Ferritic stainless steel having improved workability and wrinkle resistance, and method for manufacturing same

Abstract

The present invention relates to a ferritic stainless steel having improved workability and wrinkle resistance, and a method for manufacturing the same. The ferritic stainless steel having improved processability and wrinkle resistance according to one embodiment of the present invention may contain, in wt%, 0.0005 to 0.02% of carbon (C), 0.01 to 0.2% of nitrogen (N), 0.01 to 1.0% of silicon (Si), 0.01 to 1.0% of manganese (Mn), 0.001 to 0.05% of phosphorus (P), 13.0 to 20.0% of chromium (Cr), 0.05 to 0.2% of titanium (Ti), a remainder of iron (Fe) and unavoidable impurities, may satisfy the following formula (1), and may have a crystal grain size in the range of 20 to 25 [mu] m. Formula (1): 2 # imgabs0 # [Ti] / [N] < = 2.3, in formula (1), [Ti] and [N] represent the weight% content of each element.

Description

Technical Field

[0001] The present invention relates to a ferritic stainless steel having improved workability and wrinkle resistance and a method for manufacturing the same. Background Art

[0002] Ferritic stainless steel sheets are steel sheets that have excellent corrosion resistance while adding a small amount of expensive alloying elements, and have higher price competitiveness compared to austenitic stainless steel sheets. Ferritic stainless steel sheets are used for applications such as building materials, transportation devices, household appliances, and kitchen devices.

[0003] Ferritic stainless steel cold-rolled products have a problem of generating streaky ridging defects in forming processes such as deep drawing. Such ridging defects not only deteriorate the appearance of the product, but also increase the manufacturing cost because a grinding process needs to be added after forming when the ridging is severe.

[0004] To solve the ridging defect, various manufacturing methods have been proposed in the past, such as hot rolling, cold rolling, and cold rolling and repressing at extremely low temperatures. However, the manufacturing methods proposed in the past have problems in that they are difficult to apply on site, increase the manufacturing cost, and thus reduce the productivity of the product. Summary of the Invention

[0005] (I) Technical Problem to be Solved

[0006] An object of the present invention is to provide a ferritic stainless steel and a method for manufacturing the same, which control the crystal grain size of the final cold-rolled annealed material by optimizing the composition and manufacturing process of the steel, improve workability and wrinkle resistance, and thus improve the workability of cold-rolled products.

[0007] The technical problems to be solved by the present invention are not limited to the above technical problems, and those skilled in the art can clearly understand other technical problems not described through the following description.

[0008] (II) Technical Solution

[0009] The ferritic stainless steel having improved workability and wrinkle resistance according to one aspect of the present invention may contain, by weight %: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance of iron (Fe) and inevitable impurities, the ferritic stainless steel may satisfy the following formula (1), and the crystal grain size may satisfy the range of 20 - 25 μm.

[0010] Formula (1): 2 [Ti] / [N] ≤ 2.3

[0011] In the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

[0012] The wrinkle height measured after 15% elongation of the ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment may be 10 μm or less.

[0013] The elongation of the ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment may be 32% or more.

[0014] The method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to one aspect of the present invention may include the following steps: manufacturing a slab which, by weight %, comprises: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance being iron (Fe) and unavoidable impurities, and the slab satisfying the following formula (1); reheating the slab; hot rolling the reheated slab followed by hot rolling annealing; and cold rolling the hot rolled material followed by cold rolling annealing at 800 - 850°C.

[0015] Formula (1): 2 [Ti] / [N] ≤ 2.3

[0016] In the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

[0017] In the method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment, the reheating step may be carried out at 1000 - 1300°C.

[0018] In the method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment, the crystal grain size of the stainless steel may satisfy the range of 20 - 25 μm.

[0019] In the method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment, the wrinkle height measured after 15% elongation of the stainless steel may be 10 μm or less.

[0020] In the method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment, the elongation of the stainless steel may be 32% or more.

[0021] (III) Advantageous Effects

[0022] The present invention can provide a ferritic stainless steel and a manufacturing method thereof, which control the crystal grain size of the finally cold-rolled and annealed material by optimizing the composition and manufacturing process of the steel, improve the workability and wrinkle resistance, and thus improve the workability of the cold-rolled product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A graph showing the wrinkle height (solid line) and elongation rate (dashed line) according to the annealing temperature when manufacturing stainless steel according to an embodiment.

[0024] Figure 2a A photograph showing the crystal grain size of stainless steel manufactured at a cold-rolled annealing temperature of 750°C.

[0025] Figure 2b A photograph showing the crystal grain size of stainless steel manufactured at a cold-rolled annealing temperature of 800°C.

