WO2012133563A1 - 冷延鋼板及びその製造方法 - Google Patents
冷延鋼板及びその製造方法 Download PDFInfo
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- WO2012133563A1 WO2012133563A1 PCT/JP2012/058199 JP2012058199W WO2012133563A1 WO 2012133563 A1 WO2012133563 A1 WO 2012133563A1 JP 2012058199 W JP2012058199 W JP 2012058199W WO 2012133563 A1 WO2012133563 A1 WO 2012133563A1
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
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Definitions
- the present invention relates to a high-strength cold-rolled steel sheet excellent in ductility and hole expansibility and a method for producing the same.
- the present invention relates to a steel sheet using a TRIP (Transformation Induced Plasticity) phenomenon.
- TRIP Transformation Induced Plasticity
- TRIP steel is excellent in strength and ductility, it is generally characterized by low local deformability such as hole expansibility. Furthermore, in order to reduce the weight of automobile bodies in the future, it is necessary to increase the strength level of use of high-strength steel sheets more than before. Therefore, for example, in order to use a high-strength steel plate for the suspension part, local deformability such as hole expansibility must be improved.
- an object of the present invention is to provide a high-strength cold-rolled steel sheet having improved ductility and hole expansibility in TRIP steel and a method for producing the same.
- the present inventors have found that, among TRIP steels, a cold-rolled steel sheet in which the pole density of a predetermined crystal orientation is controlled has excellent strength, ductility, hole expansibility, and a balance thereof.
- the present inventors have succeeded in producing a steel plate excellent in strength, ductility and hole expansibility by optimizing the chemical composition and production conditions of TRIP steel and controlling the microstructure of the steel plate.
- the cold-rolled steel sheet according to one embodiment of the present invention has a chemical composition of steel sheet in mass%, C: 0.02% or more and 0.4% or less, Si: 0.001% or more, and 2.5 %: Mn: 0.001% or more and 4.0% or less, Al: 0.001% or more and 2.0% or less, P: 0.15% or less, S: 0.03% or less, N: 0.01% or less, O: 0.01% or less, the balance is made of iron and unavoidable impurities, and in the chemical composition of the steel sheet, the total amount of Si and Al is 1.0% by mass.
- ⁇ 100 ⁇ ⁇ 011>, ⁇ 116 ⁇ ⁇ 110>, ⁇ 114 ⁇ ⁇ 110> , ⁇ 112 ⁇ ⁇ 110>, ⁇ 223 ⁇ ⁇ 110> is the polar density represented by the arithmetic average of the polar densities of each crystal orientation, ⁇ 100 ⁇
- the average pole density of the 011> to ⁇ 223 ⁇ ⁇ 110> orientation group is 1.0 or more and 6.5 or less, and the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> is 1.0 or more and 5.0 or less.
- this microstructure has an area ratio of 5% to 80% ferrite, 5% to 80% bainite, and residual austenite. 2% or more and 30% or less.
- the area ratio is limited to 20% or less of martensite, 10% or less of pearlite, and 60% or less of tempered martensite, and is perpendicular to the rolling direction.
- the Rankford value rC is 0.70 or more and 1.10 or less, and the Rankford value r30 in the direction forming 30 ° with respect to the rolling direction is 0.70 or more and 1.10 or less. .
- the chemical composition of the steel sheet is further mass%, Ti: 0.001% or more and 0.2% or less, Nb: 0.005% or more and 0.2% or less, B: 0.0001% to 0.005%, Mg: 0.0001% to 0.01%, REM: 0.0001% to 0.1%, Ca: 0.0001% to 0.01%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, V: 0.001% to 1. 0% or less, W: 0.001% to 1.0%, Ni: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Co: 0.00%. 0001% or more and 1.0% or less, Sn: 0.0001% or more and 0.2% or less, Zr: 0.0 0.1% or more and 0.2% or less, As: 0.0001% or more and may contain one or more selected from 0.5% or less.
- the volume average diameter of the crystal grains may be 2 ⁇ m or more and 15 ⁇ m or less.
- the average pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups is 1.0 or more.
- the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> may be 1.0 or more and 4.0 or less.
- the length of crystal grains in the rolling direction is the length of crystal grains in the plate thickness direction among the plurality of crystal grains.
- the proportion of crystal grains whose value divided by 3.0 is 3.0 or less may be 50% or more and 100% or less.
- the bainite has a Vickers hardness of 180 HV or more, and an average C concentration of the retained austenite is 0.9% or more. There may be.
- rL which is a Rankford value in the rolling direction
- R60 which is the Rankford value in the direction of 60 ° with respect to the angle
- a hot dip galvanized layer or an alloyed hot dip galvanized layer may be provided on the surface of the steel sheet.
- the cumulative reduction ratio is 50% or more in the temperature range of T1 + 30 ° C or more and T1 + 200 ° C or less, including a large reduction pass with a reduction ratio of 30% or more in the temperature range of T1 + 200 ° C or less.
- the second hot rolling in which the cumulative rolling reduction in the temperature range of Ar 3 ° C or higher and lower than T1 + 30 ° C is limited to 30% or less, and the rolling end temperature is Ar 3 ° C or higher calculated by the following formula 4
- the steel is subjected to primary cooling so that the waiting time t from the completion of the final pass to the start of cooling satisfies the following formula 2;
- the steel is wound in a temperature range; the steel is pickled; the steel is cold-rolled at a rolling rate of 30% or more and 90% or less; the average heating rate HR1 in the temperature range of room temperature to 650 ° C. is 0.00. 3 °C / second or more 650 ° C. Ultra and Ac 1 ° C.
- the time t OA seconds or more and 1000 seconds or less calculated by the following formula 6 within the temperature range is held to obtain a steel plate, or the steel is further cooled to 350 ° C. or less and 350 ° C. or more and 500 ° C. or less.
- T1 850 + 10 ⁇ ([C] + [N]) ⁇ [Mn] (Formula 1)
- [C], [N] and [Mn] are mass percentages of the amounts of C, N and Mn in the steel, respectively.
- t1 is represented by the following formula 3.
- t1 0.001 ⁇ ((Tf ⁇ T1) ⁇ P1 / 100) 2 ⁇ 0.109 ⁇ ((Tf ⁇ T1) ⁇ P1 / 100) +3.1
- Tf is the temperature in degrees Celsius of the steel at the completion of the final pass
- P1 is a percentage of the rolling reduction in the final pass.
- the steel further has, as the chemical composition, mass%, Ti: 0.001% or more and 0.2% or less, Nb: 0. 0.005% or more and 0.2% or less, B: 0.0001% or more and 0.005% or less, Mg: 0.0001% or more and 0.01% or less, REM: 0.0001% or more and 0.1 %: Ca: 0.0001% or more and 0.01% or less, Mo: 0.001% or more and 1.0% or less, Cr: 0.001% or more and 2.0% or less, V: 0.001 %: 1.01% or less, W: 0.001% or more and 1.0% or less, Ni: 0.001% or more and 2.0% or less, Cu: 0.001% or more and 2.0% or less Co: 0.0001% or more and 1.0% or less, Sn: 0.0001% or more and 0.001% or less.
- the temperature calculated by the following equation 7 may be the T1 ° C.
- T1 850 + 10 ⁇ ([C] + [N]) ⁇ [Mn] + 350 ⁇ [Nb] + 250 ⁇ [Ti] + 40 ⁇ [B] + 10 ⁇ [Cr] + 100 ⁇ [Mo] + 100 ⁇ [V].
- the waiting time t seconds may satisfy the following formula 8 using the t1. 0 ⁇ t ⁇ t1 (Expression 8)
- the waiting time t seconds may satisfy the following formula 9 using the t1.
- the first hot rolling includes at least one pass having a rolling reduction of 40% or more.
- the average austenite grain size of the steel may be 100 ⁇ m or less.
- the secondary cooling is performed after passing through the final rolling stand and within 10 seconds after the completion of the primary cooling. You may start.
- the primary cooling may be performed between rolling stands.
- a hot-dip galvanized layer or an alloyed hot-dip galvanized layer may be formed on the surface of the steel sheet.
- FIG. 6 is a diagram showing the relationship between the average pole density D1 of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups and the tensile strength TS ⁇ the hole expansion ratio ⁇ .
- FIG. 6 is a diagram showing the relationship between the average pole density D1 of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups and the tensile strength TS ⁇ elongation EL. It is a figure which shows the relationship between the pole density D2 of ⁇ 332 ⁇ ⁇ 113> orientation, and tensile strength TSx hole expansion rate (lambda).
- the amount of retained austenite and the amount of C in the retained austenite are increased by concentrating C in the austenite during the annealing process, and the tensile properties are improved.
- the present inventors optimize the steel components and the microstructure during production, start cooling from the temperature range of the two-phase region of ferrite and austenite or the single-phase region of austenite, and a predetermined temperature range. It was found that a steel plate excellent in the balance of strength, ductility and hole expansibility can be obtained by controlling the cooling (two-stage cooling) and maintaining the temperature within this temperature range.
- Polar density of crystal orientation (D1 and D2): In the cold-rolled steel sheet according to the present embodiment, the plate thickness ranges from 5/8 to 3/8 (the thickness of the steel sheet from the surface of the steel sheet to the thickness direction (depth direction) of the steel sheet) as the pole density of two types of crystal orientations. Average of ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups with respect to the sheet thickness section parallel to the rolling direction at the sheet thickness central portion, which is a range separated by a distance of 5/8 to 3/8)
- the pole density D1 hereinafter may be abbreviated as the average pole density
- the pole density D2 of the crystal orientation ⁇ 332 ⁇ ⁇ 113> are controlled.
- the average pole density is a characteristic point (orientation accumulation degree, texture development degree) of a particularly important texture (crystal orientation of crystal grains in the microstructure).
- the average pole density is the phase of pole density in each crystal orientation of ⁇ 100 ⁇ ⁇ 011>, ⁇ 116 ⁇ ⁇ 110>, ⁇ 114 ⁇ ⁇ 110>, ⁇ 112 ⁇ ⁇ 110>, ⁇ 223 ⁇ ⁇ 110>. It is the pole density expressed as an arithmetic mean.
- X-ray diffraction is performed on a cross section in the central portion of the plate thickness that is a thickness range of 5/8 to 3/8, and the intensity ratio of the X-ray diffraction intensity in each direction with respect to a random sample is obtained.
- the average pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups is obtained.
- the undercarriage part for which the steel plate is most recently requested The characteristics required for processing (indexes TS ⁇ ⁇ and TS ⁇ EL described later) can be satisfied. That is, as this characteristic, the tensile strength TS, the hole expansion ratio ⁇ , and the elongation EL can satisfy TS ⁇ ⁇ ⁇ 30000 (see FIG. 1) and TS ⁇ EL ⁇ 14000 (see FIG. 2).
- the average pole density is preferably 4.0 or less, more preferably 3.5 or less, and 3.0 or less. More preferably.
- the average pole density exceeds 6.5, the anisotropy of the mechanical properties of the steel sheet becomes extremely strong. As a result, the hole expandability only in a specific direction is improved, but the hole expandability in a direction different from that direction is significantly deteriorated. Therefore, in this case, the steel plate does not satisfy TS ⁇ ⁇ ⁇ 30000 and TS ⁇ EL ⁇ 14000 with respect to the characteristics required for processing the undercarriage part.
- the average pole density is less than 1.0, there is a concern about deterioration of hole expansibility. Therefore, the average pole density is preferably 1.0 or more.
- the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> in the central portion of the plate thickness that is a plate thickness range of 5/8 to 3/8 is 5.0 or less.
- 3 and 4 show the relationship between the polar density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> obtained by X-ray diffraction and the indices (TS ⁇ ⁇ and TS ⁇ EL) as in FIGS. Show.
- the pole density is preferably 5.0 or less in order to sufficiently secure each index.
- the steel plate has TS ⁇ ⁇ ⁇ 30000 and the characteristics required for the processing of the recently required undercarriage parts.
- TS ⁇ EL ⁇ 14000 can be satisfied.
- the pole density is preferably 4.0 or less, and more preferably 3.0 or less.
- the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> is more than 5.0, the anisotropy of the mechanical properties of the steel sheet becomes extremely strong.
- the steel plate does not satisfy TS ⁇ ⁇ ⁇ 30000 and TS ⁇ EL ⁇ 14000 with respect to the characteristics required for processing the undercarriage part.
- the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> is less than 1.0, there is a concern about deterioration of hole expansibility. Therefore, it is preferable that the pole density of the ⁇ 332 ⁇ ⁇ 113> crystal orientation is 1.0 or more.
- the pole density is synonymous with the X-ray random intensity ratio.
- the X-ray random intensity ratio is obtained by measuring the diffraction intensity (X-rays and electrons) of a standard sample that does not accumulate in a specific orientation and the diffraction intensity of the specimen by the X-ray diffraction method under the same conditions. It is a numerical value obtained by dividing the diffraction intensity of the obtained specimen by the diffraction intensity of the standard sample. This extreme density can be measured using X-ray diffraction, EBSD (Electron Back Scattering Diffraction), or electronic channeling.
- EBSD Electro Back Scattering Diffraction
- the pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups is a plurality of pole figures among ⁇ 110 ⁇ , ⁇ 100 ⁇ , ⁇ 211 ⁇ , ⁇ 310 ⁇ pole figures measured by these methods.
- ODF three-dimensional texture
- the steel plate is reduced to a predetermined thickness by mechanical polishing, and then the strain is removed by chemical polishing, electrolytic polishing, etc. and at the same time 5/8 of the plate thickness.
- the sample density may be measured according to the method described above by adjusting the sample so that an appropriate surface including the range of ⁇ 3 / 8 becomes the measurement surface.
- the hole expandability can be further improved.
- the material at the central portion of the plate thickness generally represents the material characteristics of the entire steel plate. Therefore, the average pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation group and the pole density of the crystal orientation of ⁇ 332 ⁇ ⁇ 113> in the central portion of the thickness of 5/8 to 3/8 It stipulates.
