KR101940427B1 - Ferritic stainless steel sheet - Google Patents

Abstract

In ferritic stainless steels, ferritic stainless steels having excellent corrosion resistance and excellent processability equivalent to or better than SUH409L are provided. Wherein the steel sheet contains 0.025% or less of C, 0.01 to 1.00% of Si, 0.05 to 1.00% of Mn, 0.020 to 0.040% of P, 0.030% or less of S, 0.001 to 0.100% of Al, 12.5 to 14.4% , Ni: 0.01 to 0.80%, Ti: 0.11 to 0.40%, Nb: 0.010 to 0.100% and N: 0.020% or less, with the balance being Fe and unavoidable impurities.

Description

FIELD STAINLESS STEEL SHEET [0002]

The present invention relates to a ferritic stainless steel sheet having excellent corrosion resistance and workability equal to or higher than that of SUH409L.

Ferritic stainless steels are used for a variety of applications, including automotive exhaust system parts, construction materials, kitchen utensils and home appliance parts, due to their excellent corrosion resistance and resource saving. The most important alloying element included in the ferritic stainless steel is Cr. Generally, when the Cr content is increased, the corrosion resistance is improved, but the workability is lowered. This feature makes it possible to produce a low-Cr steel type steel having excellent workability but poor corrosion resistance (SUH409L (Japanese Industrial Standard JIS G 4312: 2011, 11 mass% Cr-0.3 mass% Ti) Cr type steels (SUS430 (Japanese Industrial Standard JIS G 4305: 2012, 16 mass% Cr) is a representative steel grade) is often used depending on its use.

2. Description of the Related Art [0002] In recent years, with the diversification of designs in home telephone products, components have complicated shapes. Among them, when ferritic stainless steels are applied to parts requiring particularly high corrosion resistance, maintenance is unnecessary over a long period of time, and lifecycle cost can be reduced. From the viewpoint of processing into a complicated shape, the application of SUH409L, which is excellent in workability, is considered appropriate. However, since SUH409L is insufficient in corrosion resistance, it is difficult to apply it to the above components. Therefore, a ferritic stainless steel having excellent corrosion resistance and superior workability equal to or higher than that of SUH409L is required.

Improvements in corrosion resistance and workability are described in Patent Document 1 and Patent Document 2, respectively. Patent Document 1 discloses a high-purity ferritic stainless steel excellent in surface characteristics and corrosion resistance. In Patent Document 1, the corrosion resistance is improved by controlling the shape of the Ti-based precipitate.

Patent Document 2 discloses a ferritic stainless steel sheet excellent in ductility. In Patent Document 2, improvement of elongation is realized by controlling the shape of Mg inclusions and Ti carbosulfide.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-288544 Patent Document 2: Japanese Patent Application Laid-Open No. 2001-294990

However, although Patent Document 1 examines the formal potential, which is an index of corrosion resistance, the workability such as the total elongation and the r value has not been studied. In Patent Document 2, character elongation (breaking elongation) which is an index of workability is examined, but corrosion resistance is not examined. As can be seen from these studies, there are very few studies on the corrosion resistance and workability of ferritic stainless steels.

An object of the present invention is to provide a ferritic stainless steel having excellent corrosion resistance and excellent workability equal to or higher than that of SUH409L in a ferritic stainless steel.

The inventors of the present invention conducted a comprehensive study for satisfying both of the corrosion resistance and the workability with respect to the above problems.

First, it has been found that by adding Ti and Nb in combination, corrosion resistance can be improved. This effect is obtained when the content of Ti is 0.11% or more and 0.40% or less and the content of Nb is 0.010% or more and 0.100% or less. As a result, it was found that excellent corrosion resistance was obtained in a ferritic stainless steel containing 12.5% or more of Cr. In addition, "%" representing the content means "% by mass".

