WO2016051437A1 - Ferritic stainless steel and method for producing same - Google Patents
Ferritic stainless steel and method for producing same Download PDFInfo
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- WO2016051437A1 WO2016051437A1 PCT/JP2014/005038 JP2014005038W WO2016051437A1 WO 2016051437 A1 WO2016051437 A1 WO 2016051437A1 JP 2014005038 W JP2014005038 W JP 2014005038W WO 2016051437 A1 WO2016051437 A1 WO 2016051437A1
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Definitions
- the present invention relates to a ferritic stainless steel having sufficient corrosion resistance and excellent formability and ridging resistance and a method for producing the same.
- ferritic stainless steel Since ferritic stainless steel is inexpensive and has excellent corrosion resistance, it is used in various applications such as building materials, transportation equipment, home appliances, kitchen equipment, and automobile parts, and its application range has been further expanded in recent years. In order to be applied to these applications, not only corrosion resistance but also sufficient formability (high elongation and average Rankford value (hereinafter sometimes referred to as average r value)) that can be processed into a predetermined shape is required. .
- ferritic stainless steel is often applied to applications that require a good appearance, and is also required to have excellent ridging resistance. Ridging is surface irregularities that occur due to molding distortion. Ferritic stainless steel may produce a group of crystal grains (colonies) with similar crystal orientations during casting and / or hot rolling, and in steel sheets with colonies remaining, the amount of strain at the colony and other parts during forming Since a large difference occurs in the surface, surface irregularities (ridging) occur after molding. When excessive ridging occurs after molding, there is a problem that a polishing step is required to remove surface irregularities, and the manufacturing cost of the molded product increases.
- Patent Document 1 in mass%, C: 0.02 to 0.06%, Si: 1.0% or less, Mn: 1.0% or less, P: 0.05% or less, S: 0.01% or less, Al: 0.005% or less , Ti: 0.005% or less, Cr: 11-30%, Ni: 0.7% or less, and 0.06 ⁇ (C + N) ⁇ 0.12, 1 ⁇ N / C and 1.5 ⁇ 10 ⁇ 3 ⁇ (V ⁇ N) ⁇ 1.5
- a ferritic stainless steel excellent in formability and ridging resistance characterized by satisfying ⁇ 10 ⁇ 2 (C, N, and V each represents mass% of each element) is disclosed.
- Patent Document 1 it is necessary to perform so-called box annealing (for example, annealing at 860 ° C. for 8 hours) after hot rolling. Such box annealing takes about one week when heating and cooling processes are included, and productivity is low.
- box annealing for example, annealing at 860 ° C. for 8 hours
- Patent Document 2 C: 0.01 to 0.10%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, Ni: 0.01 to 0.50%, Cr: 10 to 20%, Mo: 0.005 to 0.50%, Cu: 0.01 to 0.50%, V: 0.001 to 0.50%, Ti: 0.001 to 0.50%, Al: 0.01 to 0.20%, Nb: 0.001 to 0.50%, N: 0.005 to 0.050%, and B: 0.00010 to 0.00500 % Hot-rolled steel, hot-rolled sheet annealing in the ferrite single-phase temperature range using a box furnace or AP line (annealing and pickling line) continuous furnace, followed by cold rolling and finish annealing A ferritic stainless steel excellent in workability and surface properties characterized by being performed is disclosed.
- AP line annealing and pickling line
- Patent Document 1 when a box furnace is used, there is a problem that productivity is low as in Patent Document 1 described above.
- elongation when hot-rolled sheet annealing is performed in a ferrite single-phase temperature range using a continuous annealing furnace, recrystallization becomes insufficient due to the low annealing temperature, and the ferrite single-phase temperature is low. The elongation decreases compared to the case where box annealing is performed in the region.
- ferritic stainless steel as in Patent Document 2 generates a group of crystal grains (colonies) having a similar crystal orientation during casting and / or hot rolling. If done, the ferrite phase colonies cannot be destroyed sufficiently. Therefore, there is a problem that the colony expands and remains in the rolling direction by cold rolling after hot-rolled sheet annealing, and ridging occurs after forming.
- Japanese Patent No. 3588281 Japanese Patent Publication No. 2000-60134
- Japanese Patent No. 3582001 Japanese Patent No. 3582001 (JP 2001-3143)
- An object of the present invention is to solve such problems, and to provide a ferritic stainless steel having sufficient corrosion resistance, excellent formability and ridging resistance, and a method for producing the same.
- sufficient corrosion resistance refers to a salt spray cycle test ((salt spray (35)) on a steel plate whose surface is polished with # 600 emery paper and then the end face is sealed. °C, 5% NaCl, spray 2h) ⁇ drying (60 ° C, relative humidity 40%, 4h) ⁇ wet (50 ° C, relative humidity
- Excellent formability means that the elongation at break (El) in a tensile test in accordance with JIS Z2241 is 28% or more in a specimen perpendicular to the rolling direction, and a strain of 15% in a tensile test in accordance with JIS Z2241.
- r L is an r value when a tensile test is performed in a direction parallel to the rolling direction
- r D is an r value when a tensile test is performed in a direction of 45 ° with respect to the rolling direction
- r C is a direction perpendicular to the rolling direction. The r value when a tensile test is performed.
- excellent ridging resistance means that the ridging height measured by the method described below is 2.5 ⁇ m or less.
- a JIS No. 5 tensile test piece is taken in parallel with the rolling direction.
- the surface of the collected specimen is polished with # 600 emery paper, and then 20% tensile strain is applied.
- the arithmetic average waviness (Wa) defined by JIS B 0601 (2001) is measured with a surface roughness meter in the direction perpendicular to the rolling direction on the polished surface at the center of the parallel part of the test piece.
- the measurement conditions are a measurement length of 16 mm, a high cut filter wavelength of 0.8 mm, and a low cut filter wavelength of 8 mm. This arithmetic mean swell is defined as the ridging height.
- hot rolled sheet annealing was performed in a temperature range in which the ferrite phase and the austenite phase are two phases before hot rolling and cold rolling on ferritic stainless steel having an appropriate component.
- cold-rolled sheet annealing at a higher temperature than in the conventional single-phase temperature range, a ferritic stainless steel with sufficient corrosion resistance and excellent formability and ridging resistance can be obtained. I found.
- a ferritic stainless steel having sufficient corrosion resistance and excellent formability and ridging resistance can be obtained.
- the ferritic stainless steel of the present invention is used for various applications such as building material parts, home appliance parts, kitchen appliances, and automobile parts by press working. In order to be applied to these applications, sufficient formability (elongation and average r value are large) is required.
- the elongation characteristics are insufficient, it cannot be molded due to necking or breakage in the direction of the worst elongation during molding.
- the appearance of the product may be deteriorated due to the fact that the thickness of the overhang portion after forming varies greatly depending on the direction of the steel plate before forming.
- large pans manufactured by drawing or the like are necked or broken when the average r value is low, and cannot be formed into a predetermined product shape.
- the plate thickness of the body of the pan varies greatly depending on the location, which may cause problems in heat transfer characteristics. Thus, it is desired that the elongation and the average r value are large.
- SUS430LX (16mass% Cr-0.15mass% Ti or 16mass% Cr-0.4mass% Nb), SUS436L (18mass% Cr-1.0mass% Mo-0.25) specified in Japanese Industrial Standard JIS G4305 mass% Ti) contains a large amount of Ti and Nb, has a high El and average r value, has excellent formability, and is used in many applications.
- SUS436L (18mass% Cr-1.0mass% Mo-0.25) specified in Japanese Industrial Standard JIS G4305 mass% Ti
- SUS430 (16 mass% Cr), which is most produced among ferritic stainless steels, is less expensive than SUS430LX and SUS436L because it does not contain a large amount of Ti or Nb, but its formability is SUS430LX or SUS436L. Inferior. Therefore, SUS430 having improved formability has been demanded.
- ferritic stainless steel generates surface irregularities called ridging on the surface of the steel sheet due to forming strain, so a product that requires surface aesthetics requires a polishing step to remove the surface irregularities, There is a problem that the manufacturing cost increases.
- the colonies that cause ridging contain Ti and Nb, and steels with less solid solution carbon are more likely to form. Therefore, the above SUS430LX and SUS436L have poor ridging resistance properties compared to SUS430.
- the inventors have El ⁇ 28%, an average r value ⁇ 0.70, and a ridging height of an appropriate component of ferritic stainless steel (particularly SUS430 (16 mass% Cr)) that does not contain a large amount of Ti or Nb.
- the method of obtaining ferritic stainless steel satisfying 2.5 ⁇ m or less was studied intensively.
- box annealing batch annealing
- continuous annealing as methods for annealing (hereinafter referred to as hot rolled sheet annealing) before cold rolling the ferritic stainless steel sheet after hot rolling.
