Ferritic stainless steel and its manufacturing method

Abstract

The present invention provides a ferritic stainless steel with improved workability, and a manufacturing method thereof, by optimizing the steel composition and manufacturing process to control the texture. [Solution] The method for producing a ferritic stainless steel sheet of the present invention includes the steps of producing a slab containing, by weight, C: 0.0005-0.02%, N: 0.005-0.02%, Si: 0.01-1.0%, Mn: 0.01-1.0%, P: 0.001-0.05%, Cr: 13.0-20.0%, Ti: 0.05-0.5%, with the remainder being Fe and unavoidable impurities; hot rolling the produced slab in a heating furnace at 1100-1300°C; after hot rolling, performing primary rolling to a reduction ratio of 25-65%; after primary rolling, performing hot rolling annealing at 900-1100°C; performing secondary rolling; and performing cold rolling annealing, wherein the reduction ratio in the secondary rolling step is 40% or more.

Description

[Technical Field]

[0001] The present invention relates to a ferritic stainless steel and a method for producing the same, and more particularly to a ferritic stainless steel having excellent workability due to texture control, and a method for producing the same. [Background technology]

[0002] Ferritic stainless steels are used in a variety of industrial applications, including home appliances, kitchenware, and automotive parts, and therefore require high formability that allows them to be processed in a variety of ways. However, because ferritic stainless steels have a BCC crystal structure, they lack the TRIP phenomenon seen in austenitic stainless steels, resulting in relatively low elongation. On the other hand, ferritic stainless steels exhibit a high {111} texture under appropriate manufacturing conditions, which can be used to achieve high R-values ​​and is advantageous for deep drawing. Therefore, because ferritic stainless steels have a lower elongation rate than austenitic stainless steels, technology is needed to enable them to be processed in a variety of ways in the various fields in which they are used. Summary of the Invention [Problem to be solved by the invention]

[0003] In order to solve the above-mentioned problems, an object of the present invention is to provide a ferritic stainless steel having improved workability by optimizing the steel composition and manufacturing process to control the texture, and a manufacturing method thereof.

[0004] The problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0005] As a means for achieving the above object, the present invention provides a ferritic stainless steel sheet having excellent workability, characterized in that the ferritic stainless steel sheet contains, by weight, 0.0005-0.02% C, 0.005-0.02% N, 0.01-1.0% Si, 0.01-1.0% Mn, 0.001-0.05% P, 13.0-20.0% Cr, 0.05-0.5% Ti, with the remainder being Fe and unavoidable impurities, and has a {111} texture fraction of 50% or more in a region from the surface to ¼ thickness.

[0006] The ferritic stainless steel sheet of the present invention can be a ferritic stainless steel sheet with an R-bar value of 1.7 or more and excellent workability.

[0007] The method for producing a ferritic stainless steel sheet having excellent workability of the present invention includes the steps of producing a slab containing, by weight, C: 0.0005-0.02%, N: 0.005-0.02%, Si: 0.01-1.0%, Mn: 0.01-1.0%, P: 0.001-0.05%, Cr: 13.0-20.0%, Ti: 0.05-0.5%, with the remainder being Fe and unavoidable impurities; hot rolling the produced slab in a heating furnace at 1100-1300°C; after the hot rolling, performing primary rolling to a reduction ratio of 25-65%; after the primary rolling, performing hot rolling annealing at 900-1100°C; second rolling; and cold rolling annealing.

[0008] The method for producing a ferritic stainless steel sheet of the present invention can be a method for producing a ferritic stainless steel sheet with excellent workability, in which the reduction ratio in the secondary rolling step is 40% or more.

[0009] The method for producing a ferritic stainless steel sheet of the present invention can be a method for producing a ferritic stainless steel sheet with excellent workability, in which the cold rolling and annealing step is carried out at 850 to 1050°C.

[0010] The method for producing a ferritic stainless steel sheet of the present invention can be a method for producing a ferritic stainless steel sheet with excellent workability, in which the hot-rolled and annealed hot-rolled material has a {111} texture fraction of 10% or more in the region from the surface layer to ¼ thickness.

[0011] The method for producing a ferritic stainless steel of the present invention can be used to produce a ferritic stainless steel sheet with excellent workability, in which the cold-rolled and annealed cold-rolled material has a {111} texture fraction of 50% or more in the region from the surface layer to ¼ thickness.

