JPH0673458A - Production of ferritic stainless steel sheet excellent in surface property, ridging property and workability - Google Patents

Abstract

PURPOSE:To obtain a ferritic stainless steel sheet excellent in surface properties, ridging properties and workability. CONSTITUTION:The slab of ferritic stainless steel showing the two phase structure of ferrite + austenite in a hot working temp. region and having a balance of chemical components in which gamma max conforming to the formula (1) is regulated to 10 to <35 as well as contg. B is produced. This slab is heated to 1150 to 1250 deg.C, and rough hot rolling is started. The finish hot rolling is completed at >=860 deg.C finish rolling outlet side temp. at >=7.0m/s finish rolling outlet side rate, and it is coiled at 650 to 900 deg.C. After that, cold rolling and recrystallization annealing are executed. The austenitic phase granularly dispersed by the incorporation of B is subjected to the high speed high temp. hot rolling in a state in which it is coexistent with the ferritic phase, by which the refining of the ferritic phase and the accumulation of strains are promoted. In this way, the ferritic stainless steel sheet securing good surface properties and high productivity and excellent in ridging properties and workability can be obtd.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an efficient method for producing a ferrite-type stainless steel sheet for forming, which has excellent surface properties and ridging properties and processability for press forming, bending, roll forming and other processes. Regarding The steel of the present invention is put on the market in the form of a cold-rolled steel strip or a cold-rolled steel sheet, but in the present specification, these may be collectively referred to as a steel sheet.

[0002]

2. Description of the Related Art Ferrite stainless steel represented by SUS430 has good corrosion resistance, does not contain expensive Ni, and has economical advantages as compared with austenitic stainless steel. Widely used mainly for durable consumer goods.

Conventionally, in order to produce a ferritic stainless steel sheet, a continuously cast slab is hot rolled into a hot rolled steel strip, which is annealed in a box furnace or a continuous annealing furnace and then pickled. A general method is to perform cold rolling once or multiple cold rolling including intermediate annealing, and then recrystallize annealing to commercialize. However, although hot-rolled sheet annealing may be omitted, hot-rolled sheet annealing may be performed for press forming applications of thin sheets, which are particularly important for ridging and workability such as deep drawing. It is manufactured by carrying out two cold rolling processes including intermediate annealing.

The hot rolling conditions that are standardly adopted in the production of such a cold-rolled ferrite stainless steel sheet are as follows. Temperature Plate thickness (mm) Slab heating 1100 to 1200 ° C 200 Finishing rough hot rolling 950 to 1050 ° C 25 to 30 Finishing hot rolling 800 to 850 ° C 3.0 to 4.5 Winding 600 to 650 ° C 3.0 to 4.5

Regarding the rolling speed, which is particularly important in terms of production efficiency, in the conventional ferrite type stainless steel, the finishing rolling exit speed is about 4.0 to 6.0 m / s. This is considerably slower than about 8 m / s or more for austenitic stainless steel and about 10 m / s or more for ordinary steel.

The workability of the ferrite stainless steel is generally inferior to that of the austenitic stainless steel, and there is a problem that peculiar wrinkle-like surface irregularities called ridging occur during press forming. Ridging is a major problem in the processing of ferritic stainless steels because it not only impairs the aesthetics of molded products and reduces their commercial value, but it also increases the polishing load to remove them.

A number of researches and developments and proposals have been made so far for improving the workability of SUS430 series steel. In the old days, B addition (Japanese Patent Publication No. 44-736) and B-Ti
Addition (JP-B-47-4786, JP-B-51-8733), A
There are examples of ferritic stainless steels such as additions (for example, Japanese Examined Patent Publication No. 51-44888), and steels containing a small amount of Ti and / or a small amount of Zr in addition to B and V proposed by the present inventors (special characteristics). Kaihei 3-94043).

On the other hand, there are many reports on ridging, but the cause is that the unit region consisting of a group of crystal grains with a close orientation derived from the cast structure or hot rolled sheet structure is preserved in the cold rolled annealed sheet. Therefore, it is considered that each unit region shows different deformation behavior during processing such as press forming, and ridge-like surface undulation occurs in the rolling direction of the steel sheet. Therefore, to improve the ridging property, it is effective to miniaturize and pulverize this unit area, and various improvement measures have been proposed from this viewpoint.