- ⁇ hkl ⁇ ⁇ uvw> indicates that the normal direction of the plate surface is parallel to ⁇ hkl> and the rolling direction is parallel to ⁇ uvw> when the sample is collected by the above method.
- the crystal orientation is usually expressed as (hkl) or ⁇ hkl ⁇ in the direction perpendicular to the plate surface and [uvw] or ⁇ uvw> in the direction parallel to the rolling direction.
- ⁇ Hkl ⁇ ⁇ uvw> is a general term for equivalent planes, and (hkl) [uvw] refers to individual crystal planes.
- the body-centered cubic structure (bcc structure) is targeted, for example, (111), ( ⁇ 111), (1-11), (11-1), ( ⁇ 1-11) ), (-11-1), (1-1-1), and (-1-1-1) are equivalent and cannot be distinguished. In such a case, these orientations are collectively referred to as ⁇ 111 ⁇ planes. Since the ODF display is also used for displaying the orientation of other crystal structures with low symmetry, in the ODF display, the individual orientation is generally displayed as (hkl) [uvw]. , ⁇ Hkl ⁇ ⁇ uvw> and (hkl) [uvw] are synonymous.
- the r value (Rankford value) of the steel sheet will be described.
- the r value in each direction (the r value rL in the rolling direction described later, the r value r30 in the direction forming 30 ° with respect to the rolling direction, and the rolling direction)
- the r value r60 in the direction forming 60 ° and the r value rC in the direction perpendicular to the rolling direction may be set within a predetermined range.
- R value (rC) in the direction perpendicular to the rolling direction That is, as a result of intensive studies by the present inventors, it has been found that good hole expansibility can be obtained by setting each pole density within the above range and simultaneously setting rC to 0.70 or more. Therefore, rC is 0.70 or more. As for the upper limit of rC, in order to obtain more excellent hole expandability, rC is preferably 1.10 or less.
- R value (r30) in a direction forming 30 ° with respect to the rolling direction As a result of intensive studies by the present inventors, it was found that good hole expansibility can be obtained by setting each pole density within the above range and at the same time r30 being 1.10 or less. Therefore, r30 is 1.10 or less.
- the lower limit of r30 is preferably r30 of 0.70 or more in order to obtain better hole expansibility.
- R value (rL) in the rolling direction r value (r60) in the direction forming 60 ° with respect to the rolling direction: Furthermore, as a result of intensive studies by the present inventors, the above-described extreme densities, rC, and r30 are set within the above-described ranges, and at the same time, rL and r60 satisfy rL ⁇ 0.70 and r60 ⁇ 1.10. Thus, it was found that better TS ⁇ ⁇ can be obtained. Therefore, rL is preferably 0.70 or more and r60 is 1.10 or less. As for the upper limit of rL and the lower limit of r60, rL is preferably 1.10 or less and r60 is 0.70 or more in order to obtain better hole expansibility.
- the above r values are evaluated by a tensile test using a JIS No. 5 tensile test piece. Considering the case of a normal high-strength steel sheet, the r value may be evaluated in a range where the tensile strain is in the range of 5 to 15% and which corresponds to uniform elongation.
- the basic microstructure of the cold rolled steel sheet according to the present embodiment is composed of ferrite, bainite, and retained austenite.
- this basic microstructure component in place of part of ferrite, bainite, retained austenite, pearlite, martensite, tempered martensite as necessary or unavoidable.
- pearlite in place of part of ferrite, bainite, retained austenite
- pearlite martensite
- tempered martensite as necessary or unavoidable.
- each microstructure is evaluated by the area ratio.
- Ferrite and bainite are essential for improving the elongation by the TRIP effect because C is concentrated in the retained austenite. Furthermore, ferrite and bainite contribute to improvement of hole expansibility. It is possible to change the fraction of ferrite and bainite depending on the strength level targeted for development, but it is excellent by making ferrite 5% to 80% and bainite 5% to 80%. The ductility and hole expandability can be obtained. Therefore, ferrite is 5% or more and 80% or less, and bainite is 5% or more and 80% or less.
- Residual austenite is a structure that enhances ductility, particularly uniform elongation, by transformation-induced plasticity, and requires a retained austenite of 2% or more in area ratio.
- retained austenite is transformed into martensite by processing, which contributes to improvement in strength. The higher the area ratio of retained austenite, the better.
- the upper limit of the area ratio of retained austenite is set to 30% or less.
- the retained austenite is preferably 3% or more, more preferably 5% or more, and most preferably 8% or more.
- tempered martensite By generating martensite to some extent during cooling before the start of bainite transformation, the effect of promoting bainite transformation and the effect of stabilizing retained austenite can be obtained. Since such martensite is tempered by reheating, tempered martensite may be contained in the microstructure as necessary. However, if the tempered martensite exceeds 60% in area ratio, the ductility is lowered, so the tempered martensite is limited to 60% or less in area ratio. Further, the microstructure may contain pearlite within a range of 10% or less and martensite within a range of 20% or less as necessary. When the amount of pearlite and martensite increases, the workability and local deformability of the steel sheet decrease, or the utilization rate of C that generates retained austenite decreases. Therefore, in the microstructure, pearlite is limited to 10% or less and martensite is limited to 20% or less.
- the area ratio of austenite can be determined from the diffraction intensity obtained by performing X-ray diffraction on a plane parallel to the plate surface in the vicinity of the 1/4 plate thickness position.
- the area ratio of ferrite, pearlite, bainite, and martensite is within the range of 1/8 to 3/8 thickness (that is, the thickness range centered at 1/4 thickness position). It can be determined from an image obtained by observation with a microscope (FE-SEM: Field Emission Scanning Electron Microscope). In this FE-SEM observation, a sample is taken so that a plate thickness cross section parallel to the rolling direction of the steel plate becomes the observation surface, and polishing and nital etching are performed on this observation surface.
- the microstructure (component) of the steel sheet may be significantly different from other parts due to decarburization and Mn segregation, respectively. For this reason, in the present embodiment, the microstructure is observed based on the 1 ⁇ 4 thickness position.
- the size of the crystal grains in the microstructure may be refined. Furthermore, by reducing the volume average diameter, the fatigue characteristics (fatigue limit ratio) required for automobile steel sheets and the like are improved. Since the influence of the number of coarse grains on elongation is higher than that of fine grains, the elongation is more strongly correlated with the volume average diameter calculated by the weighted average of the volume than the number average diameter. Therefore, in order to obtain the above effect, the volume average diameter is 2 to 15 ⁇ m, preferably 2 to 9.5 ⁇ m.
- the volume average diameter when the volume average diameter is reduced, local strain concentration occurring at the micro order is suppressed, strain at the time of local deformation can be dispersed, and elongation, particularly uniform elongation, is improved.
- the grain boundary that becomes a barrier to dislocation motion can be controlled appropriately, and this grain boundary acts on repeated plastic deformation (fatigue phenomenon) caused by the dislocation motion, thereby improving fatigue characteristics. .
- each crystal grain can be determined as follows.
- the pearlite is specified by observing the structure with an optical microscope.
- the grain units of ferrite, austenite, bainite, martensite, and tempered martensite are specified by EBSD. If the crystal structure of the region determined by EBSD is a face-centered cubic structure (fcc structure), this region is determined to be austenite. If the crystal structure of the region determined by EBSD is a body-centered cubic structure (bcc structure), this region is determined as one of ferrite, bainite, martensite, and tempered martensite.
- Ferrite, bainite, martensite, and tempered martensite can be identified using the KAM (Kernel Average) method equipped with EBSP-OIM (registered trademark, Electron Back Scattering Pattern Pattern-Orientation Image Microscopy).
- KAM Kernel Average
- EBSP-OIM registered trademark, Electron Back Scattering Pattern Pattern-Orientation Image Microscopy
- the second approximation using all 12 pixels (19 pixels in total), or the third approximation using all 18 pixels outside these 12 pixels (total 37 pixels) the orientation difference between each pixel And the average value obtained is determined as the value of the center pixel, and such an operation is performed on the entire pixel.
- a map expressing the orientation change in the grain can be created. This map represents a strain distribution based on local orientation changes in the grains.
- the azimuth difference between adjacent pixels is calculated by the third approximation.
- the grain size of ferrite, bainite, martensite, and austenite is measured, for example, by performing the above-mentioned orientation measurement at a measurement step of 0.5 ⁇ m or less at a magnification of 1500 times, and at a position where the orientation difference between adjacent measurement points exceeds 15 °. It is obtained by defining the boundary (this grain boundary is not necessarily a general grain boundary) and calculating the equivalent circle diameter.
- the crystal grain size of pearlite can be calculated by applying image processing methods such as binarization and cutting to the image obtained by the optical microscope. it can.
- the volume average diameter can be determined by the weighted average.
- the coarse particle fraction described below can be obtained by dividing the area ratio of coarse particles obtained by this method by the area to be measured.
- the equiaxed grain fraction described below can be obtained by dividing the area ratio of equiaxed grains obtained by this method by the area to be measured.
- the ratio of the area (coarse grain fraction) occupied by grains (coarse grains) having a grain size exceeding 35 ⁇ m per unit area is 10% for all the constituent elements of the microstructure. Restrict to the following. As the number of large grains increases, the tensile strength decreases and the local deformability also decreases. Therefore, it is preferable to make the crystal grains as fine as possible. In addition, since all the crystal grains are uniformly and equivalently strained, the hole expansibility is improved. Therefore, by restricting the amount of coarse grains, local crystal grain strain can be suppressed.
- the present inventors have expanded the holes when the above-mentioned pole densities (and r values) satisfy the above-mentioned conditions and the crystal grains are excellent in equiaxedness. It was found that the processing direction dependency is small and the local deformability is further improved. Therefore, when improving local deformability more, it is good that it is 50% or more and 100% or less of the equiaxed grain fraction which is the parameter
- the equiaxed grain fraction is 50% or more, the deformability in the L direction, which is the rolling direction, and the deformability in the C direction, which is perpendicular to the rolling direction, are relatively uniform, and the local deformability is improves.
- the equiaxed grain fraction is obtained by dividing the length dL of crystal grains in the rolling direction by the length dt of crystal grains in the plate thickness direction among the crystal grains (for example, all crystal grains) in the microstructure of the steel sheet.
- the value (dL / dt) is the ratio of grains (equal axis grains) excellent in equiaxedness having a value of 3.0 or less.
- ⁇ ⁇ Vickers hardness of bainite affects tensile properties. As the bainite transformation proceeds, the retained austenite is stabilized, and this retained austenite contributes to the improvement of elongation. In addition, if the bainite hardness is 180 HV or higher, the tensile strength and hole expandability can be further improved. In order to obtain a good balance between tensile strength and hole expansibility, and a balance between tensile strength and elongation, the Vickers hardness of bainite is preferably 180 HV or higher. In addition, about Vickers hardness, it measures using a micro Vickers measuring machine.
- the average C concentration in the retained austenite greatly contributes to the stability of retained austenite.
- the average C concentration in the retained austenite is 0.9% or more, sufficient stability of retained austenite can be obtained, so that the TRIP effect can be effectively obtained and the elongation is improved. Therefore, the average C concentration in the retained austenite is preferably 0.9% or more.
- C 0.02% or more and 0.4% or less C is essential for securing high strength and securing retained austenite. In order to obtain a sufficient amount of retained austenite, 0.02% or more of C should be contained in the steel. On the other hand, if the steel sheet contains excessive C, the weldability is impaired, so the upper limit of the C content is set to 0.4%. In the case where the strength and elongation are further improved, the C content is preferably 0.05% or more, more preferably 0.10% or more, and most preferably 0.12% or more. . Moreover, when improving weldability more, it is preferable that C amount is 0.38% or less, and it is more preferable that it is 0.36% or less.
- Si 0.001% or more and 2.5% or less Si is a deoxidizer, and it is preferable that 0.001% or more of Si is contained in the steel. Further, Si stabilizes ferrite during annealing and suppresses cementite precipitation during bainite transformation (when kept within a predetermined temperature range). Therefore, Si increases the C concentration of austenite and contributes to securing retained austenite. The effect increases as the amount of Si increases. However, when Si is excessively added to the steel, surface properties, paintability, weldability, and the like deteriorate. Therefore, the upper limit of Si content is set to 2.5%.
- the Si amount is preferably 0.02% or more, preferably 0.50% or more, and 0.60% or more. Most preferably it is.
- the Si content is preferably 2.2% or less, and more preferably 2.0% or less.
- Mn 0.001% or more and 4.0% or less
- Mn is an element that stabilizes austenite and improves hardenability.
- 0.001% or more of Mn is preferably contained in the steel.
- the upper limit of the Mn content is 4.0%.
- the amount of Mn is preferably 0.1% or more, more preferably 0.5% or more, and most preferably 1.0% or more.
- the amount of Mn is 3.8% or less, and it is more preferable that it is 3.5% or less.
- P 0.15% or less
- P is an impurity, and if P is excessively contained in steel, ductility and weldability are impaired. Therefore, the upper limit of the P content is 0.15%.
- P acts as a solid solution strengthening element, but is inevitably contained in the steel, so the lower limit of the amount of P is not particularly limited and is 0%. In consideration of current general refining (including secondary refining), the lower limit of the P amount may be 0.001%.
- the P content is preferably 0.10% or less, and more preferably 0.05% or less.
- S 0.03% or less S is an impurity.
- the upper limit of S content is 0.03%.
- the lower limit of the amount of S is not particularly limited, and is 0%. In consideration of the current general refining (including secondary refining), the lower limit of the amount of S may be 0.0005%.
- the S content is preferably 0.020% or less, and more preferably 0.015% or less.
- N 0.01% or less N is an impurity, and if the amount of N exceeds 0.01%, ductility deteriorates. Therefore, the upper limit of the N amount is 0.01% or less.