- box annealing batch annealing
- continuous annealing as methods for annealing
- the problem with the prior art using a continuous annealing furnace is that annealing is performed in a temperature range in which the metal structure becomes a single phase of ferrite, so that sufficient recrystallization does not occur, sufficient elongation cannot be obtained, The ridging resistance was not obtained because it remained even after finish annealing. Therefore, the inventors performed hot rolling sheet annealing in the two-phase region of the ferrite phase and austenite phase, then cold-rolled by a conventional method, and further performed finish annealing (cold rolling sheet annealing) at a higher temperature than conventional, We finally devised a ferrite single-phase structure again. Specifically, it is as follows.
- the austenite phase is the ferrite before annealing. It has a crystal orientation different from that of the phase.
- the metal structure after hot-rolled sheet annealing becomes a martensite phase generated during cooling due to transformation from the ferrite phase and austenite phase, and then at the heterogeneous interface between the soft ferrite phase and the hard martensite phase during cold rolling. Rolling strain is introduced more concentratedly and becomes a recrystallization site during cold-rolled sheet annealing.
- the ferrite phase colonies are effectively destroyed and the ridging resistance is improved.
- the martensite phase is decomposed into carbonitride and ferrite phases, resulting in excellent ridging resistance of 2.5 ⁇ m or less in ridging height Is obtained.
- C 0.005-0.035%
- C promotes the formation of the austenite phase and has the effect of expanding the two-phase temperature range where the ferrite phase and the austenite phase appear during hot-rolled sheet annealing. In order to acquire this effect, 0.005% or more needs to be contained. However, if the C content exceeds 0.035%, the steel sheet becomes hard and ductility decreases. Therefore, the C content is in the range of 0.005 to 0.035%. Preferably it is 0.010 to 0.030% of range. More preferably, it is in the range of 0.015 to 0.025%.
- Si 0.25 to less than 0.40% Si is an element to increase the T A point. In order to obtain this effect, a content of 0.25% or more is necessary. However, when the Si content is 0.40% or more, the steel sheet becomes hard and the rolling load during hot rolling increases, and the ductility after annealing of the cold-rolled sheet decreases, and a predetermined breaking elongation cannot be obtained. Therefore, the Si content is in the range of 0.25% to less than 0.40%. Preferably it is 0.25 to 0.35% of range. More preferably, it is in the range of 0.25 to 0.30%.
- Mn 0.05-0.35% Mn, like C, promotes the formation of an austenite phase and has the effect of expanding the two-phase temperature range in which the ferrite phase and austenite phase appear during hot-rolled sheet annealing. In order to acquire this effect, 0.05% or more needs to be contained. However, Mn amount is not obtained predetermined breaking elongation is too low T A point exceeds 0.35%. Therefore, the Mn content is in the range of 0.05 to 0.35%. Preferably it is 0.10 to 0.30% of range. More preferably, it is in the range of 0.15 to 0.25%.
- the martensite phase generated by hot-rolled sheet annealing is decomposed and removed into a ferrite phase and carbide by cold-rolled sheet annealing, and the metal structure is converted into a single ferrite phase. It is necessary to increase the grain size of the ferrite crystal grains by causing sufficient grain growth.
- the martensite phase generated by hot-rolled sheet annealing rapidly decomposes in a temperature range of about 750 ° C. or higher in the cold-rolled sheet annealing after cold rolling, and the temperature range of 800 ° C. or higher.
- ferrite crystal grains were formed by recrystallization.
- the temperature of the lower generating austenite by adjusting the steel component (T A point) by a high temperature than the conventional made it possible to more ferrite single phase region annealing at a high temperature.
- ferrite crystal grains can be sufficiently grown without generating an austenite phase.
- the temperature increase at the T A point is realized by adjusting the balance of the Si and Mn contents within a suitable range.
- Si increases the T A point with increasing and content ferrite forming element.
- Mn lowers the T A point with increasing and content austenite forming element.
- P 0.040% or less
- P is an element that promotes grain boundary fracture due to grain boundary segregation, so a lower value is desirable, and the upper limit is made 0.040%. Preferably it is 0.035% or less. More preferably, it is 0.030% or less.
- S 0.01% or less
- S is an element that exists as sulfide inclusions such as MnS and reduces ductility, corrosion resistance, and the like, and particularly when the content exceeds 0.01%, the adverse effects thereof are remarkably generated. Therefore, it is desirable that the S amount be as low as possible.
- the upper limit of the S amount is 0.01%. Preferably it is 0.007% or less. More preferably, it is 0.005% or less.
- Cr 15.5-18.0%
- Cr is an element having an effect of improving the corrosion resistance by forming a passive film on the steel sheet surface.
- the Cr content needs to be 15.5% or more.
- the Cr content is in the range of 15.5 to 18.0%.
- it is 16.0 to 17.5% of range. More preferably, it is in the range of 16.0 to 17.0%.
- Al 0.001 to 0.10%
- Al is an element that acts as a deoxidizer. In order to acquire this effect, 0.001% or more needs to be contained. However, when the Al content exceeds 0.10%, Al-based inclusions such as Al 2 O 3 increase, and the surface properties tend to deteriorate. Therefore, the Al content is set in the range of 0.001 to 0.10%. Preferably it is 0.001 to 0.05% of range. More preferably, it is in the range of 0.001 to 0.03%.
- N 0.01-0.06% N, like C and Mn, promotes the formation of the austenite phase and has the effect of expanding the two-phase temperature range in which the ferrite phase and austenite phase appear during hot-rolled sheet annealing.
- the N content needs to be 0.01% or more.
- the N content is in the range of 0.01 to 0.06%.
- it is 0.01 to 0.05% of range. More preferably, it is in the range of 0.02 to 0.04%.
- the balance is Fe and inevitable impurities.
- Cu and Ni are elements that improve corrosion resistance. In particular, it is effective to contain it when high corrosion resistance is required. Further, Cu and Ni have an effect of promoting the formation of the austenite phase and expanding the two-phase temperature range in which the ferrite phase and the austenite phase appear during hot-rolled sheet annealing. These effects become significant when the content is 0.1% or more. However, if the Cu content exceeds 0.5%, formability may be deteriorated, which is not preferable. Therefore, if Cu is contained, the content is made 0.1 to 0.5%. Preferably it is 0.2 to 0.3% of range. If the Ni content exceeds 0.6%, the moldability is lowered, which is not preferable. Therefore, when Ni is contained, the content is made 0.1 to 0.6%. Preferably it is 0.1 to 0.3% of range.
- Mo is an element that improves corrosion resistance, and it is effective to contain it particularly when high corrosion resistance is required. This effect becomes significant when the content is 0.1% or more. However, when the Mo content exceeds 0.5%, the austenite phase is not sufficiently generated during hot-rolled sheet annealing, and predetermined material characteristics cannot be obtained. Therefore, if it contains Mo, the content is made 0.1 to 0.5%. Preferably it is 0.2 to 0.3% of range.
- Co is an element that improves toughness. This effect is obtained when the content is 0.01% or more. On the other hand, if the content exceeds 0.3%, the moldability is lowered. Therefore, if Co is contained, the content is made 0.01 to 0.3%.
- V 0.01-0.10%
- Ti 0.001-0.05%
- Nb 0.001-0.05%
- Ca 0.0002-0.0020%
- Mg 0.0002-0.0050%
- B 0.0002-0.0050%
- REM Of 0.01-0.10%
- V combines with C and N in the steel to reduce solute C and solute N. This improves the average r value.
- the surface behavior is improved by controlling the precipitation behavior of carbonitrides on the hot-rolled sheet to suppress the occurrence of linear flaws caused by hot rolling and annealing.
- the V content needs to be 0.01% or more.
- the amount of V exceeds 0.10%, the workability decreases and the manufacturing cost increases. Therefore, when V is contained, the content is made 0.01 to 0.10%. Preferably it is 0.03 to 0.08% of range.
- Ti and Nb are elements with a high affinity for C and N, and precipitate as carbides or nitrides during hot rolling, reducing solid solution C and solid solution N in the matrix, and cold rolling. There is an effect of improving the workability after sheet annealing (after finish annealing). In order to obtain these effects, it is necessary to contain 0.001% or more of Ti or 0.001% or more of Nb. However, if the Ti content or Nb content exceeds 0.05%, it is not possible to obtain good surface properties due to precipitation of excess TiN and NbC.
- the range when Ti is contained, the range is 0.001 to 0.05%, and when Nb is contained, the range is 0.001 to 0.05%.
- the amount of Ti is preferably in the range of 0.003 to 0.020%.
- the amount of Nb is preferably in the range of 0.005 to 0.020%. More preferably, it is in the range of 0.010 to 0.015%.
- Ca 0.0002-0.0020%
- Ca is an effective component for preventing nozzle clogging due to crystallization of Ti-based inclusions that are likely to occur during continuous casting. In order to acquire the effect, 0.0002% or more needs to be contained. However, if the Ca content exceeds 0.0020%, CaS is generated and the corrosion resistance decreases. Therefore, when Ca is contained, the content is made 0.0002 to 0.0020%.
- the range is preferably 0.0005 to 0.0015. More preferably, it is in the range of 0.0005 to 0.0010%.