[0026] Figure 2c A photograph showing the crystal grain size of stainless steel manufactured at a cold-rolled annealing temperature of 850°C.

[0027] Figure 2d A photograph showing the crystal grain size of stainless steel manufactured at a cold-rolled annealing temperature of 900°C.

[0028] Figure 2e A photograph showing the crystal grain size of stainless steel manufactured at a cold-rolled annealing temperature of 950°C. BEST MODE FOR CARRYING OUT THE INVENTION

[0029] The ferritic stainless steel having improved workability and wrinkle resistance according to an embodiment may contain, by weight%: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance being iron (Fe) and inevitable impurities, and the ferritic stainless steel satisfies the following formula (1), and the crystal grain size may satisfy the range of 20 - 25 μm.

[0030] Formula (1): 2 [Ti] / [N] ≤ 2.3

[0031] In the formula (1), [Ti] and [N] represent the weight% content of each element. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention can be deformed into various other forms, and the technical idea of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely describe the present invention to those skilled in the art.

[0033] The terms used in this application are only for explaining specific examples. Therefore, unless it is clearly indicated as singular in the context, the singular expression includes the plural expression. In addition, it should be noted that terms such as "comprising", "including" or "having" used in this application are used to clearly specify the existence of features, steps, functions, components or combinations thereof described in the specification, rather than to pre-exclude the existence of other features, steps, functions, components or combinations thereof.

[0034] In addition, unless otherwise defined, all terms used in this specification should be regarded as having the same meaning as that generally understood by those skilled in the technical field to which the present invention belongs. Therefore, in this specification, unless otherwise clearly defined, specific terms should not be interpreted in an overly ideal or formal meaning. For example, in this specification, the singular expression includes the plural expression, unless the context clearly indicates an exception.

[0035] In addition, with respect to "about", "substantially", etc. in this specification, when allowing errors in manufacturing and materials inherent in the mentioned meaning are proposed, it is used in the meaning of this value or close to this value, and is used to prevent immoral infringers from illegally using the mentioned accurate or absolute numerical values to help understand the disclosure of the present invention.

[0036] The ferritic stainless steel having improved workability and wrinkle resistance according to one aspect of the present invention may contain, by weight%: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance of iron (Fe) and inevitable impurities.

[0037] Hereinafter, the reasons for limiting the composition ranges of the respective alloy elements will be described. Hereinafter, unless otherwise specified, the unit is weight%.

[0038] The content of carbon (C) may be 0.0005 - 0.02 wt%, preferably may be 0.01 - 0.02 wt%.

[0039] C is an element that has a great influence on improving the strength of steel. When the amount of carbon (C) is less than 0.0005% by weight, the refining cost for manufacturing high-purity products may become expensive. However, when the carbon content exceeds 0.02% by weight, the corrosion resistance and formability may decrease.

[0040] The content of nitrogen (N) can be 0.01 - 0.2% by weight, preferably 0.04 - 0.2% by weight.

[0041] Nitrogen is an element that forms nitrides and exists in an interstitial form. Therefore, when an excessive amount of nitrogen is contained, it may cause a decrease in impact toughness and formability. Considering this, the upper limit of the nitrogen content is limited to 0.2% by weight or less. However, when the content of nitrogen (N) is too low, the crystallinity of TiN decreases, which may reduce the equiaxed crystallinity of the slab.

[0042] The content of silicon (Si) can be 0.01 - 1.0% by weight, preferably 0.05 - 0.60% by weight.

[0043] Si can be added to deoxidize the molten steel during steelmaking. Si is an element effective in stabilizing ferrite. When the amount of silicon (Si) is less than 0.01% by weight, there is a problem of expensive refining cost. However, when the silicon content exceeds 1.0% by weight, there are problems of increased impurities and decreased formability.

[0044] The content of manganese (Mn) can be 0.01 - 1.0% by weight, preferably 0.20 - 0.95% by weight.

[0045] Mn is an element effective in improving corrosion resistance. When the amount of manganese (Mn) is less than 0.01% by weight, there is a problem of expensive refining cost. When the amount of manganese (Mn) exceeds 1.0% by weight, there are problems of increased impurities and decreased formability.

[0046] The content of phosphorus (P) can be 0.001 - 0.05% by weight, preferably 0.001 - 0.020% by weight.

[0047] When the amount of phosphorus (P) is less than 0.001% by weight, there is a problem of expensive refining cost. However, when the phosphorus content exceeds 0.05% by weight, there are problems of increased impurities and decreased formability.

