WO2015133433A1 - Ferritic/austenitic two-phase stainless-steel sheet with excellent polishability and process for producing same - Google Patents

Abstract

A ferritic/austenitic two-phase stainless-steel sheet from which mirror-finished products that are less apt to develop flaws or cracks even in long-term use and that can be reduced in weight due to enhanced strength are provided by subjecting the stainless-steel sheet to mirror polishing for accurately forming reflected images. The ferritic/austenitic two-phase stainless-steel sheet has excellent polishability, and is characterized by: having a composition which contains, in terms of mass%, up to 0.03% C, 19.0-22.0% Cr, 0.06-0.20% N, 5.0-7.5% one or more of Ni, Mn, and Cu, up to 1.0% Si and/or Al, up to 0.045% P, up to 1.0% Mo, up to 0.005% S, and up to 0.01% O, with the remainder comprising Fe and unavoidable impurities; having a dual-phase structure composed of a ferrite phase and an austenite phase; and having a grain-diameter difference between the ferrite grains and the austenite grains, ΔGs, of 15 µm or less.

Description

Ferritic / austenitic duplex stainless steel sheet with excellent abrasiveness and method for producing the same

The present invention relates to a stainless steel plate having excellent grindability and a method for producing the same used in various fields where a mirror surface having high glossiness and high image clarity is required.

In recent years, the direction of beauty has been increasing. Mirror finish stainless steel with excellent design and beauty is used for general building materials, interior materials, exterior materials such as exterior panels, mirror surface materials such as decorative mirrors and curved mirrors, and commercial kitchens. It is used for kitchen utensils such as kitchen tables, sink top plates, refrigerator doors, and cooking utensils such as square bats and pans. Among these applications, for example, regarding mirror-related applications, conventional glass-based products are easily damaged when subjected to impacts, and the damage may lead to injury. Due to its high cost, the use of mirror-finished stainless steel as a mirror to replace glass has become widespread.

Conventionally, austenitic stainless steel used for the above-mentioned applications is soft because it has an annealed structure, and wrinkles are easily generated during cleaning and handling, and the aesthetic appearance is impaired. Also, in polishing, if Al-based oxide or Si-based oxide, which is a deoxidation product, is present on the surface, it causes grounding and increases the polishing process.

In Patent Document 1, the addition amount of Al, which is a deoxidizing element, is reduced in the steelmaking stage, and the formation of Al ₂ O ₃ contained in the product is suppressed, thereby eliminating ground during polishing and improving the polishability. Steel is described.

In Patent Document 2, the production of steel with limited crystal grain size and Al concentration in the base metal is performed in order to improve fineness by suppressing fine skin roughness caused by temper rolling, which is the final process, using a bright annealed material. A method is described.

On the other hand, in ferritic stainless steel, Patent Document 3 discloses a steel that improves the grindability by reducing the rolling speed to suppress the formation of oil pits caused by rolling lubricating oil and reducing the white streaks caused by the oil pits. Is described.

Furthermore, Patent Document 4 describes a steel that achieves both ferritic workability and martensitic scratch resistance by applying a ferrite phase + martensitic phase duplex steel sheet to mirror polishing.

However, in Patent Document 1, although an austenitic stainless steel with a small amount of earth is obtained, it is not possible to eliminate wrinkles that occur during handling. In Patent Document 2, although the surface waviness after temper rolling is eliminated and the polishing process can be reduced, the process is limited to the BA process. In Patent Document 3, although the generation of oil pits during rolling is suppressed and the deterioration of the abrasiveness due to the material is suppressed, since it is a ferritic stainless steel, if the grindstone is deep and rough during rough polishing, Since the load of the polishing process is increased, the polishing performance is deteriorated.