- the lower limit of the N amount is not particularly limited and is 0%. In consideration of current general refining (including secondary refining), the lower limit of the N amount may be 0.0005%. In order to further increase the ductility, the N content is preferably 0.005% or less.
- Al 0.001% or more and 2.0% or less
- Al is a deoxidizer, and considering current general refining (including secondary refining), the steel contains 0.001% or more of Al. It is preferable.
- Al stabilizes ferrite during annealing and suppresses cementite precipitation during bainite transformation (when kept within a predetermined temperature range). Therefore, Al increases the C concentration of austenite and contributes to securing retained austenite. The effect increases as the amount of Al increases, but surface properties, paintability, weldability, and the like deteriorate when Al is added excessively to the steel. Therefore, the upper limit of the Al amount is set to 2.0%.
- the Al content is preferably 0.01% or more, and more preferably 0.02% or more. In order to further ensure the surface properties, paintability, weldability, etc., the Al content is preferably 1.8% or less, and more preferably 1.5% or less.
- O 0.01% or less
- O (oxygen) is an impurity, and when the amount of O exceeds 0.01%, ductility deteriorates. Therefore, the upper limit of the O amount is 0.01%.
- the lower limit of the amount of O is not particularly limited and is 0%. In consideration of current general refining (including secondary refining), the lower limit of the O amount may be 0.0005%.
- Si + Al 1.0% or more and 4.5% or less
- the total of the Si amount and the Al amount is preferably 1.0% or more.
- Both Si and Al stabilize ferrite during annealing and suppress cementite precipitation during bainite transformation (when kept within a predetermined temperature range). Therefore, these elements increase the C concentration of austenite and contribute to securing retained austenite.
- the total amount of Si and Al is made 4.5% or less.
- the total is preferably 4.0% or less, more preferably 3.5% or less, and 3.0% or less. Most preferred.
- the above chemical elements are the basic components (basic elements) of the steel in the present embodiment, the basic elements are controlled (contained or restricted), and the chemical composition consisting of iron and unavoidable impurities as the balance is Basic composition.
- the following chemical elements may be further contained in the steel as necessary.
- these selection elements are inevitably mixed in the steel (for example, an amount less than the lower limit of the amount of each selection element), the effect in the present embodiment is not impaired.
- the cold-rolled steel sheet according to the present embodiment has Ti, Nb, B, Mg, REM, Ca, Mo, Cr as selective elements in order to improve local formability by, for example, inclusion control or precipitate refinement.
- V, W, Ni, Cu, Co, Sn, Zr, As may be included.
- Ti, Nb, B, Cu, W improve material through mechanisms such as carbon and nitrogen fixation, precipitation strengthening, microstructure control, fine grain strengthening. Therefore, you may add any 1 or more types in Ti, Nb, B, Cu, and W as needed.
- the Ti amount is 0.001% or more
- the Nb amount is 0.005% or more
- the B amount is 0.0001% or more
- the Cu amount is 0.001% or more
- W The amount is desirably 0.001% or more.
- these chemical elements are excessively added to the steel, a remarkable effect is not obtained, but rather the workability and manufacturability are deteriorated.
- Nb content is 0.2% or less
- B content is 0.005% or less
- Cu content is 2.0% or less
- W content is limited to 1.0% or less.
- the lower limits of the amounts of Ti, Nb, B, Cu, and W are all 0%.
- Mg, REM (Rare Earth Metal), and Ca are selective elements that are important for controlling inclusions in a harmless form. Therefore, if necessary, one or more of Mg, REM, and Ca may be added to the steel.
- the lower limit of the amount of each chemical element is preferably 0.0001%.
- the Mg amount is 0.01% or less
- the REM amount is 0.1% or less
- the amount of Ca is limited to 0.01% or less.
- the lower limits of the amounts of Mg, REM, and Ca are all 0%.
- Mo and Cr have the effect of increasing the mechanical strength and the effect of improving the material
- one or more of Mo and Cr may be added to the steel as necessary.
- the Mo amount is 0.001% or more and the Cr amount is 0.001% or more.
- the upper limit of the amount of each chemical element is 1.0% Mo and 2.0% Cr. Restrict.
- the lower limits of the amounts of Mo and Cr are both 0%.
- V is effective for precipitation strengthening and has a small allowance for deterioration of hole expandability due to this precipitation strengthening. Therefore, V is an effective selection element when high strength and better hole expandability are required. Therefore, you may add V in steel as needed.
- the V amount is preferably 0.001% or more. However, if V is excessively added to the steel, the workability deteriorates, so the V content is limited to 1.0% or less. Further, in order to reduce the alloy cost, it is not necessary to intentionally add V to the steel, and the lower limit of the V amount is 0%.
- Ni, Co, Sn, Zr, and As are selective elements that increase the strength, any one or more of Ni, Co, Sn, Zr, and As may be added to the steel as necessary.
- the effective content (lower limit) of each chemical element is as follows: Ni amount is 0.001% or more, Co amount is 0.0001% or more, Sn amount is 0.0001% or more, and Zr amount is 0.00. It is desirable that it is 0001% or more and the As amount is 0.0001% or more. However, if these chemical elements are excessively added to the steel, formability is lost, so the upper limit of the amount of each chemical element is 2.0% Ni or less and 1.0% Co.
- the Sn amount is limited to 0.2% or less
- the Zr amount is limited to 0.2% or less
- the As amount is limited to 0.5% or less.
- the lower limits of the amounts of Ni, Co, Sn, Zr, and As are all 0%.
- the cold-rolled steel sheet according to the present embodiment includes the above-described basic element, and the balance is selected from the chemical composition consisting of Fe and inevitable impurities, or the above-described basic element and the above-described selective element. It has at least one kind, and the balance has a chemical composition consisting of Fe and inevitable impurities.
- the surface of the cold-rolled steel sheet described above is subjected to hot-dip galvanizing treatment or alloying treatment after galvanizing, and the cold-rolled steel sheet is hot-dip galvanized layer or alloyed hot-dip galvanized layer on the surface.
- hot-dip galvanizing treatment or alloying treatment after galvanizing
- the cold-rolled steel sheet is hot-dip galvanized layer or alloyed hot-dip galvanized layer on the surface.
- cold-rolled steel sheets including hot-dip galvanized steel sheets and galvannealed steel sheets
- various surface treatments electroroplating, hot-dip plating, vapor deposition plating, chromate treatment, non-chromic treatment, laminating treatment.
- Various salt treatments may be performed, and a metal coating (plating, etc.) or an organic coating (laminate film, etc.) may be provided on the surface thereof.
- the thickness of the cold-rolled steel sheet is not particularly limited, but may be, for example, 0.5 to 2.5 mm, or 0.5 mm or more and less than 2.0 mm.
- the strength of the cold-rolled steel sheet is not particularly limited, and for example, the tensile strength may be 440 to 1500 MPa.
- the manufacturing method preceding hot rolling is not particularly limited.
- various secondary refining can be performed subsequent to smelting and refining in a blast furnace, electric furnace, converter, etc., and steel satisfying the above chemical composition can be melted to obtain steel (molten steel).
- the steel can be cast by a casting method such as a normal continuous casting method, an ingot method, or a thin slab casting method.
- the steel may be once cooled to a low temperature (for example, room temperature) and reheated, and then the steel may be hot-rolled, or the steel immediately after casting (cast slab) may be continuously It may be hot rolled.
- a scrap for the raw material of steel (molten steel).
- molten steel molten steel
- a sheet bar may be joined after rough rolling, and finish rolling may be performed continuously.
- the coarse bar may be wound once in a coil shape, stored in a cover having a heat retaining function as necessary, and rewound again before joining.
- the austenite grain size after rough rolling that is, before finish rolling is important. That is, it is desirable that the austenite grain size before finish rolling is small, and it has been found that if the average austenite grain size is 200 ⁇ m or less, it is effective to ensure sufficient local deformability.
- the average austenite grain size before finish rolling is preferably 200 ⁇ m or less.
- the steel In order to obtain the average austenite grain size before finish rolling of 200 ⁇ m or less, as shown in FIG. 5, rough rolling in the temperature range of 1000 ° C. or higher and 1200 ° C. or lower (preferably 1150 ° C. or lower) In hot rolling, the steel may be rolled once (one pass) at a rolling reduction of 40% or more.
- the finer austenite grains can be obtained as the reduction ratio and the number of reductions are increased. For example, it is desirable to control to an average austenite grain size of 100 ⁇ m or less in rough rolling, and in order to perform this grain size control, rolling with a rolling reduction of 40% or more in one pass is performed twice (two passes) or more. Is desirable. However, in rough rolling, by reducing the reduction rate of one pass to 70% or less, or limiting the number of reductions (number of passes) to 10 times or less, the concern about the decrease in temperature and excessive generation of scale is reduced. Can be made. Therefore, in rough rolling, the rolling reduction of one pass may be 70% or less, and the number of rolling (number of passes) may be 10 or less.
- reducing the austenite grain size before finish rolling promotes recrystallization of austenite in subsequent finish rolling, and is effective in improving hole expandability.
- it is also effective to reduce the austenite grain size before finish rolling in terms of controlling rC and r30. This is presumably due to the function of the austenite grain boundary after rough rolling (that is, before finish rolling) as one of the recrystallization nuclei during finish rolling.
- the steel sheet is cooled at an average cooling rate of 10 ° C./s or more.
- the cross section of the plate piece collected from the steel plate obtained by cooling is etched to make the austenite grain boundary in the microstructure stand up and measured with an optical microscope.
- the particle size of austenite is measured by image analysis or a cutting method with respect to 20 or more fields of view at a magnification of 50 times or more, and each austenite particle size is averaged to obtain an average austenite particle size.
- the average pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups and the crystal of ⁇ 332 ⁇ ⁇ 113> in the central portion of the thickness that is the thickness range of 5/8 to 3/8 As one condition for controlling the pole density of the azimuth within the above-mentioned range, in the finish rolling after the rough rolling (second hot rolling), depending on the chemical composition (mass%) of the steel, The rolling is controlled based on the temperature T1 (° C.) determined as described above.
- T1 850 + 10 ⁇ ([C] + [N]) ⁇ [Mn] + 350 ⁇ [Nb] + 250 ⁇ [Ti] + 40 ⁇ [B] + 10 ⁇ [Cr] + 100 ⁇ [Mo] + 100 ⁇ [V].
- [C], [N], [Mn], [Nb], [Ti], [B], [Cr], [Mo], and [V] are C, It is a mass percentage of N, Mn, Nb, Ti, B, Cr, Mo and V. The amount of chemical element (chemical component) not included in (Formula 11) is calculated as 0%.
- a large rolling reduction is ensured, and the rolling reduction is limited to a small range (including 0%) in a temperature range of Ar 3 ° C or higher and lower than T1 + 30 ° C.
- the local deformability of the final product can be enhanced.
- This temperature T1 itself has been determined empirically.
- the present inventors have empirically found through experiments that the temperature range in which recrystallization in the austenite region of each steel can be promoted can be determined based on the temperature T1.
- the cumulative rolling reduction in the temperature range of T1 + 30 ° C. or more and T1 + 200 ° C. or less is 50% or more.
- the cumulative rolling reduction is desirably 70% or more from the viewpoint of promoting recrystallization due to strain accumulation.
- the cumulative rolling reduction may be 90% or less.
- Finish rolling is controlled to include the path.
- at least one rolling reduction of 30% or more is performed in a temperature range of T1 + 30 ° C. or higher and T1 + 200 ° C. or lower.
- the reduction rate of the final pass in this temperature range is 30% or more, that is, the final pass is a large reduction pass.
- the final two-pass rolling reduction in the temperature range of T1 + 30 ° C. or higher and T1 + 200 ° C. or lower is preferably 30% or higher.
- the rolling reduction of the large rolling pass (1 pass) is preferably 40% or more.
- the rolling reduction of a large rolling down pass (1 pass) is 70% or less.
- T1 + 30 ° C. or more and T1 + 200 ° C. or less are desirable to suppress the temperature rise of the steel plate between each pass during the reduction in the temperature range to 18 ° C. or less.
- uniform recrystallized austenite can be obtained by suppressing the temperature rise of the steel sheet between each rolling pass.
- the austenite can be uniformly and finely recrystallized in finish rolling to control the texture of the product and improve the hole expandability.
- the steel sheet finally obtained is such that the average pole density of the ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110> orientation groups is 1.0 or more and 6.5 or less in the center portion of the plate thickness. , ⁇ 332 ⁇ ⁇ 113> does not satisfy at least one of the conditions that the polar density of the crystal orientation is 1.0 or more and 5.0 or less.
- finish rolling when rolling is performed in a temperature range higher than T1 + 200 ° C. or the cumulative rolling reduction is too small, coarse or mixed grains are included in the microstructure, or the microstructure becomes mixed. To do. In this case, the coarse particle fraction and the volume average diameter increase.
- the rolling reduction can be obtained by actual results or calculation from measurement of rolling load or sheet thickness.
- the rolling temperature (for example, each of the above temperature ranges) can be measured by an inter-stand thermometer, or can be calculated by a calculation simulation considering processing heat generation from line speed, rolling reduction, etc. (both actual measurement and calculation) It can be obtained by performing.
- the reduction ratio in one pass is the amount of reduction in one pass with respect to the inlet plate thickness before passing through the rolling stand (difference between the inlet plate thickness before passing through the rolling stand and the outlet plate thickness after passing through the rolling stand). The percentage.
- the cumulative reduction ratio is based on the inlet plate thickness before the first pass in rolling in each of the above temperature ranges, and the cumulative reduction amount relative to this reference (the inlet plate thickness before the first pass in rolling in each of the above temperature ranges and the above mentioned It is a percentage of the difference between the outlet plate thickness after the final pass in rolling in each temperature range.
- the Ar 3 temperature is obtained by the following equation (13).
