr is a basic element of stainless steel, and by containing 10.0% or more, Cr has an effect of forming a passive film on the surface of the steel material to enhance corrosion resistance. However, if the Cr content is excessive, δ ferrite is generated at a high temperature, and the hot workability of the steel is significantly deteriorated. Therefore, the Cr content is set to 10.0% or more and 25.0% or less. The Cr content is preferably 15% or more and 20% or less.

(Ni: 3.5 to 10.0%)
Ni is a basic element of austenitic stainless steel. In order to stably obtain an austenitic phase having an excellent balance between strength and ductility at room temperature, Ni is contained in an amount of 3.5% or more. However, if the Ni content is too large, the austenite phase is excessively stabilized, the work-induced martensitic transformation during deformation is suppressed, and work hardening becomes difficult, resulting in a decrease in elongation. Therefore, the Ni content is set to 3.5% or more and 10.0% or less. The Ni content is preferably 3.5% or more and 8% or less.

(Mn: 0.5-5.0%)
Mn is used as a deoxidizer during melting. Further, Mn is an austenite stabilizing element and has an effect of increasing the solid solubility limit of C and N to dissolve a large amount of C and N, and contains an appropriate amount in consideration of balance with other elements. . However, if the Mn content is excessive, a coarse Mn compound is produced in the production process, and the coarse Mn compound becomes a starting point of destruction, and the moldability deteriorates. For the above reasons, the Mn content is set to 0.5% or more and 5.0% or less. The Mn content is preferably 1.0% or more and 5.0% or less, and more preferably 1.5% or more and 5.0% or less.

(N: 0.10 to 0.40%)
N, like C, is a solid solution strengthening element and is effective for increasing the strength at a high strain rate. Solid solution N is the object of the present invention because, like solid solution C, the deterioration in ductility at a low strain rate is small compared to solid solution strengthening by alloy elements, strengthening by dislocation, and strengthening by precipitates. It is extremely effective in increasing strength at high strain rates and improving ductility at low strain rates. For this reason, N content shall be 0.10% or more. However, if the N content is excessive, coarse nitrides are produced in the manufacturing process, and the balance between strength and ductility deteriorates. Therefore, the N content is set to 0.40% or less. The N content is preferably 0.15% or more and 0.30% or less, and more preferably 0.20% or more and 0.25% or less.

(C + 3 × N: 0.4% or more)
As described above, C and N are solid solution strengthening elements, and greatly contribute to increasing the strength at a high strain rate. Since the solid solution strengthening by C and N has less ductile deterioration at a low strain rate than the solid solution strengthening by alloying element, the strengthening by dislocation, and the strengthening by precipitates, the high strain which is the object of the present invention In order to achieve both high strength at a speed and ductility at a low strain rate, C + 3 × N is set to 0.4% or more.

  The austenitic stainless steel according to the present invention may further contain an optional additive element described below as required.

(Si: 0 to 3.0%)
Si is a solid solution strengthening element, contributes to increasing the strength of steel, and is also used as a deoxidizer during melting. Si may be contained as necessary. In order to increase the strength, it is desirable to contain 0.1% or more. However, if the Si content is excessive, coarse Si compounds are produced during the production process, and these coarse Si compounds cause deterioration of hot workability and cold workability. For this reason, Si content is 3.0% or less, Preferably it is 2.8% or less.

(Mo: 0 to 3.0% or Cu: 0 to 3.0%, or both)
Mo is an element effective for improving the corrosion resistance, and may be contained as necessary. However, if the Mo content is too large, ductility is lowered, so the Mo content is 3.0% or less. The Mo content is preferably 2.5% or less, and preferably 0.4% or more in order to reliably obtain the effect of improving corrosion resistance.

  Cu is effective in improving cold workability and ductility, and may be contained as necessary. However, if the Cu content is too high, hot brittleness is induced, so the Cu content is 3.0% or less. The Cu content is preferably 2.5% or less, and is preferably contained in an amount of 0.4% or more in order to surely improve the cold workability and ductility.