As a countermeasure for these, the steel described in Patent Document 4 was invented, but the duplex stainless steel of ferrite phase + martensite phase has a fine mixed structure consisting of a soft ferrite phase and a hard martensite phase. Therefore, the advantages of both were utilized, the glossiness after the mirror finish was excellent, and it had moderate workability and strength, and the scratch resistance was better than that of the austenite system. Further, since it has a fine mixed structure, for example, on a mirror surface having a curvature such as a curved mirror, the surface roughness after plastic working is small, and the polishing load for removing the roughness is small. However, since the hardness of the material is remarkably high, such as about HV350, there is a problem that the polishing eyes are difficult to be noticed and the load on the polishing apparatus and the consumption of the grindstone are increased.

Japanese Patent Laid-Open No. 4-99215 JP-A-8-309405 JP-A-2-173215 Japanese Patent Laid-Open No. 11-152550

The present invention has been devised to solve such problems. Even when mirror polishing is performed to accurately reflect a reflected image, the gloss is high and the load on the polishing apparatus is high. And a ferrite-austenitic duplex stainless steel sheet that can reduce the consumption of grindstones, and is a mirror-finished steel sheet that does not easily wrinkle or crack even when used for a long time, and can be reduced in weight by increasing strength. For the purpose. In addition, general building materials using the mirror-finished steel sheet, interior materials, exterior materials such as exterior panels, mirrors such as decorative mirrors and curved mirrors, kitchen utensils for commercial kitchens, sink top plates, refrigerator doors, etc. An object is to provide cooking utensils such as a square bat and a pan.

The ferrite-austenitic duplex stainless steel sheet of the present invention and the method for producing the same are as follows.

(1) By mass%, C: 0.03% or less, Cr: 19.0-22.0%, N: 0.06-0.20%, Ni, Mn, Cu: 1 type or 2 types or more 5.0-7.5% in total, Si, Al: 1 type or 2 types in total 1.0% or less, P: 0.045% or less, Mo: 1.0% or less, S: 0.005 %, O: 0.01% or less, the balance being Fe and inevitable impurities, having a multiphase structure of ferrite phase and austenite phase, and the difference in particle size ΔGs between ferrite and austenite is 15 μm or less. A ferritic / austenitic duplex stainless steel sheet excellent in abrasiveness, characterized by being.

(2) The composition further comprises, in mass%, Sn: 0.005 to 0.2%, Nb: 0.01 to 0.2%, Ti: 0.01 to 0.2%, B: 0.00. The ferritic / austenitic duplex stainless steel sheet having excellent grindability as described in (1) above, containing one or more of 01% or less.

(3) The composition is further in terms of mass%, Y: 0.01 to 0.20%, REM: 0.01 to 0.20%, V: 0.005 to 0.20%, Al: 0.00. The ferritic / austenitic duplex stainless steel sheet having excellent abrasiveness as described in (1) or (2) above, comprising one or more of 005 to 0.20%.

(4) The ferritic / austenitic duplex stainless steel sheet having excellent abradability according to any one of (1) to (3), which is used for a mirror surface material.

(5) The ferritic / austenitic duplex stainless steel sheet having excellent polishing properties according to any one of the above (1) to (3), which is used for exterior materials.

(6) The ferritic / austenitic duplex stainless steel sheet having excellent abradability according to any one of (1) to (3), which is used for kitchen equipment.

(7) The ferritic / austenitic duplex stainless steel sheet having excellent polishing properties according to any one of (1) to (3), which is used for cooking utensils.

(8) The steel slab having the composition described in any one of the above (1) to (3) is hot-rolled, then hot-rolled sheet annealed and pickled, and then subjected to a final pass at a rolling rate of 80% or more. After carrying out cold rolling at a later plate temperature of 80 ° C. or higher, final annealing is performed at a temperature of 1000 to 1100 ° C., and then the cooling rate to 500 ° C. is set to 25 ° C./s or higher and pickling treatment is performed ( (1) A method for producing a ferritic / austenitic duplex stainless steel sheet having excellent polishing properties according to any one of (7).