One of them is a method of increasing the austenite potential in the balance of chemical composition of steel.
The amount of austenite (γ) phase coexisting with the ferrite (α) phase during hot rolling is increased, and the coarse α band in the (α + γ) band structure is reduced to improve the ridging property.

On the other hand, it is known that low-temperature rolling is effective as a measure for improving ridging related to hot rolling, and for ferrite stainless steel, hot rolling is usually carried out at a lower temperature than austenitic stainless steel. . More positively, so-called delay rolling is effective for improving ridging, in which rolling passes are performed at a relatively low temperature and under high pressure, and the material is temporarily held during rolling to increase the time between passes. Is also known. For example, Japanese Patent Publication Sho-45-340
No. 16 gazette shows that at least 50% reduction of hot rolling is 871 ° C.
A ridging improvement method has been proposed in which the rolling is performed at the following temperature, and the rolling is temporarily stopped during the hot rolling, the material is cooled to a temperature not higher than 760 to 871 ° C, and then the subsequent hot rolling is performed. .

[0011]

The ferrite stainless steel containing B, Ti, Al, etc. for the purpose of improving the workability of SUS430 described above results in a lower austenite potential because these elements are ferrite-forming elements. , γ
The refinement of the microstructure during hot rolling using the steel cannot be expected, and the ridging property after cold annealing is not necessarily excellent.

Japanese Patent Publication No. 44-736, Japanese Patent Publication No. 47-4786
B-added steel and B-Ti of Japanese Patent Publication No. 51-8733 and Japanese Patent Publication No. 51-8733.
It has been shown that the added steels have excellent ridging properties, but these are manufactured by the ingot method. When such an ingot is hot-rolled as a slab by slabbing, it is advantageous in terms of ridging property also from the viewpoint of miniaturization and pulverization of the unit area. However, it cannot be said that good and sufficient ridging properties can always be secured in the current manufacturing method using a continuously cast slab as a hot rolled material.

On the other hand, in the method of increasing the austenite potential and improving the ridging property, therefore, it is necessary to increase the amount of austenite forming elements such as C, N or Mn, which leads to hardening of the material and deterioration of the workability. become.

Further, although the low temperature hot rolling is certainly effective in improving the ridging property, surface defects are apt to occur and the surface quality of the steel strip is deteriorated. This is because when the temperature is low, the rolling resistance increases because the deformation resistance of the material to be rolled increases, causing seizure between the roll and the material to be rolled, and part of the material to be rolled moves to the roll surface as an adherent. It is thought that this is because they are worn and then transferred to the surface of the steel strip. Moreover, when the rolling temperature is low, the oxide film formed on the surface of the steel strip is thin, which may further promote seizure. For this reason, the surface load of the steel strip needs to be polished in the subsequent process, resulting in an increase in the process load.

In addition, in the conventional method for improving ridging property by lowering the hot rolling temperature, the lowering of the rolling speed is inevitably accompanied by the lowering of the temperature, so that the productivity cannot be reduced. In fact, as mentioned above, the finish rolling speed of ferritic stainless steel is much slower than that of austenitic stainless steel, and its productivity is poor. In addition, delay rolling is not an economical method because it causes an increase in rolling time and a decrease in productivity.

Therefore, in the production of a ferritic stainless cold-rolled steel sheet using a continuously cast slab as a hot-rolled material,
Good deep drawability and ductility required for cold-rolled steel sheets for cold rolling are achieved without lowering the productivity and surface quality of hot-rolled steel strip due to low-temperature hot rolling and without intermediate annealing. The economical industrial hot rolling technology for ferritic stainless steel that improves the ridging property while maintaining the above-mentioned properties has not been completed yet. An object of the present invention is to complete this.

[0017]

[Means for Solving the Problems] In order to solve the above problems, the present inventors have made a detailed study on the effects of alloy composition, metal structure and hot rolling conditions on the ridging property and workability of ferrite stainless steel. I went. As a result, we found some useful facts as follows.

(1) Even for steel with a relatively small amount of γ phase at high temperature, if high temperature / high speed hot rolling is carried out in finish hot rolling, fragmentation of the ferrite phase and strain accumulation will be achieved, and Recovery or recrystallization of the ferrite phase is promoted after or during annealing of the hot rolled sheet, which improves the ridging property after cold rolling and annealing. (2) By adding an appropriate amount of B, the γ phase during high temperature and high speed hot rolling becomes a dispersed distribution form, further promoting the fragmentation and strain accumulation of the ferrite phase and further improving the ridging property. (3) If the addition of V, Ti, Nb, and Zr is used in combination with the above method, the workability is further improved. (4) On the basis of this, hot rolling at high temperature and high speed using a continuous casting slab avoids seizure with hot rolling rolls, makes it possible to obtain hot-rolled steel strips with excellent surface properties with good productivity, and cools them once. A ferrite cold-rolled steel sheet having excellent ridging property and workability can be obtained by a single-time cold rolling method in which the hot rolling method and the hot rolling method are omitted.