- Ar 3 879.4-516.1 ⁇ [C] ⁇ 65.7 ⁇ [Mn] + 38.0 ⁇ [Si] + 274.7 ⁇ [P] (Formula 13)
- the hot rolling is finished at a temperature of Ar 3 ° C or higher.
- the steel is rolled in a two-phase region (two-phase region) of austenite and ferrite, so that ⁇ 100 ⁇ ⁇ 011> to ⁇ 223 ⁇ ⁇ 110 > Accumulation of crystal orientation in the orientation group becomes strong, and as a result, hole expansibility is significantly deteriorated.
- the finishing temperature of finish rolling is T1 ° C. or higher, the amount of strain in the temperature range of T1 ° C. or lower can be reduced to further reduce anisotropy. Therefore, the finish temperature of finish rolling may be T1 ° C. or higher.
- cooling primary cooling
- T1 + 30 ° C. or more and T1 + 200 ° C. or less greatly affects the grain size of the austenite.
- the diameter has a strong influence on the equiaxed grain fraction and coarse grain fraction of the microstructure after cold rolling and annealing.
- the final reduction pass in the hot rolling in the hot rolling is a reduction (pass) of a reduction rate of 30% or more in a temperature range of T1 + 30 ° C. or more and T1 + 200 ° C. or less).
- t1 in (Expression 14) can be obtained by the following (Expression 15).
- Tf in (Expression 15) is the temperature (° C.) of the steel plate when the final pass of the large reduction pass is completed, and P1 is the reduction rate (%) of the final pass of the large reduction passes.
- operability for example, controllability of shape correction and secondary cooling
- primary cooling is preferably performed between rolling stands.
- the primary cooling described above can be performed between the rolling stands or after the last stand. That is, after primary cooling, a low rolling reduction (for example, 30% or less (or less than 30%) in a temperature range of Ar 3 ° C or higher (for example, Ar 3 (° C) to T1 + 30 (or Tf) (° C)) )) Rolling may be performed.
- a low rolling reduction for example, 30% or less (or less than 30%) in a temperature range of Ar 3 ° C or higher (for example, Ar 3 (° C) to T1 + 30 (or Tf) (° C))
- Rolling may be performed.
- the change in cooling temperature which is the difference between the steel plate temperature (steel temperature) at the start of cooling in primary cooling and the steel plate temperature (steel temperature) at the end of cooling, is preferably 40 ° C. or higher and 140 ° C. or lower. Further, it is desirable that the steel plate temperature T2 at the end of the primary cooling is T1 + 100 ° C. or less. If this cooling temperature change is 40 ° C. or higher, the grain growth of recrystallized austenite grains can be further suppressed, and the strength and elongation can be increased. If the cooling temperature change is 140 ° C. or lower, recrystallization can be proceeded more sufficiently and the pole density can be further improved, so that the hole expandability can be further enhanced.
- the cooling temperature change by limiting the cooling temperature change to 140 ° C or lower, not only can the temperature of the steel sheet be controlled relatively easily, but also variant selection (avoidance of variant restrictions) can be controlled more effectively, further improving the texture development. It can also be suppressed. Therefore, in this case, the isotropic property can be further increased, and the orientation dependency of workability can be further reduced. Furthermore, when the steel plate temperature T2 at the end of the primary cooling is T1 + 100 ° C. or less, a more sufficient cooling effect can be obtained. By this cooling effect, crystal grain growth can be suppressed, and an increase in crystal grain size can be further suppressed. Moreover, it is desirable that the average cooling rate in primary cooling is 50 ° C./second or more.
- the average cooling rate in the primary cooling is 50 ° C./second or more, the grain growth of the recrystallized austenite grains can be further suppressed.
- the upper limit of the average cooling rate is not particularly required, but the average cooling rate may be 200 ° C./second or less from the viewpoint of the plate shape.
- cooling is not particularly limited, and a cooling pattern is set according to the purpose, and within the above-mentioned microstructure.
- the microstructure can be controlled flexibly.
- cooling this cooling is included in the secondary cooling
- secondary cooling is started within 10 seconds after completion of primary cooling, the crystal grains can be made finer.
- the steel (hot rolled original plate) is wound in a temperature range of 650 ° C. or less. If the steel is wound before reaching a temperature of 650 ° C. or lower, the anisotropy of the steel sheet after cold rolling becomes large, and the hole expansibility is significantly lowered.
- the lower limit of the coiling temperature is not particularly limited, but may be 350 ° C. or higher in order to suppress martensite formation and suppress the cold rolling load.
- cold rolling is performed at a rolling rate (cold rolling rate) of 30% or more and 90% or less. If the rolling rate is less than 30%, it becomes difficult to cause recrystallization in the subsequent annealing step, and texture control (extreme density control) by recrystallized ferrite described later becomes difficult. In addition, in this case, the equiaxed grain fraction is lowered and the crystal grains after annealing are coarsened. On the other hand, when the rolling rate exceeds 90%, the texture develops during annealing, and the anisotropy of crystal orientation becomes strong. For this reason, the rolling rate of cold rolling shall be 30% or more and 90% or less.
- the rolling rate of cold rolling is 40% or more. Further, in order to further reduce the crystal orientation anisotropy, the rolling rate of cold rolling is preferably 80% or less, more preferably 70% or less, and most preferably 60% or less. preferable.
- the heating rate in the temperature range of 650 ° C. to Ac 1 ° C. is small.
- the driving force for recrystallization is a strain accumulated by rolling
- the heating rate up to 650 ° C. is low, dislocations introduced by cold rolling recover and recrystallization does not occur.
- the texture developed during the cold rolling remains as it is, and the local deformability is deteriorated.
- the heating rate in the temperature range from room temperature (for example, 25 ° C.) to 650 ° C. is low, the density of dislocations contained in the microstructure becomes small at the start of recrystallization.
- the average heating rate HR1 (° C./second) in the temperature range (for example, 25 ° C.) to 650 ° C. (previous stage) is 0.3 ° C./second or more, a temperature range of more than 650 ° C. and less than Ac 1 ° C.
- the average heating rate HR2 (° C./second) in (the latter stage) is 0.5 ⁇ HR 1 ° C./second or less.
- the upper limit of the average heating rate HR1 in the former stage and the lower limit of the average heating rate HR2 in the latter stage are not particularly limited.
- HR1 may be 200 ° C./second or less
- HR2 is 0.15 ° C. / Second or more.
- this two-stage heating can be performed by a continuous annealing equipment, a continuous hot dip galvanizing equipment, and a continuous alloying hot dip galvanizing equipment.
- the heating conditions during annealing were controlled to the above conditions when the texture of the hot-rolled sheet was not properly controlled. Even so, the local deformability of the steel sheet deteriorates. Therefore, if the hot rolling is controlled as described above as a precondition before cold rolling and annealing and the texture of the hot rolled original sheet is randomized, the heating conditions during annealing are controlled to the above conditions. Ductility and hole expansibility can be improved sufficiently. Furthermore, steel heated for 1 second or more and 300 seconds or less is held in the temperature range of Ac 1 ° C. or more and 900 ° C. or less by this two-stage heating.
- the steel is cooled to a temperature range of 580 ° C. to 780 ° C. at an average cooling rate of 1 ° C./s to 20 ° C./s (third cooling, first stage cooling). If the average cooling rate is less than 1 ° C./s or the end point temperature of cooling is 780 ° C. or higher, the required ferrite fraction cannot be obtained, and the elongation decreases. On the other hand, when the average cooling rate is 20 ° C./s or more or the cooling end point temperature is less than 580 ° C., pearlite is generated, so that the hole expansibility decreases.
- the steel is cooled to a temperature range of 350 ° C. or more and 500 ° C. or less at an average cooling rate of 5 ° C./s or more and 200 ° C./s or less (fourth cooling, second stage cooling).
- the steel is kept in the temperature range of 350 ° C. or more and 500 ° C. or less as it is for t OA seconds or more and 1000 seconds or less.
- the steel is further cooled to 350 ° C. or lower as it is (fifth cooling), and then the steel is reheated to a temperature range of 350 ° C. or higher and 500 ° C. or lower, and 350 ° C. or higher.
- the steel is held in the temperature range of 500 ° C. or less for t OA seconds or more and 1000 seconds or less.
- the bainite transformation does not proceed sufficiently, and good hole expandability cannot be obtained.
- a lot of martensite is generated, so that elongation is reduced in addition to hole expansibility.
- the formation of pearlite can be further suppressed by setting the average cooling rate of the quaternary cooling to 5 ° C./s or more.
- the upper limit of the average cooling rate of the quaternary cooling is not particularly limited, but may be 200 ° C./s in order to increase the accuracy of temperature control.
- t OA can be obtained by the following (formula 21).
- TOA is a holding temperature in a temperature range of 350 ° C. or more and 500 ° C. or less.
- This skin pass rolling it is possible to prevent stretcher strain generated during processing and to correct the steel plate shape.
- the cold-rolled steel sheet manufactured as described above is subjected to hot-dip galvanizing treatment or alloying hot-dip galvanizing treatment as necessary, and a hot-dip galvanized layer or an alloyed hot-dip galvanized layer is formed on the surface of the cold-rolled steel plate. It may be formed.
- the logarithm of the ratio of the water vapor partial pressure p H2O to the hydrogen partial pressure p H2 (log (p H2O / p H2 )) satisfies ⁇ 3.0 to 0.0 before forming the plating layer. It is preferable to perform annealing (for example, heating under the above-mentioned predetermined conditions or holding within a predetermined temperature range) by controlling the atmosphere in the furnace.
- FIGS. 9 and 10 are flowcharts showing an outline of a method for manufacturing a cold-rolled steel sheet according to this embodiment.
- the steel that has been cooled as it is or to room temperature is reheated and heated to a temperature range of 900 ° C. to 1300 ° C., and then the steel plate is manufactured under the production conditions shown in Tables 4 to 7.
- Hot rolling was performed while controlling the temperature. After the hot rolling was completed at a temperature of Ar 3 or higher, the steel was cooled, and this steel was wound up to obtain a hot rolled original sheet having a thickness of 2 to 5 mm. Thereafter, this steel (hot rolled sheet) was pickled and cold-rolled to a thickness of 1.2 to 2.3 mm, and heated and held for annealing.
- the obtained steel sheet was cooled and held in two stages, and skin pass rolling was performed on the steel sheet at a rolling rate of 0.5% to obtain a cold-rolled steel sheet.
- the cold-rolled steel sheet is manufactured so that the manufacturing conditions after hot rolling satisfy the manufacturing conditions shown in Tables 8 to 11.
- production No. For A1 in addition to the unplated cold-rolled steel sheet (cold-rolled original sheet), a hot-dip galvanized layer and an alloyed hot-dip galvanized layer were formed to produce a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet.
- t1 could not be calculated because the reduction was not more than 30% at T1 + 30 ° C. to T1 + 200 ° C. Therefore, this production No. For O2, the rolling reduction of the final pass from T1 + 30 ° C. to T1 + 200 ° C. was used as P1.
- Tables 1 to 3 show the chemical composition of each steel, and Tables 4 to 7 and Tables 8 to 11 show the production conditions.
- Tables 12 to 15 show the microstructures and mechanical properties of the steel sheets obtained.
- F, B, residual ⁇ , M, P, and tM represent the area ratios of ferrite, bainite, residual austenite, martensite, pearlite, and tempered martensite, respectively.
- strength TS and hole expansibility (lambda) is shown in FIG. 6
- strength TS and elongation EL is shown in FIG.
- the pole density is set at a pitch of 0.5 ⁇ m with respect to the central portion of the plate thickness in the region of 5/8 to 3/8 of the plate thickness cross section parallel to the rolling direction at 1/4 of the plate width direction. It was measured.
- a steel sheet in which the chemical composition and microstructure (particularly the extreme density of each crystal orientation) of the steel sheet are appropriately controlled has both excellent hole expansibility and ductility. Recognize.
- production No. In the hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel sheet obtained from A1, the microstructure and mechanical properties of each plated steel sheet were measured according to Production No. It was the same as the microstructure and mechanical properties of the cold-rolled sheet (Tables 12 to 15) corresponding to.
- TRIP steel it is possible to provide a high-strength cold-rolled steel sheet excellent in ductility and hole expandability and a method for producing the same.