Since the multi-phase structure stainless steel sheet of the present invention has a mixed structure of ferrite phase + austenite phase, it has a high hardness that does not impair the fine grain size and abrasiveness, and as a variety of mirror-finished products that are difficult to have surface flaws. used. In addition, the mirror-finished multiphase stainless steel sheet has a high glossiness and cannot be used on an austenitic stainless steel sheet represented by SUS304 and a ferritic stainless steel sheet represented by SUS430 because surface flaws are likely to occur. In other fields, it can be used for mirror materials, exterior materials, kitchen equipment, and cooking utensils.

It is a figure which shows the relationship between the particle size difference of a ferrite and austenite, and the surface roughness after 1 pass of grinding | polishing. It is a figure which shows the relationship between the surface roughness after 1 pass of grinding | polishing, and glossiness.

Hereinafter, the alloy components, content ratios, and the like included in the stainless steel targeted by the present invention will be described. In addition,% of the content rate of a component shows the mass%.

C: 0.03% or less C is a strong austenite-forming element and has a large strengthening ability, and thus effectively acts to increase the strength. However, when a large amount of C exceeding 0.03% is contained, a large amount of carbide is generated after the heat treatment, and the corrosion resistance and toughness are lowered. Therefore, it was made 0.03% or less. Desirably, it is in the range of 0.01 to 0.02%.

Cr: 19.0-22.0%
Cr is an important element in maintaining the corrosion resistance as stainless steel. In a duplex stainless steel composed of a ferrite phase and an austenite phase, Cr distribution to the austenite phase is suppressed, so 19.0% or more is necessary to ensure the corrosion resistance of the austenite phase. However, when excess Cr exceeding 22.0% is contained, toughness will fall. Excessive Cr content causes a decrease in manufacturability. Desirably, it is in the range of 20.0 to 21.0%.

Ni, Mn, Cu: 5.0 or 7.5% in total of 1 type or 2 types or more
All act as austenite-forming elements and are alloy elements necessary for obtaining a ferrite + austenite structure at room temperature. As the content of Ni, Mn and / or Cu increases, the austenite phase increases and the hardness (strength) increases. When one or more of Ni, Mn, and Cu are included in a total of 5.0% or more, the hardness of the austenite phase is equal to that of the ferrite phase. However, when excessive Ni, Mn and / or Cu exceeding 7.5% are contained, the amount of austenite at a high temperature is excessively increased, and hot workability is deteriorated. Desirably, it is in the range of 5.5 to 6.5%.

N: 0.06 to 0.20%
N is an austenite generating element like C, and therefore the N content needs to be determined from the component content in balance with other ferrite forming elements. Further, this N also has an effect of improving pitting corrosion resistance, and the N content must be at least 0.06%. However, if it exceeds 0.20%, the hot workability deteriorates, so 0.06 to 0.20% was set. Desirably, it is 0.10 to 0.18% of range.

Si and Al: 1.0% or less in total of one or two types Si and Al are known as elements necessary for deoxidation, and are extremely useful for increasing the cleanliness in steel and reducing soil. It is an important element. On the other hand, Si promotes precipitation of the σ phase and causes embrittlement, and Al also combines with N in the steel to generate AlN. Therefore, the total amount of these elements is 1.0% or less, preferably 0.2 to 0.6%. However, excessive reduction leads to an increase in refining costs, and also leads to poor deoxidation, so the lower limit is preferably 0.05% or more.

P: 0.045% or less Since P is an element harmful to corrosion resistance, the smaller the better. However, in order to reduce the content rate excessively, a special smelting technique is required, leading to an increase in production cost. Therefore, P needs to be controlled to 0.045% or less.

S: 0.005% or less Since S is an element that precipitates at the grain boundaries of ferrite and austenite to deteriorate hot workability and adversely affects corrosion resistance, the lower the better. In particular, when the S content exceeds 0.005%, the influence becomes significant, so S is made 0.005% or less. Preferably, it is 0.002% or less.