The present invention has been completed on the basis of such findings, and the gist of the invention is to rough-roll hot-roll a ferritic stainless steel exhibiting a dual-phase structure of ferrite and austenite in the hot working temperature range. And when producing a cold rolled steel sheet or strip by combining cold rolling and annealing into a hot rolled strip after finishing hot rolling, γmax expressed by the following equation (1) is 10 or more and less than 35. A slab of ferritic stainless steel containing 0.0010 to 0.0300% B (boron) is manufactured by balancing the chemical composition so that (However, this steel contains all the components in formula (1). Γmax is calculated assuming 0% for the components that do not contain).
After heating to 0 ° C to start rough hot rolling, finishing hot rolling was completed when the finishing rolling exit speed was 7.0 m / s or higher and the finishing rolling exit temperature was 860 ° C or higher, and 650 ° C or higher and 900 ° C or higher. It is a method for producing a ferritic stainless steel sheet having excellent surface properties, ridging property and workability, which is characterized by being wound up below.

Γ max = 420 (% C) +470 (% N) +23 (% Ni) +7 (% Mn) -11.5 (% Cr) -11.5 (% Si) -23 (% V) -49 (% Ti)- 50 (% Nb) -50 (% Zr) +189 ・ ・ (1)

[0021]

FUNCTION γmax is an index corresponding to the maximum amount of austenite phase at high temperature such as hot rolling temperature range. The steel targeted by the present invention may basically be a ferrite stainless steel containing 0.0010 to 0.030% B and having the γmax of 10 or more and less than 35. Further, as a ferrite stainless steel that can be advantageously achieved by the present invention, C: 0.
10% or less, Si: 0.40% or less, Mn: 2.0% or less, Ni: 0.
50% or less, Cr: 10.00 to 20.00%, N: 0.04% or less,
B: 0.0010 to 0.030%, depending on the case, V: 0.01 to 0.30%, Ti: 0.01 to 0.03%, Nb: 0.01
~ 0.30%, Zr: 0.01 to 0.30%, 1 or 2 or more, the balance consisting of Fe and inevitable impurities, and γmax represented by the above formula (1) is 10 or more and less than 35 Thus, a ferrite stainless steel sheet excellent in ridging property and workability can be obtained.

The operation and effect of the present invention will be specifically described below with reference to representative experimental results.

Two types of test steels having the chemical compositions shown in Table 1 were melted to prepare a continuously cast slab having a thickness of 200 mm. Steel No.1
Is a steel with a general chemical composition as SUS430.
No. 2 is a 17% Cr steel containing B (boron) and Ti.

These slabs were formed into hot-rolled steel strips having a plate thickness of 3.6 mm under the hot-rolling conditions shown in Table 2, and in each case 850 ° C.
The hot-rolled sheet was annealed for 6 hours, pickled, cold-rolled to a thickness of 0.7 mm, and annealed at 830 ° C for 1 minute.

The metallographic structure of each hot rolled steel strip was observed and the ridging property of the cold rolled annealed sheet was investigated. The ridging property is parallel to the rolling direction from the cold-rolled annealed sheet, and the parallel part 35 mm width ×
A tensile test piece with a length of 120 mm was taken, 20% tensile strain was applied, the centerline average roughness Ra in the direction perpendicular to the rolling direction was measured using a surface roughness meter, and the ridging that appeared on the surface was measured. The evaluation was made according to the following 5 grades.

[0026]

[0027]

[Table 1]

[0028]

[Table 2]

FIG. 1 shows steel No. 1 in Table 1 and hot rolling condition N in Table 2
It shows the metallographic structure of hot-rolled sheet hot-rolled under o.1 (conventional hot-rolling condition). The ridging evaluation of the cold-rolled annealed sheet produced from the hot-rolled sheet of FIG. 1 was D. As can be seen from Fig. 1, the metallographic structure of the hot-rolled sheet when hot-rolling ordinary SUS430 under the conventional hot-rolling conditions is a transformation phase elongated in the rolling direction.
It exhibits a layered structure of (γ phase at high temperature) and ferrite phase.

