JP2004290988A - Method for cooling hot-rolled steel sheet and its production method, and hot-rolling facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cooling a hot-rolled steel sheet, its production method and a hot-rolling facility for preventing over-cooling at the edge parts of the hot-rolled steel sheet over the whole length of this steel sheet. <P>SOLUTION: This cooling method for hot-rolled steel sheet is the cooling method for steel sheet by providing edge mask shiftable in the width direction of the hot-rolled steel sheet and using a cooling device disposed at the outlet side of a finish-rolling mill while masking the edge part of the steel sheet with the edge mask. A meandering detector for detecting the meandering of the steel sheet is disposed between the finish-rolling mill and the cooling device and also, a temperature profile meter is disposed at the outlet side of the cooling device or on the downstream side of the edge mask in the cooling device. The edge mask is shifted in the width direction of the steel sheet while following the meandering of the steel sheet based on the output of the meandering detector, and the masking position of the edge parts in the steel sheet with the edge mask is controlled based on the output of the temperature profile meter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４１】
ここで、図３中の▲１▼〜▲４▼の位置とは、▲１▼は鋼帯トップ近傍位置、▲２▼は鋼帯トップより約２０ｍの位置、▲３▼は鋼帯がオペ側に約２０ｍｍ蛇行した直後の位置で、トップより約１５０ｍの位置、▲４▼は鋼帯トップより約１７０ｍの位置である。
【００４２】
上記の特徴を有する対象材に対して、比較例として、ハ）エッジマスクを全く使用しない場合、ニ）エッジマスク位置を鋼帯幅センター基準にＦＳとＤＳ側に同じ距離を必要量離して固定した場合、ホ）冷却装置出側に設置した温度プロフィル計の出力にのみ基づきエッジマスクを鋼帯幅方向に移動させる場合の、図３中の▲１▼〜▲４▼の鋼帯位置での冷却装置出側温度プロフィル計による鋼帯幅方向の温度分布測定結果を図４（ｂ）および表１に併せて示した。
【００４３】
図４および表１より、本発明例である、仕上圧延機と冷却装置との間に設置した蛇行検出器および冷却装置出側出側に設置した温度プロフィル計の出力に基づきエッジマスクを鋼帯幅方向に移動させる場合（イの場合）、鋼帯エッジ部の温度偏差（実績温度−目標温度）は最大で−１５℃であった。上記イ）の条件に、仕上圧延機と冷却装置との間にさらに温度プロフィル計を設置し、これらの出力に基づきエッジマスクを鋼帯幅方向に移動させる場合（ロの場合）、鋼帯エッジ部の温度偏差（実績温度−目標温度）は最大で−１０℃となり、より好ましい。
【００４４】
これに対して、比較例である、ハ）エッジマスクを全く使用しない場合、ニ）エッジマスク位置を鋼帯幅センター基準にＦＳとＤＳ側に同じ距離を必要量離して固定した場合、ホ）冷却装置出側に設置した温度プロフィル計の出力にのみ基づきエッジマスクを鋼帯幅方向に移動させる場合の鋼帯エッジ部の温度偏差（実績温度−目標温度）は最大で、それぞれ−６０℃、−３５℃、−４５℃であり、本発明例により、熱延鋼帯全長に亘って熱延鋼帯幅方向の温度分布を均一にでき、熱延鋼帯のエッジ部の過冷却を防ぐためのエッジマスキング位置を正確に設定できることが判る。
【００４５】
【発明の効果】
以上説明したように、本発明によれば、特許文献１に示すような冷却装置を用いて冷却する際に、熱延鋼帯全長に亘って熱延鋼帯のエッジ部の過冷却を防ぐためのエッジマスキング位置を正確に設定できるので、鋼帯の歩留まりが向上する。
【図面の簡単な説明】
【図１】本発明の熱間圧延設備の一例を示す側面図
【図２】本発明の熱延鋼帯の冷却方法に用いるエッジマスクの構造の一例を示す側面図
【図３】（ａ）は本対象材の仕上圧延機出側の幅方向の温度分布を示し、（ｂ）は本対象材のコイル長に対する蛇行量を示すグラフ
【図４】（ａ）は本発明例の冷却装置出側温度プロフィル計による鋼帯幅方向の温度分布を示し、（ｂ）は比較例の冷却装置出側温度プロフィル計による鋼帯幅方向の温度分布を示すグラフ
【符号の説明】
１ 熱延鋼帯
２ 上部冷却手段
３ 下部冷却手段
４ 冷却装置
５ 水切り手段
６ 搬送ロール
７ 蛇行検出器
８ａ〜８ｄ 油圧シリンダー
９ エッジマスク
９ａ 鋼帯上面ドライブ側エッジマスク
９ｂ 鋼帯下面ドライブ側エッジマスク
９ｃ 鋼帯上面オペ側エッジマスク
９ｄ 鋼帯下面オペ側エッジマスク
１０ 仕上圧延機
１１ 温度プロフィル計
１２ 温度プロフィル計
１３ エッジマスク移動制御装置[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a cooling method for cooling a hot-rolled steel strip by using a cooling device arranged on an outlet side of a finishing mill, a manufacturing method thereof, and a hot rolling facility.