Mo: 1.0% or less Mo is an element that contributes to improvement of corrosion resistance such as pitting corrosion resistance and crevice corrosion resistance, and to solid solution strengthening of the ferrite phase. On the other hand, if it exceeds 1.0%, the ductility is lowered and the toughness is deteriorated with curing, and the production cost is increased. Therefore, Mo is contained in a range of 1.0% or less. Desirably, it is 0.5% or less. In addition, although Mo exhibits an effect according to an addition amount, in order to fully obtain the effect of improving the corrosion resistance of Mo, it is preferable to contain 0.01% or more.

O: 0.01% or less O is present as an oxide in steel. Oxides are generally high in hardness and tend to cause flaws on the steel surface during polishing, so it is desirable that the oxides be small. However, the deoxidation time and the elements necessary for deoxidation greatly affect productivity and cost. Therefore, it was made 0.01% or less. Desirably, it is 0.006% or less.

The above are the basic components of the stainless steel targeted by the present invention, and the following components can be contained as necessary, comprising the balance and inevitable impurities.

Sn: 0.005 to 0.2%
Sn is an element that improves the corrosion resistance, but is also a solid solution strengthening element of the ferrite phase, and the upper limit was set to 0.2% due to a decrease in hardness difference. Since the effect of improving the corrosion resistance is exhibited from 0.005%, it was set to 0.005 to 0.2%. Desirably, it is 0.03 to 0.1% of range.

Nb: 0.01 to 0.2%, Ti: 0.01 to 0.2%
Nb and Ti are both stabilizing elements in the ferrite phase, and are effective elements for improving local corrosion resistance. However, in any case, addition of 0.01% or less has no effect. On the other hand, if it exceeds 0.2%, a large amount of precipitates are precipitated, so that the hot workability is deteriorated due to the deterioration of toughness, and the production cost is also reduced. Is disadvantageous. Accordingly, the amounts of Nb and Ti added are both 0.01 to 0.2%, preferably 0.05 to 0.12%.

B: 0.01% or less B is an element that exists at the grain boundary of the alloy with a small amount of addition and improves hot workability. However, at the same time, it is an element that deteriorates corrosion resistance such as intergranular corrosion. Therefore, the B content is set to 0.01% or less.

In addition to the alloy components described above, the stainless steel targeted by the present invention is further effective to improve oxidation resistance, 0.01 to 0.20% Y and 0.01 to 0.20% REM ( Rare earth metals excluding Y), 0.005 to 0.20% V effective in improving oxidation resistance, and 0.005 to 0.20% Al effective in deoxidation.
Further, other elements can be added as long as the effects of the present invention are not impaired.

In the present invention, the contents of various alloy components contained in stainless steel are regulated as described above, and the alloy components are adjusted to each other so that a multiphase structure of ferrite phase + austenite phase is obtained at room temperature. . As the multiphase structure obtained at room temperature, a structure consisting essentially of 50 to 60% by volume of a stretched ferrite phase and 40 to 50% by volume of a granular austenite phase is preferable.

Ferrite and austenite grain size difference ΔGs is 15μm
Using the steels of the components shown in Table 1 as test materials, cold-rolled products of duplex stainless steel consisting of a ferrite phase and austenite phase having various particle sizes are produced as shown in the examples described later. The particle size of austenite was measured by electron beam backscatter diffraction (EBSD). The particle size was measured by converting the particle sizes of all ferrite and austenite in the 1000-fold field of view into equivalent circle diameters. The average values of the measured ferrite and austenite particle sizes were determined, respectively, and were used as the ferrite average particle size and the austenite average particle size. The difference between the ferrite average particle size and the austenite average particle size was defined as ΔGs of the field of view. This was performed for five arbitrary visual fields, and the average value of ΔGs of the five visual fields was defined as ΔGs of the steel sheet. Next, the surface roughness Rz and the glossiness Gs60 before and after performing one pass of # 400 buffing were measured, and the relationship between the particle size difference and the surface roughness was compared. As shown in FIG. 1, when the particle size difference ΔGs between ferrite and austenite (ferrite particle size−austenite particle size) is 15 μm or less, the surface roughness is stably reduced. FIG. 2 shows the relationship between the surface roughness and the glossiness. The lower the surface roughness, the better the glossiness. 1 and 2, the glossiness is 350 or more when the particle size difference is within 15 μm.