FIG. 2 shows steel No. 2 in Table 1 and hot rolling conditions in Table 2.
It shows the metallographic structure of hot-rolled sheet hot-rolled under No. 1 (conventional hot-rolling condition). The cold rolling annealed sheet produced from the hot rolled sheet of FIG.

FIG. 3 shows steel No. 2 in Table 1 and hot rolling conditions in Table 2.
It shows the metallographic structure of hot-rolled sheet hot-rolled by No. 2 (high-temperature, high-speed hot-rolling). The cold rolling annealed sheet produced from the hot rolled sheet of FIG.

As can be seen in FIG. 2, B (boron) and T
Steel No. 2 containing i shows a tendency for the transformation phase to be fragmented even under the conventional hot rolling conditions, which improves the ridging property. However, it is not always enough. On the other hand, as shown in Fig. 3, when the high temperature high speed hot rolling is applied, the transformation phase becomes granular and exhibits a dispersed distribution form. The ridging property of the cold-rolled annealed sheet is also improved with the change in the metal structure of the hot-rolled sheet.

The reason why good ridging characteristics can be obtained even by high temperature hot rolling by the addition of B and high speed hot rolling is considered as follows.

First, looking at the role of austenite in hot rolling, the precipitation nose of austenite is 10
It is in the range of 50 to 1100 ℃, which corresponds to the temperature range in the latter half of rough hot rolling. A large amount of Cr such as ferrite stainless steel
Γ → α transformation is slower in the steels containing Cr than in ordinary steels, and the austenite produced in the rough hot rolling stage is carried almost as it is during finish hot rolling. Therefore, the austenite phase, which has a higher deformation resistance during hot rolling than the ferrite phase, co-exists with the ferrite phase during hot rolling for finish, and this contributes to the fragmentation of the ferrite phase and strain accumulation.

The effect of coexisting austenite is greater as the rolling temperature is lower, but even at higher temperatures, the strain rate is high in high-speed hot rolling, and therefore, the same effect as hot rolling at substantially low temperature is brought about. Presumed. Further, B (boron) has an effect of dispersing and distributing the austenite phase at high temperature (transformed phase after cooling in the photograph) in a granular form as shown in, for example, FIG. 2 and FIG. The effect of coexistence is further enhanced, and recovery and recrystallization of the ferrite phase is promoted after winding or during annealing of hot rolled sheet,
It is considered to improve the ridging property.

The mechanism of the effect of B on the distribution state of austenite (transformed phase after cooling) is not always clear at this point. However, there are probably many precipitates in which B is involved in the ferrite. It is considered that this is because it serves as a site for austenite formation during rolling.

The reasons for limiting the content of each component in the ferrite stainless steel targeted by the present invention will be outlined below.

As described above, B has the function of uniformly dispersing the transformation phase distribution of the hot-rolled sheet and miniaturizing and dividing the unit region that causes ridging. The effect is 0.0010%
Less than is not enough. On the other hand, if it exceeds 0.0300%, slab casting defects increase and weldability deteriorates, so the appropriate content is specified to be 0.0010% to 0.0300%.

C is an element that enhances γmax, increases austenite in the hot rolling temperature range, works finely for the refinement of the structure, and is preferable for improving the ridging property. However, C is also an element that increases the strength after cold rolling annealing, and if it is too high, the ductility decreases, so the upper limit is 0.10%.

Si is an element effective for deoxidation, but it has a large solid solution strengthening ability, and if the content is high, the material hardens and the ductility decreases, so it is made 0.40% or less.

Mn is an austenite forming element and γmax
It can be effectively used for the control of aluminum, and has a small solid solution strengthening ability and has little adverse effect on the material. However, addition of more than 2.0% causes deterioration of corrosion resistance and cost increase, so 2.0% is made the upper limit.

Like Mn, Ni is an austenite forming element and is an element effective in controlling γmax. However, 0.50
Addition of more than 0.5% causes hardening and cost increase, so 0.50%
Is the upper limit.

The lower limit of 10.00% of Cr is the minimum amount necessary to maintain the corrosion resistance of stainless steel. On the other hand, a large content causes a decline in workability, so the upper limit is 20.00%.

N, like C, is an element that increases γmax,
Suitable for improving ridging property. However, addition of a large amount causes a decrease in ductility due to hardening and the occurrence of surface defects, so 0.04%
Is the upper limit.