[0048] The content of chromium (Cr) can be 13.0 - 20.0% by weight, preferably 13.5 - 17.5% by weight.

[0049] Cr is an effective element to ensure the corrosion resistance of steel. When the amount of chromium (Cr) is less than 13.0% by weight, there is a problem of poor corrosion resistance. However, when the chromium content exceeds 20.0% by weight, there is a problem of decreased formability.

[0050] The content of titanium (Ti) may be 0.05 - 0.2% by weight, preferably 0.05 - 0.17% by weight.

[0051] Ti is an element that can preferentially combine with interstitial elements such as C and N to form precipitates. When the amount of titanium (Ti) is less than 0.05% by weight, it may be difficult to form Ti-based inclusions during manufacturing. When the content of titanium is excessive, the Ti component reacts with oxygen and turns yellow, thus there may be a problem of generating surface defects.

[0052] The remaining component of the ferritic stainless steel according to the present invention is iron (Fe). However, in the normal manufacturing process, unnecessary impurities will inevitably be mixed in from raw materials or the surrounding environment, so these impurities cannot be excluded. These impurities are well known to those skilled in the normal manufacturing process, so all of their contents are not specifically mentioned in this specification.

[0053] In addition, the ferritic stainless steel according to an embodiment may satisfy the following formula (1).

[0054] Formula (1): 2 [Ti] / [N] ≤ 2.3

[0055] In the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

[0056] In the present invention, in order to improve the wrinkle resistance of the stainless steel, by adjusting the contents of Ti and N, TiN precipitates are formed to obtain a fine casting structure. When the value of 2 [Ti] / [N] in formula (1) calculated by alloy composition exceeds 2.3, there is not enough N to combine with Ti, so the effect of refining the casting structure cannot be obtained.

[0057] In the formula (1), the value of 2 [Ti] / [N] can be, specifically can be 0.5 to 2.3, more specifically can be 1.0 to 2.3, and more specifically can be 1.7 to 2.3. Within the above range, the ferritic stainless steel according to an embodiment of the present invention can further improve the effect of controlling the fine structure, and thus can have more excellent workability and wrinkle resistance.

[0058] The wrinkle height measured after stretching the ferritic stainless steel according to an embodiment by 15% in the direction perpendicular to the rolling direction can be 10 μm or less. In addition, the elongation rate of the ferritic stainless steel according to an embodiment can be 32% or more. Preferably, the elongation rate of the cold-rolled annealed material with a thickness of about 0.4 - 0.6 mm can be 32% or more. The higher the elongation rate, the more the workability can be improved.

[0059] For the workability of cold-rolled stainless steel products for household appliances, both wrinkle resistance and elongation must be satisfied simultaneously. Since the steel must have good elongation during forming, in order to meet an elongation of more than 32%, fewer streaks after processing, and a desired glossiness, it is preferable to limit the wrinkle height to about 10 μm or less, and preferably to 8.5 μm or less.

[0060] The crystal grain size of the ferritic stainless steel according to one embodiment can satisfy 20 - 25 μm, and preferably can satisfy the range of 20 - 23 μm.

[0061] If the average crystal grain size of the stainless steel is limited to 20 - 25 μm, due to the refinement of the casting structure, the desired elongation and wrinkle height can be satisfied simultaneously.

[0062] Next, a method for manufacturing a ferritic stainless steel having improved wrinkle resistance according to another aspect of the present invention will be described.

[0063] A method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to one aspect of the present invention may include the following steps: manufacturing a slab which, by weight %, contains: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance being iron (Fe) and inevitable impurities, and the slab satisfies the following formula (1); reheating the slab; hot rolling the reheated slab followed by hot rolling annealing; and cold rolling the hot-rolled material followed by cold rolling annealing.

[0064] Formula (1): 2 [Ti] / [N] ≤ 2.3

[0065] In the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

[0066] The component range values of the respective alloy compositions and the limiting reasons for formula (1) are as described above, and the following is a more detailed description of each manufacturing step.

[0067] First, a slab satisfying the above alloy composition is manufactured, and then it can undergo a series of processes of reheating, hot rolling, hot rolling annealing, cold rolling, and cold rolling annealing.

[0068] First, the slab can be heated to a temperature of 1000 - 1300 °C in a hot rolling heating furnace and then hot rolled to manufacture a hot-rolled steel sheet.

[0069] When the heating temperature is relatively low, it may be difficult to re-dissolve the coarse precipitates generated during the slab manufacturing process. Considering this, the heating temperature can be 1000 °C or higher. However, when the heating temperature is too high, the internal grains may become overly coarse, resulting in severe surface oxidation, which may trigger surface defects. Considering this, the upper limit of the heating temperature can be restricted to 1300 °C.