The phenomenon that the surface roughness after polishing is stably reduced due to such a particle size difference is considered as follows. It is presumed that the factor that hinders the reduction in the surface roughness when polishing a cold-rolled product is the ground caused by the grain boundary erosion grooves and the inclusions that are present due to the pickling treatment. This grain boundary erosion groove is a phenomenon in which grain boundaries are selectively dissolved, and generally occurs in the austenite phase. About 50% of the austenite phase is present on the product surface of the steel of the present invention, and the surface roughness after polishing is improved by reducing the grain boundary erosion grooves in this portion. However, it is impossible to control only the austenite grain size.

Therefore, it is important to control the particle size difference between ferrite and austenite. In order to reduce the grain boundary erosion grooves of austenite, it is desirable that the austenite grain size is 8 μm or less, but at the same time, ferrite grains grow. Since the ferrite phase of the steel according to the present invention is softer than the austenite phase, if coarse grains are present, the ground tends to be generated. In order to achieve both of these, it is necessary to make the particle size difference within 15 μm.

Next, the manufacturing method for obtaining the duplex stainless steel sheet of this invention is demonstrated.
The steel slab adjusted to the above component content is hot-rolled, then hot-rolled sheet annealed and pickled, then cold-rolled, and finally annealed and pickled. However, in order to obtain a duplex stainless steel having a particle size difference of 15 μm or less, cold rolling and final annealing are performed as follows.

Cold rolling rate: 80% or more, plate temperature after final pass 80 ° C or more When manufacturing cold-rolled steel strip, the cold rolling rate (rolling rate in cold rolling) is 80% or more in order to reduce the crystal grain size difference. It is necessary to. This is because the coarse ferrite texture is pulverized by cold rolling to obtain fine recrystallized grains. If the cold rolling rate is less than 80%, coarse ferrite grains can be confirmed, so the cold rolling rate is set to 80% or more.

In addition, the introduction of strain at the time of cold rolling becomes a nucleus for formation of recrystallized grains. However, in high-strength steel such as the present invention, if work hardening progresses, a great load is generated in the cold rolling process. Therefore, the load is reduced by increasing the plate temperature during cold rolling. This effect is useful not only in increasing the cold rolling process load but also in the control of the crystal grain size because it does not increase the number of recrystallization nuclei. It is necessary to control the plate temperature after the pass to 80 ° C. or higher. The upper limit of the plate temperature is about 300 ° C. The plate temperature after the final pass can be controlled by changing the rolling rate and rolling speed per pass.

Final annealing: 1000-1100 ° C
A finishing heat treatment is applied to heat in a temperature range of 1000 to 1100 ° C. The temperature range of 1000 to 1100 ° C. has been found as a result of various investigations and studies by the present inventors on the grain growth behavior of crystal grains, and the ferrite and austenite crystal grains necessary for improving the abrasiveness are found. This is an important requirement for controlling the difference in diameter and hardness. At a heating temperature that does not reach 1000 ° C., the recrystallization of austenite cannot be sufficiently completed, and a part of austenite remains as recovery expanded grains. Since the grain boundary erosion groove of coarse grains becomes deep, the surface roughness after polishing finish is deteriorated. On the other hand, when heated to a high temperature exceeding 1100 ° C., the material softens and the ferrite becomes coarser, so that the crystal grain size difference and the hardness difference increase, resulting in a decrease in scratch resistance and a deterioration in surface roughness. Inviting, it leads to a significant decrease in polishability.