Abstract
Description
本願は、2011年3月28日に、日本に出願された特願2011-70725号に基づき優先権を主張し、その内容をここに援用する。
T1=850+10×([C]+[N])×[Mn]・・・(式1)
ここで、[C]、[N]及び[Mn]は、それぞれ、前記鋼中のC、N及びMn量の質量百分率である。
t≦2.5×t1・・・(式2)
ここで、t1は下記式3で表される。
t1=0.001×((Tf-T1)×P1/100)2-0.109×((Tf-T1)×P1/100)+3.1・・・(式3)
ここで、Tfは前記最終パス完了時の前記鋼の摂氏温度であり、P1は前記最終パスでの圧下率の百分率である。
Ar3=879.4-516.1×[C]-65.7×[Mn]+38.0×[Si]+274.7×[P]・・・(式4)
Ac1=723-10.7×[Mn]-16.9×[Ni]+29.1×[Si]+16.9×[Cr]+290×[As]+6.38×[W]・・・(式5)
T1=850+10×([C]+[N])×[Mn]+350×[Nb]+250×[Ti]+40×[B]+10×[Cr]+100×[Mo]+100×[V]・・・(式7)
ここで、[C]、[N]、[Mn]、[Nb]、[Ti]、[B]、[Cr]、[Mo]及び[V]は、それぞれ、C、N、Mn、Nb、Ti、B、Cr、Mo及びVの質量百分率である。
0≦t<t1・・・(式8)
t1≦t≦2.5×t1・・・(式9)
本発明者らは、そのようなTRIP鋼板において、鋼成分や製造途中のミクロ組織を最適化し、フェライト及びオーステナイトの2相域またはオーステナイト単相域の温度範囲から冷却を開始し、所定の温度範囲での冷却(2段階の冷却)を制御して、この温度範囲内に保持することによって、強度と延性と穴拡げ性とのバランスに優れた鋼板を得ることができることを見出した。
まず、冷延鋼板の結晶方位の極密度について述べる。
本実施形態に係る冷延鋼板では、2種類の結晶方位の極密度として、5/8~3/8の板厚範囲(鋼板の表面から鋼板の板厚方向(深さ方向)に板厚の5/8~3/8の距離だけ離れた範囲)である板厚中央部における圧延方向に平行な板厚断面に対して、{100}<011>~{223}<110>方位群の平均極密度D1(以下では、平均極密度と省略する場合がある)と、{332}<113>の結晶方位の極密度D2とを制御している。
本実施形態では、平均極密度は、特に重要な集合組織(ミクロ組織中の結晶粒の結晶方位)の特徴点(方位集積度、集合組織の発達度)である。なお、平均極密度は、{100}<011>、{116}<110>、{114}<110>、{112}<110>、{223}<110>の各結晶方位の極密度の相加平均で表される極密度である。
図1及び2では、5/8~3/8の板厚範囲である板厚中央部における断面に対してX線回折を行い、ランダム試料に対する各方位のX線回折強度の強度比を求め、この各強度比から{100}<011>~{223}<110>方位群の平均極密度を求めている。
これら図1及び2に示されるように、{100}<011>~{223}<110>方位群の平均極密度が6.5以下であれば、鋼板が直近要求されている足回り部品の加工に必要とされる特性(後述の指数TS×λ及びTS×EL)を満足しうる。すなわち、この特性として、引張強度TSと、穴拡げ率λと、伸びELとが、TS×λ≧30000(図1参照)及びTS×EL≧14000(図2参照)を満たしうる。これらの指数TS×λ及びTS×ELをより高める場合には、この平均極密度は、4.0以下であることが好ましく、3.5以下であることがより好ましく、3.0以下であることがさらに好ましい。
また、平均極密度が6.5超では、鋼板の機械的特性の異方性が極めて強くなる。その結果、特定の方向のみの穴拡げ性が改善するが、その方向とは異なる方向での穴拡げ性が著しく劣化する。そのため、この場合には、足回り部品の加工に必要とされる特性について、鋼板が、TS×λ≧30000及びTS×EL≧14000を満足しない。
一方、平均極密度が1.0未満になると、穴拡げ性の劣化が懸念される。そのため、平均極密度が1.0以上であることが好ましい。
一方、{332}<113>の結晶方位の極密度が1.0未満になると、穴拡げ性の劣化が懸念される。そのため、{332}<113>の結晶方位の極密度が1.0以上であることが好ましい。
しかしながら、上述の板厚中央部の方位集積が最も強く鋼板の異方性に与える影響が大きいため、この板厚中央部の材質が概ね鋼板全体の材質特性を代表する。そのため、5/8~3/8の板厚中央部における{100}<011>~{223}<110>方位群の平均極密度と、{332}<113>の結晶方位の極密度とを規定している。
圧延方向に対して直角方向のr値(rC):
すなわち、本発明者等が鋭意検討した結果、上記各極密度を上記の範囲内にすると同時に、rCを0.70以上にすることにより、良好な穴拡げ性を得ることができることを見出した。そのため、rCが0.70以上である。
rCの上限は、より優れた穴拡げ性を得るためには、rCが1.10以下であるとよい。
本発明者等が鋭意検討した結果、上記各極密度を上記の範囲内にすると同時に、r30を1.10以下にすることにより、良好な穴拡げ性を得ることができることを見出した。そのため、r30が1.10以下である。
r30の下限は、より優れた穴拡げ性を得るためには、r30が0.70以上であるとよい。
さらに、本発明者等が鋭意検討した結果、上記各極密度、rC、r30を上述した範囲内にすると同時に、rLおよびr60が、それぞれrL≧0.70、r60≦1.10を満足することにより、より良好なTS×λを得ることができることを見出した。そのため、rLが0.70以上であり、r60が1.10以下であるとよい。
上述のrLの上限およびr60の下限は、より優れた穴拡げ性を得るためには、rLが1.10以下、r60が0.70以上であるとよい。
本実施形態に係る冷延鋼板の基本的なミクロ組織は、フェライトと、ベイナイトと、残留オーステナイトとからなる。本実施形態では、この基本的なミクロ組織の構成要素に加え(フェライト、ベイナイト、残留オーステナイトの一部の代わりに)、さらに、必要に応じてまたは不可避的に、パーライト、マルテンサイト、焼戻しマルテンサイトの1種以上を選択的なミクロ組織の構成要素としてミクロ組織中に含んでいてもよい。なお、本実施形態では、個々のミクロ組織を面積率により評価する。
また、ミクロ組織が、パーライトを10%以下の範囲で、マルテンサイトを20%以下の範囲でそれぞれ必要に応じて含んでもよい。パーライト及びマルテンサイトの量が多くなると、鋼板の加工性及び局部変形能が低下したり、残留オーステナイトを生成させるCの利用率が低下したりする。そのため、ミクロ組織中において、パーライトを10%以下に、マルテンサイトを20%以下に制限する。
また、フェライト、パーライト、ベイナイト及びマルテンサイトの面積率は、1/8~3/8の板厚範囲(すなわち、1/4の板厚位置が中心になる板厚範囲)を電界放射型走査電子顕微鏡(FE-SEM:Field Emission Scanning Electron Microscope)により観察し、得られた画像から決定することができる。このFE-SEM観察では、鋼板の圧延方向に平行な板厚断面が観察面になるように試料を採取し、この観察面に対して研磨及びナイタールエッチングを行っている。
なお、板厚方向について、鋼板表面近傍及び鋼板中心近傍では、それぞれ、脱炭及びMn偏析により鋼板のミクロ組織(構成要素)がその他の部分と大きく異なる場合がある。そのため、本実施形態では、1/4の板厚位置を基準としたミクロ組織の観察を行っている。
細粒に比べると粗大粒の数が伸びへ与える影響度が高いため、伸びは、個数平均径よりも体積の重み付け平均で算出される体積平均径と強く相関する。そのため、上記の効果を得る場合には、体積平均径が、2~15μm、望ましくは、2~9.5μmであるとよい。
パーライトは、光学顕微鏡による組織観察により特定される。また、フェライト、オーステナイト、ベイナイト、マルテンサイト、焼戻しマルテンサイトの粒単位は、EBSDにより特定される。EBSDにより判定された領域の結晶構造が面心立方構造(fcc構造)であれば、この領域をオーステナイトと判定する。また、EBSDにより判定された領域の結晶構造が体心立方構造(bcc構造)であれば、この領域をフェライト、ベイナイト、マルテンサイト、焼戻しマルテンサイトのいずれかと判定する。フェライト、ベイナイト、マルテンサイト及び焼戻しマルテンサイトは、EBSP-OIM(登録商標、Electron Back Scatter Diffraction Pattern-Orientation Image Microscopy)に装備されているKAM(Kernel Average Misorientation)法を用いて識別することができる。KAM法では、測定データのうちのある正六角形のピクセル(中心のピクセル)とこのピクセルに隣り合う6個のピクセルを用いた第一近似(全7ピクセル)、もしくはこれら6個のピクセルのさらに外側の12個のピクセルも用いた第二近似(全19ピクセル)、もしくはこれら12個のピクセルのさらに外側の18個のピクセルも用いた第三近似(全37ピクセル)について、各ピクセル間の方位差を平均し、得られた平均値をその中心のピクセルの値に決定し、このような操作をピクセル全体に対して行う。このKAM法による計算を粒界を超えないように行うことにより、粒内の方位変化を表現するマップを作成できる。このマップは、粒内の局所的な方位変化に基づく歪みの分布を表している。
また、下記の粗大粒分率は、この方法により得られた粗大粒の面積率を測定対象の面積で除することにより得ることができる。
加えて、下記の等軸粒分率は、この方法により得られた等軸粒の面積率を測定対象の面積で除することにより得ることができる。
残留オーステナイトの平均C濃度は、X線回折により求められる。すなわち、Cu-Kα線によるX線解析においてオーステナイトの(200)面、(220)面、(311)面の反射角から格子定数a(単位はオングストローム)を求め、次の(式10)に従い残留オーステナイトの炭素濃度Cγを算出することが出来る。
Cγ=(a-3.572)/0.033・・・(式10)
C:0.02%以上かつ0.4%以下
Cは、高強度を確保し、かつ残留オーステナイトを確保するために必須である。十分な残留オーステナイト量を得るためには、鋼中に0.02%以上のC量を含むとよい。一方、鋼板がCを過剰に含有すると、溶接性を損なうため、C量の上限を0.4%とした。強度と伸びとをより向上させる場合には、C量が、0.05%以上であることが好ましく、0.10%以上であることがより好ましく、0.12%以上であることが最も好ましい。また、より溶接性を向上させる場合には、C量が、0.38%以下であることが好ましく、0.36%以下であることがより好ましい。
Siは脱酸剤であり、鋼中に0.001%以上のSiを含むことが好ましい。また、Siは、焼鈍時にフェライトを安定化させ、かつ、ベイナイト変態時(所定温度範囲内の保持時)のセメンタイト析出を抑制する。そのため、Siは、オーステナイトのC濃度を高め、残留オーステナイトの確保に寄与する。Si量が多いほどその効果は大きくなるが、Siを過剰に鋼中に添加すると、表面性状、塗装性、溶接性などが劣化する。そのため、Si量の上限を2.5%とする。安定な残留オーステナイトを得る効果をSiによって十分に発現させる場合には、Si量が、0.02%以上であることが好ましく、0.50%以上であることが好ましく、0.60%以上であることが最も好ましい。また、表面性状、塗装性、溶接性などをさらに確保する場合には、Si量が、2.2%以下であることが好ましく、2.0%以下であることがより好ましい。
Mnは、オーステナイトを安定化させ、焼入れ性を高める元素である。十分な焼入れ性を確保するためには、鋼中に0.001%以上のMnを含むとよい。一方、Mnを鋼中に過剰に添加すると、延性を損なうため、Mn量の上限を4.0%とする。より高い焼入れ性を確保する場合には、Mn量が、0.1%以上であることが好ましく、0.5%以上であることがより好ましく、1.0%以上であることが最も好ましい。また、より高い延性を確保する場合には、Mn量が、3.8%以下であることが好ましく、3.5%以下であることがより好ましい。
Pは不純物であり、Pを過剰に鋼中に含有すると延性や溶接性を損なう。したがって、P量の上限を0.15%とする。なお、Pは、固溶強化元素として作用するが、不可避的に鋼中に含まれるため、P量の下限は、特に制限する必要がなく、0%である。また、現行の一般的な精錬(二次精錬を含む)を考慮すると、P量の下限は、0.001%であってもよい。延性及び溶接性をより高める場合には、P量が、0.10%以下であることが好ましく、0.05%以下であることがより好ましい。
S:0.03%以下
Sは不純物であり、Sを過剰に鋼中に含有すると、熱間圧延によって伸張したMnSが生成し、延性及び穴拡げ性などの成形性が劣化する。したがって、S量の上限を0.03%とする。なお、Sは、不可避的に鋼中に含まれるため、S量の下限は、特に制限する必要がなく、0%である。また、現行の一般的な精錬(二次精錬を含む)を考慮すると、S量の下限は、0.0005%であってもよい。延性及び穴拡げ性をより高める場合には、S量が、0.020%以下であることが好ましく、0.015%以下であることがより好ましい。
Nは、不純物であり、N量が0.01%を超えると延性が劣化する。したがって、N量の上限を0.01%以下とする。なお、Nは、不可避的に鋼中に含まれるため、N量の下限は、特に制限する必要がなく、0%である。また、現行の一般的な精錬(二次精錬を含む)を考慮すると、N量の下限は、0.0005%であってもよい。より延性を高める場合には、N量が、0.005%以下であることが好ましい。
Alは脱酸剤であり、現行の一般的な精錬(二次精錬を含む)も考慮すると、鋼中に0.001%以上のAlを含むことが好ましい。また、Alは、焼鈍時にフェライトを安定化させ、かつ、ベイナイト変態時(所定温度範囲内の保持時)のセメンタイト析出を抑制する。そのため、Alは、オーステナイトのC濃度を高め、残留オーステナイトの確保に寄与する。Al量が多いほどその効果は大きくなるが、Alを過剰に鋼中に添加すると、表面性状、塗装性、溶接性などが劣化する。そのため、Al量の上限を2.0%とする。安定な残留オーステナイトを得る効果をAlによって十分に発現させる場合には、Al量が、0.01%以上であることが好ましく、0.02%以上であることがより好ましい。また、表面性状、塗装性、溶接性などをさらに確保する場合には、Al量が、1.8%以下であることが好ましく、1.5%以下であることがより好ましい。
O(酸素)は不純物であり、O量が0.01%を超えると延性が劣化する。したがって、O量の上限を0.01%とする。なお、Oは、不可避的に鋼中に含まれるため、O量の下限は、特に制限する必要がなく、0%である。また、現行の一般的な精錬(二次精錬を含む)を考慮すると、O量の下限は、0.0005%であってもよい。
これらの元素は、上述のように、脱酸剤であり、Si量とAl量との合計が1.0%以上であることが好ましい。また、Si、Alの両方とも、焼鈍時にフェライトを安定化させ、かつ、ベイナイト変態時(所定温度範囲内の保持時)のセメンタイト析出を抑制する。そのため、これらの元素は、オーステナイトのC濃度を高め、残留オーステナイトの確保に寄与する。しかし、これらの元素を過剰に鋼中に添加すると、表面性状、塗装性、溶接性などが劣化するので、Si量とAl量との合計を4.5%以下とする。表面性状、塗装性、溶接性などをさらに高める場合には、この合計が、4.0%以下であることが好ましく、3.5%以下であることがより好ましく、3.0%以下であることが最も好ましい。
すなわち、本実施形態に係る冷延鋼板が、例えば介在物制御や析出物微細化により局部成形能を向上させるために、選択元素として、Ti、Nb、B、Mg、REM、Ca、Mo、Cr、V、W、Ni、Cu、Co、Sn、Zr、Asのうちいずれか1種以上を含有しても構わない。
Vは、析出強化に有効であり、この析出強化に起因する穴拡げ性の劣化代が小さいため、高強度でよりよい穴拡げ性が必要な場合に効果的な選択元素である。そのため、必要に応じて、Vを鋼中に添加してもよい。この場合、V量が0.001%以上であることが望ましい。しかしながら、Vを過剰に鋼中に添加すると、加工性が劣化することから、V量を1.0%以下に制限する。また、合金コストの低減のためには、Vを意図的に鋼中に添加する必要がなく、V量の下限は、0%である。
加えて、本実施形態では、冷延鋼板(溶融亜鉛めっき鋼板及び合金化溶融亜鉛めっき鋼板を含む)が、各種の表面処理(電気めっき、溶融めっき、蒸着めっき、クロメート処理、ノンクロ処理、ラミネート処理、各種塩類処理等)がなされていてもよく、その表面に、金属被膜(めっき等)や有機被膜(ラミネートフィルム等)を備えてもよい。