[0002]
[Prior art]
In general, a hot-rolled steel strip heats a slab to a predetermined temperature in a heating furnace, and rolls the heated slab to a predetermined thickness in a rough rolling mill to form a coarse bar, and then the coarse bar comprises a plurality of rolling stands. It is manufactured by finish rolling in a finish rolling mill to form a hot-rolled steel strip having a predetermined thickness, cooling the hot-rolled steel strip on a hot run table by a cooling device, and winding it by a coiler.
[0003]
As such a cooling device, a lower cooling unit which is disposed between conveying rolls constituting a hot run table disposed on the exit side of a finishing mill and supplies cooling water to a lower surface of a hot-rolled steel strip running on the hot run table. Means, an upper cooling means that is located above the hot run table and is arranged at a position facing the lower cooling means in the vertical direction, and supplies cooling water to the upper surface of the hot rolled steel strip running on the hot run table, Drainage means arranged near the upper surface of the hot-rolled steel strip and arranged along the width direction of the steel strip in order to suppress the outflow of the cooling water supplied from the upper cooling means in the longitudinal direction of the hot-rolled steel strip. BACKGROUND ART A cooling device for a hot-rolled steel strip is known (for example, see Patent Document 1).
[0004]
[Patent Document 1]
In the conventional cooling of a hot-rolled steel strip using such a cooling device, an edge mask is usually installed in the cooling device, and the edge portion of the steel strip is masked by the edge mask. Although the steel strip is cooled, the temperature drop of the steel strip edge is detected according to the output of the profile thermometer installed on the outlet side of the cooling device or downstream of the edge mask in the cooling device, and the steel strip edge is detected. However, the masking position of the steel strip edge was determined so as not to cause excessive cooling.
[0005]
[Problems to be solved by the invention]
However, the above-described prior art has the following problems.
[0006]
Conventionally, when the hot-rolled steel strip meanders on the exit side of the finish rolling mill, the response is delayed by feedback control in which the masking position of the steel strip edge is determined based only on the output of the profile thermometer on the exit side of the cooling device. However, the supercooled portion of the steel strip edge remained.
[0007]
Accordingly, an object of the present invention is to provide a method of cooling a hot-rolled steel strip for preventing overcooling of an edge portion of the hot-rolled steel strip over the entire length of the hot-rolled steel strip, a method of manufacturing the same, and a hot rolling facility. Is to do.
[0008]
[Means for Solving the Problems]
The method for cooling a hot-rolled steel strip, the method for manufacturing the same, and the hot rolling equipment according to the present invention for solving the above-mentioned problems have the following features.
[0009]
(1) Equipped with an edge mask movable in the width direction of the hot-rolled steel strip, and cooling the steel strip while masking the edge of the steel strip with the edge mask using a cooling device arranged on the exit side of the finishing mill. In the method, a meandering detector for detecting meandering of the steel strip is installed between the finishing mill and the cooling device, and a temperature profile meter is provided on the outlet side of the cooling device or on the downstream side of the edge mask in the cooling device. In accordance with the output of the meandering detector, the edge mask is moved in the width direction of the steel strip following the meandering of the steel strip, and based on the output of the temperature profile meter, masking of the steel strip edge portion by the edge mask is performed. A method for cooling a hot-rolled steel strip, comprising controlling the position.