Further, it was found that Nb content of 0.010% or more and 0.100% or less is effective for improvement of processability. The added Nb is dissolved in the steel and has the effect of grain refining the crystal grains. Crystal grains in the {111} < 001 > orientation are likely to be generated from the local uneven portion in the vicinity of the grain boundaries. Therefore, with the refinement of the crystal grains by the Nb addition, the generation frequency of the {111} . ({110} < 001 &gt;) which increases the in-plane anisotropy is suppressed along with increase in the generation frequency of the recrystallized grains in the {111} plane, the in-plane anisotropy of the structure is reduced and El _min The minimum value of El) and _rmin (the minimum value of r) are improved. By this effect, it was found that workability equivalent to or higher than that of SUH409L was obtained in a ferritic stainless steel containing 14.4% or less of Cr.

In order to realize a ferritic stainless steel having superior corrosion resistance and workability equal to or higher than that of SUH409L by studying both the corrosion resistance and the workability described above, it is required that the ferritic stainless steel containing 12.5 to 14.4% of Cr has a Ti content of 0.11 to 0.40 % And Nb: 0.010 to 0.100%.

The present invention is based on the above-described findings, and its constitution is as follows.

[1] A steel according to the above item [1], wherein C is 0.025% or less, Si is 0.01-1.00%, Mn is 0.05-1.00%, P is 0.020-0.040%, S is 0.030 or less, Al is 0.001-0.100% , And the balance of Fe and unavoidable impurities is contained in an amount of 0.1 to 14.4%, Ni: 0.01 to 0.80%, Ti: 0.11 to 0.40%, Nb: 0.010 to 0.100% and N: .

[2] The ferritic stainless steel sheet according to [1], wherein the content of Ti and the content of Nb satisfy the following formula (1)

0.10? Nb / Ti? 0.30 (1)

The symbol of the element in the formula (1) means the content of each element.

[3] The steel material according to any one of [1] to [4], further comprising at least one selected from the group consisting of Mo: 0.01 to 0.30%, Cu: 0.01 to 0.50%, Co: 0.01 to 0.50%, and W: The ferritic stainless steel sheet according to [1] or [2]

[4] A piezoelectric ceramic composition comprising, by mass%, V: 0.01 to 0.25%, Zr: 0.01 to 0.30%, B: 0.0003 to 0.0030%, Mg: 0.0005 to 0.0030%, Ca: 0.0003 to 0.0030% The ferritic stainless steel sheet according to any one of [1] to [3], further comprising one or more selected from among REM (rare earth metals): 0.001 to 0.10%.

[5] A ferritic stainless steel according to any one of [1] to [4], further comprising one or two selected from the group consisting of 0.001 to 0.50% Sn and 0.001 to 0.50% Steel plate.

[6] A steel sheet according to any one of [1] to [5], wherein V: 0.01 to 0.25%, Ti content and Nb content satisfies the following formula (1), Ti content, Nb content, The ferritic stainless steel sheet according to any one of [1] to [5], characterized in that the ferritic stainless steel sheet is subjected to heat treatment.

0.10? Nb / Ti? 0.30 (1)

0.20? V / (Ti + Nb)? 1.00 (2)

The symbol of element in the formulas (1) and (2) means the content of each element.

The ferritic stainless steel sheet of the present invention is excellent in corrosion resistance and processability. Specifically, according to the present invention, a ferritic stainless steel having excellent corrosion resistance and workability equal to or higher than that of SUH409L can be obtained.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graph showing the effect of Ti content and Nb content on corrosion resistance.
2 is a graph showing the influence of the Ti content, the Nb content and the V content on the corrosion resistance.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.

The ferritic stainless steel sheet according to the present invention contains 0.025% or less of C, 0.01 to 1.00% of Si, 0.05 to 1.00% of Mn, 0.020 to 0.040% of P, 0.030% or less of S and 0.001 to 0.10% , Ni: 0.01 to 0.80%, Ti: 0.11 to 0.40%, Nb: 0.010 to 0.100%, and N: 0.020% or less.

In the following description, the percentages of the components of the ferritic stainless steel sheet means% by mass unless otherwise specified.

C: not more than 0.025%

C is an effective element for increasing the strength of steel. From the viewpoint of obtaining the effect, the C content is preferably 0.001% or more. However, if the C content exceeds 0.025%, corrosion resistance and workability are significantly deteriorated. Therefore, the C content is 0.025% or less, and more preferably 0.015% or less. And most preferably 0.010% or less.