優れた穴拡げ性及び伸びを実現するためには、異方性が少ない極密度を有する集合組織(未発達の集合組織)を形成させることが重要である。そのため、製造された冷延鋼板が上記の各極密度の条件を満たすための製造条件の詳細を以下に記す。
また、後述の熱間圧延では、粗圧延後にシートバーを接合し、連続的に仕上げ圧延を行っても良い。その際、粗バーを、一旦コイル状に巻き、必要に応じて保温機能を有するカバーに格納し、再度巻き戻してから接合を行っても良い。
まず、局部変形能を高めるためには、粗圧延後すなわち仕上げ圧延前のオーステナイト粒径が重要である。すなわち、仕上げ圧延前のオーステナイト粒径が小さいことが望ましく、平均オーステナイト粒径が200μm以下であれば十分な局部変形能を確保するために効果的であることが判明した。加えて、rC及びr30を、それぞれ0.70以上及び1.10以下により効率よく制御する場合には、仕上げ圧延前の平均オーステナイト粒径が200μm以下であるとよい。
これは、仕上げ圧延中の再結晶核の1つとして粗圧延後の(すなわち、仕上げ圧延前の)オーステナイト粒界が機能することによると推測される。
T1=850+10×([C]+[N])×[Mn]+350×[Nb]+250×[Ti]+40×[B]+10×[Cr]+100×[Mo]+100×[V]・・・(式11)
なお、この(式11)では、[C]、[N]、[Mn]、[Nb]、[Ti]、[B]、[Cr]、[Mo]及び[V]は、それぞれ、C、N、Mn、Nb、Ti、B、Cr、Mo及びVの質量百分率である。また、(式11)中に含まれない化学元素(化学成分)の量は、0%として計算する。そのため、上記の基本成分のみを含む基本組成では、上記(式11)の代わりに、下記(式12)を使用してもよい。
T1=850+10×([C]+[N])×[Mn]・・・(式12)
また、鋼が選択元素を含む場合には、(式12)により算出される温度の代わりに(式11)により算出される温度をT1(℃)とする必要がある。
仕上げ圧延では、上記(式11)または(式12)により得られる温度T1(℃)を基準に、T1+30℃以上かつT1+200℃以下の温度範囲(望ましくはT1+50℃かつT1+100℃以下の温度範囲)では、大きな圧下率を確保し、Ar3℃以上かつT1+30℃未満の温度範囲では、圧下率を小さな範囲(0%を含む)に制限する。上記の粗圧延に加え、このような仕上げ圧延を行うことにより、最終製品の局部変形能を高めることができる。
なお、T1+30℃以上かつT1+200℃以下の温度範囲において、圧延の各パス間の鋼板の温度上昇を抑制することにより、均一な再結晶オーステナイトを得ることができる。
また、Ar3℃以上かつT1+30℃未満の温度範囲での圧下率が大きいと、再結晶したオーステナイト粒が展伸し、穴拡げ性が劣化する。
すなわち、本実施形態に係る製造条件では、仕上げ圧延においてオーステナイトを均一かつ微細に再結晶させることで製品の集合組織を制御して穴拡げ性を改善することができる。
Ar3=879.4-516.1×[C]-65.7×[Mn]+38.0×[Si]+274.7×[P]・・・(式13)
上記熱間圧延における大圧下パス(上述のように、大圧下パスは、T1+30℃以上かつT1+200℃以下の温度範囲における30%以上の圧下率の圧下(パス)である)のうちの最終パスの完了から一次冷却を開始するまでの待ち時間t(秒)が下記の(式14)を満たすように、大圧下パスのうちの最終パスに相当する圧延スタンド後に鋼を冷却する(一次冷却)。ここで、(式14)中のt1は、下記(式15)により求めることができる。(式15)中のTfは、大圧下パスの最終パス完了時の鋼板の温度(℃)であり、P1は、大圧下パスのうちの最終パスの圧下率(%)である。ここで、操業性(例えば、形状矯正や二次冷却の制御性)を考慮する場合には、一次冷却を圧延スタンド間で行うとよい。
待ち時間tが(式14)の右辺の値(t1×2.5)を超えると、ほとんど再結晶が完了している一方で、結晶粒が著しく成長して結晶粒径が増加するため、r値(例えば、rC及びr30)及び伸びが著しく低下する。そのため、待ち時間tが下記(式14)を満足するように冷却開始を制御することにより、結晶粒径を適切に制御して十分な伸びを確保するのに有効である。
t≦2.5×t1・・・(式14)
t1=0.001×((Tf-T1)×P1/100)2-0.109×((Tf-T1)×P1/100)+3.1・・・(式15)
t<t1・・・(式16)
t1≦t≦2.5×t1・・・(式17)
また、冷却温度変化を140℃以下に制限することにより、鋼板の温度を比較的容易に制御できるだけでなく、バリアント選択(バリアント制限の回避)をより効果的に制御でき、集合組織の発達をさらに抑制することもできる。したがって、この場合には、より等方性を高めることができ、加工性の方位依存性をより小さくすることができる。さらに、一次冷却の冷却終了時の鋼板温度T2がT1+100℃以下であると、より十分な冷却効果が得られる。この冷却効果により、結晶粒成長を抑制することができ、結晶粒径の増加をさらに抑制することができる。
また、一次冷却における平均冷却速度が50℃/秒以上であることが望ましい。この一次冷却での平均冷却速度が50℃/秒以上であると、再結晶したオーステナイト粒の粒成長をより抑制することができる。一方、平均冷却速度の上限を特に定める必要はないが、板形状の観点から平均冷却速度が200℃/秒以下であってもよい。
さらに、650℃以下の温度まで鋼を冷却後(この冷却は、二次冷却に含まれる)、650℃以下の温度範囲で鋼(熱延原板)を巻取る。650℃以下の温度に達する前に鋼を巻取ると、冷延後の鋼板の異方性が大きくなり、穴拡げ性が著しく低下する。巻き取り温度の下限は、特に制限されないが、マルテンサイトの生成を抑制して冷間圧延の負荷を抑制するために、350℃以上であってもよい。
さらに、この二段階の加熱によりAc1℃以上かつ900℃以下の温度範囲に、1秒以上かつ300秒以下加熱された鋼が保持される。このAc1℃よりも低い温度もしくはこの1秒よりも短い時間では、フェライト等の低温相からオーステナイトへの逆変態が十分に進まず、その後の冷却工程で第二相を得ることができず、十分な強度が得られない。加えて、この場合には、フェライト等の低温相とともに、冷延後の集合組織がそのまま残ることになり、局部変形能の劣化をもたらす。一方、900℃よりも高い温度もしくは300秒よりも長い時間では、保持により結晶粒が粗大化し、r値や伸びが低下する。
ここで、Ac1、前段での平均加熱速度HR1及び後段での平均加熱速度HR2は、それぞれ、以下の式18、式19及び式20により得られる。
Ac1=723-10.7×[Mn]-16.9×[Ni]+29.1×[Si]+16.9×[Cr]+290×[As]+6.38×[W]・・・(式18)
HR1≧0.3・・・(式19)
HR2≦0.5×HR1・・・(式20)
ここで、tOAは、下記の(式21)で求めることができる。
加えて、得られた冷延鋼板に、上述のような各種の表面処理を適用してもよい。
参考のため、図9及び10に、本実施形態に係る冷延鋼板の製造方法の概略を示すフローチャートを示す。
表1~表3に示した化学組成(残部が鉄及び不可避的不純物)を有する鋼No.A~Y及び鋼No.a~gを用いて検討した結果について説明する。
また、得られた結果について、強度TSと穴拡げ性λとの関係を図6に、強度TSと伸びELとの関係を図7に示す。
なお、JIS Z 2241に準拠した引張試験により、引張強度TS、伸び(全伸び)EL、各方向のr値(rL、rC、r30、r60:JIS Z 2254(2008)(ISO10113(2006))に準拠)を決定した。また、鉄連規格JFS T1001に準拠した穴拡げ試験により、穴拡げ性λを決定した。なお、r値の測定におけるその他の条件は、上記実施形態の条件と同様である。
また前述のEBSDを用いて、板幅方向の1/4における圧延方向に平行な板厚断面の5/8~3/8の領域の板厚中央部に対して0.5μmピッチで極密度を測定した。
Claims (19)
- 鋼板の化学組成が、質量%で、
C:0.02%以上かつ0.4%以下、
Si:0.001%以上かつ2.5%以下、
Mn:0.001%以上かつ4.0%以下、
Al:0.001%以上かつ2.0%以下
を含有し、
P:0.15%以下、
S:0.03%以下、
N:0.01%以下、
O:0.01%以下
に制限し、残部が鉄及び不可避的不純物からなり、
前記鋼板の化学組成では、Si量とAl量との合計が1.0質量%以上かつ4.5質量%以下であり、
5/8~3/8の板厚範囲である板厚中央部では、{100}<011>、{116}<110>、{114}<110>、{112}<110>、{223}<110>の各結晶方位の極密度の相加平均で表される極密度である、{100}<011>~{223}<110>方位群の平均極密度が1.0以上かつ6.5以下であり、{332}<113>の結晶方位の極密度が1.0以上かつ5.0以下であり、
前記鋼板のミクロ組織に、複数の結晶粒が存在し、このミクロ組織が、面積率で、フェライトを5%以上かつ80%以下、ベイナイトを5%以上かつ80%以下、残留オーステナイトを2%以上かつ30%以下含み、前記ミクロ組織では、面積率で、マルテンサイトが20%以下、パーライトが10%以下、焼戻しマルテンサイトが60%以下に制限され、
圧延方向に対して直角方向のランクフォード値であるrCが0.70以上かつ1.10以下であり、前記圧延方向に対して30°をなす方向のランクフォード値であるr30が0.70以上かつ1.10以下である
ことを特徴とする冷延鋼板。 - 前記鋼板の化学組成が、さらに、質量%で、
Ti:0.001%以上かつ0.2%以下、
Nb:0.005%以上かつ0.2%以下、
B:0.0001%以上かつ0.005%以下、
Mg:0.0001%以上かつ0.01%以下、
REM:0.0001%以上かつ0.1%以下、
Ca:0.0001%以上かつ0.01%以下、
Mo:0.001%以上かつ1.0%以下、
Cr:0.001%以上かつ2.0%以下、
V:0.001%以上かつ1.0%以下、
W:0.001%以上かつ1.0%以下、
Ni:0.001%以上かつ2.0%以下、
Cu:0.001%以上かつ2.0%以下、
Co:0.0001%以上かつ1.0%以下、
Sn:0.0001%以上かつ0.2%以下、
Zr:0.0001%以上かつ0.2%以下、
As:0.0001%以上かつ0.5%以下
から選択される1種以上を含有することを特徴とする請求項1に記載の冷延鋼板。 - 前記結晶粒の体積平均径が2μm以上かつ15μm以下であることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記{100}<011>~{223}<110>方位群の平均極密度が、1.0以上かつ5.0以下であり、前記{332}<113>の結晶方位の極密度が1.0以上かつ4.0以下であることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記複数の結晶粒のうち、35μmを超える結晶粒の面積割合が10%以下に制限されていることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記複数の結晶粒のうち、圧延方向の結晶粒の長さを板厚方向の結晶粒の長さで除した値が3.0以下である結晶粒の割合が、50%以上かつ100%以下であることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記ベイナイトのビッカース硬さが180HV以上であり、前記残留オーステナイトの平均C濃度が0.9%以上であることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記圧延方向のランクフォード値であるrLが0.70以上かつ1.10以下であり、前記圧延方向に対して60°をなす方向のランクフォード値であるr60が0.70以上かつ1.10以下であることを特徴とする請求項1または2に記載の冷延鋼板。
- 前記鋼板の表面に、溶融亜鉛めっき層または合金化溶融亜鉛めっき層を備えることを特徴とする請求項1または2に記載の冷延鋼板。
- 質量%で、
C:0.02%以上かつ0.4%以下、
Si:0.001%以上かつ2.5%以下、
Mn:0.001%以上かつ4.0%以下、
Al:0.001%以上かつ2.0%以下
を含有し、
P:0.15%以下、
S:0.03%以下、
N:0.01%以下、
O:0.01%以下
に制限し、残部が鉄及び不可避的不純物からなり、Si量とAl量との合計が1.0質量%以上かつ4.5質量%以下である化学組成を有する鋼に対して、1000℃以上かつ1200℃以下の温度範囲で、40%以上の圧下率のパスを少なくとも1回含む第1の熱間圧延を行い、前記鋼の平均オーステナイト粒径を200μm以下とし;
下記式1により算出される温度をT1℃とした場合、T1+30℃以上かつT1+200℃以下の温度範囲に30%以上の圧下率の大圧下パスを含み、T1+30℃以上かつT1+200℃以下の温度範囲での累積圧下率が50%以上であり、下記式4により算出されるAr3℃以上かつT1+30℃未満の温度範囲での累積圧下率が30%以下に制限され、圧延終了温度が下記式4により算出されるAr3℃以上である第2の熱間圧延を前記鋼に対して行い;
前記大圧下パスのうちの最終パスの完了から冷却開始までの待ち時間t秒が、下記式2を満たすように、前記鋼に対して一次冷却を行い;
650℃以下の温度範囲で前記鋼を巻取り;
前記鋼を酸洗し;
30%以上かつ90%以下の圧延率で前記鋼を冷間圧延し;
室温~650℃の温度範囲における平均加熱速度HR1が0.3℃/秒以上であり、650℃超かつ下記式5により算出されるAc1℃以下の温度範囲における平均加熱速度HR2が単位を℃/秒として0.5×HR1以下である二段階の加熱を行い;
Ac1℃以上かつ900℃以下の温度範囲内に1秒以上かつ300秒以下前記鋼を保持し;
580℃以上かつ780℃以下の温度範囲まで1℃/s以上かつ20℃/s以下の平均冷却速度で前記鋼を冷却し;
5℃/s以上かつ200℃/s以下の平均冷却速度で350℃以上かつ500℃以下の温度範囲内の温度TOAに前記鋼を冷却し;
350℃以上かつ500℃以下の温度範囲内に下記式6により算出される時間tOA秒以上かつ1000秒以下前記鋼を保持し、鋼板を得る、もしくは、350℃以下まで前記鋼をさらに冷却して350℃以上かつ500℃以下の温度範囲まで前記鋼を再加熱した後、350℃以上かつ500℃以下の温度範囲内に下記式6により計算される時間tOA秒以上かつ1000秒以下前記鋼を保持し、鋼板を得る
ことを特徴とする冷延鋼板の製造方法。
T1=850+10×([C]+[N])×[Mn]・・・(式1)
ここで、[C]、[N]及び[Mn]は、それぞれ、前記鋼中のC、N及びMn量の質量百分率である。
t≦2.5×t1・・・(式2)
ここで、t1は下記式3で表される。
t1=0.001×((Tf-T1)×P1/100)2-0.109×((Tf-T1)×P1/100)+3.1・・・(式3)
ここで、Tfは前記最終パス完了時の前記鋼の摂氏温度であり、P1は前記最終パスでの圧下率の百分率である。
Ar3=879.4-516.1×[C]-65.7×[Mn]+38.0×[Si]+274.7×[P]・・・(式4)
Ac1=723-10.7×[Mn]-16.9×[Ni]+29.1×[Si]+16.9×[Cr]+290×[As]+6.38×[W]・・・(式5)
- 前記鋼は、前記化学組成として、さらに、質量%で、
Ti:0.001%以上かつ0.2%以下、
Nb:0.005%以上かつ0.2%以下、
B:0.0001%以上かつ0.005%以下、
Mg:0.0001%以上かつ0.01%以下、
REM:0.0001%以上かつ0.1%以下、
Ca:0.0001%以上かつ0.01%以下、
Mo:0.001%以上かつ1.0%以下、
Cr:0.001%以上かつ2.0%以下、
V:0.001%以上かつ1.0%以下、
W:0.001%以上かつ1.0%以下、
Ni:0.001%以上かつ2.0%以下、
Cu:0.001%以上かつ2.0%以下、
Co:0.0001%以上かつ1.0%以下、
Sn:0.0001%以上かつ0.2%以下、
Zr:0.0001%以上かつ0.2%以下、
As:0.0001%以上かつ0.5%以下
から選択される1種以上を含有し、前記式1により算出される温度の代わりに下記式7により算出される温度を前記T1℃とすることを特徴とする請求項10に記載の冷延鋼板の製造方法。
T1=850+10×([C]+[N])×[Mn]+350×[Nb]+250×[Ti]+40×[B]+10×[Cr]+100×[Mo]+100×[V]・・・(式7)
ここで、[C]、[N]、[Mn]、[Nb]、[Ti]、[B]、[Cr]、[Mo]及び[V]は、それぞれ、C、N、Mn、Nb、Ti、B、Cr、Mo及びVの質量百分率である。 - 前記待ち時間t秒が、前記t1を用いた下記式8を満たすことを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