[0010]
(2) A temperature profile meter is further provided between the finishing mill and the cooling device, and the masking position of the steel strip edge portion by the edge mask is controlled based on the output of the temperature profile meter. The method for cooling a hot-rolled steel strip according to 1).
[0011]
(3) The edge mask for masking each edge portion of the hot-rolled steel strip includes an upper edge mask for masking the upper surface of the steel strip edge and a lower edge mask for masking the lower surface of the steel strip edge. The method for cooling a hot-rolled steel strip according to the above (1) or (2), wherein the lower edge masks are independently movable in the width direction of the steel strip.
[0012]
(4) A cooling device provided with an edge mask movable in the width direction of the hot-rolled steel strip, and a meandering of the steel strip is detected between the finishing mill and the cooling device disposed on the exit side of the finishing mill. A meandering detector, a temperature profile meter for measuring the temperature distribution in the width direction of the steel strip on the outlet side of the cooling device or downstream of the edge mask in the cooling device, and the edge mask based on the outputs of the meandering detector and the temperature profiler. Hot-rolling equipment, comprising: an edge mask movement control device that moves the steel sheet in the width direction of the steel strip and controls the amount of movement.
[0013]
(5) The hot rolling equipment according to the above (5), wherein a temperature profile meter is further provided between the finishing mill and the cooling device.
[0014]
(6) a heating step of heating the slab, a rough rolling step of roughly rolling the slab heated in the heating step, a finish rolling step of finish rolling a coarse bar roughly rolled in the rough rolling step, A cooling step of cooling the steel strip finish-rolled in the finish rolling step by the method of cooling a hot-rolled steel strip according to any one of the above (1) to (3); A method for producing a hot-rolled steel strip, comprising: a winding step;
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Drawing 1 is a side view showing an example of the hot rolling equipment of the present invention.
[0016]
The hot rolling equipment includes a plurality of lower cooling means 3 for supplying cooling water to the lower surface of the hot-rolled steel strip 1 running on a hot run table, and a plurality of lower cooling means for supplying cooling water to the upper surface of the hot-rolled steel strip 1. A cooling device 4 comprising the upper cooling means 2; an edge mask 9 movable in the width direction of the hot-rolled steel strip disposed in the cooling device 4; a transport roll 6 for passing the hot-rolled steel strip; A meandering detector 7 for detecting the meandering of the steel strip between the cooling device 4 and a temperature profile meter for measuring the widthwise temperature distribution of the steel strip between the finishing mill 10 and the cooling device 4; 12, a temperature profile meter 11 installed on the outlet side of the cooling device 4, and an edge mask movement control device for moving the edge mask in the width direction of the steel strip and controlling the amount of movement.
[0017]
The lower cooling means 3 is disposed between the transport rolls 6 constituting the hot run table, and is provided at a suitable interval along the longitudinal direction of the header and a header disposed along the width direction of the hot-rolled steel strip. It consists of a plurality of cooling nozzles.
[0018]
The upper cooling means 2 comprises a header arranged along the width direction of the hot-rolled steel strip, and a plurality of cooling nozzles provided at appropriate intervals along the longitudinal direction of the header. The lower cooling means 3 is disposed at an appropriate distance from the lower cooling means 3 in the vertical direction. Further, it is arranged between the draining means 5 which is arranged close to the upper surface of the hot-rolled steel strip and along the width direction of the steel strip.
[0019]
The draining means 5 is preferably a draining roll. It is effective for suppressing the sheet passing property and flaw generation of the hot-rolled steel strip.
[0020]
The meandering detector 7 measures the displacement of the position of the hot-rolled steel strip with respect to the line center on the exit side of the finishing mill 10 and outputs it to the edge mask movement control device 13 to perform feedforward control of the movement of the edge mask 9. .
[0021]
The temperature profile meter 11 measures the temperature distribution in the width direction of the steel strip on the exit side of the cooling device 4 and outputs the measured temperature distribution to the edge mask movement control device 13 to feedback-control the movement of the edge mask 9.
[0022]
The temperature profile meter 12 may not be installed between the finishing mill 10 and the cooling device 4 in some cases, but is preferably installed. The temperature distribution in the width direction of the steel strip on the exit side of the finishing mill 10 is measured and output to the edge mask movement control device 13 to feed-forward control the movement of the edge mask 9.