Cooling rate: 25 ° C / s or more (up to 500 ° C)
After being heated to a temperature range of 1000 to 1100 ° C. and then slowly cooled, the grain boundary N increases as the N solubility limit of the ferrite phase decreases, and Cr nitride precipitates. This Cr nitride causes grain boundary erosion grooves in the subsequent descaling process and degrades the polishing properties. Therefore, the cooling rate was set to 25 ° C./s. Moreover, since precipitation of Cr nitride was suppressed at 500 degrees C or less, it was set to 500 degrees C.

By this finishing heat treatment, a fine mixed structure composed of about 50 to 60% by volume of ferrite phase and about 40 to 50% by volume of austenite phase is obtained, and a material having a ferrite and austenite grain size difference ΔGs of 15 μm or less is obtained.

Finished heat-treated stainless steel is subjected to rough polishing finish, intermediate finish polishing, and final mirror polishing finish, resulting in a product with a mirror finish. Since the product thus obtained is not damaged by impact like a glass mirror, troubles such as injury due to damage are prevented. Further, since the surface hardness is high, surface wrinkles that tend to occur during cleaning and handling are reduced. Therefore, transportation related to automobiles, two-wheeled vehicles, various vehicles, etc., aircraft-related, housing, buildings, stores, roads and other construction / civil engineering-related, optics, medical and other chemical equipment-related, machinery, electricity, electronics, etc. The material is suitable for a wide range of fields such as equipment, general household appliances, kitchen appliances, cooking utensils, and office appliances.

A hot-rolled steel strip having a thickness of 6.0 mm is obtained by hot-rolling a stainless steel made of steel A satisfying the component range of the present invention shown in Table 1 and steel B not satisfying the component range of the present invention. I made it. Subsequently, the hot-rolled steel strip was subjected to hot-rolled sheet annealing at 980 ° C. for 60 minutes, and the sheet thickness was changed so that various cold rolling rates were obtained, and cold rolling was performed. The obtained cold-rolled steel sheet was introduced into an annealing furnace and subjected to heat treatment at a temperature shown in Table 2 as a finish heat treatment to produce a stainless steel strip having a multiphase structure of ferrite phase + austenite phase.

Specimens were cut out from each multiphase stainless steel strip and subjected to one pass of # 400 buffing to give a mirror finish. Since the hardness of the test piece was about HV250, the load on the polishing apparatus was small, and consumption of the grindstone could be suppressed. About each mirror-polished test piece, the surface roughness was measured according to the ten-point average roughness Rz of JIS B0601'1994, and the glossiness was measured according to the specular gloss measurement method of JIS Z8741. The results are shown in Table 2.

As is apparent from Table 2, the present invention test No. in which the component range and production conditions satisfy the present invention range. 1, 2, 5, 6, 8, 9, 12, 16, 17, 19, 20, 22, 23, 24, 25, 26, the grain size difference between the ferrite phase and the austenite phase is within 15 μm, and after polishing, The glossiness Gs60 was as good as 350 or more. On the other hand, the comparative example test No. of steel B whose component range deviates from the range of the present invention. In Nos. 1 to 15, the difference in particle size between the ferrite phase and the austenite phase exceeded 15 μm even when the production conditions were satisfied, and the glossiness after polishing was also inferior.

On the other hand, even when steel A whose component satisfies the scope of the invention is used, if the manufacturing method deviates from the present invention, the glossiness after polishing may be inferior. Steel A Comparative Example Test No. In Nos. 3, 14, and 27, the plate temperature after the final pass was low and the difference in particle size was large. As a result, the surface roughness after polishing was rough and the glossiness was low. Steel A Comparative Example Test No. In No. 4, the cooling rate after annealing was slow, and the grain boundary of the γ phase formed grain boundary erosion grooves after pickling, so the surface roughness after polishing was rough and the glossiness was low. Steel A Comparative Example Test No. Nos. 7 and 21 have a low cold rolling rate and a high annealing temperature. Nos. 10 and 28 have a low cold rolling rate. In No. 15, since the annealing temperature was high, the coarsening of the α phase was remarkable, the particle size difference exceeded the range of the present invention, and the glossiness after polishing was not improved. Steel A Comparative Example Test No. In No. 13, the annealing temperature was low, the recrystallization of the γ phase was insufficient, and the expanded grains remained, so that the grain boundary erosion grooves were deep and the surface roughness after polishing was deteriorated. Steel A Comparative Example Test No. In Nos. 11 and 18, the heat treatment conditions after the cold rolling rate and the final pass exceed the range of the invention, and the cooling rate is slow and the grain boundary erosion grooves become prominent. Later gloss was poor.