[0070] During the hot rolling process, finish rolling can be carried out at 700 - 900 °C.

[0071] When the finish rolling temperature is lower than 700 °C, sticking may occur on the slab surface during the hot rolling process. However, when the finish rolling temperature exceeds 900 °C, coarse ferrite grains are formed, so the wrinkle resistance may decrease.

[0072] The hot-rolled material is recrystallized by hot rolling annealing of the casting structure. At this time, the hot rolling annealing can be carried out at a temperature of 700 - 900 °C.

[0073] If the hot rolling annealing temperature is low, the stress formed during hot rolling cannot be fully removed, so the workability may decrease. However, when the hot rolling annealing temperature is too high, due to the coarsening of the grains, the strength decreases, and the wrinkle resistance may also decrease.

[0074] The hot-rolled material annealed by hot rolling can be made into cold-rolled steel sheets through cold rolling annealing after cold rolling. At this time, the cold rolling annealing can be carried out at a temperature of 800 - 850 °C.

[0075] By meeting the cold rolling annealing temperature, the crystal grain size can be controlled within the range of 20 - 25 μm. When the cold rolling annealing temperature exceeds 850 °C, the grain size becomes coarser, so the {001} / ND crystal orientation structure that reduces the wrinkle resistance will grow. When the {001} / ND crystal orientation structure grows, the plastic anisotropy with the matrix will increase, which will not only reduce the wrinkle resistance but also deteriorate the surface roughness. However, when the cold rolling annealing temperature is lower than 800 °C, recrystallization does not occur, so both the elongation and the wrinkle resistance will deteriorate.

[0076] As described above, by optimizing the alloy composition and the composition relationship, re-heating, hot rolling annealing, and cold rolling annealing processes, the grain refinement within the casting structure can be achieved, thereby ensuring the wrinkle resistance and elongation of ferritic stainless steel.

[0077] The crystal grain size of the stainless steel manufactured according to an embodiment can meet the range of 20 - 25 μm. By meeting the crystal grain size range, a stainless steel with excellent workability having the desired workability and wrinkle resistance can be obtained.

[0078] The wrinkle height measured after stretching the stainless steel manufactured according to an embodiment by 15% in a direction perpendicular to the rolling direction may be 10 μm or less. By satisfying the above wrinkle height range, fewer streaks are generated after processing, and stainless steel with a desired glossiness can be obtained.

[0079] The elongation of the stainless steel manufactured according to an embodiment may be 32% or more. By satisfying the above elongation range, the steel has good elongation during forming, and thus stainless steel with excellent formability can be obtained.

[0080] Hereinafter, the present invention will be described in more detail by way of examples. However, the descriptions of these examples are only for illustrating the implementation of the present invention, and the present invention is not limited by the descriptions of these examples.

[0081] [Examples]

[0082] For various alloy composition ranges shown in Table 1 below, slabs were manufactured in a vacuum induction melting furnace. The obtained slabs were reheated in a heating furnace at 1100 °C and then hot-rolled to produce hot-rolled steel sheets, which were air-cooled. The air-cooled hot-rolled steel sheets were subjected to hot-rolling annealing at 850 °C, then cold-rolled to a thickness of 0.5 mm, and then cold-rolled annealing at the temperatures shown in Table 2 below to produce cold-rolled steel sheet specimens.

[0083] In addition, in Table 1 below, the value of the following formula (1) is shown by calculation.

[0084] Formula (1): 2 [Ti] / [N]

[0085] In the above formula (1), [Ti] and [N] represent the weight % content of each element.

[0086] [Table 1]

[0087]

[0088] In Table 2 below, the average crystal grain size, wrinkle height measured after stretching by 15%, and elongation in the casting structure at different cold-rolling annealing temperatures of the steel with the alloy composition shown in Table 1 are measured and shown. In addition, Figure 1 the relationship between the wrinkle height and elongation of the cold-rolling annealing temperature of the steel with the alloy composition of Steel 3 is shown. The crystal grain size is measured by photographing the casting structure with an optical microscope (OM). Figures 2a to 2eThey are respectively photos showing the crystal grain sizes of stainless steels made of alloys with Steel 3 composition, processed at cold rolling annealing temperatures of 750°C, 800°C, 850°C, 900°C, and 950°C. The wrinkling height was measured with a surface roughness tester after stretching the test piece by 15% in the direction perpendicular to the rolling direction of the test piece.

[0089] The elongation rate is calculated by dividing the amount of stretching of the cold-rolled stainless steel product under uniaxial tension until the moment of fracture by the initial length.