[0012] The method for producing a ferritic stainless steel of the present invention can be a method for producing a ferritic stainless steel sheet having an R-bar value of 1.7 or more and excellent workability. [Effects of the Invention]

[0013] According to the present invention, a ferritic stainless steel with excellent workability and a method for producing the same can be provided by forming a {111} texture through the steps of primary rolling and hot rolling annealing. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 10 is a diagram showing the {111} texture of the hot-rolled material of Example 5 measured by EBSD. [Figure 2] FIG. 1 is a diagram showing the {111} texture of the hot-rolled material of Comparative Example 2 measured by EBSD. [Figure 3] FIG. 1 is a diagram showing the fraction of {111} texture in hot-rolled and cold-rolled materials. [Figure 4] FIG. 1 is a diagram showing the relationship between the reduction ratio in the first rolling and the fraction of the {111} texture in the region from the surface layer to 1 / 4 thickness of the cold-rolled material. [Figure 5] FIG. 1 shows the relationship between the fraction of {111} texture and R-bar in the region from the surface to 1 / 4 thickness. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will be described below. However, the embodiments of the present invention can be modified into various other forms, and the technical concept of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those having average knowledge in the art. The terms used in this application are merely used to describe specific examples. Therefore, for example, singular expressions include plural expressions unless the context clearly dictates otherwise. In addition, it should be noted that the terms "comprise" or "include" used in this application are used to clearly indicate the presence of features, steps, functions, components, or combinations thereof described in the specification, and are not used to preliminarily exclude the presence of other features, steps, functions, components, or combinations thereof. Meanwhile, unless otherwise defined, all terms used herein should be considered to have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Therefore, unless clearly defined herein, specific terms should not be construed in an overly ideal or formal sense.

[0016] Furthermore, in this specification, the terms "about," "substantially," and the like are used to mean a numerical value or a value close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are given, and are used to prevent unscrupulous infringers from unfairly utilizing the disclosure in which precise or absolute numerical values ​​are mentioned to aid in the understanding of the present invention.

[0017] The ferritic stainless steel of the present invention may be a ferritic stainless steel containing, by weight, C: 0.0005-0.02%, N: 0.005-0.02%, Si: 0.01-1.0%, Mn: 0.01-1.0%, P: 0.001-0.05%, Cr: 13.0-20.0%, Ti: 0.05-0.5%, with the remainder being Fe and unavoidable impurities, and having a {111} texture fraction of 50% or more in a region from the surface to one-quarter thickness.

[0018] The ferritic stainless steel of the present invention may be a ferritic stainless steel having an R-bar value of 1.7 or more.

[0019] The reasons for limiting the range of each alloying element are as follows.

[0020] The C content may be 0.0005 to 0.02% by weight.

[0021] If the C content is less than 0.0005%, the refining cost for producing a high-purity product will be high, and if the C content exceeds 0.02%, corrosion resistance and formability may be impaired. Taking this into consideration, the C content can be set to 0.0005 to 0.02 wt%.

[0022] The N content may be 0.005 to 0.02% by weight.

[0023] If the N content is less than 0.005%, TiN crystallization is low and the equiaxed crystal ratio of the slab is low, while if the N content exceeds 0.02%, corrosion resistance and formability may be deteriorated. Taking this into consideration, the N content can be set to 0.005 to 0.02%.

[0024] The Si content may be 0.01 to 1.0% by weight.

[0025] If the Si content is less than 0.01%, the refining cost will be high, and if the Si content exceeds 1.0%, impurities will increase and formability may be deteriorated. Taking this into consideration, the Si content can be set to 0.01 to 1.0%.

[0026] The Mn content may be 0.01 to 1.0% by weight.

[0027] If the Mn content is less than 0.01%, the refining cost will be high, and if the Mn content exceeds 1.0%, impurities will increase and formability may be deteriorated. In consideration of this, the Mn content can be set to 0.01 to 1.0%.

[0028] The P content may be 0.001 to 0.05% by weight.

[0029] If the P content is less than 0.001%, the refining cost will be high, and if the P content exceeds 0.05%, impurities will increase and formability may be deteriorated. Taking this into consideration, the P content can be set to 0.001 to 0.05%.