Ti, Nb, Zr and V are all effective elements for increasing the r value and improving the deep drawability. However, on the other hand, it is a ferrite-producing element and is also an element that lowers γmax and is not necessarily preferable for ridging property.
Therefore, the appropriate content range for each is 0.
It is regulated to 01-0.30%.

As described above, γmax is an index of the maximum austenite amount in the hot rolling temperature range. γmax is 10
In the following, since the amount of austenite at a high temperature is small, the addition of B and high speed / high temperature hot rolling specified in the present invention are sufficient and ridging property cannot be obtained. On the other hand, increasing γmax is effective for improving the ridging property, but for that reason, C, N,
It is necessary to increase the amount of austenite-forming elements such as Mn and Ni, which cause hardening of the material and increase in cost, so γmax is specified to be less than 35.

In the present invention, it is permissible to appropriately add other elements such as Mo, Cu and Al for the purpose of improving various properties such as corrosion resistance and oxidation resistance.

Next, the reasons for limiting the numerical values of the manufacturing conditions adopted in the present invention will be outlined.

If the slab heating temperature is less than 1150 ° C., even if high speed rolling is carried out, the problems of productivity drop and surface defects which are problems in conventional hot rolling cannot be completely solved. On the other hand, adopting a slab heating temperature above 1250 ° C is disadvantageous because it raises the energy cost.
For this reason, the slab heating temperature should be in the range of 1150 to 1250 ℃.

The regulation of the finish rolling speed is an important point of the present invention, and it is possible to obtain a good ridging property even in the case of hot rolling at a high temperature, to improve the productivity and to secure the rolling temperature, and to obtain a heat having a good surface quality. It is regulated to 7.0 m / s or more to obtain a rolled steel strip.

When the slab heating temperature of 1150 ° C. or higher is adopted, the finish rolling finish temperature is set to be less than 860 ° C.
Since it is necessary to control the rolling speed and strengthen the cooling of the strip during hot rolling, the risk of surface defects due to seizure with the roll increases, so the temperature is specified to be 860 ° C or higher.

In order to lower the coiling temperature, it is necessary to take measures such as positive water cooling from the exit side of the finish rolling mill to the coiler, resulting in defective shape of the steel strip. Further, in order to omit the hot-rolled sheet annealing, it is advantageous to wind it at a high temperature and accelerate the transformation of austenite or the transformation phase to ferrite in the subsequent temperature lowering process. On the contrary, if the coiling temperature is higher than necessary, the energy cost will increase. Therefore, the slab heating temperature and finish rolling end temperature specified in the present invention are adopted, and the coiling temperature at which 650 ° C. or more and 900 ° C. or less is specified as the winding temperature that does not require special water cooling or heat treatment.

[0053]

Example: Steel having the chemical composition shown in Table 3 was melted to form a continuously cast slab, and hot rolling was performed under the conditions shown in Table 4 to form a hot rolled steel strip having a plate thickness of 3.6 mm and a rolling roll. It was confirmed whether or not a surface flaw was generated due to seizure of.

This hot-rolled steel strip was divided into two parts, one of which had a temperature of 850 ° C.
Each of them was annealed at 830 ° C for 1 min after being descaled, cold-rolled to a thickness of 0.7 mm, and annealed for 6 hours, and the other was not subjected to hot-rolled sheet annealing.

For comparison, steel which is ordinary SUS430
No. 5 was hot-rolled under the conventional conditions and hot-rolled sheet was annealed, and was also manufactured by the double cold-rolling process including intermediate annealing with a sheet thickness of 1.5 mm (Comparative Example No. 3). Comparative Example No. 1 and Comparative Example No. 2
Under the same conditions as Comparative Example No. 3 except that the intermediate annealing was not performed.

With respect to the obtained cold rolled steel strip, ridging property,
The tensile properties and r-values were investigated. The investigation and evaluation of ridging property are the same as the above-mentioned method. Tensile properties and r
The values are 45 ^° with rolling direction, using JIS 13B test piece.
Direction, rolling direction and 90 ^° direction were measured and averaged. The obtained results are also shown in Table 4.

[0057]

[Table 3]

[0058]

[Table 4]

As can be seen from Table 4, all the steel sheets according to the present invention have no surface flaws in the hot-rolled steel strip and have good surface properties. The cold-rolled and annealed sheet is as good as or better than the double cold-rolled process material (Comparative Example No. 3) in the low-speed hot rolling of ordinary SUS430 (Steel No. 5) regardless of whether or not the hot-rolled sheet is annealed. It has excellent ridging property and processability.