- Mg 0.0002-0.0050%
- Mg is an element that has the effect of improving hot workability. In order to acquire this effect, 0.0002% or more needs to be contained. However, when the Mg content exceeds 0.0050%, the surface quality decreases. Therefore, when Mg is contained, the content is made 0.0002 to 0.0050%. Preferably it is 0.0005 to 0.0035% of range. More preferably, it is in the range of 0.0005 to 0.0020%.
- B 0.0002-0.0050%
- B is an effective element for preventing low temperature secondary work embrittlement. In order to acquire this effect, 0.0002% or more needs to be contained. However, when the amount of B exceeds 0.0050%, the hot workability decreases. Therefore, when B is contained, the content is made 0.0002 to 0.0050%. Preferably it is 0.0005 to 0.0035% of range. More preferably, it is in the range of 0.0005 to 0.0020%.
- REM 0.01-0.10% REM is an element that improves the oxidation resistance, and in particular has the effect of suppressing the formation of an oxide film on the weld and improving the corrosion resistance of the weld. In order to obtain this effect, a content of 0.01% or more is necessary. However, if the content exceeds 0.10%, productivity such as pickling at the time of cold rolling annealing is lowered. Moreover, since REM is an expensive element, excessive inclusion causes an increase in manufacturing cost, which is not preferable. Therefore, when REM is contained, the content is made 0.01 to 0.10%.
- the ferritic stainless steel of the present invention is a steel slab having the above component composition, hot-rolled and then annealed at 900 to 1050 ° C. for 5 seconds to 15 minutes, After cold rolling, it is obtained by annealing in a temperature range of 800 to 950 ° C. for 5 seconds to 5 minutes.
- molten steel is melted by a known method such as a converter, electric furnace, vacuum melting furnace or the like, and is made into a steel material (slab) by a continuous casting method or an ingot-bundling method.
- This slab is heated at 1100 to 1250 ° C. for 1 to 24 hours, or directly hot-rolled as cast without heating to form a hot-rolled sheet.
- hot rolled sheet annealing is performed for 5 seconds to 15 minutes at a temperature of 900 to 1050 ° C., which is a two-phase region temperature of a ferrite phase and an austenite phase.
- pickling is performed as necessary, and cold rolling and cold rolled sheet annealing are performed. Furthermore, pickling is performed as necessary to obtain a product.
- Cold rolling is preferably performed at a rolling reduction of 50% or more from the viewpoints of extensibility, bendability, press formability, and shape correction.
- cold rolling and annealing may be repeated twice or more.
- grinding or polishing may be performed.
- Hot-rolled sheet annealing held at a temperature of 900 to 1050 ° C. for 5 seconds to 15 minutes Hot-rolled sheet annealing is an extremely important step for the present invention to obtain excellent formability and ridging resistance. If the hot-rolled sheet annealing temperature is less than 900 ° C., sufficient recrystallization does not occur and the ferrite single-phase region is obtained, so that the effects of the present invention that are manifested by two-phase region annealing may not be obtained. However, when the annealing temperature exceeds 1050 ° C, solid solution of carbide is promoted, so C concentration in the austenite phase is promoted, and a hard martensite phase is generated after hot-rolled sheet annealing, resulting in poor surface properties.
- hot-rolled sheet annealing is held at a temperature of 900 to 1050 ° C. for 5 seconds to 15 minutes.
- the holding is performed at a temperature of 920 to 1020 ° C. for 15 seconds to 5 minutes. More preferably, the temperature is maintained at 920 to 1000 ° C. for 30 seconds to 3 minutes.
- Cold-rolled sheet annealing which is held at a temperature of 800-950 ° C for 5 seconds to 5 minutes.
- Cold-rolled sheet annealing is important for making the two-phase structure of the ferrite phase and martensite phase formed by hot-rolled sheet annealing into a single-phase structure. It is a difficult process.
- the cold-rolled sheet annealing temperature is less than 800 ° C., sufficient recrystallization does not occur and a predetermined elongation at break and average r value cannot be obtained.
- the cold-rolled sheet annealing temperature exceeds 950 ° C
- the steel component becomes hard because the martensite phase is formed after the cold-rolled sheet annealing in the steel component in which the temperature is a two-phase temperature range of the ferrite phase and the austenite phase. A predetermined elongation at break cannot be obtained.
- the temperature is a steel component in the ferrite single-phase temperature range
- the glossiness of the steel sheet is lowered due to marked coarsening of crystal grains, which is not preferable from the viewpoint of surface quality.
- the annealing time is less than 5 seconds, even if annealing is performed at a predetermined temperature, the ferrite phase is not sufficiently recrystallized, so that a predetermined breaking elongation and an average r value cannot be obtained. If the annealing time exceeds 5 minutes, the crystal grains become extremely coarse and the glossiness of the steel sheet is lowered, which is not preferable from the viewpoint of surface quality. Therefore, cold-rolled sheet annealing is held at 800 to 950 ° C for 5 seconds to 5 minutes. The holding is preferably performed at 850 ° C. to 900 ° C. for 15 seconds to 3 minutes. In order to obtain more gloss, BA annealing (bright annealing) may be performed.
- Stainless steel having the chemical composition shown in Table 1 was melted in a 50 kg small vacuum melting furnace. These steel ingots were heated at 1150 ° C. for 1 h and then hot rolled to form 3.5 mm thick hot rolled sheets. Subsequently, these hot-rolled sheets were subjected to hot-rolled sheet annealing under the conditions described in Table 2. Next, the surface was descaled by shot blasting and pickling. Furthermore, after cold rolling to a sheet thickness of 0.7 mm, after performing cold-rolled sheet annealing (finish annealing) under the conditions shown in Table 2, descaling by pickling is performed to obtain a cold-rolled pickled and annealed sheet It was.
- the cold roll pickling annealed plate thus obtained was evaluated as follows.
- the salt spray cycle test consists of 1 cycle of salt spray (5 mass% NaCl, 35 ° C, spray 2h) ⁇ dry (60 ° C, 4h, relative humidity 40%) ⁇ wet (50 ° C, 2h, relative humidity ⁇ 95%) As a result, 8 cycles were performed.
- FIG. 1 shows a graph in which ductility evaluation results are arranged by Si and Mn contents for Nos. 1 to 25 where the Cr content satisfies the scope of the present invention.
- Nos. 1-17 (steel AA-AQ) whose steel components satisfy the scope of the present invention have excellent formability and ridging resistance such as breaking elongation of 28% or more, average r value of 0.70 or more, and ridging height of 2.5 ⁇ m or less. The characteristics were confirmed. Furthermore, regarding corrosion resistance, the rusting rate on the surface of the test piece after 8 cycles of the salt spray cycle test is 25% or less, and good characteristics are obtained.
- the Si and Mn contents are within the scope of the present invention, but No. 20 to 23 (steel BC to BF) in which 29.5 ⁇ Si-50 ⁇ Mn + 6 falls below the scope of the present invention has a balance of Si and Mn contents. Since it was not appropriate, an austenite phase was generated during the cold-rolled sheet annealing, and this austenite phase was transformed into a martensite phase after cooling, so that the steel sheet was hardened and a predetermined breaking elongation could not be obtained.
- FIG. 1 is a graph in which ductility evaluation results are arranged by Si and Mn contents for Nos. 1 to 25 in which the Cr content satisfies the scope of the present invention. It can be seen that the predetermined elongation at break is obtained when 29.5 ⁇ Si ⁇ 50 ⁇ Mn + 6 satisfies the scope of the present invention in addition to the Si and Mn contents.
- the ferritic stainless steel obtained in the present invention is particularly suitable for press-molded products mainly composed of a drawing and applications requiring high surface beauty, such as kitchen utensils and tableware.
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Abstract
Description
平均r値=(rL+2×rD+rC)/4 (1)
ここで、rLは圧延方向に平行な方向に引張試験した際のr値、rDは圧延方向に対して45°の方向に引張試験した際のr値、rCは圧延方向と直角方向に引張試験した際のr値である。 Excellent formability means that the elongation at break (El) in a tensile test in accordance with JIS Z2241 is 28% or more in a specimen perpendicular to the rolling direction, and a strain of 15% in a tensile test in accordance with JIS Z2241. Means that the average Rankford value (hereinafter referred to as the average r value) calculated by the following equation (1) is 0.70 or more.
Average r value = (r L + 2 × r D + r C ) / 4 (1)
Here, r L is an r value when a tensile test is performed in a direction parallel to the rolling direction, r D is an r value when a tensile test is performed in a direction of 45 ° with respect to the rolling direction, and r C is a direction perpendicular to the rolling direction. The r value when a tensile test is performed.