[0030] The Cr content may be 13.0 to 20.0 wt %.

[0031] If the Cr content is less than 13.0%, the corrosion resistance will be poor, and if the Cr content exceeds 20.0%, the formability may be poor. Taking this into consideration, the Cr content can be set to 13.0 to 20.0%.

[0032] The Ti content may be 0.05 to 0.5% by weight.

[0033] If the Ti content is less than 0.05%, recrystallization during hot rolling will be insufficient, and if the Ti content exceeds 0.5%, a large amount of steelmaking inclusions may be generated. Taking this into consideration, the Ti content can be set to 0.05 to 0.5%.

[0034] The content of Ti / (C+N) may be 1.25% or more.

[0035] If the Ti / (C+N) ratio is less than 1.25%, recrystallization during hot rolling may be insufficient, resulting in poor corrosion resistance and formability.If the Ti / (C+N) content is 1.25% or more, pre-rolling can be performed in the pre-rolling mill before hot rolling and annealing, i.e., by applying a pre-rolling reduction before hot rolling and annealing, deformation energy in the hot rolled material can be accumulated, thereby causing recrystallization and ensuring elongation and drawability in the final product.

[0036] The remaining component is iron (Fe). However, in the normal manufacturing process, unintentional impurities may be inevitably mixed in from the raw materials or the surrounding environment, and this cannot be excluded. Since these impurities are known to anyone skilled in the normal manufacturing process, not all of their contents will be specifically mentioned in this specification.

[0037] In the method for producing ferritic stainless steel of the present invention, the produced slab can be subjected to hot rolling, first rolling and hot rolling annealing, and further subjected to a second rolling and cold rolling annealing process.

[0038] The method for producing ferritic stainless steel of the present invention may include the steps of producing a slab containing, by weight, C: 0.0005-0.02%, N: 0.005-0.02%, Si: 0.01-1.0%, Mn: 0.01-1.0%, P: 0.001-0.05%, Cr: 13.0-20.0%, Ti: 0.05-0.5%, with the remainder being Fe and unavoidable impurities; hot rolling the produced slab in a heating furnace at 1100-1300°C; after hot rolling, performing primary rolling to a reduction ratio of 25-65%; after the primary rolling, performing hot rolling annealing at 900-1100°C;

[0039] The alloy composition of the method for producing a ferritic stainless steel of the present invention may be the same as that of the ferritic stainless steel of the present invention described above. The hot rolling step of the method for producing a ferritic stainless steel of the present invention may be a step of hot rolling the slab in a heating furnace at 1100 to 1300°C.

[0040] If the temperature in the hot rolling stage is less than 1100°C, hot rolling defects may cause difficulties in bundling and threading. If the temperature in the hot rolling stage is more than 1300°C, bending and threading of the slab may become difficult. Taking this into consideration, the hot rolling stage can be carried out at a temperature of 1100 to 1300°C. The first rolling step in the method for producing a ferritic stainless steel of the present invention may be a step in which reduction is performed at a reduction ratio of 25 to 65%.

[0041] If the reduction rate in the first rolling is less than 25%, the deformation energy is small, resulting in insufficient recrystallization, making it difficult to ensure a {111} texture fraction of 10% or more in the region from the surface to 1 / 4 thickness. If the reduction rate in the first rolling is more than 65%, the secondary rolling reduction is insufficient, making it difficult to ensure a {111} texture fraction of 50% or more in the region from the surface to 1 / 4 thickness in the final cold-rolled material. If the {111} texture fraction in the region from the surface to 1 / 4 thickness cannot be ensured, the R-bar value may not be ensured. Taking this into consideration, the reduction rate in the first rolling can be set to 25 to 65%.

[0042] The hot rolling and annealing step of the method for producing a ferritic stainless steel of the present invention may be a step of hot rolling and annealing at 900 to 1100°C. If the temperature in the hot rolling and annealing stage is less than 900°C, recrystallization may not occur and texture may not be formed. If the temperature in the hot rolling and annealing stage is more than 1100°C, the crystal grains may become coarse and the sheet may break. In consideration of this, the hot rolling and annealing stage can be performed at a temperature of 900 to 1100°C.