[0023]
When the temperature profile meter 12 is installed, whichever of the temperature profile meter 12 and the meandering detector 7 may be installed between the finishing mill 10 and the cooling device 4.
[0024]
The edge mask movement control device 13 moves the edge mask 9 in the width direction of the steel strip based on the outputs of the meandering detector 7, the temperature profile meter 12, and the temperature profile meter 11, and controls the amount of movement.
[0025]
In FIG. 1, a laminar cooling device, which is a so-called general slow cooling device, is provided at a stage subsequent to the cooling device 4 which is a rapid cooling device.
[0026]
FIG. 2 is a side view showing an example of the structure of an edge mask used in the method for cooling a hot-rolled steel strip according to the present invention.
[0027]
The edge mask 9 for masking each edge portion of the hot-rolled steel strip includes an upper edge mask (drive side 9a and an operation side 9c) for masking the upper surface of the steel strip edge and a lower edge mask (drive side) for masking the lower surface of the steel strip edge. The upper edge mask and the lower edge mask can be independently moved in the width direction of the steel strip.
[0028]
These edge masks 9a to 9d are driven by independent hydraulic cylinders 8a to 8d, respectively. The edge masks 9a to 9d may be driven independently of each other, and may be driven up and down between the upper drive side edge mask 9a and the lower drive side edge mask 9b, and up and down between the upper drive side edge mask 9c and the lower drive side edge mask 9d. May be driven as a single unit.
[0029]
Hereinafter, an embodiment of the method of the present invention using the above-mentioned equipment configuration will be described.
[0030]
In this embodiment, the meandering amount of the steel strip 1 is detected by using the meandering detector 7 installed between the finishing mill 10 and the cooling device 4 for the hot-rolled steel strip 1 that has been finish-rolled by the finishing mill 10. Then, the edge mask 9 is moved in the steel strip width direction following the meandering of the steel strip. In this case, the edge mask 9 has the same operation as the upper mask (the drive side 9a and the operation side 9c) and the lower edge mask (the drive side 9b and the operation side 9d) which constitute the edge mask 9. 9 moves rigidly. At the same time, the masking position of the steel strip edge by the edge mask 9 is controlled based on the output of the temperature profile meter 11 installed on the outlet side of the cooling device 4 or on the downstream side of the edge mask in the cooling device. At this time, the edge masks 9a to 9d may be independently controlled, or the upper and lower portions of the drive side edge mask and the upper and lower portions of the operation side edge mask may be controlled integrally.
[0031]
Preferably, a temperature profile meter 12 is further provided between the finishing mill 10 and the cooling device 4, and based on the output of the temperature profile meter 12, the masking position of the edge portion of the steel strip by the edge mask is preferably controlled.
[0032]
As a factor that the supercooling amount of the steel strip edge changes between the drive side and the operation side,
(1) Temperature deviation of the steel strip on the inlet side of the cooling device (2) Meandering of the steel strip (3) Equipment characteristics of the cooling device (changes depending on the cooling amount and plate size)
Is mentioned. Here, (1) can be evaluated by the temperature profile meter on the exit side of the finishing mill, (2) can be evaluated by the meandering detector, and (3) can be evaluated by the temperature profile meter on the exit side of the cooling device-finish rolling. (E.g., temperature profile meter on the outboard side-meandering detector).
[0033]
In other words, the provision of the temperature profile meter 12 on the exit side of the finishing mill is effective in (1) compensating for the deviation of the temperature of the steel strip on the inlet side of the cooling device and (3) evaluating the equipment characteristics of the cooling device.
[0034]
In the present invention, the temperature profile meter on the outlet side of the cooling device is feedback-controlled for the above (3) equipment characteristics of the cooling device. The distance to the side temperature profile meter position cannot be compensated. After the tip of the steel strip has passed the temperature profile meter position on the cooling device outlet side, control is performed so as to compensate for the equipment characteristics of the cooling device with a response delay corresponding to the distance. However, unlike the conventional method, feed-forward control is applied to the meandering part.Furthermore, by installing a temperature profile meter on the exit side of the finishing mill, feed-forward control is applied to the temperature deviation part on the inlet side of the cooling device of the steel strip. If the tracking accuracy in the longitudinal direction of the steel strip is good, there will be no response delay and the accuracy will be higher than before.