[0090] [Table 2]

[0091]

[0092] Referring to Table 1 and Table 2 above, Steel 3, Steel 5, Steel 6, and Steel 9 satisfy the alloy composition, composition range, and formula (1) proposed by the present invention. In addition, when they satisfy the cold rolling annealing temperature, the crystal grain size in the casting structure is refined to 20 - 25 μm (see Figure 2b and Figure 2c ), the wrinkling height is below 10 μm, and the elongation rate satisfies 32% or more. That is, it can be confirmed that all the inventive examples that satisfy the alloy composition, composition range, formula (1), and cold rolling annealing temperature have excellent workability and wrinkle resistance. However, in the case of the comparative examples that satisfy the alloy composition, composition range, and formula (1) proposed by the present invention but do not satisfy the cold rolling annealing temperature, one or more physical properties among the crystal grain size, wrinkling height, or elongation rate cannot be satisfied.

[0093] Specifically, referring to Figure 1 and Figure 2a , when the cold rolling annealing temperature is lower than 800°C, recrystallization does not occur, so the wrinkling height exceeds 10 μm, and the elongation rate decreases significantly.

[0094] In addition, referring to Figure 1 , Figure 2d and Figure 2e , when the cold rolling annealing temperature exceeds 850°C, the elongation rate is improved, but the grains in the casting structure become coarser, so the wrinkling height exceeds 10 μm. That is, it can be confirmed that as the cold rolling annealing temperature increases, the elongation rate is improved, but the casting structure becomes coarser, and thus the wrinkling height has a tendency to increase.

[0095] Furthermore, in Steel 1, Steel 2, Steel 4, Steel 7, and Steel 8, the value of formula (1) exceeds 2.3. Even when the cold rolling annealing temperature satisfies 800 - 850°C, the N content that can combine with Ti is low, and the refinement of equiaxed grains cannot be achieved. Thus, it can be confirmed that the wrinkle resistance is also poor.

[0096] As described above, although exemplary embodiments of the present invention have been described, the present invention is not limited thereto, and those skilled in the art should understand that various changes and modifications can be made without departing from the concept and scope of the claims.

[0097] Industrial Applicability

[0098] According to the present invention, in order to improve the workability of cold-rolled products, the crystal grain size of the final cold-rolled annealed material is controlled by optimizing the composition and manufacturing process of the steel, so that a ferritic stainless steel with improved workability and wrinkling resistance and a manufacturing method thereof can be provided. Therefore, its industrial applicability is recognized.

Claims

1. A ferritic stainless steel having improved workability and wrinkle resistance, by weight %, the ferritic stainless steel comprising: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance being iron (Fe) and inevitable impurities, the ferritic stainless steel satisfies the following formula (1), the crystal grain size satisfies the range of 20 - 25 μm, Equation (1): 2 [Ti] / [N] ≤ 2.3 in the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

2. The ferritic stainless steel having improved processability and wrinkle resistance according to claim 1, wherein, The wrinkle height measured after 15% elongation is 10 μm or less.

3. The ferritic stainless steel having improved workability and wrinkle resistance according to claim 1, wherein, The elongation is 32% or more.

4. A method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance, which includes the following steps: Manufacturing a slab, by weight %, the slab comprising: carbon (C): 0.0005 - 0.02%, nitrogen (N): 0.01 - 0.2%, silicon (Si): 0.01 - 1.0%, manganese (Mn): 0.01 - 1.0%, phosphorus (P): 0.001 - 0.05%, chromium (Cr): 13.0 - 20.0%, titanium (Ti): 0.05 - 0.2%, the balance being iron (Fe) and inevitable impurities, and satisfying the following formula (1); Reheating the slab; Performing hot rolling and then hot rolling annealing on the reheated slab; and Performing cold rolling on the hot-rolled material and then performing cold rolling annealing at 800 - 850 °C, Formula (1): 2 [Ti] / [N] ≤ 2.3 in the formula (1), [Ti] and [N] represent the weight % contents of the respective elements.

5. The manufacturing method of a ferritic stainless steel having improved workability and wrinkle resistance according to claim 4, wherein, The reheating step is performed at 1000 - 1300 °C.

6. The method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to claim 4, wherein, The crystal grain size of the stainless steel satisfies the range of 20 - 25 μm.

7. The method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to claim 4, wherein, The wrinkle height of the stainless steel measured after 15% elongation is 10 μm or less.

8. The method for manufacturing a ferritic stainless steel having improved workability and wrinkle resistance according to claim 4, wherein, The elongation of the stainless steel is 32% or more.

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