0≦t<t1・・・(式8) - 前記待ち時間t秒が、前記t1を用いた下記式9を満たすことを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
t1≦t≦2.5×t1・・・(式9) - 前記一次冷却では、冷却開始時の鋼温度と冷却終了時の鋼温度との差である冷却温度変化が40℃以上かつ140℃以下であり、前記冷却終了時の鋼温度がT1+100℃以下であることを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
- 前記第1の熱間圧延が、40%以上の圧下率のパスを少なくとも2回以上含み、前記鋼の平均オーステナイト粒径を100μm以下とすることを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
- 最終圧延スタンド通過後で、かつ、前記一次冷却の完了後10秒以内に二次冷却を開始することを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
- 前記第2の熱間圧延では、T1+30℃以上かつT1+200℃以下の温度範囲での各パス間の前記鋼の温度上昇を18℃以下とすることを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
- 前記一次冷却を圧延スタンド間で行うことを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
- 前記鋼板の表面に、溶融亜鉛めっき層または合金化溶融亜鉛めっき層を形成することを特徴とする請求項10または11に記載の冷延鋼板の製造方法。
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JP6354271B2 (ja) * | 2014-04-08 | 2018-07-11 | 新日鐵住金株式会社 | 低温靭性と均一伸びと穴拡げ性に優れた引張強度780MPa以上の高強度熱延鋼板及びその製造方法 |
JP5967320B2 (ja) * | 2014-08-07 | 2016-08-10 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
CN104233092B (zh) * | 2014-09-15 | 2016-12-07 | 首钢总公司 | 一种热轧trip钢及其制备方法 |
DE102014017273A1 (de) * | 2014-11-18 | 2016-05-19 | Salzgitter Flachstahl Gmbh | Hochfester lufthärtender Mehrphasenstahl mit hervorragenden Verarbeitungseigenschaften und Verfahren zur Herstellung eines Bandes aus diesem Stahl |
DE102014017274A1 (de) * | 2014-11-18 | 2016-05-19 | Salzgitter Flachstahl Gmbh | Höchstfester lufthärtender Mehrphasenstahl mit hervorragenden Verarbeitungseigenschaften und Verfahren zur Herstellung eines Bandes aus diesem Stahl |
CN104404367B (zh) * | 2014-12-10 | 2016-08-31 | 东北大学 | 一种高强度高塑性冷轧低碳钢及其制备方法 |
US10590504B2 (en) | 2014-12-12 | 2020-03-17 | Jfe Steel Corporation | High-strength cold-rolled steel sheet and method for manufacturing the same |
US20160230284A1 (en) | 2015-02-10 | 2016-08-11 | Arcanum Alloy Design, Inc. | Methods and systems for slurry coating |
US20180023162A1 (en) * | 2015-02-20 | 2018-01-25 | Nippon Steel & Sumitomo Metal Corporation | Hot-rolled steel sheet |
WO2016132549A1 (ja) * | 2015-02-20 | 2016-08-25 | 新日鐵住金株式会社 | 熱延鋼板 |
MX2017008622A (es) | 2015-02-20 | 2017-11-15 | Nippon Steel & Sumitomo Metal Corp | Hoja de acero laminada en caliente. |
TWI592500B (zh) | 2015-02-24 | 2017-07-21 | 新日鐵住金股份有限公司 | 冷軋鋼板及其製造方法 |
CN107406929B (zh) | 2015-02-25 | 2019-01-04 | 新日铁住金株式会社 | 热轧钢板 |
WO2016135898A1 (ja) | 2015-02-25 | 2016-09-01 | 新日鐵住金株式会社 | 熱延鋼板 |
WO2017022027A1 (ja) * | 2015-07-31 | 2017-02-09 | 新日鐵住金株式会社 | 加工誘起変態型複合組織鋼板およびその製造方法 |
DE102015112886A1 (de) * | 2015-08-05 | 2017-02-09 | Salzgitter Flachstahl Gmbh | Hochfester aluminiumhaltiger Manganstahl, ein Verfahren zur Herstellung eines Stahlflachprodukts aus diesem Stahl und hiernach hergestelltes Stahlflachprodukt |
DE102015112889A1 (de) * | 2015-08-05 | 2017-02-09 | Salzgitter Flachstahl Gmbh | Hochfester manganhaltiger Stahl, Verwendung des Stahls für flexibel gewalzte Stahlflachprodukte und Herstellverfahren nebst Stahlflachprodukt hierzu |
JP6596153B2 (ja) * | 2015-09-28 | 2019-10-23 | シーアールエス ホールディングス,インコーポレイテッド | 高強度、高衝撃靭性および優れた疲労寿命を有する泥水モータのシャフト用途のための合金鋼 |
WO2017109538A1 (en) * | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a steel sheet having improved strength, ductility and formability |
WO2017109541A1 (en) * | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a high strength coated steel sheet having improved ductility and formability, and obtained coated steel sheet |
WO2017109540A1 (en) * | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a high strength steel sheet having improved ductility and formability, and obtained steel sheet |
CN105543702A (zh) * | 2015-12-28 | 2016-05-04 | 合肥中澜新材料科技有限公司 | 一种高强度合金汽车车门 |
CN109072371B (zh) * | 2016-01-29 | 2020-08-21 | 杰富意钢铁株式会社 | 温加工用高强度钢板及其制造方法 |
CA3016296C (en) * | 2016-03-02 | 2021-05-11 | Nippon Steel & Sumitomo Metal Corporation | Railway wheel |
CN105779864B (zh) * | 2016-04-28 | 2017-11-21 | 武汉钢铁有限公司 | 弥散强化微合金高强钢及其生产方法 |
DE102016108836B4 (de) * | 2016-05-12 | 2018-05-24 | Benteler Automobiltechnik Gmbh | Kraftfahrzeugbauteil sowie Verfahren zu dessen Herstellung |
WO2017201418A1 (en) * | 2016-05-20 | 2017-11-23 | Arcanum Alloys, Inc. | Methods and systems for coating a steel substrate |
KR101795278B1 (ko) * | 2016-06-21 | 2017-11-08 | 현대자동차주식회사 | 초고강도 스프링강 |
KR101795277B1 (ko) * | 2016-06-21 | 2017-11-08 | 현대자동차주식회사 | 내식성이 우수한 고강도 스프링강 |
CN106011623A (zh) * | 2016-06-28 | 2016-10-12 | 安徽富乐泰水泵系统有限公司 | 一种耐低温强度高的泵轴材料 |
CN105950994A (zh) * | 2016-07-11 | 2016-09-21 | 吴用镜 | 一种钻进钻杆用铜镍合金钢 |
CN106191692A (zh) * | 2016-07-11 | 2016-12-07 | 吴用镜 | 一种钻进钻杆用合金钢材料 |
MX2019000051A (es) | 2016-08-05 | 2019-04-01 | Nippon Steel & Sumitomo Metal Corp | Lamina de acero y lamina de acero chapada. |
WO2018026014A1 (ja) | 2016-08-05 | 2018-02-08 | 新日鐵住金株式会社 | 鋼板及びめっき鋼板 |
BR112018073110A2 (pt) * | 2016-08-08 | 2019-03-06 | Nippon Steel & Sumitomo Metal Corp | chapa de aço |
JP6103165B1 (ja) * | 2016-08-16 | 2017-03-29 | 新日鐵住金株式会社 | 熱間プレス成形部材 |
US11401595B2 (en) | 2016-08-31 | 2022-08-02 | Jfe Steel Corporation | High-strength steel sheet and production method therefor |
JP6315044B2 (ja) * | 2016-08-31 | 2018-04-25 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
WO2018083035A1 (de) * | 2016-11-02 | 2018-05-11 | Salzgitter Flachstahl Gmbh | Mittelmanganstahlprodukt zum tieftemperatureinsatz und verfahren zu seiner herstellung |
SE1651545A1 (en) * | 2016-11-25 | 2018-03-06 | High strength cold rolled steel sheet for automotive use | |
EP3592871A1 (en) * | 2017-03-10 | 2020-01-15 | Tata Steel Limited | Hot rolled steel product with ultra-high strength minimum 1100mpa and good elongation 21% |
CN110402298B (zh) | 2017-03-13 | 2021-10-15 | 杰富意钢铁株式会社 | 高强度冷轧钢板和其制造方法 |
EP3572546B1 (en) * | 2017-03-13 | 2022-02-09 | JFE Steel Corporation | High-strength cold-rolled steel sheet and method for manufacturing the same |
BR112019019317A2 (pt) * | 2017-03-31 | 2020-04-14 | Nippon Steel Corp | folha de aço laminada a quente, parte forjada de aço e método de produção para a mesma |
WO2018189950A1 (ja) * | 2017-04-14 | 2018-10-18 | Jfeスチール株式会社 | 鋼板およびその製造方法 |
CN107130174A (zh) * | 2017-06-07 | 2017-09-05 | 武汉钢铁有限公司 | 一种抗拉强度≥780MPa的合金化热镀锌钢及生产方法 |
CN107326276B (zh) * | 2017-06-19 | 2019-06-07 | 武汉钢铁有限公司 | 一种抗拉强度500~600MPa级热轧高强轻质双相钢及其制造方法 |
US10633726B2 (en) * | 2017-08-16 | 2020-04-28 | The United States Of America As Represented By The Secretary Of The Army | Methods, compositions and structures for advanced design low alloy nitrogen steels |
CN107557692B (zh) * | 2017-08-23 | 2019-01-25 | 武汉钢铁有限公司 | 基于CSP流程的1000MPa级热轧TRIP钢及制造方法 |
CN107475627B (zh) * | 2017-08-23 | 2018-12-21 | 武汉钢铁有限公司 | 基于CSP流程的600MPa级热轧TRIP钢及制造方法 |
CN107488814B (zh) * | 2017-08-23 | 2018-12-28 | 武汉钢铁有限公司 | 基于CSP流程的800MPa级热轧TRIP钢及制造方法 |
KR101950596B1 (ko) * | 2017-08-24 | 2019-02-20 | 현대제철 주식회사 | 초고강도 강 및 그 제조방법 |
WO2019092482A1 (en) | 2017-11-10 | 2019-05-16 | Arcelormittal | Cold rolled heat treated steel sheet and a method of manufacturing thereof |
JP6866932B2 (ja) | 2017-11-24 | 2021-04-28 | 日本製鉄株式会社 | 熱延鋼板及びその製造方法 |
KR102031453B1 (ko) | 2017-12-24 | 2019-10-11 | 주식회사 포스코 | 열연강판 및 그 제조방법 |
JP6901417B2 (ja) | 2018-02-21 | 2021-07-14 | 株式会社神戸製鋼所 | 高強度鋼板および高強度亜鉛めっき鋼板、並びにそれらの製造方法 |
KR102116757B1 (ko) * | 2018-08-30 | 2020-05-29 | 주식회사 포스코 | 배기계용 냉연강판 및 그 제조방법 |
CN109321927B (zh) * | 2018-11-21 | 2020-10-27 | 天津市华油钢管有限公司 | 防腐马氏体螺旋埋弧焊管及其制备工艺 |