[0035]
Furthermore, by evaluating the equipment characteristics of the cooling device in advance for each cooling amount, steel strip size (steel type, dimensions), steel strip speed, etc., and reflecting the trend survey results in the preset settings of edge masking, The equipment characteristic of the cooling device can be compensated almost from the end of the steel strip.
[0036]
Further, the method for producing a hot-rolled steel strip according to the invention includes a heating step of heating the slab, a rough rolling step of roughly rolling the slab heated in the heating step, and finishing a rough bar roughly rolled in the rough rolling step. A finishing rolling step of rolling, a cooling step of cooling the steel strip finish-rolled in the finishing rolling step by the above-described method of cooling a hot-rolled steel strip, and a winding step of winding the steel strip cooled in the cooling step And a process.
[0037]
【Example】
Using the edge masks shown in FIGS. 1 and 2 and using a plurality of TS40K materials having a thickness of 2.8 mm and a width of 1000 mm as the target materials, the same rolling is performed to keep the conditions other than the edge mask control method as constant as possible. At the chance, it was extracted from the same heating furnace and tested.
[0038]
As shown in FIG. 3A, the temperature distribution in the width direction on the exit side of the finish rolling mill of the target material has a temperature drop of −20 ° C. from the drive-side steel strip edge 200 mm to the drive-side steel strip edge. There is a temperature drop of −10 ° C. between the operation side steel strip edge 200 mm and the operation side steel strip edge, and there is a temperature deviation between the drive side and the operation side steel strip edge. As shown in FIG. 3 (b), all of the target materials meander about 50 mm from the center of the steel strip width toward the drive side when the coil length is from top to about 140 m, and the steel length is from about 140 to the bottom. It had the characteristic of meandering about 20 mm from the band width center to the operation side.
[0039]
For the target material having the above characteristics, as an example of the present invention, a) based on the output of the meandering detector installed between the finishing mill and the cooling device and the temperature profile meter installed on the outlet side of the cooling device. When the edge mask is moved in the width direction of the steel strip, b) a temperature profile meter is further installed between the finishing mill and the cooling device under the above condition a), and based on these outputs, the edge mask is moved to the width of the steel strip. FIG. 4 (a) and Table 1 show the results of measuring the temperature distribution in the steel strip width direction by the cooling device outlet temperature profile meter at the steel strip positions (1) to (4) in FIG. It was shown to.
[0040]
[Table 1]

[0041]
Here, the positions of (1) to (4) in FIG. 3 are (1) a position near the top of the steel strip, (2) a position about 20 m from the top of the steel strip, and (3) an operation of the steel strip. Immediately after meandering about 20 mm to the side, the position is about 150 m from the top, and {circle around (4)} is about 170 m from the top of the steel strip.
[0042]
For the target material having the above characteristics, as a comparative example, c) when the edge mask is not used at all, d) fix the edge mask position to the FS and the DS side at a required distance from the center of the steel strip width center by a necessary amount. E) In the case where the edge mask is moved in the width direction of the steel strip based only on the output of the temperature profile meter installed on the outlet side of the cooling device, at the positions of the steel strips (1) to (4) in FIG. FIG. 4B and Table 1 also show the results of measuring the temperature distribution in the width direction of the steel strip by the cooling device outlet temperature profile meter.
[0043]
FIG. 4 and Table 1 show that the edge mask is a steel strip based on the output of the meandering detector installed between the finishing mill and the cooling device and the temperature profile meter installed on the outlet side of the cooling device. When it was moved in the width direction (in the case of (a)), the temperature deviation (actual temperature-target temperature) of the steel strip edge portion was at most -15 ° C. Under the conditions of a) above, when a temperature profile meter is further installed between the finishing mill and the cooling device, and the edge mask is moved in the width direction of the steel strip based on these outputs (in the case of b), The temperature deviation of the part (actual temperature-target temperature) is at most -10 ° C, which is more preferable.