(One or more selected from Ti: 0 to 0.10%, Nb: 0 to 0.50% and V: 0 to 1.0%)
Ti, Nb, and V are all precipitated as fine carbides or nitrides in the manufacturing process and have an effect of suppressing crystal grain growth due to the pinning effect, and may be contained as necessary. However, if the content of these elements is excessive, coarse carbides and nitrides are formed, which become the starting points of fracture during deformation and significantly deteriorate the moldability. Therefore, the Ti content is 0.10% or less, the Nb content is 0.50% or less, and the V content is 1.0% or less. Preferably, the Ti content is 0.05% or less, the Nb content is 0.2% or less, and the V content is 0.5% or less. In order to reliably obtain the effect of suppressing crystal grain growth, Ti is preferably contained in an amount of 0.01% or more, Nb is contained in an amount of 0.02% or more, and V is contained in an amount of 0.02% or more.

  The balance other than those described above is Fe and impurities. Examples of the impurities include those contained in raw materials such as ore and scrap and those contained in the manufacturing process. Typical impurities include P: 0.05% or less, S: 0.03% or less, and the like.

(Md ₃₀ value is 0 ° C or more and 50 ° C or less)
The Md ₃₀ value is an index indicating austenite stability, and is a processing temperature at which 50% is transformed into martensite when an elongation strain of 30% is applied. The Md ₃₀ value is defined by the following equation (1). By setting the Md ₃₀ value to 0 ° C. or more and 50 ° C. or less, processing-induced martensite is appropriately generated at the time of deformation, and the TRIP effect is exhibited, so that a better balance between strength and ductility can be obtained.

2. Metal structure (crystal grain size of austenite matrix: 10 μm or less)
The refinement of crystal grains is a strengthening method in which the deterioration of the ductility of the steel is small, and it has been found that it is an effective strengthening method even in the stainless steel targeted by the present invention. In addition, by reducing the crystal grain size and increasing the density of the crystal grain boundaries, the strain concentrated on the crystal grain boundaries at the time of deformation can be dispersed to suppress the generation of cracks. Therefore, the crystal grain size of the austenite matrix is set to 10 μm or less. The crystal grain size of the austenite matrix is preferably 7 μm or less, more preferably 6 μm or less.

(Volume ratio of Cr carbonitride: 1.0% or less)
As described above, increasing the C and N contents improves the balance between strength at a high strain rate and ductility at a low strain rate, but this increases the strength in the case of solute C and N. This is because the strain rate dependence is large. Therefore, even if a large amount of C and N is added, this effect cannot be obtained if they exist as Cr carbide or Cr nitride. Here, Cr ₂₃ C ₆ is exemplified as the Cr carbide, and Cr ₂ N, CrN is exemplified as the Cr nitride. Here, the Cr carbide includes Cr ₂₃ (C, N) ₆ in which a small amount of N is dissolved, and the Cr nitride includes Cr ₂ (C, N), Cr (C, N) in which a small amount of C is dissolved. N). Furthermore, when a coarse compound such as Cr carbide or Cr nitride exists, the Cr carbide, Cr nitride itself, or the interface between the Cr carbide, Cr nitride and the parent phase is likely to be a crack starting point, and the ductility is remarkable. To deteriorate. For this reason, it is desirable that the amount of Cr carbide and Cr nitride is small. Specifically, the volume ratio of Cr carbide and Cr nitride is set to 1.0% or less.

3. Manufacturing Method The present invention is characterized by obtaining an excellent balance between strength and ductility by dissolving a large amount of C and N in a solid solution. However, for example, in hot-rolled sheet annealing at 1080 ° C. for about 60 seconds disclosed in Patent Document 2, C and N precipitated or concentrated at the time of hot rolling are not sufficiently uniformed, and these precipitation or concentration C, N may remain even after the subsequent solution heat treatment and annealing, and in the cooling process after the solution heat treatment and annealing, it is easy to precipitate as a nucleus in which the Cr carbide and nitride remain, C and N cannot be made a solid solution.