Si: 0.01 to 1.00%

Si is a useful element as a deoxidizer. This effect is obtained by making the Si content 0.01% or more. On the other hand, when the Si content exceeds 1.00%, the steel is hardened and the workability is lowered. Therefore, the Si content is limited to a range of 0.01 to 1.00%. And more preferably 0.03 to 0.50%. And most preferably in the range of 0.06 to 0.20%.

Mn: 0.05 to 1.00%

Mn has a deoxidizing effect. From the viewpoint of obtaining this effect, the Mn content is set to 0.05% or more. On the other hand, when the Mn content exceeds 1.00%, precipitation and coarsening of MnS are promoted and corrosion resistance is lowered. Therefore, the Mn content is limited to a range of 0.05 to 1.00%. And more preferably in the range of 0.10 to 0.40%. And most preferably in the range of 0.20 to 0.30%.

P: 0.020 to 0.040%

P is an element degrading the corrosion resistance. P is segregated in the grain boundaries, and hot workability is lowered. Therefore, the P content is preferably as low as possible, and is set to 0.040% or less. However, excessive reduction of the P content to less than 0.020% results in an increase in the steelmaking cost. Therefore, the P content is limited to a range of 0.020 to 0.040%. And more preferably 0.020 to 0.030%.

S: not more than 0.030%

S forms Mn and precipitate MnS. The interface between the MnS and the stainless steel base material becomes the starting point of the formula and degrades the corrosion resistance of the ferritic stainless steel. Therefore, the S content is preferably low, and is set to 0.030% or less. Preferably 0.020% or less. More preferably 0.010% or less.

Al: 0.001 to 0.100%

Al is an effective element for deoxidation. This effect is obtained by setting the Al content to 0.001% or more. On the other hand, if the Al content exceeds 0.100%, the surface quality deteriorates due to the increase of the surface damage caused by the Al-based non-metallic inclusions. Therefore, the Al content is limited within the range of 0.001 to 0.100%. And more preferably in the range of 0.01 to 0.08%. And most preferably 0.02 to 0.06%.

Cr: 12.5-14.4%

Cr is an important element for determining the corrosion resistance and workability of ferritic stainless steels. Corrosion resistance of ferritic stainless steel is obtained by Cr forming a passive film on the steel surface. Therefore, as the Cr content is increased, the corrosion resistance is improved. In the present invention, the Cr content is adjusted to a specific range, and the Ti content and the Nb content, which will be described later, are also adjusted to a specific range to improve the corrosion resistance of the steel. In the present invention, it is necessary to contain at least 12.5% Cr in order to obtain excellent corrosion resistance. On the other hand, as the Cr content increases, the workability of the ferritic stainless steel decreases. In the present invention, the workability is improved by the addition of Nb, which will be described later. In the present invention, up to 14.4% of Cr may be contained in order to obtain workability equal to or higher than that of SUH409L. Therefore, the Cr content is limited to the range of 12.5 to 14.4%. And more preferably in the range of 13.0 to 13.8%.

Ni: 0.01 to 0.80%

Ni is an element that inhibits the anode reaction by an acid and enables passivation to be maintained even at a lower pH. Namely, Ni has an effect of enhancing the interstitial corrosion resistance and remarkably suppresses the progress of corrosion in the active dissolution state, thereby improving the corrosion resistance of the ferritic stainless steel.

This effect is obtained when the Ni content is 0.01% or more. On the other hand, when the Ni content exceeds 0.80%, the steel is hardened and the workability is lowered. Therefore, the Ni content is limited to a range of 0.01 to 0.80%. And more preferably in the range of 0.10 to 0.40%.

Ti: 0.11 to 0.40%

Ti is an element that fixes C and N to prevent sensitization by Cr carbonitride and improves corrosion resistance. Further, Ti further improves corrosion resistance by a composite effect with Nb, which will be described later.

The effect is obtained when the Ti content is 0.11% or more. On the other hand, when the Ti content exceeds 0.40%, the stainless steel sheet is hardened and the workability is lowered. Further, Ti-based inclusions are generated on the surface, and the surface quality is lowered. Therefore, the Ti content is set in the range of 0.11 to 0.40%. And more preferably in the range of 0.20 to 0.35%.