[0044]
On the other hand, in the comparative example, c) when the edge mask is not used at all, d) when the edge mask position is fixed to the FS and the DS side by a required distance from the center of the steel strip width center, and e) When the edge mask is moved in the width direction of the steel strip based only on the output of the temperature profile meter installed on the outlet side of the cooling device, the temperature deviation (actual temperature−target temperature) of the steel strip edge is -60 ° C. −35 ° C. and −45 ° C. According to the present invention, the temperature distribution in the width direction of the hot-rolled steel strip can be made uniform over the entire length of the hot-rolled steel strip, and overcooling of the edge portion of the hot-rolled steel strip is prevented. It can be seen that the edge masking position can be set accurately.
[0045]
【The invention's effect】
As described above, according to the present invention, in order to prevent overcooling of the edge portion of a hot-rolled steel strip over the entire length of the hot-rolled steel strip when cooling using a cooling device as disclosed in Patent Document 1. Since the edge masking position of the steel strip can be set accurately, the yield of the steel strip is improved.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of the hot rolling equipment of the present invention. FIG. 2 is a side view showing an example of the structure of an edge mask used in the method of cooling a hot-rolled steel strip of the present invention. Fig. 4 shows the temperature distribution in the width direction of the target material on the exit side of the finishing mill, and Fig. 4 (b) is a graph showing the meandering amount with respect to the coil length of the target material. Graph showing the temperature distribution in the steel strip width direction by the side temperature profile meter, and (b) is a graph showing the temperature distribution in the steel strip width direction by the cooling device outlet temperature profile meter of the comparative example.
DESCRIPTION OF SYMBOLS 1 Hot rolled steel strip 2 Upper cooling means 3 Lower cooling means 4 Cooling device 5 Drainage means 6 Conveyance roll 7 Meandering detectors 8a-8d Hydraulic cylinder 9 Edge mask 9a Steel strip upper surface drive side edge mask 9b Steel band lower surface drive side edge mask 9c Steel strip upper surface operation side edge mask 9d Steel strip lower surface operation side edge mask 10 Finishing mill 11 Temperature profile meter 12 Temperature profile meter 13 Edge mask movement control device

Claims (6)

A method for cooling a steel strip with an edge mask movable in the width direction of the hot-rolled steel strip and using a cooling device arranged on the output side of the finishing mill, wherein the edge mask is used to mask the edges of the steel strip. In addition to installing a meandering detector for detecting meandering of the steel strip between the finishing mill and the cooling device, installing a temperature profile meter on the outlet side of the cooling device or downstream of the edge mask in the cooling device, Based on the output of the meandering detector, the edge mask is moved in the width direction of the steel strip following the meandering of the steel strip, and based on the output of the temperature profile meter, the masking position of the steel strip edge portion by the edge mask is controlled. A method for cooling a hot-rolled steel strip. The temperature profile meter is further provided between the finishing mill and the cooling device, and a masking position of an edge portion of the steel strip by an edge mask is controlled based on an output of the temperature profile meter. Cooling method of hot rolled steel strip. An edge mask for masking each edge portion of the hot-rolled steel strip comprises an upper edge mask for masking the upper surface of the steel strip edge, and a lower edge mask for masking the lower surface of the steel strip edge, wherein the upper edge mask and the lower edge mask are provided. 3. The method of cooling a hot-rolled steel strip according to claim 1 or 2, wherein each of the steel strips is independently movable in a width direction of the steel strip. A cooling device provided with an edge mask movable in the width direction of the hot-rolled steel strip, a cooling device arranged on the exit side of the finishing mill, and a meandering detector for detecting the meandering of the steel strip between the finishing mill and the cooling device. A temperature profile meter for measuring the temperature distribution in the width direction of the steel strip on the outlet side of the cooling device or on the downstream side of the edge mask in the cooling device, and the edge mask based on the output of the meandering detector and the temperature profile meter. A hot rolling facility, comprising: an edge mask movement control device that moves in the width direction and controls the amount of movement. The hot rolling equipment according to claim 5, wherein a temperature profile meter is further provided between the finishing mill and the cooling device. A heating step of heating the slab, a rough rolling step of roughly rolling the slab heated in the heating step, a finish rolling step of finish rolling a coarse bar roughly rolled in the rough rolling step, and the finish rolling step A cooling step of cooling the steel strip finish-rolled by the method of cooling a hot-rolled steel strip according to any one of claims 1 to 3, and a winding step of winding the steel strip cooled in the cooling step. A method for producing a hot-rolled steel strip, comprising:

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