[0043] By including a step of performing the first rolling before the hot rolling annealing, deformation energy of the hot rolled material can be accumulated, and recrystallization can be achieved through the hot rolling annealing.

[0044] After the hot rolling, first rolling and hot rolling annealing steps of the method for producing a ferritic stainless steel of the present invention, the hot rolled and annealed hot rolled material may have a {111} texture fraction of 10% or more in a region from the surface to one-quarter thickness. The second rolling step in the method for producing a ferritic stainless steel of the present invention may be a step in which the reduction ratio is 40% or more. When the reduction rate of the second rolling is 40% or more, recrystallization occurs and the {111} texture fraction in the region from the surface to 1 / 4 thickness of the final cold-rolled material can be maintained at 50% or more. When the {111} texture fraction in the region from the surface to 1 / 4 thickness is maintained, the R-bar value can be ensured. Taking this into consideration, the reduction rate of the second rolling can be set to 40% or more.

[0045] The cold rolling and annealing step in the method for producing a ferritic stainless steel of the present invention may be a step of cold rolling and annealing at 850 to 1050°C.

[0046] If the temperature of the cold rolling annealing step is 850°C or higher, recrystallization occurs and texture can be formed. If the temperature of the cold rolling annealing step is 1050°C or lower, grain coarsening and sheet breakage can be prevented. In consideration of this, the cold rolling annealing step can be performed at a temperature of 850 to 1050°C.

[0047] In the method for producing ferritic stainless steel of the present invention, after the second rolling and cold-rolling annealing steps, the cold-rolled and annealed material may have a {111} texture fraction of 50% or more in the region from the surface to 1 / 4 thickness. In the method for producing ferritic stainless steel of the present invention, the ferritic stainless steel that has been subjected to first rolling, second rolling, and then cold-rolling annealing can have an R-bar value of 1.7 or more by ensuring a {111} texture fraction of 50% or more in the region from the surface to 1 / 4 thickness.

[0048] Here, R-bar is (R0+R 90 +2*R 45 ) / 4, and can be 1.7 or more. R0 is the R value in the 0° direction relative to the rolling direction of the test piece, and R 45 is the R value in the 45° direction, R 90 is the R value in the 90° direction. The R value is the width deformation ratio / thickness deformation ratio. A higher R-bar value means that it is more advantageous for the elongation rate and deep drawing processing.

[0049] The present invention will be described in more detail below with reference to examples and drawings. However, such description is for the purpose of explaining the implementation of the present invention, and the present invention is not limited by such description of the embodiments. The scope of the present invention is determined by the matters described in the claims and matters reasonably inferred therefrom. [Example]

[0050] The alloy compositions shown in Table 1 below were prepared.

[0051] [Table 1] Table 2 below shows the {111} texture fraction and R-bar value in the region from the surface to 1 / 4 thickness of hot-rolled and cold-rolled materials obtained by performing primary rolling on slabs having the alloy compositions shown in Table 1, with or without primary rolling and with different reduction rates. The primary rolling and reduction rate were varied as shown in Table 2 below. The reheating temperature of the hot-rolled slab was 1200°C, and the primary rolling reduction rate was varied as shown in Table 2 below. The hot-rolling annealing temperature was 1000°C, and the secondary rolling reduction rate was 40%, with the cold-rolling annealing temperature being 950°C. The {111} texture fraction (%) in the region from the surface layer to 1 / 4 thickness of the hot-rolled material refers to the value measured by EBSD attached to a scanning electron microscope for the hot-rolled material after hot-rolling and annealing.

[0052] The {111} texture fraction (%) in the region from the surface to 1 / 4 of the thickness of the cold-rolled material refers to the value measured by EBSD attached to a scanning electron microscope after cold-rolling and annealing.