Nb: 0.010 to 0.100%

Nb is dissolved in the steel and has the effect of refining the grain. Since the crystal grains in the {111} < 001 > orientation are likely to be generated from the vicinity of grain boundaries, the ratio of recrystallized grains in the {111} plane increases in the recrystallization process accompanying grain refinement by Nb addition. This increases the in-plane anisotropy and suppresses the generation of crystal grains in the Goss orientation ({110} < 001 &gt;) which lowers the workability and reduces the in-plane anisotropy of the structure. As a result, El _min (the minimum value in elongation in each direction with the direction perpendicular to the rolling direction and the direction perpendicular to the rolling direction as the L direction, the D direction, and the C direction) and r _min (L, D , The minimum value among the r values in the C direction) increases, and the workability improves. Further, Nb further improves the corrosion resistance by a composite effect with Ti to be described later. The effect is obtained when the Nb content is 0.010% or more. On the other hand, when the Nb content exceeds 0.100%, the ferritic stainless steel is hardened and the workability is lowered. Therefore, the Nb content is in the range of 0.010 to 0.100%. And more preferably 0.030 to 0.070%.

In completing the present invention, it has been found that by adding Ti and Nb in combination, corrosion resistance can be improved. The apparatus is considered as follows. Corrosion of stainless steels is known to be caused by the destruction of local passive films called formulations. As a cause of the occurrence of the formulas, there is a local gap erosion in the gap formed near the surface of the precipitate-steel base material interface due to the difference in the amount of distortion applied to the precipitate and the steel base material at the time of processing such as rolling. MnS and Ti carbonitride are representative of the precipitates forming this gap. Further, since the Ti carbonitride has a coarse and linear interface, the anodic reaction is concentrated at the gap formed at the interface, and the corrosion resistance of the steel is lowered. However, it has been found that the Ti-Nb complex carbonitrides are deposited in such a manner that the Nb carbonitride adheres to the periphery of the Ti carbonitride by the addition of Nb to Ti. The interface between the Ti-Nb composite carbonitrides and the stainless steel base material thus obtained is not linear, unlike the Ti carbonitride. That is, since the total length of the interface is increased and the anode reaction is dispersed, the formula hardly occurs and the corrosion resistance is improved.

In order to exhibit this effect and to improve the processability, it is necessary that the contents of Ti and Nb respectively fall within the above-mentioned range. More preferably, the ratio of the Nb content to the Ti content (Nb / Ti) is 0.10 or more and 0.30 or less. This further improves the corrosion resistance. By setting the ratio (Nb / Ti) to 0.10 or more, precipitation of Nb carbonitride to the periphery of the Ti carbonitride becomes sufficient. When the ratio (Nb / Ti) is set to 0.30 or less, the carbonitride of Nb alone is hardly precipitated, and Ti-Nb complex carbonitrides are easily formed.

N: 0.020% or less

N is an element that is inevitably incorporated into the river. However, when the N content exceeds 0.020%, the corrosion resistance and workability remarkably deteriorate. Therefore, the N content should be 0.020% or less. More preferably, it is 0.015% or less.

The essential components have been described above. However, in the present invention, other elements described below can be appropriately contained.

Mo: 0.01 to 0.30%

Mo has an effect of improving the interstitial corrosion resistance of ferritic stainless steel. The effect is obtained by setting the Mo content to 0.01% or more. However, when the Mo content exceeds 0.30%, the effect is saturated and the workability is lowered. Therefore, when Mo is added, the Mo content is set to 0.01 to 0.30%. More preferably, it is 0.03 to 0.10%.

Cu: 0.01 to 0.50%

Cu has an effect of improving the toughness of steel. The effect is obtained when the Cu content is 0.01% or more. On the other hand, if the Cu content exceeds 0.50%, the toughness of the steel decreases and the workability decreases. Therefore, when Cu is added, the Cu content is set to 0.01 to 0.50%. , More preferably from 0.01% to less than 0.10%. And most preferably 0.03 to 0.06%.

Co: 0.01-0.50%

Co is an element which improves the corrosion resistance of the stainless steel in the gap. This effect is obtained by setting the Co content to 0.01% or more. However, when the Co content exceeds 0.50%, the effect is saturated and the workability is lowered. Therefore, when Co is added, the Co content is set to 0.01 to 0.50%. And more preferably 0.03 to 0.30%. And most preferably in the range of 0.05 to 0.10%.