  As a result of detailed examination of the annealing temperature T (° C.), the annealing time t (sec), and the diffusion of C and N, the present inventors have found that the annealing temperature T is such that C and N in the hot-rolled sheet diffuse 150 μm or more. It has also been found that by performing hot-rolled sheet annealing with an annealing time t, C and N precipitated or concentrated during hot rolling are sufficiently dissolved and uniformized.

Here, the diffusion distance λ is arranged by the diffusion coefficient D and time t as shown in the equation (3). Furthermore, the diffusion coefficient D (m ² / sec) of N in the austenitic stainless steel is represented by the formula (4) according to literature (for example, physical properties of steel and nitrogen, page 69 Agne Technical Center).

  Formula (2) is a summary of the conditions under which N diffuses by 150 μm or more based on formulas (3) and (4). Further, FIG. 1 illustrates the equation (2). A portion painted in gray (upper right portion) in FIG. 1 is a range satisfying the expression (2). Since C in the austenitic stainless steel has a diffusion coefficient substantially the same as N, C is sufficiently diffused and uniformized by performing hot-rolled sheet annealing at an annealing temperature and an annealing time satisfying the formula (2). The

  Further, even if C and N are diffused and uniformized during hot-rolled sheet annealing, if the cooling rate is slow, C and N may precipitate as Cr carbide and Cr nitride during cooling. In particular, the cooling rate is preferably 2.0 ° C./sec or more up to 700 ° C. where Cr carbide and Cr nitride are likely to precipitate. Also in the solution treatment and annealing after hot-rolled sheet annealing, the temperature is preferably maintained at 900 ° C. or higher, and the cooling rate from the holding temperature to 700 ° C. is preferably 2.0 ° C./sec or higher.

A 17 kg ingot of stainless steel having the chemical composition shown in Table 1 was melted. In Table 1, steel types A1 to A25 are materials whose chemical composition, (C + 3 × N) amount, and Md ₃₀ value all satisfy the scope of the present invention, and steel types B1 to B14 have chemical compositions (C + 3 × N). ) At least one of the quantities, Md ₃₀ values, is a material outside the scope of the present invention. In Table 1, “-” indicates that inclusion is not intended (the content is less than the desired range or 0).

  This stainless steel ingot was cut to obtain a hot rolling material having a thickness of 45 mm. Thereafter, hot rolling was performed to obtain a hot-rolled steel sheet having a thickness of 6.0 mm, and then the hot-rolled steel sheet was subjected to hot-rolled sheet annealing at an annealing temperature and an annealing time shown in Table 2, respectively. The steel plates 28, 34, 35, 43, and 44 are examples in which the annealing temperature T (° C.) and the annealing time t (sec) in hot-rolled sheet annealing do not satisfy the above formula (2).

Thereafter, cold rolling and annealing were repeated 2 to 3 times to obtain a cold rolled sheet having a thickness of 1.0 mm. Finally, annealing was performed at 900 to 1000 ° C. for 180 seconds.
Cr volume fraction V (%), average grain size D (μm), 10% flow stress (10% FS) at a strain rate of 1000 / s, uniform elongation at a strain rate of 0.1 / s (UEL) was measured by the following method.

(Volume ratio of Cr carbonitride)
After the steel plate was chemically polished until the plate thickness was 3/4, X diffraction measurement was performed with the characteristic X-rays in the range of Co-Kα rays and 2θ in the range of 30-100 (degrees). The volume fraction V of Cr carbide and Cr nitride was calculated using the detected diffraction peak. The X-ray diffraction peaks of the parent phase are from the (111) plane, (200) plane, (220) plane of the austenite phase, and the (110) plane, (200) plane, (211) plane of the parent martensite phase. The diffraction peak of was used. The diffraction peak from the (420) plane, the (422) plane and the (440) plane of Cr ₂₃ C ₆ as the X-ray diffraction peak of carbide, the (110) plane of Cr ₂ N as the X-ray diffraction peak of nitride, (002 ) Plane, (111) plane, and diffraction peaks from CrN (111) plane, (220) plane, and (311) plane were used.