[1]質量%で、C:0.005~0.035%、Si:0.25~0.40未満%、Mn: 0.05~0.35%、P: 0.040%以下、S: 0.01%以下、Cr: 15.5~18.0%、Al: 0.001~0.10%、N: 0.01~0.06%を含有し、SiおよびMnが29.5×Si-50×Mn+6≧0(ただし、式中のSi、Mnは含有量(質量%)を示す)を満たし、残部がFeおよび不可避的不純物からなることを特徴とするフェライト系ステンレス鋼。
[2]質量%で、さらに、Cu:0.1~0.5%、Ni: 0.1~0.6%、Mo: 0.1~0.5%、Co: 0.01~0.3%のうちから選ばれる1種または2種以上を含むことを特徴とする上記[1]に記載のフェライト系ステンレス鋼。
[3]質量%で、さらに、V: 0.01~0.10%、Ti: 0.001~0.05%、Nb: 0.001~0.05%、Ca: 0.0002~0.0020%、Mg: 0.0002~0.0050%、B: 0.0002~0.0050%、REM: 0.01~0.10%のうちから選ばれる1種または2種以上を含むことを特徴とする上記[1]または[2]に記載のフェライト系ステンレス鋼。
[4]圧延方向と直角方向の破断伸びが28%以上、平均ランクフォード値が0.70以上、リジング高さが2.5μm以下であることを特徴とする上記[1]~[3]のいずれかに記載のフェライト系ステンレス鋼。
[5]上記[1]から[4]のいずれかに記載のフェライト系ステンレス鋼の製造方法であって、鋼スラブに対して、熱間圧延を施した後、900~1050℃の温度範囲で5秒~15分間保持する焼鈍を行い、次いで、冷間圧延を施した後、800~950℃の温度範囲で5秒~5分間保持する焼鈍を行うことを特徴とするフェライト系ステンレス鋼の製造方法。
なお、本明細書において、鋼の成分を示す%はすべて質量%である。 This invention is made | formed based on the above knowledge, and makes the following a summary.
[1] By mass%, C: 0.005 to 0.035%, Si: 0.25 to less than 0.40%, Mn: 0.05 to 0.35%, P: 0.040% or less, S: 0.01% or less, Cr: 15.5 to 18.0%, Al: Contains 0.001 to 0.10%, N: 0.01 to 0.06%, and Si and Mn are 29.5 × Si-50 × Mn + 6 ≧ 0 (where Si and Mn indicate the content (% by mass)) Ferritic stainless steel characterized by being filled with the balance being Fe and inevitable impurities.
[2] By mass%, further containing one or more selected from Cu: 0.1 to 0.5%, Ni: 0.1 to 0.6%, Mo: 0.1 to 0.5%, Co: 0.01 to 0.3% The ferritic stainless steel as described in [1] above.
[3] By mass%, V: 0.01 to 0.10%, Ti: 0.001 to 0.05%, Nb: 0.001 to 0.05%, Ca: 0.0002 to 0.0020%, Mg: 0.0002 to 0.0050%, B: 0.0002 to 0.0050% REM: The ferritic stainless steel according to the above [1] or [2], comprising one or more selected from 0.01 to 0.10%.
[4] Any one of the above [1] to [3], wherein the elongation at break in the direction perpendicular to the rolling direction is 28% or more, the average Rankford value is 0.70 or more, and the ridging height is 2.5 μm or less. The ferritic stainless steel described.
[5] A method for producing a ferritic stainless steel according to any one of [1] to [4] above, wherein the steel slab is hot-rolled and then subjected to a temperature range of 900 to 1050 ° C. Manufacture of ferritic stainless steel characterized by annealing for 5 seconds to 15 minutes, followed by cold rolling, followed by annealing for 5 seconds to 5 minutes in the temperature range of 800 to 950 ° C Method.
In the present specification, “%” indicating the component of steel is “% by mass”.
以下、特に断らない限り%は質量%を意味する。 Next, the component composition of the ferritic stainless steel of the present invention will be described.
Hereinafter, unless otherwise specified,% means mass%.
Cはオーステナイト相の生成を促進し、熱延板焼鈍時にフェライト相とオーステナイト相が出現する二相温度域を拡大する効果がある。この効果を得るためには0.005%以上の含有が必要である。しかし、C量が0.035%を超えると鋼板が硬質化して延性が低下する。そのため、C量は0.005~0.035%の範囲とする。好ましくは0.010~0.030%の範囲である。さらに好ましくは0.015~0.025%の範囲である。 C: 0.005-0.035%
C promotes the formation of the austenite phase and has the effect of expanding the two-phase temperature range where the ferrite phase and the austenite phase appear during hot-rolled sheet annealing. In order to acquire this effect, 0.005% or more needs to be contained. However, if the C content exceeds 0.035%, the steel sheet becomes hard and ductility decreases. Therefore, the C content is in the range of 0.005 to 0.035%. Preferably it is 0.010 to 0.030% of range. More preferably, it is in the range of 0.015 to 0.025%.
SiはTA点を上げる元素である。この効果を得るためには0.25%以上の含有が必要である。しかし、Si量が0.40%以上になると、鋼板が硬質化して熱間圧延時の圧延負荷が増大するとともに、冷延板焼鈍後の延性が低下し、所定の破断伸びが得られない。そのため、Si量は0.25%以上0.40%未満の範囲とする。好ましくは0.25~0.35%の範囲である。さらに好ましくは0.25~0.30%の範囲である。 Si: 0.25 to less than 0.40%
Si is an element to increase the T A point. In order to obtain this effect, a content of 0.25% or more is necessary. However, when the Si content is 0.40% or more, the steel sheet becomes hard and the rolling load during hot rolling increases, and the ductility after annealing of the cold-rolled sheet decreases, and a predetermined breaking elongation cannot be obtained. Therefore, the Si content is in the range of 0.25% to less than 0.40%. Preferably it is 0.25 to 0.35% of range. More preferably, it is in the range of 0.25 to 0.30%.
MnはCと同様にオーステナイト相の生成を促進し、熱延板焼鈍時にフェライト相とオーステナイト相が出現する二相温度域を拡大する効果がある。この効果を得るためには0.05%以上の含有が必要である。しかし、Mn量が0.35%を超えるとTA点が下がりすぎて所定の破断伸びが得られない。そのため、Mn量は0.05~0.35%の範囲とする。好ましくは0.10~0.30%の範囲である。さらに好ましくは0.15~0.25%の範囲である。 Mn: 0.05-0.35%
Mn, like C, promotes the formation of an austenite phase and has the effect of expanding the two-phase temperature range in which the ferrite phase and austenite phase appear during hot-rolled sheet annealing. In order to acquire this effect, 0.05% or more needs to be contained. However, Mn amount is not obtained predetermined breaking elongation is too low T A point exceeds 0.35%. Therefore, the Mn content is in the range of 0.05 to 0.35%. Preferably it is 0.10 to 0.30% of range. More preferably, it is in the range of 0.15 to 0.25%.
本発明では、オーステナイトが生成する下限の温度(TA点)の調整が極めて重要な要素となる。前述したように、本発明では熱延板焼鈍をフェライト相+オーステナイト相の二相温度域で行い熱延板焼鈍後の組織をフェライト相+マルテンサイト相の二相組織とするが、冷間圧延後に実施する冷延板焼鈍をフェライト単相温度域で行い、最終的な組織はフェライト単相とすることを大きな特徴としている。この方法で優れた破断伸びを得るためには、熱延板焼鈍によって生成したマルテンサイト相を冷延板焼鈍によってフェライト相と炭化物へと分解させて除去し、金属組織をフェライト単相化するとともに、十分な粒成長を生じさせてフェライト結晶粒の粒径を大きくする必要がある。発明者らが検討したところ、熱延板焼鈍によって生成したマルテンサイト相は冷間圧延後の冷延板焼鈍において約750℃以上の温度域で急速に分解が進むとともに、800℃以上の温度域で再結晶によりフェライト結晶粒が生成した。 29.5 × Si-50 × Mn + 6 ≧ 0 (However, Si and Mn in the formula indicate the content (% by mass))
In the present invention, adjustment of the temperature of the lower limit austenite generated (T A point) becomes an extremely important element. As described above, in the present invention, hot-rolled sheet annealing is performed in a two-phase temperature range of ferrite phase + austenite phase, and the structure after hot-rolled sheet annealing is a two-phase structure of ferrite phase + martensite phase. A great feature is that the cold-rolled sheet annealing to be performed later is performed in the ferrite single-phase temperature range, and the final structure is a ferrite single-phase. In order to obtain an excellent elongation at break by this method, the martensite phase generated by hot-rolled sheet annealing is decomposed and removed into a ferrite phase and carbide by cold-rolled sheet annealing, and the metal structure is converted into a single ferrite phase. It is necessary to increase the grain size of the ferrite crystal grains by causing sufficient grain growth. As a result of investigations by the inventors, the martensite phase generated by hot-rolled sheet annealing rapidly decomposes in a temperature range of about 750 ° C. or higher in the cold-rolled sheet annealing after cold rolling, and the temperature range of 800 ° C. or higher. Thus, ferrite crystal grains were formed by recrystallization.