W: 0.01 to 0.50%

W is an element improving the interstitial corrosion resistance of the ferritic stainless steel. In order to obtain this effect, the W content is preferably 0.01% or more. However, if the content exceeds 0.50%, the effect becomes saturated and the workability decreases. Therefore, when W is added, the W content is set to 0.01 to 0.50%. And more preferably 0.03 to 0.30%. And most preferably in the range of 0.05 to 0.10%.

V: 0.01 to 0.25%

V is an element which improves the interstitial corrosion resistance of the ferritic stainless steel. This effect is obtained by setting the V content to 0.01% or more. On the other hand, if the V content exceeds 0.25%, the effect becomes saturated and the processability is deteriorated. Therefore, V is limited to a range of 0.01 to 0.25%. And more preferably 0.03 to 0.20%. And most preferably 0.05 to 0.10% or less.

In completing the present invention, it has been found that the effect of improving the corrosion resistance by the addition of Ti and Nb described above becomes more remarkable by adjusting the V content with respect to the total of the Ti content and the Nb content when V is added. The mechanism is not clear, but is considered as follows.

The inclusion of V in the steel causes V to be contained in the carbonitride of Ti or Nb and the composite carbonitride of Ti and V ((Ti, V) (C, N)) or composite carbonitride of Nb and V (Ti, Nb, V) (C, N) in which V is added to the above-mentioned Ti-Nb complex carbonitrides are formed. As a result of these carbonitrides, the temperature at which precipitation peak temperature, which is the precipitation peak temperature, is promoted is lower than in the case where V is not contained. As a result, the grain growth also occurs at a lower temperature. Since the diffusion is delayed at the low-temperature region, the coarsening of each grain is suppressed, and V for the carbonitride of Ti or Nb and the composite carbonitride (also collectively referred to as Ti-Nb composite carbonitride) (Collectively referred to as Ti-Nb-V composite carbonitrides) are relatively small in size and take a more dispersed form of precipitation. As the size of each composite carbonitride becomes smaller, the gap formed between the carbonitride-steel base material at the time of processing such as rolling becomes small. As a result, local gap corrosion hardly occurs, and occurrence of a formula is suppressed, thereby improving corrosion resistance.

The content of Ti, Nb, and V is controlled to fall within the above-mentioned respective ranges, and the ratio of the Nb content to the Ti content (Nb / Ti) is adjusted so that the effect is exhibited to realize excellent corrosion resistance and good processability. (V / (Ti + Nb)) of the V content to the total of the Ti content and the Nb content is set to be not less than 0.20 and not more than 1.00. This further improves the corrosion resistance. (Ti, V) (C, N) or (Nb, V) (C, N) is remarkably lowered by setting the ratio (V / (Ti + Nb) Also, when the ratio (V / (Ti + Nb)) is set to 1.00 or less, V alone carbonitride is hardly precipitated and Ti-Nb-V composite carbonitride is easily formed.

Zr: 0.01 to 0.30%

Zr has the effect of fixing C and N similarly to Ti and Nb to prevent sensitization by Cr carbonitride and improve corrosion resistance. The effect is obtained when the Zr content is 0.01% or more. However, when the Zr content exceeds 0.30%, ZrO ₂ or the like is generated and surface damage occurs. Therefore, when Zr is added, the Zr content is set to 0.01 to 0.30%. More preferably, it is 0.01 to 0.20%.

B: 0.0003 to 0.0030%

B is an element that improves hot workability and secondary workability. B is known to be effective in addition to Ti-added steel. This effect is obtained by setting the B content to 0.0003% or more. On the other hand, when the B content exceeds 0.0030%, workability decreases. Therefore, when B is added, the B content is set in the range of 0.0003 to 0.0030%. And more preferably 0.0010 to 0.0025%. And most preferably in the range of 0.0015 to 0.0020%.

Mg: 0.0005 to 0.0030%

Mg forms Mg oxide with Al in molten steel and acts as a deoxidizer. This effect is obtained by setting the Mg content to 0.0005% or more. On the other hand, when the Mg content exceeds 0.0030%, the toughness of the steel is lowered and the productivity is lowered. Therefore, when Mg is added, the Mg content is limited within the range of 0.0005 to 0.0030%.