Even with peaks from the same phase, the reflectivity of X-rays varies depending on the surface. Therefore, the integrated intensity of each peak was divided by the relative intensity of each peak of the JCPDS card and normalized.
Also, if the constituent elements of each phase are different, the atomic scattering factors of those constituent elements are different, so that the X-ray reflectivity is different. However, according to “BDCullity: Elements of X-ray Diffraction, 2nd ed., Addison-Wesley, Massachussets, (1978)”, which is a representative document relating to X-ray diffraction measurement, Since the difference in atomic scattering factors of Fe, Cr, Ni, and Mn, which are the main elements of phases and carbides and nitrides, is small, the effect of the difference in the constituent elements of each phase on the reflectance is within the scope of this example. Can be ignored.

Thus, the volume fraction V of Cr carbide and Cr nitride can be expressed by the following equation (5). V _C , V _N , V _γ , V _{α ′} are obtained by dividing the integrated intensity of the peak of each surface of the Cr carbide, Cr nitride, austenite phase, and martensite phase by the relative strength of the JCPDS card, respectively. It is the value added together.

An example is shown in equation (6). Here, I _{gamma (hkl)} is the integrated intensity of the peaks from the obtained gamma (hkl) plane obtained by X-ray diffraction measurement, RI _{gamma (hkl)} is the relative intensity of JCPDS card RI _{gamma (hkl)} .

(Crystal grain size)
The cross-section in the rolling direction of the steel plate was polished, and after the nitric acid electrolytic corrosion, the metal structure was photographed with a scanning microscope. The nominal grain size obtained from the photograph taken was taken as the average crystal grain size of the parent phase.

(10% flow stress at a strain rate of 1000 / s, uniform elongation at a strain rate of 0.1 / s)
Tensile tests were performed at strain rates of 1000 / s and 0.1 / s. Each steel plate was subjected to a tensile test three times, and the average value was taken as the characteristic value. Here, 10% flow stress at a strain rate of 1000 / s is used as the strength of the high strain rate equivalent to the collision, and uniform elongation at a strain rate of 0.1 / s is used as the ductility at the low strain rate equivalent to the press. Was measured. The product of these 10% flow stress and uniform elongation was used as an index of balance between strength and ductility.

  Table 2 shows the volume fraction V (%) of Cr carbide and Cr nitride of these steel sheets, the average crystal grain size D (μm), 10% flow stress in a tensile test at a strain rate of 1000 / s, and a strain rate of 0. The uniform elongation in a tensile test at 1 / s and the product of these are shown together.

Steel plates 1 to 26 in Table 2 are steel plates according to examples of the present invention.

  Each of the steel plates 1 to 26 has an excellent balance between strength and ductility. Specifically, it is a steel in which the product of 10% flow stress at a strain rate of 1000 / s and uniform elongation at a strain rate of 0.1 / s exceeds 450 MPa.

On the other hand, the steel plates 27 to 44 are comparative steels and are inferior in balance between strength and ductility.
The steel plates 27 and 28 are inferior in balance between strength and ductility because the C content is out of the scope of the present invention.

The steel plates 29 and 30 have an N content that is out of the range of the present invention. In particular, the steel plate 29 has a smaller amount of (C + 3 × N) than the range of the present invention, so that the balance between strength and ductility is poor.
The steel plates 31 and 32 have a (C + 3 × N) amount less than the range of the present invention. In particular, the steel plate 31 has a balance between strength and ductility because both the C content and the N content are outside the range of the present invention. Inferior.

The steel plates 33 and 34 are inferior in balance between strength and ductility because the Cr content and the Md ₃₀ value are out of the scope of the present invention.
The steel plate 35 is inferior in the balance between strength and ductility because the Ni content and the Md ₃₀ value are out of the scope of the present invention.

The steel plate 36 is inferior in balance between strength and ductility because the Ni content and the Md ₃₀ value are out of the scope of the present invention.
The steel plate 37 is inferior in the balance between strength and ductility because the Si content and the Mn content are out of the scope of the present invention.

The steel plate 38 is inferior in balance between strength and ductility because the Si content, the Mn content and the Ti content deviate from the scope of the present invention.
The steel plate 39 is inferior in the balance between strength and ductility because the Mo content and the Nb content deviate from the scope of the present invention.