Pは粒界偏析による粒界破壊を助長する元素であるため低い方が望ましく、上限を0.040%とする。好ましくは0.035%以下である。さらに好ましくは0.030%以下である。 P: 0.040% or less
P is an element that promotes grain boundary fracture due to grain boundary segregation, so a lower value is desirable, and the upper limit is made 0.040%. Preferably it is 0.035% or less. More preferably, it is 0.030% or less.
SはMnSなどの硫化物系介在物となって存在して延性や耐食性等を低下させる元素であり、特に含有量が0.01%を超えた場合にそれらの悪影響が顕著に生じる。そのためS量は極力低い方が望ましく、本発明ではS量の上限を0.01%とする。好ましくは0.007%以下である。さらに好ましくは0.005%以下である。 S: 0.01% or less
S is an element that exists as sulfide inclusions such as MnS and reduces ductility, corrosion resistance, and the like, and particularly when the content exceeds 0.01%, the adverse effects thereof are remarkably generated. Therefore, it is desirable that the S amount be as low as possible. In the present invention, the upper limit of the S amount is 0.01%. Preferably it is 0.007% or less. More preferably, it is 0.005% or less.
Crは鋼板表面に不動態皮膜を形成して耐食性を向上させる効果を有する元素である。この効果を得るためにはCr量を15.5%以上とする必要がある。しかし、Cr量が18.0%を超えると、熱延板焼鈍時にオーステナイト相の生成が不十分となり、所定の耐リジング特性が得られない。そのため、Cr量は15.5~18.0%の範囲とする。好ましくは16.0~17.5%の範囲である。さらに好ましくは16.0~17.0%の範囲である。 Cr: 15.5-18.0%
Cr is an element having an effect of improving the corrosion resistance by forming a passive film on the steel sheet surface. In order to obtain this effect, the Cr content needs to be 15.5% or more. However, if the Cr content exceeds 18.0%, the austenite phase is not sufficiently generated during hot-rolled sheet annealing, and a predetermined ridging resistance characteristic cannot be obtained. Therefore, the Cr content is in the range of 15.5 to 18.0%. Preferably it is 16.0 to 17.5% of range. More preferably, it is in the range of 16.0 to 17.0%.
AlはSiと同様に脱酸剤として作用する元素である。この効果を得るためには0.001%以上の含有が必要である。しかし、Al量が0.10%を超えると、Al2O3等のAl系介在物が増加し、表面性状が低下しやすくなる。そのため、Al量は0.001~0.10%の範囲とする。好ましくは0.001~0.05%の範囲である。さらに好ましくは0.001~0.03%の範囲である。 Al: 0.001 to 0.10%
Al, like Si, is an element that acts as a deoxidizer. In order to acquire this effect, 0.001% or more needs to be contained. However, when the Al content exceeds 0.10%, Al-based inclusions such as Al 2 O 3 increase, and the surface properties tend to deteriorate. Therefore, the Al content is set in the range of 0.001 to 0.10%. Preferably it is 0.001 to 0.05% of range. More preferably, it is in the range of 0.001 to 0.03%.
Nは、CおよびMnと同様にオーステナイト相の生成を促進し、熱延板焼鈍時にフェライト相とオーステナイト相が出現する二相温度域を拡大する効果がある。この効果を得るためにはN量を0.01%以上とする必要がある。しかし、N量が0.06%を超えると延性が著しく低下する上、Cr窒化物の析出を助長することによる耐食性の低下が生じる。そのため、N量は0.01~0.06%の範囲とする。好ましくは0.01~0.05%の範囲である。さらに好ましくは0.02~0.04%の範囲である。 N: 0.01-0.06%
N, like C and Mn, promotes the formation of the austenite phase and has the effect of expanding the two-phase temperature range in which the ferrite phase and austenite phase appear during hot-rolled sheet annealing. In order to obtain this effect, the N content needs to be 0.01% or more. However, when the N content exceeds 0.06%, the ductility is remarkably lowered and the corrosion resistance is lowered by promoting the precipitation of Cr nitride. Therefore, the N content is in the range of 0.01 to 0.06%. Preferably it is 0.01 to 0.05% of range. More preferably, it is in the range of 0.02 to 0.04%.
CuおよびNiはいずれも耐食性を向上させる元素であり、特に高い耐食性が要求される場合には含有することが有効である。また、CuおよびNiにはオーステナイト相の生成を促進し、熱延板焼鈍時にフェライト相とオーステナイト相が出現する二相温度域を拡大する効果がある。これらの効果は各々0.1%以上の含有で顕著となる。しかし、Cu含有量が0.5%を超えると成形性が低下する場合があり好ましくない。そのためCuを含有する場合は0.1~0.5%とする。好ましくは0.2~0.3%の範囲である。Ni含有量が0.6%を超えると成形性が低下するため好ましくない。そのためNiを含有する場合は0.1~0.6%とする。好ましくは0.1~0.3%の範囲である。 One or more selected from Cu: 0.1 to 0.5%, Ni: 0.1 to 0.6%, Mo: 0.1 to 0.5%, Co: 0.01 to 0.3% Both Cu and Ni are elements that improve corrosion resistance. In particular, it is effective to contain it when high corrosion resistance is required. Further, Cu and Ni have an effect of promoting the formation of the austenite phase and expanding the two-phase temperature range in which the ferrite phase and the austenite phase appear during hot-rolled sheet annealing. These effects become significant when the content is 0.1% or more. However, if the Cu content exceeds 0.5%, formability may be deteriorated, which is not preferable. Therefore, if Cu is contained, the content is made 0.1 to 0.5%. Preferably it is 0.2 to 0.3% of range. If the Ni content exceeds 0.6%, the moldability is lowered, which is not preferable. Therefore, when Ni is contained, the content is made 0.1 to 0.6%. Preferably it is 0.1 to 0.3% of range.
V: 0.01~0.10%
Vは鋼中のCおよびNと化合して、固溶Cおよび固溶Nを低減する。これにより、平均r値を向上させる。さらに、熱延板での炭窒化物の析出挙動を制御して熱延および焼鈍起因の線状疵の発生を抑制して表面性状を改善する。これらの効果を得るためにはV量を0.01%以上含有する必要がある。しかし、V量が0.10%を超えると加工性が低下するとともに、製造コストの上昇を招く。そのため、Vを含有する場合は0.01~0.10%の範囲とする。好ましくは0.03~0.08%の範囲である。 V: 0.01-0.10%, Ti: 0.001-0.05%, Nb: 0.001-0.05%, Ca: 0.0002-0.0020%, Mg: 0.0002-0.0050%, B: 0.0002-0.0050%, REM: Of 0.01-0.10% One or more selected from V: 0.01-0.10%
V combines with C and N in the steel to reduce solute C and solute N. This improves the average r value. Furthermore, the surface behavior is improved by controlling the precipitation behavior of carbonitrides on the hot-rolled sheet to suppress the occurrence of linear flaws caused by hot rolling and annealing. In order to obtain these effects, the V content needs to be 0.01% or more. However, if the amount of V exceeds 0.10%, the workability decreases and the manufacturing cost increases. Therefore, when V is contained, the content is made 0.01 to 0.10%. Preferably it is 0.03 to 0.08% of range.
TiおよびNbはVと同様に、CおよびNとの親和力の高い元素であり、熱間圧延時に炭化物あるいは窒化物として析出し、母相中の固溶Cおよび固溶Nを低減させ、冷延板焼鈍後(仕上げ焼鈍後)の加工性を向上させる効果がある。これらの効果を得るためには、0.001%以上のTiあるいは0.001%以上のNbを含有する必要がある。しかし、Ti量あるいはNb量が0.05%を超えると、過剰なTiNおよびNbCの析出により良好な表面性状を得ることができない。そのため、Tiを含有する場合は0.001~0.05%の範囲、Nbを含有する場合は0.001~0.05%の範囲とする。Ti量は好ましくは0.003~0.020%の範囲である。Nb量は好ましくは0.005~0.020%の範囲である。さらに好ましくは0.010~0.015%の範囲である。 Ti: 0.001-0.05%, Nb: 0.001-0.05%,
Ti and Nb, like V, are elements with a high affinity for C and N, and precipitate as carbides or nitrides during hot rolling, reducing solid solution C and solid solution N in the matrix, and cold rolling. There is an effect of improving the workability after sheet annealing (after finish annealing). In order to obtain these effects, it is necessary to contain 0.001% or more of Ti or 0.001% or more of Nb. However, if the Ti content or Nb content exceeds 0.05%, it is not possible to obtain good surface properties due to precipitation of excess TiN and NbC. Therefore, when Ti is contained, the range is 0.001 to 0.05%, and when Nb is contained, the range is 0.001 to 0.05%. The amount of Ti is preferably in the range of 0.003 to 0.020%. The amount of Nb is preferably in the range of 0.005 to 0.020%. More preferably, it is in the range of 0.010 to 0.015%.