[0053] [Table 2]

[0054] As shown in Tables 1 and 2, Examples 1 to 3, in which steel type A, whose alloy composition falls within the range of the present invention, was subjected to primary rolling at a rolling reduction of 30%, Examples 4 to 6, in which steel type B was subjected to primary rolling at a rolling reduction of 40%, and Examples 7 to 9, in which steel type C was subjected to primary rolling at a rolling reduction of 60%, all have a {111} texture fraction of 10% or more in the region from the surface to one-quarter of the thickness of the hot-rolled material, and a {111} texture fraction of 50% or more in the region from the surface to one-quarter of the thickness of the cold-rolled material, which therefore fall within the range of the present invention. Therefore, the R-bar value is 1.7 or more, and therefore falls within the range of the present invention. This indicates that when a slab satisfying the alloy composition of the present invention is subjected to primary rolling at a reduction ratio of 25 to 65%, the {111} texture fraction in the region from the surface to one-quarter of the thickness of the hot-rolled material is 10% or more, and the {111} texture fraction in the region from the surface to one-quarter of the thickness of the cold-rolled material is 50% or more, thereby satisfying the control range of the present invention and ensuring an R-bar value of 1.7 or more.

[0055] Comparative Examples 1 to 3 correspond to cases where no primary rolling was performed on steel types A, B, and C, which satisfy the range of the present invention. In Comparative Examples 1 to 3, the {111} texture fraction in the region from the surface layer to the ¼ thickness of the hot-rolled material was less than 10%, and the {111} texture fraction in the region from the surface layer to the ¼ thickness of the cold-rolled material was less than 50%, so these do not satisfy the range of the present invention. Consequently, the R-bar value was less than 1.7, so these do not satisfy the range of the present invention.

[0056] This indicates that even if the alloy composition is satisfied, if primary rolling is not performed at all, the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the hot-rolled material will be less than 10%, and the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the cold-rolled material will be less than 50%, failing to satisfy the control range of the present invention, and as a result, it is not possible to ensure an R-bar value of 1.7 or more.

[0057] Comparative Examples 4 to 6 correspond to the cases where steel types A, B, and C, which satisfy the range of the present invention, were subjected to primary rolling at a reduction ratio of 20%. In Comparative Examples 4 to 6, the {111} texture fraction in the region from the surface layer to the 1 / 4 thickness of the hot-rolled material was less than 10%, and the {111} texture fraction in the region from the surface layer to the 1 / 4 thickness of the cold-rolled material was less than 50%, so these do not satisfy the range of the present invention. Therefore, the R-bar value was less than 1.7, so they do not satisfy the range of the present invention.

[0058] This indicates that even if the alloy composition is satisfied, if the primary rolling reduction is less than 25%, the {111} texture fraction in the region from the surface to one-quarter of the thickness of the hot-rolled material will be less than 10%, and the {111} texture fraction in the region from the surface to one-quarter of the thickness of the cold-rolled material will be less than 50%, so the control range of the present invention cannot be satisfied, and as a result, it is not possible to ensure an R-bar value of 1.7 or more.

[0059] Comparative Examples 7 to 9 correspond to cases where steel types A, B, and C, which satisfy the range of the present invention, were subjected to primary rolling at a reduction ratio of 70%. In Comparative Examples 7 to 9, the {111} texture fraction in the region from the surface layer to the 1 / 4 thickness of the hot-rolled material was 10% or more, but the {111} texture fraction in the region from the surface layer to the 1 / 4 thickness of the cold-rolled material was less than 50%, which does not satisfy the range of the present invention. Therefore, the R-bar value was less than 1.7, which does not satisfy the range of the present invention.

[0060] This indicates that even if the alloy composition is satisfied, if the primary rolling reduction exceeds 65%, even if the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the hot-rolled material is ensured to be 10% or more, the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the cold-rolled material will be less than 50%, which does not satisfy the control range of the present invention, and as a result, it is confirmed that the R-bar value cannot be ensured to be 1.7 or more.

[0061] The method for producing a ferritic stainless steel sheet having excellent workability according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the {111} texture obtained by measuring the {111} texture fraction in the region from the surface layer to ¼ thickness of the hot-rolled material of Example 5 by EBSD. FIG. 2 is a diagram showing the {111} texture obtained by measuring the {111} texture fraction in the region from the surface layer to ¼ thickness of the hot-rolled material of Comparative Example 2 by EBSD.

[0062] Inventive Example 5 and Comparative Example 2 were performed using a slab of steel type B that satisfied the alloy composition of the present invention. Inventive Example 5, the primary rolling was performed at a reduction ratio of 40%, while Comparative Example 2 was performed without primary rolling at all.