On the other hand, a comparative example in which steel No. 5 was hot-rolled at high speed
No. 1 is inferior in workability and ridging property.

Comparative Example No. 2 in which SUS430 steel No. 5 was hot-rolled under conventional conditions (low speed) and cold-rolled without intermediate annealing
In the hot rolled steel strip, surface defects occur, and the workability and ridging property of the cold rolled annealed sheet are inferior to those of the examples of the present invention.

Comparative Example No. 4 is a high-speed hot rolled steel No. 6 having a low γmax of 8.2, but has poor ridging.

Comparative Example N in which steel No. 2 was hot rolled under conventional conditions
Although o.5 has excellent cold-rolled annealed sheet characteristics, surface defects due to seizure with rolls frequently occur on the hot-rolled steel strip, and surface polishing in a post-process is required for commercialization. It was a requirement.

[0064]

As described above, according to the present invention, it is possible to obtain a ferrite stainless steel sheet having good surface properties, excellent ridging property and workability, without lowering productivity and increasing cost. You can According to the present invention,
Good ridging property and workability can be obtained without intermediate annealing. However, these characteristics are further improved if intermediate annealing is performed in the cold rolling process while allowing an increase in manufacturing cost.

[Brief description of drawings]

FIG. 1 is a photograph showing the metallographic structure of a hot rolled sheet obtained by hot rolling Steel No. 1 in Table 1 under conventional hot rolling conditions.

FIG. 2 is a photograph showing the metallographic structure of a hot rolled sheet obtained by hot rolling No. 2 B-containing steel in Table 1 under conventional hot rolling conditions.

FIG. 3 is a photograph showing a metallographic structure of a hot rolled sheet obtained by hot rolling No. 2 B-containing steel in Table 1 under hot rolling conditions according to the present invention.

Claims (4)

[Claims] 1. A ferrite rolled stainless steel exhibiting a dual phase structure of ferrite and austenite in a hot working temperature range is formed into a hot rolled steel strip through rough hot rolling and finish hot rolling, and cold rolling and annealing are performed. When manufacturing cold-rolled steel sheets or strips in combination, if the γmax shown in the following formula (1) (provided that the components not contained in the steel among the components in the formula are calculated as 0%) is 10 or more, A slab of ferrite stainless steel containing 0.0010 to 0.0300% B (boron) is manufactured by balancing the chemical composition so that it is less than 35, and heating this slab to 1150 to 1250 ° C and performing rough hot rolling. The finishing hot rolling was completed when the finishing rolling exit speed was 7.0 m / s or more and the finishing rolling exit temperature was 860 ° C or more.
Ferrite-based stainless steel with excellent surface properties, ridging property, and workability, characterized by being wound at 0 ° C or higher and 900 ° C or lower, cold-rolled to the target plate thickness without intermediate annealing, and then recrystallized and annealed. Steel plate manufacturing method. γ max = 420 (% C) +470 (% N) +23 (% Ni) +7 (% Mn) -11.5 (% Cr) -11.5 (% Si) -23 (% V) -49 (% Ti) -50 (% Nb) -50 (% Zr) +189 ・ ・ (1) 2. Ferrite-based stainless steel is mass%
And, C: 0.10% or less, Si: 0.40% or less, Mn: 2.0% or less, Ni: 0.50% or less, Cr: 10.00 to 20.00%, N: 0.04
% Or less, B: 0.0010 to 0.0300%, the balance consisting of Fe and unavoidable impurities, and γmax of 10 or more and less than 35. 3. Ferrite-based stainless steel is mass%
And, C: 0.10% or less, Si: 0.40% or less, Mn: 2.0% or less, Ni: 0.50% or less, Cr: 10.00 to 20.00%, N: 0.04
% Or less, B: 0.0010 to 0.0300%, and V:
0.01 to 0.30%, Nb: 0.01 to 0.30%, Zr: 0.01 to 0.30%
Or Ti: 0.01 to 0.30% of 1 or 2 or more, the balance being Fe and inevitable impurities, and γm
The production method according to claim 1, wherein ax is 10 or more and less than 35. 4. The manufacturing method according to claim 1, wherein the cold rolling is performed without performing hot-rolled sheet annealing.