Caは、連続鋳造の際に発生しやすいTi系介在物の晶出によるノズルの閉塞を防止するのに有効な成分である。その効果を得るためには0.0002%以上の含有が必要である。しかし、Ca量が0.0020%を超えるとCaSが生成して耐食性が低下する。そのため、Caを含有する場合は0.0002~0.0020%の範囲とする。好ましくは0.0005~0.0015の範囲である。さらに好ましくは0.0005~0.0010%の範囲である。 Ca: 0.0002-0.0020%
Ca is an effective component for preventing nozzle clogging due to crystallization of Ti-based inclusions that are likely to occur during continuous casting. In order to acquire the effect, 0.0002% or more needs to be contained. However, if the Ca content exceeds 0.0020%, CaS is generated and the corrosion resistance decreases. Therefore, when Ca is contained, the content is made 0.0002 to 0.0020%. The range is preferably 0.0005 to 0.0015. More preferably, it is in the range of 0.0005 to 0.0010%.
Mgは熱間加工性を向上させる効果がある元素である。この効果を得るためには0.0002%以上の含有が必要である。しかし、Mg量が0.0050%を超えると表面品質が低下する。そのため、Mgを含有する場合は0.0002~0.0050%の範囲とする。好ましくは0.0005~0.0035%の範囲である。さらに好ましくは0.0005~0.0020%の範囲である。 Mg: 0.0002-0.0050%
Mg is an element that has the effect of improving hot workability. In order to acquire this effect, 0.0002% or more needs to be contained. However, when the Mg content exceeds 0.0050%, the surface quality decreases. Therefore, when Mg is contained, the content is made 0.0002 to 0.0050%. Preferably it is 0.0005 to 0.0035% of range. More preferably, it is in the range of 0.0005 to 0.0020%.
Bは低温二次加工脆化を防止するのに有効な元素である。この効果を得るためには0.0002%以上の含有が必要である。しかし、B量が0.0050%を超えると熱間加工性が低下する。そのため、Bを含有する場合は0.0002~0.0050%の範囲とする。好ましくは0.0005~0.0035%の範囲である。さらに好ましくは0.0005~0.0020%の範囲である。 B: 0.0002-0.0050%
B is an effective element for preventing low temperature secondary work embrittlement. In order to acquire this effect, 0.0002% or more needs to be contained. However, when the amount of B exceeds 0.0050%, the hot workability decreases. Therefore, when B is contained, the content is made 0.0002 to 0.0050%. Preferably it is 0.0005 to 0.0035% of range. More preferably, it is in the range of 0.0005 to 0.0020%.
REMは耐酸化性を向上させる元素であり、特に溶接部の酸化皮膜の形成を抑制し溶接部の耐食性を向上させる効果がある。この効果を得るためには0.01%以上の含有が必要である。しかし、0.10%を超えて含有すると冷延焼鈍時の酸洗性などの製造性を低下させる。また、REMは高価な元素であるため、過度な含有は製造コストの増加を招くため好ましくない。そのため、REMを含有する場合は0.01~0.10%の範囲とする。 REM: 0.01-0.10%
REM is an element that improves the oxidation resistance, and in particular has the effect of suppressing the formation of an oxide film on the weld and improving the corrosion resistance of the weld. In order to obtain this effect, a content of 0.01% or more is necessary. However, if the content exceeds 0.10%, productivity such as pickling at the time of cold rolling annealing is lowered. Moreover, since REM is an expensive element, excessive inclusion causes an increase in manufacturing cost, which is not preferable. Therefore, when REM is contained, the content is made 0.01 to 0.10%.
本発明のフェライト系ステンレス鋼は、上記の成分組成を有する鋼スラブに対して、熱間圧延を施した後、900~1050℃の温度範囲で5秒~15分間保持する焼鈍を行い、次いで、冷間圧延を施した後、800~950℃の温度範囲で5秒~5分間保持する焼鈍を行うことで得られる。 Next, the manufacturing method of the ferritic stainless steel of this invention is demonstrated.
The ferritic stainless steel of the present invention is a steel slab having the above component composition, hot-rolled and then annealed at 900 to 1050 ° C. for 5 seconds to 15 minutes, After cold rolling, it is obtained by annealing in a temperature range of 800 to 950 ° C. for 5 seconds to 5 minutes.
その後、フェライト相とオーステナイト相の二相域温度となる900~1050℃の温度で5秒~15分間保持する熱延板焼鈍を行う。 First, molten steel is melted by a known method such as a converter, electric furnace, vacuum melting furnace or the like, and is made into a steel material (slab) by a continuous casting method or an ingot-bundling method. This slab is heated at 1100 to 1250 ° C. for 1 to 24 hours, or directly hot-rolled as cast without heating to form a hot-rolled sheet.
Thereafter, hot rolled sheet annealing is performed for 5 seconds to 15 minutes at a temperature of 900 to 1050 ° C., which is a two-phase region temperature of a ferrite phase and an austenite phase.
熱延板焼鈍は本発明が優れた成形性および耐リジング特性を得るために極めて重要な工程である。熱延板焼鈍温度が900℃未満では十分な再結晶が生じないうえ、フェライト単相域となるため、二相域焼鈍によって発現する本発明の効果が得られない場合がある。しかし、焼鈍温度が1050℃を超えると炭化物の固溶が促進されるためにオーステナイト相中へのC濃化が助長され、熱延板焼鈍後に硬質なマルテンサイト相が生成し、表面性状が悪化する場合がある。焼鈍時間が5秒未満の場合、所定の温度で焼鈍したとしてもオーステナイト相の生成とフェライト相の再結晶が十分に生じないため、所望の成形性が得られない場合がある。一方、焼鈍時間が15分を超えるとオーステナイト相中へのC濃化が助長され、上記と同様の機構によって表面性状が悪化する場合がある。そのため、熱延板焼鈍は900~1050℃の温度で、5秒~15分間保持する。好ましくは、920~1020℃の温度で15秒~5分間保持である。さらに好ましくは920~1000℃の温度で30秒~3分間保持である。 Hot-rolled sheet annealing held at a temperature of 900 to 1050 ° C. for 5 seconds to 15 minutes Hot-rolled sheet annealing is an extremely important step for the present invention to obtain excellent formability and ridging resistance. If the hot-rolled sheet annealing temperature is less than 900 ° C., sufficient recrystallization does not occur and the ferrite single-phase region is obtained, so that the effects of the present invention that are manifested by two-phase region annealing may not be obtained. However, when the annealing temperature exceeds 1050 ° C, solid solution of carbide is promoted, so C concentration in the austenite phase is promoted, and a hard martensite phase is generated after hot-rolled sheet annealing, resulting in poor surface properties. There is a case. When the annealing time is less than 5 seconds, even if annealing is performed at a predetermined temperature, generation of austenite phase and recrystallization of the ferrite phase do not occur sufficiently, so that desired formability may not be obtained. On the other hand, if the annealing time exceeds 15 minutes, C concentration in the austenite phase is promoted, and surface properties may be deteriorated by the same mechanism as described above. Therefore, hot-rolled sheet annealing is held at a temperature of 900 to 1050 ° C. for 5 seconds to 15 minutes. Preferably, the holding is performed at a temperature of 920 to 1020 ° C. for 15 seconds to 5 minutes. More preferably, the temperature is maintained at 920 to 1000 ° C. for 30 seconds to 3 minutes.
冷延板焼鈍は熱延板焼鈍で形成したフェライト相とマルテンサイト相の二相組織をフェライト単相組織とするために重要な工程である。冷延板焼鈍温度が800℃未満では再結晶が十分に生じず所定の破断伸びおよび平均r値を得ることができない。一方、冷延板焼鈍温度が950℃を超えた場合、当該温度がフェライト相とオーステナイト相の二相温度域となる鋼成分では冷延板焼鈍後にマルテンサイト相が生成するために鋼板が硬質化し所定の破断伸びを得ることができない。また、当該温度がフェライト単相温度域となる鋼成分であったとしても、結晶粒の著しい粗大化により、鋼板の光沢度が低下するため表面品質の観点で好ましくない。焼鈍時間が5秒未満の場合、所定の温度で焼鈍したとしてもフェライト相の再結晶が十分に生じないため、所定の破断伸びおよび平均r値を得ることができない。焼鈍時間が5分を超えると、結晶粒が著しく粗大化し、鋼板の光沢度が低下するため表面品質の観点で好ましくない。そのため、冷延板焼鈍は800~950℃の範囲で5秒~5分間保持とする。好ましくは、850℃~900℃で15秒~3分間保持である。より光沢を求めるためにBA焼鈍(光輝焼鈍)を行っても良い。 Cold-rolled sheet annealing, which is held at a temperature of 800-950 ° C for 5 seconds to 5 minutes. Cold-rolled sheet annealing is important for making the two-phase structure of the ferrite phase and martensite phase formed by hot-rolled sheet annealing into a single-phase structure. It is a difficult process. When the cold-rolled sheet annealing temperature is less than 800 ° C., sufficient recrystallization does not occur and a predetermined elongation at break and average r value cannot be obtained. On the other hand, when the cold-rolled sheet annealing temperature exceeds 950 ° C, the steel component becomes hard because the martensite phase is formed after the cold-rolled sheet annealing in the steel component in which the temperature is a two-phase temperature range of the ferrite phase and the austenite phase. A predetermined elongation at break cannot be obtained. Moreover, even if the temperature is a steel component in the ferrite single-phase temperature range, the glossiness of the steel sheet is lowered due to marked coarsening of crystal grains, which is not preferable from the viewpoint of surface quality. When the annealing time is less than 5 seconds, even if annealing is performed at a predetermined temperature, the ferrite phase is not sufficiently recrystallized, so that a predetermined breaking elongation and an average r value cannot be obtained. If the annealing time exceeds 5 minutes, the crystal grains become extremely coarse and the glossiness of the steel sheet is lowered, which is not preferable from the viewpoint of surface quality. Therefore, cold-rolled sheet annealing is held at 800 to 950 ° C for 5 seconds to 5 minutes. The holding is preferably performed at 850 ° C. to 900 ° C. for 15 seconds to 3 minutes. In order to obtain more gloss, BA annealing (bright annealing) may be performed.