As described above, the multiphase stainless steel sheet of the present invention has a mixed structure of ferrite phase + austenite phase, and thus has a high hardness that does not impair the fine grain size and the abrasiveness, and has a surface roughness. Used as various mirror surface products that are difficult to attach. In addition, the mirror-finished multiphase stainless steel sheet has a high glossiness and cannot be used on an austenitic stainless steel sheet represented by SUS304 and a ferritic stainless steel sheet represented by SUS430 because surface flaws are likely to occur. It can also be used as a mirror material in other fields.

Using the stainless steel of the present invention, transportation related to automobiles, motorcycles, various vehicles, etc., aircraft related, construction, civil engineering related to houses, buildings, stores, road incidental facilities, etc., chemical equipment related such as optics and medical, machinery In addition, it is possible to prevent troubles such as injuries caused by damage to mirror materials such as various appliances such as electricity and electronics, general household appliances, kitchen appliances, cooking appliances, and office appliances, and to reduce clean surface defects. The industrial effect of the present invention is extremely remarkable.

Claims (8)

In mass%, C: 0.03% or less, Cr: 19.0 to 22.0%, N: 0.06 to 0.20%, Ni, Mn, Cu: 1 type or 2 types or more in total 5 0.0 to 7.5%, Si, Al: 1 type or 2 types in total, 1.0% or less, P: 0.045% or less, Mo: 1.0% or less, S: 0.005% or less, O: 0.01% or less, with the balance being Fe and inevitable impurities, having a multiphase structure of ferrite phase and austenite phase, and having a particle size difference ΔGs between ferrite and austenite of 15 μm or less Ferritic / austenitic duplex stainless steel sheet with excellent polishing characteristics. Further, the composition is, by mass%, Sn: 0.005 to 0.2%, Nb: 0.01 to 0.2%, Ti: 0.01 to 0.2%, B: 0.01% or less The ferritic / austenitic duplex stainless steel sheet with excellent abrasiveness according to claim 1, comprising one or more of the following. Further, the composition is, in mass%, Y: 0.01 to 0.20%, REM: 0.01 to 0.20%, V: 0.005 to 0.20%, Al: 0.005 to 0 The ferritic / austenitic duplex stainless steel sheet with excellent abrasiveness according to claim 1 or 2, characterized in that it contains 20% or more. 4. The ferritic / austenitic duplex stainless steel sheet with excellent abrasiveness according to claim 1, which is used for mirror materials. The ferritic / austenitic duplex stainless steel sheet excellent in abrasiveness according to any one of claims 1 to 3, which is used for exterior materials. The ferritic / austenitic duplex stainless steel sheet having excellent abrasiveness according to any one of claims 1 to 3, which is used for kitchen equipment. The ferritic / austenitic duplex stainless steel sheet having excellent abrasiveness according to any one of claims 1 to 3, which is used for cooking utensils. The steel slab having the composition according to any one of claims 1 to 3 is hot-rolled, then hot-rolled sheet annealed and pickled, and then the sheet temperature after the final pass at a rolling rate of 80% or more. The cold-rolling is performed at a temperature of 1000 to 1100 ° C after the cold rolling at 80 ° C or higher, and then the pickling treatment is performed at a cooling rate of 500 ° C or higher at 25 ° C / s or higher. The manufacturing method of the ferrite austenitic duplex stainless steel plate excellent in the polishability of any one of Claims 1.

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