KR102178728B1 (ko) * | 2018-12-18 | 2020-11-13 | 주식회사 포스코 | 강도 및 연성이 우수한 강판 및 그 제조방법 |
KR102164078B1 (ko) * | 2018-12-18 | 2020-10-13 | 주식회사 포스코 | 성형성이 우수한 고강도 열연강판 및 그 제조방법 |
CN109881093B (zh) * | 2019-03-01 | 2020-11-13 | 北京科技大学 | 一种热气胀成型用空冷强化钢及其制备方法 |
CN113286910B (zh) | 2019-03-29 | 2023-03-17 | 日本制铁株式会社 | 钢板及其制造方法 |
US20220389554A1 (en) * | 2019-10-01 | 2022-12-08 | Nippon Steel Corporation | Hot-rolled steel sheet |
CN110777297B (zh) * | 2019-10-12 | 2022-07-05 | 河钢股份有限公司 | 一种高扩孔性高拉延性高强度钢板及其制造方法 |
WO2021167079A1 (ja) * | 2020-02-20 | 2021-08-26 | 日本製鉄株式会社 | 熱延鋼板 |
MX2023000811A (es) * | 2020-07-20 | 2023-02-27 | Arcelormittal | Hoja de acero laminada en frio tratada termicamente y un metodo para la fabricacion de la misma. |
WO2022070840A1 (ja) * | 2020-09-30 | 2022-04-07 | 日本製鉄株式会社 | 高強度鋼板 |
CN112501516A (zh) * | 2020-11-30 | 2021-03-16 | 日照钢铁控股集团有限公司 | 一种1080MPa级高强度高塑性热轧钢生产方法 |
KR102469876B1 (ko) * | 2020-12-18 | 2022-11-23 | 주식회사 포스코 | 밀착성이 우수한 고강도 법랑용 냉연강판 및 이의 제조방법 |
EP4299769A1 (en) * | 2021-05-13 | 2024-01-03 | Nippon Steel Corporation | Steel sheet for hot stamping and hot stamped molded body |
DE102022102418A1 (de) | 2022-02-02 | 2023-08-03 | Salzgitter Flachstahl Gmbh | Hochfestes schmelztauchbeschichtetes Stahlband mit durch Gefügeumwandlung bewirkter Plastizität und Verfahren zu dessen Herstellung |
CN115055918B (zh) * | 2022-06-17 | 2023-09-19 | 首钢智新迁安电磁材料有限公司 | 一种无取向硅钢的连轧方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61217529A (ja) | 1985-03-22 | 1986-09-27 | Nippon Steel Corp | 延性のすぐれた高強度鋼板の製造方法 |
JPH0559429A (ja) | 1991-09-03 | 1993-03-09 | Nippon Steel Corp | 加工性に優れた高強度複合組織冷延鋼板の製造方法 |
JP2003113440A (ja) * | 2001-10-04 | 2003-04-18 | Nippon Steel Corp | 形状凍結性に優れる絞り可能な高強度薄鋼板およびその製造方法 |
JP2004250744A (ja) * | 2003-02-19 | 2004-09-09 | Nippon Steel Corp | 形状凍結性に優れた高加工性高強度熱延鋼板とその製造方法 |
JP2009114523A (ja) * | 2007-11-08 | 2009-05-28 | Nippon Steel Corp | 剛性、深絞り性及び穴拡げ性に優れた高強度冷延鋼板及びその製造方法 |
Family Cites Families (42)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000119804A (ja) | 1998-10-16 | 2000-04-25 | Nippon Steel Corp | 深絞り性に優れる熱延鋼板およびその製造方法 |
JP2000144314A (ja) | 1998-11-02 | 2000-05-26 | Nippon Steel Corp | 角筒絞り性に優れる熱延鋼板およびその製造方法 |
JP3539548B2 (ja) * | 1999-09-20 | 2004-07-07 | Jfeスチール株式会社 | 加工用高張力熱延鋼板の製造方法 |
US6589369B2 (en) * | 2000-04-21 | 2003-07-08 | Nippon Steel Corporation | High fatigue strength steel sheet excellent in burring workability and method for producing the same |
JP3990553B2 (ja) | 2000-08-03 | 2007-10-17 | 新日本製鐵株式会社 | 形状凍結性に優れた高伸びフランジ性鋼板およびその製造方法 |
KR100543956B1 (ko) | 2000-09-21 | 2006-01-23 | 신닛뽄세이테쯔 카부시키카이샤 | 형상 동결성이 우수한 강판 및 그 제조방법 |
JP3814134B2 (ja) | 2000-09-21 | 2006-08-23 | 新日本製鐵株式会社 | 加工時の形状凍結性と衝撃エネルギー吸収能に優れた高加工性高強度冷延鋼板とその製造方法 |
AUPR047900A0 (en) | 2000-09-29 | 2000-10-26 | Bhp Steel (Jla) Pty Limited | A method of producing steel |
JP3927384B2 (ja) * | 2001-02-23 | 2007-06-06 | 新日本製鐵株式会社 | 切り欠き疲労強度に優れる自動車用薄鋼板およびその製造方法 |
ATE383452T1 (de) * | 2001-10-04 | 2008-01-15 | Nippon Steel Corp | Ziehbares hochfestes dünnes stahlblech mit hervorragender formfixierungseigenschaft und herstellungsverfahren dafür |
JP4028719B2 (ja) | 2001-11-26 | 2007-12-26 | 新日本製鐵株式会社 | 形状凍結性に優れる絞り可能なバーリング性高強度薄鋼板およびその製造方法 |
FR2836930B1 (fr) | 2002-03-11 | 2005-02-25 | Usinor | Acier lamine a chaud a tres haute resistance et de faible densite |
JP3821036B2 (ja) * | 2002-04-01 | 2006-09-13 | 住友金属工業株式会社 | 熱延鋼板並びに熱延鋼板及び冷延鋼板の製造方法 |
JP3901039B2 (ja) | 2002-06-28 | 2007-04-04 | Jfeスチール株式会社 | 成形性に優れる超高強度冷延鋼板およびその製造方法 |
JP4160839B2 (ja) | 2003-02-19 | 2008-10-08 | 新日本製鐵株式会社 | 形状凍結性に優れた異方性の小さな高加工性高強度熱延鋼板とその製造方法 |
JP4235030B2 (ja) | 2003-05-21 | 2009-03-04 | 新日本製鐵株式会社 | 局部成形性に優れ溶接部の硬さ上昇を抑制した引張強さが780MPa以上の高強度冷延鋼板および高強度表面処理鋼板 |
TWI248977B (en) | 2003-06-26 | 2006-02-11 | Nippon Steel Corp | High-strength hot-rolled steel sheet excellent in shape fixability and method of producing the same |
JP4384523B2 (ja) | 2004-03-09 | 2009-12-16 | 新日本製鐵株式会社 | 形状凍結性に極めて優れた低降伏比型高強度冷延鋼板およびその製造方法 |
JP4692015B2 (ja) | 2004-03-30 | 2011-06-01 | Jfeスチール株式会社 | 伸びフランジ性と疲労特性に優れた高延性熱延鋼板およびその製造方法 |
JP4464748B2 (ja) | 2004-07-06 | 2010-05-19 | 新日本製鐵株式会社 | 形状凍結性と伸びフランジ成形性に優れた高強度鋼板、高強度溶融亜鉛めっき鋼板、および、高強度合金化溶融亜鉛めっき鋼板とそれらの製造方法 |
CN101238233B (zh) | 2005-08-03 | 2012-11-28 | 住友金属工业株式会社 | 热轧钢板及冷轧钢板及它们的制造方法 |
EP1767659A1 (fr) | 2005-09-21 | 2007-03-28 | ARCELOR France | Procédé de fabrication d'une pièce en acier de microstructure multi-phasée |
JP5058508B2 (ja) | 2005-11-01 | 2012-10-24 | 新日本製鐵株式会社 | 低降伏比型高ヤング率鋼板、溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及び鋼管、並びにそれらの製造方法 |
JP4714574B2 (ja) | 2005-12-14 | 2011-06-29 | 新日本製鐵株式会社 | 高強度鋼板及びその製造方法 |
JP2007291514A (ja) | 2006-03-28 | 2007-11-08 | Jfe Steel Kk | 冷延−再結晶焼鈍後の面内異方性が小さい熱延鋼板、面内異方性が小さい冷延鋼板およびそれらの製造方法 |
JP5228447B2 (ja) | 2006-11-07 | 2013-07-03 | 新日鐵住金株式会社 | 高ヤング率鋼板及びその製造方法 |
JP5214905B2 (ja) * | 2007-04-17 | 2013-06-19 | 株式会社中山製鋼所 | 高強度熱延鋼板およびその製造方法 |
JP5053157B2 (ja) * | 2007-07-04 | 2012-10-17 | 新日本製鐵株式会社 | プレス成形性の良好な高強度高ヤング率鋼板、溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板及び鋼管、並びに、それらの製造方法 |
JP5088021B2 (ja) | 2007-07-05 | 2012-12-05 | 新日本製鐵株式会社 | 高剛性高強度冷延鋼板及びその製造方法 |
JP2009097545A (ja) | 2007-10-13 | 2009-05-07 | Toyota Motor Corp | 車両用電子制御カップリング |
JP5217395B2 (ja) | 2007-11-30 | 2013-06-19 | Jfeスチール株式会社 | 伸びの面内異方性が小さい高強度冷延鋼板およびその製造方法 |
JP4894863B2 (ja) | 2008-02-08 | 2012-03-14 | Jfeスチール株式会社 | 加工性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
AU2009234667B2 (en) * | 2008-04-10 | 2012-03-08 | Nippon Steel Corporation | High-strength steel sheets which are extremely excellent in the balance between burring workability and ductility and excellent in fatigue endurance, zinc-coated steel sheets, and processes for production of both |
JP5068689B2 (ja) | 2008-04-24 | 2012-11-07 | 新日本製鐵株式会社 | 穴広げ性に優れた熱延鋼板 |
KR20100010169A (ko) | 2008-07-22 | 2010-02-01 | 박은정 | 다층인쇄회로기판 및 그 제조방법 |
JP5245647B2 (ja) | 2008-08-27 | 2013-07-24 | Jfeスチール株式会社 | プレス成形性と磁気特性に優れた熱延鋼板およびその製造方法 |
JP5206244B2 (ja) * | 2008-09-02 | 2013-06-12 | 新日鐵住金株式会社 | 冷延鋼板 |
JP5370016B2 (ja) | 2008-09-11 | 2013-12-18 | 新日鐵住金株式会社 | 穴広げ性に優れた高強度熱延鋼板及びその製造方法 |
JP4737319B2 (ja) | 2009-06-17 | 2011-07-27 | Jfeスチール株式会社 | 加工性および耐疲労特性に優れた高強度合金化溶融亜鉛めっき鋼板およびその製造方法 |
EP2578711B1 (en) | 2010-05-27 | 2019-10-09 | Nippon Steel Corporation | Steel sheet and a method for its manufacture |
US9273370B2 (en) | 2010-07-28 | 2016-03-01 | Nippon Steel & Sumitomo Metal Corporation | Hot-rolled steel sheet, cold-rolled steel sheet, galvanized steel sheet, and methods of manufacturing the same |
EP2692895B1 (en) | 2011-03-28 | 2018-02-28 | Nippon Steel & Sumitomo Metal Corporation | Cold-rolled steel sheet and production method thereof |
-
2012
- 2012-03-28 EP EP12763971.4A patent/EP2692895B1/en active Active
- 2012-03-28 MX MX2013011063A patent/MX338997B/es active IP Right Grant
- 2012-03-28 US US14/007,583 patent/US9546413B2/en active Active
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61217529A (ja) | 1985-03-22 | 1986-09-27 | Nippon Steel Corp | 延性のすぐれた高強度鋼板の製造方法 |
JPH0559429A (ja) | 1991-09-03 | 1993-03-09 | Nippon Steel Corp | 加工性に優れた高強度複合組織冷延鋼板の製造方法 |
JP2003113440A (ja) * | 2001-10-04 | 2003-04-18 | Nippon Steel Corp | 形状凍結性に優れる絞り可能な高強度薄鋼板およびその製造方法 |
JP2004250744A (ja) * | 2003-02-19 | 2004-09-09 | Nippon Steel Corp | 形状凍結性に優れた高加工性高強度熱延鋼板とその製造方法 |
JP2009114523A (ja) * | 2007-11-08 | 2009-05-28 | Nippon Steel Corp | 剛性、深絞り性及び穴拡げ性に優れた高強度冷延鋼板及びその製造方法 |
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