表1に示す化学組成を有するステンレス鋼を50kg小型真空溶解炉にて溶製した。これらの鋼塊を1150℃で1h加熱後、熱間圧延を施して3.5mm厚の熱延板とした。次いで、これらの熱延板に表2に記載の条件で熱延板焼鈍を施した。次いで、表面にショットブラスト処理と酸洗による脱スケールを行った。さらに、板厚0.7mmまで冷間圧延した後、表2に記載の条件で冷延板焼鈍(仕上げ焼鈍)を行った後、酸洗による脱スケール処理を行い、冷延酸洗焼鈍板を得た。 Hereinafter, the present invention will be described in detail with reference to examples.
Stainless steel having the chemical composition shown in Table 1 was melted in a 50 kg small vacuum melting furnace. These steel ingots were heated at 1150 ° C. for 1 h and then hot rolled to form 3.5 mm thick hot rolled sheets. Subsequently, these hot-rolled sheets were subjected to hot-rolled sheet annealing under the conditions described in Table 2. Next, the surface was descaled by shot blasting and pickling. Furthermore, after cold rolling to a sheet thickness of 0.7 mm, after performing cold-rolled sheet annealing (finish annealing) under the conditions shown in Table 2, descaling by pickling is performed to obtain a cold-rolled pickled and annealed sheet It was.
冷延酸洗焼鈍板から、圧延方向と直角にJIS 13B号引張試験片を採取し、引張試験をJIS Z2241に準拠して行い、破断伸びを測定し、各方向の破断伸びが28%以上の場合を合格(○)、一方向でも28%未満のものがある場合を不合格(×)とした。 (1) Evaluation of ductility JIS 13B tensile test specimens were sampled from cold-rolled pickled and annealed sheets at right angles to the rolling direction, tensile tests were performed in accordance with JIS Z2241, and elongation at break was measured. A case where the elongation was 28% or more was judged as acceptable (◯), and a case where the elongation was less than 28% in one direction was regarded as unacceptable (x).
冷延酸洗焼鈍板から、圧延方向に対して平行(L方向)、45°(D方向)およびに直角(C方向)となる方向にJIS 13B号引張試験片を採取し、JIS Z2411に準拠した引張試験をひずみ15%まで行って中断し、各方向のr値を測定し平均r値(=(rL+2rD+rC)/4)を算出した。ここで、rL、rD、rCはそれぞれL方向、D方向およびC方向のr値である。平均r値は0.70以上を合格(○)、0.70未満を不合格(×)とした。 (2) Evaluation of average r value JIS 13B tensile test specimens in the direction parallel to the rolling direction (L direction), 45 ° (D direction) and perpendicular to the rolling direction (C direction) from the cold rolled pickling annealed plate Then, the tensile test based on JIS Z2411 was interrupted to a strain of 15%, the r value in each direction was measured, and the average r value (= (r L + 2r D + r C ) / 4) was calculated. Here, r L , r D , and r C are r values in the L direction, the D direction, and the C direction, respectively. As for the average r value, 0.70 or more was regarded as acceptable (◯), and less than 0.70 was regarded as unacceptable (x).
冷延酸洗焼鈍板から、圧延方向に平行にJIS 5号引張試験片を採取し、その表面を#600のエメリーペーパーを用いて研磨した後、20%の引張ひずみを付与し、その試験片の平行部中央の研磨面で圧延方向に直角の方向に、表面粗度計を用いて、JIS B 0601(2001年)で規定される算術平均うねり(Wa)を、測定長16mm、ハイカットフィルター波長0.8mm、ローカットフィルター波長8mmで測定した。算術平均うねり(Wa)が2.5μm以下の場合を合格(○)、2.5μm超の場合を不合格(×)とした。 (3) Evaluation of ridging resistance properties JIS No. 5 tensile test specimens were collected from cold-rolled pickled and annealed sheets parallel to the rolling direction, and the surface was polished with # 600 emery paper, and then 20% tensile. Using a surface roughness meter in the direction perpendicular to the rolling direction on the polished surface at the center of the parallel part of the test piece, strain was applied, and the arithmetic average waviness (Wa) defined in JIS B 0601 (2001) was applied. Measured with a measurement length of 16 mm, a high-cut filter wavelength of 0.8 mm, and a low-cut filter wavelength of 8 mm. Arithmetic mean waviness (Wa) of 2.5 μm or less was accepted (◯), and the case of over 2.5 μm was rejected (×).
冷延酸洗焼鈍板から、60×100mmの試験片を採取し、表面を#600エメリーペーパーにより研磨仕上げした後に端面部をシールした試験片を作製し、JIS H 8502に規定された塩水噴霧サイクル試験に供した。塩水噴霧サイクル試験は、塩水噴霧(5質量%NaCl、35℃、噴霧2h)→乾燥(60℃、4h、相対湿度40%)→湿潤(50℃、2h、相対湿度≧95%)を1サイクルとして、8サイクル行った。
塩水噴霧サイクル試験を8サイクル実施後の試験片表面を写真撮影し、画像解析により試験片表面の発錆面積を測定し、試験片全面積との比率から発錆率((試験片中の発錆面積/試験片全面積)×100 [%])を算出した。発錆率が10%以下を特に優れた耐食性で合格(◎)、10%超25%以下を合格(○)、25%超を不合格(×)とした
評価結果を焼鈍条件と併せて表2に示す。また、Cr含有量が本発明範囲を満たすNo.1~25について、延性の評価結果をSiおよびMn含有量で整理したグラフを図1として示す。 (4) Evaluation of corrosion resistance A 60 x 100 mm test piece was taken from a cold rolled pickled and annealed sheet, and the test piece was prepared by polishing the surface with # 600 emery paper and sealing the end face. Subjected to the prescribed salt spray cycle test. The salt spray cycle test consists of 1 cycle of salt spray (5 mass% NaCl, 35 ° C, spray 2h) → dry (60 ° C, 4h, relative humidity 40%) → wet (50 ° C, 2h, relative humidity ≥95%) As a result, 8 cycles were performed.
Photograph the surface of the specimen after 8 cycles of the salt spray cycle test, measure the rusting area on the specimen surface by image analysis, and determine the rusting rate ((development in the specimen) from the ratio to the total area of the specimen. Rust area / total area of test piece) × 100 [%]) was calculated. Rust rate of 10% or less passed with excellent corrosion resistance (◎), more than 10% 25% or less passed (○), and more than 25% rejected (×). It is shown in 2. Further, FIG. 1 shows a graph in which ductility evaluation results are arranged by Si and Mn contents for Nos. 1 to 25 where the Cr content satisfies the scope of the present invention.
Mn含有量が本発明の範囲を上回るNo.24(鋼BG)は、過度のMn含有によって29.5×Si-50×Mn+6が本発明の範囲を下回り、冷延板焼鈍中にオーステナイト相が生成し、このオーステナイト相が冷却後にマルテンサイト相に変態したために鋼板が硬質化し、所定の破断伸びを得ることができなかった。以上の評価結果のうち、Cr含有量が本発明範囲を満たすNo.1~25について、延性の評価結果をSiおよびMn含有量で整理したグラフが図1である。所定の破断伸びはSiおよびMn含有量に加え、29.5×Si-50×Mn+6が本発明の範囲を満たした場合に得られていることがわかる。 The Si and Mn contents are within the scope of the present invention, but No. 20 to 23 (steel BC to BF) in which 29.5 × Si-50 × Mn + 6 falls below the scope of the present invention has a balance of Si and Mn contents. Since it was not appropriate, an austenite phase was generated during the cold-rolled sheet annealing, and this austenite phase was transformed into a martensite phase after cooling, so that the steel sheet was hardened and a predetermined breaking elongation could not be obtained.