Ca: 0.0003 to 0.0030%

Ca is an effective component for preventing clogging of the nozzle due to crystallization of Ti-based inclusions likely to occur during continuous casting. This effect is obtained when the Ca content is 0.0003% or more. On the other hand, when the Ca content exceeds 0.0030%, the toughness of the steel is lowered and the productivity is lowered. When the Ca content exceeds 0.0030%, corrosion resistance is deteriorated by precipitation of CaS. Therefore, when Ca is added, the Ca content is limited to a range of 0.0003 to 0.0030%. And more preferably in the range of 0.0010 to 0.0020%.

Y: 0.001-0.20%

Y decreases the viscosity of the molten steel and is an element improving the cleanliness. This effect is obtained at Y content of 0.001% or more. On the other hand, if the Y content exceeds 0.20%, the effect becomes saturated and the workability deteriorates. Therefore, when Y is added, the Y content is limited to a range of 0.001 to 0.20%. And more preferably 0.001 to 0.10%.

REM (rare earth metals): 0.001 to 0.10%

REM (rare earth metals: elements of atomic numbers 57 to 71 such as La, Ce, Nd) are elements that improve the high temperature oxidation resistance. This effect is obtained with a REM content of 0.001% or more. On the other hand, when the REM content exceeds 0.10%, not only the effect is saturated but also surface defects occur during hot rolling. Therefore, when REM is added, the REM content is limited to a range of 0.001 to 0.10%. And more preferably 0.005 to 0.05%.

Sn, Sb: 0.001 to 0.50%

These elements are effective for improving the anti-ridging property by promoting the generation of the deformation zone at the time of rolling. This effect is obtained when the content of any one of these elements is 0.001% or more. However, when the content of each of these elements exceeds 0.50%, the effect is not only saturated but also the workability is lowered. Therefore, when Sn or Sb is added, the content thereof is set to 0.001 to 0.50%. More preferably, each content is in the range of 0.003 to 0.20%.

The remainder other than the above components are Fe and unavoidable impurities.

Next, a preferred method of producing the ferritic stainless steel sheet of the present invention will be described. The steel having the above-mentioned composition is subjected to a known method such as a converter, an electric furnace or a vacuum melting furnace, and is made into a steel material (slab) by a continuous casting method or a coarse- The steel material is heated to 1000 to 1200 占 폚 and then hot rolled at a finishing temperature of 700 占 폚 to 1000 占 폚 to a sheet thickness of 2.0 mm to 5.0 mm. The hot-rolled steel sheet thus produced is annealed at a temperature of 800 ° C to 1100 ° C, pickled, cold-rolled, and cold-rolled sheet annealed at a temperature of 700 ° C to 1000 ° C. After annealing the cold rolled sheet, pickling is carried out and the scale is removed. The cold rolled steel sheet from which the scale has been removed may be subjected to skin pass rolling.

Example

Table 1 (Table 1-1, Table 1-2, Table 1-3 together) 1 to 82 were vacuum-melted in a vacuum melting furnace, and then cast into a 30-kg steel ingot. The steel ingot was heated to a temperature of 1050 占 폚 and then subjected to hot rolling at a finish temperature of 900 占 폚 to obtain a hot-rolled steel sheet having a thickness of 5 mm. Thereafter, the steel sheet was subjected to annealing at 1000 to 1050 캜 for 1 minute in an Ar atmosphere, immersed in sulfuric acid to conduct pickling, and cold rolled to obtain a cold-rolled steel sheet having a thickness of 1.0 mm. The obtained cold-rolled steel sheet was subjected to annealing at 900 DEG C for 1 minute in an Ar atmosphere, and then subjected to neutral salt electrolysis, superficic acid immersion, and nitrate electrolysis to obtain a cold-rolled annealed pickled steel sheet.