The steel plate 40 is inferior in balance between strength and ductility because the Cu content and the V content deviate from the scope of the present invention.
The steel plates 41 and 42 both have a chemical composition that satisfies the scope of the present invention, a (C + 3 × N) amount, and an Md ₃₀ value, but the crystal grain size is out of the scope of the present invention, so that the balance between strength and ductility is achieved. Inferior to By comparing the steel plates 1, 41, 42 produced from the steel type A1, it can be seen that an excellent balance of strength and ductility can be obtained by making the crystal grain size 10 μm or less.

Further, the steel plates 43 and 44 both have a chemical composition that satisfies the scope of the present invention, a (C + 3 × N) amount and an Md ₃₀ value, but the total volume of Cr carbide and Cr nitride of the cold-rolled annealing material. The rate exceeds 1%, and the balance between strength and ductility is poor. By comparing steel plates 3, 4, 43, and 44 made from steel type A3, the balance of excellent strength and ductility can be obtained by making the total volume fraction of Cr carbide and Cr nitride 1% or less. I understand.

  FIG. 2 is a graph showing the analysis result of the hot-rolled annealed plate by EPMA line analysis, FIG. 2 (a) shows the analysis result of the steel plate 3, FIG. 2 (b) shows the analysis result of the steel plate 43, and FIG. c) shows the analysis result of the steel plate 44.

  Although the steel plates 43 and 44 have a chemical composition that satisfies the scope of the present invention, the annealing temperature and annealing time of hot-rolled sheet annealing after hot rolling do not satisfy the formula (2), and FIG. As can be seen from the EPMA analysis result of the hot rolled annealed sheet 2 (c), there is a region where C and N are concentrated after the hot rolled sheet anneal. These remain until after the final annealing and exist as a large amount of Cr carbide and nitride.

Claims (4)

In mass%, C: 0.02 to 0.30%, Cr: 10.0 to 25.0%, Ni: 3.5 to 10.0%, Si: 0.1 to 3.0%, Mn: 0.5% to 5.0%, N: 0.10 to 0.40%, Mo: 0 to 3.0%, Cu: 0 to 3.0%, Ti: 0 to 0.10%, Nb: 0 to 0.50%, V: 0 to 1.0%, C + 3 × N: 0.4% or more, and the balance is Fe and impurities, and the Md ₃₀ value defined by the following formula (1) is and at 0 ℃ than 50 ° C. or less, and a volume ratio of Cr carbide and Cr nitrides than 1%, and the average crystal grain size of the matrix phase is Ri der less 10 [mu] m, 10% flow at a strain rate of 1000 / s An austenitic stainless steel sheet in which the product of stress and uniform elongation at a strain rate of 0.1 / s is 450 MPa or more .

  The austenitic stainless steel sheet according to claim 1, which contains at least one of Mo: 0.4 to 3.0% and Cu: 0.4 to 3.0% by mass%.   One or more selected from the group consisting of Ti: 0.01 to 0.10%, Nb: 0.02 to 0.50%, and V: 0.02 to 1.0% by mass% The austenitic stainless steel sheet according to claim 1 or 2, which is contained.   A method for producing the austenitic stainless steel sheet according to claim 1,
  In mass%, C: 0.02 to 0.30%, Cr: 10.0 to 25.0%, Ni: 3.5 to 10.0%, Si: 0.1 to 3.0%, Mn: 0.5% to 5.0%, N: 0.10 to 0.40%, Mo: 0 to 3.0%, Cu: 0 to 3.0%, Ti: 0 to 0.10%, Nb: 0 to 0.50%, V: 0 to 1.0%, C + 3 × N: 0.4% or more, obtained after hot rolling a stainless steel material composed of the remaining Fe and impurities. A method for producing an austenitic stainless steel sheet, wherein the hot-rolled steel sheet is subjected to hot-rolled sheet annealing at an annealing temperature T (° C.) and an annealing time t (sec) satisfying the following expression (2).

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