In No.24 (steel BG), whose Mn content exceeds the range of the present invention, 29.5 × Si-50 × Mn + 6 falls below the range of the present invention due to excessive Mn content, and an austenite phase is formed during cold-rolled sheet annealing. Since the austenite phase was transformed into a martensite phase after cooling, the steel sheet was hardened and a predetermined elongation at break could not be obtained. Of the above evaluation results, FIG. 1 is a graph in which ductility evaluation results are arranged by Si and Mn contents for Nos. 1 to 25 in which the Cr content satisfies the scope of the present invention. It can be seen that the predetermined elongation at break is obtained when 29.5 × Si−50 × Mn + 6 satisfies the scope of the present invention in addition to the Si and Mn contents.
Claims (5)
- 質量%で、C:0.005~0.035%、Si:0.25~0.40未満%、Mn: 0.05~0.35%、P: 0.040%以下、S: 0.01%以下、Cr: 15.5~18.0%、Al: 0.001~0.10%、N: 0.01~0.06%を含有し、SiおよびMnが29.5×Si-50×Mn+6≧0(ただし、式中のSi、Mnは含有量(質量%)を示す)を満たし、残部がFeおよび不可避的不純物からなることを特徴とするフェライト系ステンレス鋼。 In mass%, C: 0.005 to 0.035%, Si: 0.25 to less than 0.40%, Mn: 0.05 to 0.35%, P: 0.040% or less, S: 0.01% or less, Cr: 15.5 to 18.0%, Al: 0.001 to 0.10 %, N: 0.01-0.06%, Si and Mn satisfy 29.5 × Si-50 × Mn + 6 ≧ 0 (where Si and Mn indicate content (mass%)), the balance A ferritic stainless steel characterized by comprising Fe and inevitable impurities.
- 質量%で、さらに、Cu:0.1~0.5%、Ni: 0.1~0.6%、Mo: 0.1~0.5%、Co: 0.01~0.3%のうちから選ばれる1種または2種以上を含むことを特徴とする請求項1に記載のフェライト系ステンレス鋼。 It is characterized by containing one or more selected from Cu: 0.1 to 0.5%, Ni: 0.1 to 0.6%, Mo: 0.1 to 0.5%, and Co: 0.01 to 0.3%. The ferritic stainless steel according to claim 1.
- 質量%で、さらに、V: 0.01~0.10%、Ti: 0.001~0.05%、Nb: 0.001~0.05%、Ca: 0.0002~0.0020%、Mg: 0.0002~0.0050%、B: 0.0002~0.0050%、REM: 0.01~0.10%のうちから選ばれる1種または2種以上を含むことを特徴とする請求項1または2に記載のフェライト系ステンレス鋼。 In mass%, V: 0.01-0.10%, Ti: 0.001-0.05%, Nb: 0.001-0.05%, Ca: 0.0002-0.0020%, Mg: 0.0002-0.0050%, B: 0.0002-0.0050%, REM: The ferritic stainless steel according to claim 1 or 2, comprising one or more selected from 0.01 to 0.10%.
- 圧延方向と直角方向の破断伸びが28%以上、平均ランクフォード値が0.70以上、リジング高さが2.5μm以下であることを特徴とする請求項1~3のいずれか一項に記載のフェライト系ステンレス鋼。 The ferrite system according to any one of claims 1 to 3, wherein the elongation at break in the direction perpendicular to the rolling direction is 28% or more, the average Rankford value is 0.70 or more, and the ridging height is 2.5 µm or less. Stainless steel.
- 請求項1~4のいずれか一項に記載のフェライト系ステンレス鋼の製造方法であって、鋼スラブに対して、熱間圧延を施した後、900~1050℃の温度範囲で5秒~15分間保持する焼鈍を行い、次いで、冷間圧延を施した後、800~950℃の温度範囲で5秒~5分間保持する焼鈍を行うことを特徴とするフェライト系ステンレス鋼の製造方法。 The method for producing a ferritic stainless steel according to any one of claims 1 to 4, wherein the steel slab is hot-rolled and then subjected to a temperature range of 900 to 1050 ° C for 5 seconds to 15 seconds. A method for producing a ferritic stainless steel, characterized in that annealing is performed for a minute, followed by cold rolling, followed by annealing at a temperature range of 800 to 950 ° C. for 5 seconds to 5 minutes.
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JP2018184660A (en) * | 2017-04-25 | 2018-11-22 | Jfeスチール株式会社 | Ferritic stainless steel plate and method for producing the same |
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EP3231882B1 (en) * | 2014-12-11 | 2020-01-15 | JFE Steel Corporation | Stainless steel and production method therefor |
JP2019081916A (en) * | 2017-10-27 | 2019-05-30 | Jfeスチール株式会社 | Ferritic stainless steel sheet and method for producing the same |
CN109881082A (en) * | 2019-03-22 | 2019-06-14 | 宁波宝新不锈钢有限公司 | A kind of automobile exhaust system cold end ferritic stainless steel and preparation method thereof |
WO2022085708A1 (en) * | 2020-10-23 | 2022-04-28 | 日鉄ステンレス株式会社 | Ferritic stainless steel, and method for manufacturing ferritic stainless steel |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1112692A (en) * | 1997-06-25 | 1999-01-19 | Kawasaki Steel Corp | Ferritic stainless steel having excellent antibacterial property |
JPH11350088A (en) * | 1998-06-11 | 1999-12-21 | Sumitomo Metal Ind Ltd | Ferritic stainless steel material and its production |
JP2000273547A (en) * | 1999-03-19 | 2000-10-03 | Nippon Steel Corp | Production of ferritic stainless steel sheet excellent in surface property |
JP2006299374A (en) * | 2005-04-25 | 2006-11-02 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel sheet superior in corrosion resistance and anti-ridging property, and manufacturing method therefor |
JP2009275268A (en) * | 2008-05-16 | 2009-11-26 | Jfe Steel Corp | Cold-rolled ferritic stainless steel sheet and method for manufacturing therefor |
JP2010047822A (en) * | 2008-08-25 | 2010-03-04 | Jfe Steel Corp | Stainless cold rolled steel sheet having excellent blanking property and method for producing the same |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS581801A (en) | 1981-06-26 | 1983-01-07 | Sony Corp | Record player |
JPS584881A (en) | 1981-06-26 | 1983-01-12 | 三菱レイヨン株式会社 | Dyeing of triacetate fiber |
JP2001089815A (en) * | 1999-09-22 | 2001-04-03 | Kawasaki Steel Corp | Method of manufacturing ferritic stainless steel sheet excellent in ductility, workability and ridging resistance |
JP2001271143A (en) * | 2000-03-28 | 2001-10-02 | Nisshin Steel Co Ltd | Ferritic stainless steel excellent in ridging resistance and its production method |
JP2006274436A (en) * | 2005-03-30 | 2006-10-12 | Jfe Steel Kk | Ferritic stainless sheet sheet and steel tube for bent tube having sectional shape for components |
KR101279052B1 (en) * | 2009-12-23 | 2013-07-02 | 주식회사 포스코 | Ferritic stainless steel sheet with excellent ridging resistance and manufacturing method thereof |
KR101600156B1 (en) * | 2011-06-16 | 2016-03-04 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Ferritic stainless-steel sheet with excellent non-ridging property and process for producing same |
KR101522077B1 (en) * | 2012-12-20 | 2015-05-20 | 주식회사 포스코 | Manufacturing method of ferritic stainless steel sheet with excellent ridging resistance |
-
2014
- 2014-10-02 US US15/516,584 patent/US20180265951A1/en not_active Abandoned
- 2014-10-02 WO PCT/JP2014/005038 patent/WO2016051437A1/en active Application Filing
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- 2014-10-02 KR KR1020177008704A patent/KR101941066B1/en active IP Right Grant
-
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- 2015-07-07 TW TW104122008A patent/TW201614079A/en unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1112692A (en) * | 1997-06-25 | 1999-01-19 | Kawasaki Steel Corp | Ferritic stainless steel having excellent antibacterial property |
JPH11350088A (en) * | 1998-06-11 | 1999-12-21 | Sumitomo Metal Ind Ltd | Ferritic stainless steel material and its production |
JP2000273547A (en) * | 1999-03-19 | 2000-10-03 | Nippon Steel Corp | Production of ferritic stainless steel sheet excellent in surface property |
JP2006299374A (en) * | 2005-04-25 | 2006-11-02 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel sheet superior in corrosion resistance and anti-ridging property, and manufacturing method therefor |
JP2009275268A (en) * | 2008-05-16 | 2009-11-26 | Jfe Steel Corp | Cold-rolled ferritic stainless steel sheet and method for manufacturing therefor |
JP2010047822A (en) * | 2008-08-25 | 2010-03-04 | Jfe Steel Corp | Stainless cold rolled steel sheet having excellent blanking property and method for producing the same |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2018198834A1 (en) * | 2017-04-25 | 2018-11-01 | Jfeスチール株式会社 | Ferritic stainless steel sheet, and production method therefor |
JP2018184660A (en) * | 2017-04-25 | 2018-11-22 | Jfeスチール株式会社 | Ferritic stainless steel plate and method for producing the same |
US11401573B2 (en) | 2017-04-25 | 2022-08-02 | Jfe Steel Corporation | Ferritic stainless steel sheet and method for manufacturing the same |
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