Further, ferritic stainless steels having the compositions shown in Nos. 83 and 84 in Table 1 were dissolved in a vacuum melting furnace and then cast into a 30-kg steel ingot. The steel ingot was heated to a temperature of 1050 占 폚 and then subjected to hot rolling at a finish temperature of 900 占 폚 to obtain a hot-rolled steel sheet having a thickness of 5 mm. Thereafter, annealing was performed in the atmosphere at 800 to 850 占 폚 for 12 hours, soaking in sulfuric acid to conduct pickling, and then cold rolling to obtain a cold-rolled sheet having a thickness of 1.0 mm. The obtained cold-rolled steel sheet was subjected to annealing at 800 ° C for 1 minute in an Ar atmosphere, and subjected to neutral salt electrolysis, ultra-hydrofluoric acid immersion and nitric acid electrolysis to obtain a cold-rolled annealed pickled steel sheet.

The results are shown in Table 1 below. 82 and 83 are SUH409L equivalent steel and SUS430 equivalent steel respectively.

The ferritic stainless steel cold-rolled annealed pickled steel sheet obtained under the above-mentioned production conditions was cut into 80 x 60 mm by shearing. After cutting, polishing was carried out with an emery polishing paper up to 320 times, and degreasing with acetone was carried out. The end and the back of the obtained steel sheet were sealed and placed in a cycle corrosion tester at an inclination of 60 °. Corrosion testing in the 0.1% NaCl-0.5 mass% H ₂ O atomisation of _second solution (30 minutes, 35 ℃, 98% RH (humidity)), drying (4 hours, 60 ℃, 30% RH) , wet (1 Hour, 40 占 폚, 95% RH) as one cycle, 240 cycles of corrosion test were carried out. This is a corrosion promotion test method for evaluating the corrosion resistance of low to heavy Cr-grade steels. After the test, the corrosion product was removed using 10% citric acid ammonium solution and the corrosion loss was measured. (Acceptable: excellent), those having a corrosion loss of 1.0 g / m 2 or less were evaluated as "good" (good: excellent) and those having a corrosion loss of 1.0 g / (pass), and those that were greater than 8.0 g / m2 and less than 16.0 g / m2 were evaluated as &quot;?&quot; (pass) and those that were greater than 16.0 g / Respectively.

Further, the 13B test piece specified in JIS Z 2201 was taken in the rolling direction, the direction at 45 degrees with respect to the rolling direction, and the direction perpendicular to the rolling direction, and a tensile test was performed at room temperature to evaluate the workability. El ( _min) was 33% or more, _rmin was 1.1 or more, and El ( _min ) was less than 33% or _rmin was less than 1.1.

The obtained results are shown in Table 1. Inventive Lecture Test No. 1 to 65 indicate that the evaluation of the corrosion resistance is "?", "?" Or "?", And the evaluation of the workability is "?", And the corrosion resistance and workability are excellent. Particularly, in the inventive steel test Nos. 34 to 47 and 55 to 65, in which the ratio (V / (Ti + Nb)) satisfies 0.20 or more and 1.00 or less, the evaluation of corrosion resistance and workability was all?

Fig. 1 is a graph showing the results of the inventive example, the results of comparative examples in which the Ti content is outside the range of the present invention, and the results of comparative examples in which the Nb content is outside the range of the present invention. As shown in Fig. 1, when the content of Ti and Nb satisfies the formula (1), it can be seen that it has better corrosion resistance.

Fig. 2 graphically shows the results of corrosion resistance as a sum of the V content and the Ti and Nb contents with respect to the present invention in which the Ti and Nb contents satisfy the formula (1). As shown in Fig. 2, when the content of Ti, Nb and V satisfies the formula (2), it is found that the corrosion resistance is better.

Tests Nos. 34 to 47 and 55 to 65 satisfying the ratio (V / (Ti + Nb)) satisfied 0.20 or more and 1.00 or less were all evaluated as "Good" in corrosion resistance and workability.

In Comparative Examples of Test Nos. 66, 68, 70, and 71, the contents of Cr, Ni, and Ti are lower than those of the present invention, respectively, so that corrosion resistance is inferior. In Comparative Examples of Test Nos. 67, 69, 72, 73, 76, 77, 78, 79 and 80, the Cr, Ni, Ti, Nb and V contents were higher than those of the present invention. In the comparative examples of Test Nos. 74 and 75, the content of Nb is lower than the component range of the present invention, so that corrosion resistance and workability are all inferior. In Comparative Example of Test No. 81, since the content of C is higher than the content range of the present invention, the corrosion resistance and workability are all inferior. Test No. 82 did not contain Nb and the Cr content was lower than the range of the present invention, so that the corrosion resistance was inferior. The test examples No. 83 and No. 84 did not contain Nb, and the C content, the N content, and the Cr content were higher than those of the present invention, resulting in poor workability.