[0063] In Figures 1 and 2, areas with a higher fraction of {111} texture are shown in darker colors. When measured by EBSD, the higher the fraction of {111} texture, the lower the brightness, and vice versa.

[0064] As shown in FIGS. 1 and 2, it can be seen that in Example 5, which was subjected to the first rolling, the fraction of the {111} texture was higher and the brightness was lower than in Comparative Example 2. Here, high brightness means close to a light color (for example, white), and low brightness means close to a dark color (for example, black). When the first rolling is performed, the shear deformation during hot rolling increases the fraction of the {111} texture in the hot-rolled material.

[0065] Figure 3 shows the fraction of the {111} texture in the hot-rolled and cold-rolled materials. It can be seen that when the fraction of the {111} texture in the hot-rolled material is high, the fraction of the {111} texture in the cold-rolled material is also high.

[0066] FIG. 4 shows the relationship between the reduction ratio in the first rolling and the fraction of the {111} texture in the region from the surface layer to the 1 / 4 thickness of the cold-rolled material. As shown in Figure 4, when the primary rolling is performed at a reduction ratio of 25 to 65%, it can be confirmed that the fraction of the {111} texture in the cold-rolled material is ensured to be 50% or more.

[0067] As shown in Figures 1 to 4, when the first rolling is performed, it is possible to ensure that the {111} texture fraction is as high as 10% or more in the region from the surface layer to one-quarter of the thickness of the hot-rolled material, and that the {111} texture fraction is as high as 50% or more in the region from the surface layer to one-quarter of the thickness of the cold-rolled material.

[0068] FIG. 5 shows the relationship between the {111} texture fraction and R-bar in the region from the surface layer to the 1 / 4 thickness of the cold-rolled material. As shown in Fig. 5, when the {111} texture fraction in the region from the surface to 1 / 4 thickness of the cold-rolled material is 50% or more, it can be confirmed that the R-bar value is secured to be 1.7 or more.

[0069] As shown in Figs. 1 to 5, when the first rolling is performed, it is possible to ensure that the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the hot-rolled material is as high as 10% or more, and that the {111} texture fraction in the region from the surface layer to one-quarter of the thickness of the cold-rolled material is as high as 50% or more, thereby ensuring an R-bar value of 1.7 or more.

Claims

1. The alloy contains, by weight, C: 0.0005 to 0.02%, N: 0.005 to 0.02%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.001 to 0.05%, Cr: 13.0 to 20.0%, Ti: 0.05 to 0.5%, and the remainder being Fe and unavoidable impurities; A ferritic stainless steel sheet with excellent workability, characterized in that the {111} texture fraction in the region from the surface layer to one-quarter of the thickness is 50% or more.

2. 2. The ferritic stainless steel sheet having excellent workability according to claim 1, characterized in that the R-bar value is 1.7 or more.

3. producing a slab containing, by weight, C: 0.0005 to 0.02%, N: 0.005 to 0.02%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.001 to 0.05%, Cr: 13.0 to 20.0%, Ti: 0.05 to 0.5%, with the remainder being Fe and unavoidable impurities; and hot rolling the produced slab in a heating furnace at 1100 to 1300°C. After hot rolling, a first rolling step is performed at a rolling reduction rate of 25 to 65%. After the first rolling, hot rolling annealing is performed at 900 to 1100 ° C.; A step of performing a second rolling. and cold rolling and annealing the steel sheet.

4. 4. The method for manufacturing a ferritic stainless steel sheet having excellent workability according to claim 3, wherein the reduction ratio in the second rolling step is 40% or more.

5. 4. The method for manufacturing a ferritic stainless steel sheet with excellent workability according to claim 3, wherein the cold rolling and annealing step is performed at 850 to 1050°C.

6. 4. The method for producing a ferritic stainless steel sheet excellent in formability according to claim 3, wherein the hot-rolled and annealed hot-rolled material has a {111} texture fraction of 10% or more in a region from the surface layer to one-quarter thickness.

7. 4. The method for producing a ferritic stainless steel sheet excellent in formability according to claim 3, wherein the cold-rolled and annealed material has a {111} texture fraction of 50% or more in a region from the surface layer to one-quarter thickness.

8. 4. The method for producing a ferritic stainless steel sheet having excellent workability according to claim 3, wherein the R-bar value is 1.7 or more.

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