[Table 1-1]

[Table 1-2]

[Table 1-3]

[Industrial Availability]

According to the present invention, since corrosion resistance and workability are excellent, it is possible to provide an interior panel of an elevator, an interior, a duct hood, a muffler cutter, a locker, a component for household appliances, And covers for drains and the like.

Claims (9)

C: not more than 0.025%, Si: 0.01 to 1.00%, Mn: 0.05 to 1.00%, P: 0.020 to 0.040%, S: not more than 0.030%, Al: 0.001 to 0.100% , Ni: 0.01 to 0.80%, Ti: 0.11 to 0.40%, Nb: 0.010 to 0.100% and N: 0.020% or less, the balance being Fe and unavoidable impurities,
A ferritic stainless steel sheet characterized in that the Ti content and the Nb content satisfy the following formula (1)
0.10? Nb / Ti? 0.30 (1)
The symbol of the element in the formula (1) means the content of each element. The method according to claim 1,
The ferritic stainless steel according to claim 1, further comprising at least one selected from the group consisting of 0.01-0.30% Mo, 0.01-0.50% Cu, 0.01-0.50% Co, and 0.01-0.50% Stainless steel plate. 3. The method according to claim 1 or 2,
The steel sheet according to any one of claims 1 to 3, wherein the steel sheet comprises, by mass%, 0.01 to 0.25% of V, 0.01 to 0.30% of Zr, 0.0003 to 0.0030% of B, 0.0005 to 0.0030% of Mg, 0.0003 to 0.0030% of Ca, 0.001 to 0.20% Metal): 0.001 to 0.10%, based on the total weight of the ferritic stainless steel sheet. 3. The method according to claim 1 or 2,
Wherein the ferritic stainless steel sheet further contains at least one selected from the group consisting of 0.001 to 0.50% Sn and 0.001 to 0.50% Sb. The method of claim 3,
Wherein the ferritic stainless steel sheet further contains at least one selected from the group consisting of 0.001 to 0.50% Sn and 0.001 to 0.50% Sb. 3. The method according to claim 1 or 2,
By mass, and V: 0.01 to 0.25%
Wherein the Ti content and the Nb content satisfy the following formula (1)
A ferritic stainless steel sheet characterized in that the Ti content, the Nb content, and the V content satisfy the following formula (2)
0.10? Nb / Ti? 0.30 (1)
0.20? V / (Ti + Nb)? 1.00 (2)
The symbol of element in the formulas (1) and (2) means the content of each element. The method of claim 3,
By mass, and V: 0.01 to 0.25%
Wherein the Ti content and the Nb content satisfy the following formula (1)
A ferritic stainless steel sheet characterized in that the Ti content, the Nb content, and the V content satisfy the following formula (2)
0.10? Nb / Ti? 0.30 (1)
0.20? V / (Ti + Nb)? 1.00 (2)
The symbol of element in the formulas (1) and (2) means the content of each element. 5. The method of claim 4,
By mass, and V: 0.01 to 0.25%
Wherein the Ti content and the Nb content satisfy the following formula (1)
A ferritic stainless steel sheet characterized in that the Ti content, the Nb content, and the V content satisfy the following formula (2)
0.10? Nb / Ti? 0.30 (1)
0.20? V / (Ti + Nb)? 1.00 (2)
The symbol of element in the formulas (1) and (2) means the content of each element. 6. The method of claim 5,
By mass, and V: 0.01 to 0.25%
Wherein the Ti content and the Nb content satisfy the following formula (1)
A ferritic stainless steel sheet characterized in that the Ti content, the Nb content, and the V content satisfy the following formula (2)
0.10? Nb / Ti? 0.30 (1)
0.20? V / (Ti + Nb)? 1.00 (2)
The symbol of element in the formulas (1) and (2) means the content of each element.

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