JP5458699B2 - Steel plate cooling device, hot-rolled steel plate manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a steel plate cooling device, a hot rolled steel plate manufacturing device and a manufacturing method, and more particularly to a steel plate cooling device, a hot rolled steel plate manufacturing device and a manufacturing method which are excellent in drainage of cooling water.

  Steel materials used for automobiles and structural materials are required to have excellent mechanical properties such as strength, workability, and toughness. To improve these mechanical properties comprehensively, the structure of the steel material is refined. It is effective. Therefore, many manufacturing methods for obtaining a steel material having a fine structure have been sought. Moreover, according to refinement | miniaturization of a structure, even if it reduces the addition amount of an alloy element, it becomes possible to manufacture the high intensity | strength hot-rolled steel plate provided with the outstanding mechanical property.

  As a method of refining the structure, particularly in the latter stage of hot finish rolling, a method of reducing the austenite grains by rolling under high pressure and accumulating rolling strain in the steel sheet to refine the ferrite grains obtained after rolling. It has been known. Further, it is effective to cool the steel plate to 600 ° C. to 700 ° C. within the shortest possible time after rolling from the viewpoint of suppressing the recrystallization and recovery of austenite to promote the ferrite transformation. That is, following the hot finish rolling, it is effective to install a cooling device capable of cooling earlier than before and quench the rolled steel sheet rapidly. And in order to quench the steel plate after rolling in this way, in order to increase the cooling capacity, it is effective to increase the amount of cooling water per unit area injected onto the steel plate, that is, the flow density.

  However, when the amount of cooling water and the flow density are increased in this way, the water (residual water) that accumulates on the upper surface of the steel sheet increases on the upper surface of the steel sheet due to the relationship between water supply and drainage, and the lower surface guide and The stagnant water between the steel plates may increase. Such stagnant water is water that has been used for cooling the steel sheet, and it is desired to discharge it as soon as possible and provide the water supplied from the nozzle to the steel sheet to ensure the cooling capacity. In addition, since the accumulated water is a layer of water, if it is thick, it becomes a resistance and the water from the nozzle may not reach the steel plate effectively. Further, the stagnant water flows from the central portion of the steel plate toward the end, and the flow velocity increases as it approaches the end of the steel plate. Therefore, when the amount of stagnant water increases, the uneven cooling in the plate width direction of the steel plate increases.

  Here, when attention is paid to the upper surface side of the steel plate, the cooling water supplied to the upper surface of the steel plate is not easily drained, and stagnant water is likely to be generated. Therefore, it is important to smoothly discharge the cooling water on the upper surface of the steel sheet and reduce the amount of stagnant water.

Several techniques for suppressing such stagnant water on the upper surface side of the steel sheet, that is, improving drainage, have been disclosed.
For example, in Patent Document 1, a nozzle is arranged so as to surround an arbitrary section on the upper surface of a steel plate, and cooling water is sprayed into the section to collect water and overflow from the top to drain water from the upper surface. Techniques that enable it are disclosed.
Patent Document 2 discloses a technique for causing cooling water flowing on the upper surface of a steel plate to collide with a draining roll and collecting the bounced cooling water.
Patent Document 3 discloses a technique of draining water by overflowing stagnant water while supplying a columnar jet from a hole penetrating the upper surface guide.
Patent Document 4 discloses an upper surface guide that smoothes drainage by providing a hole for supplying cooling water and a hole for draining.

Japanese Patent Publication No. 7-002972 JP-A-62-289315 Japanese Patent No. 3770216 Japanese Patent No. 4029871

However, the cooling device described in Patent Document 1 is formed so as to surround the entire surface of the steel plate by the nozzle header, and the nozzles are arranged so that the jets face inward, and the nozzles are densely arranged. Cannot be done, and cooling capacity is limited.
In the drainage described in Patent Document 2, it is necessary to use a draining roll. Therefore, the drainage can be applied only in the vicinity of the position where the roll is arranged, and the amount of drainage is limited.
In the upper surface drainage method described in Patent Document 3, since the hole through which the jet passes and the hole through which the drainage passes are common, the water to be supplied interferes with the water to be drained and loses its momentum to cool down. There was a risk that the performance would drop.
Although the drainage capacity is improved in the upper surface guide described in Patent Document 4, further improvement in drainage is demanded as the supply water density further increases and the absolute amount of water increases.

  Therefore, the present invention has an object to provide a steel plate cooling device, a hot rolled steel plate manufacturing apparatus, and a manufacturing method excellent in drainage without obstructing the movement (passing plate) of the steel plate in the hot rolled steel plate manufacturing line. And

  The present invention will be described below. Here, for ease of understanding, reference numerals in the drawings are appended in parentheses, but the present invention is not limited to this.

The invention according to claim 1 is a steel plate (1) which is arranged on the lower process side of the final stand (11g) of the hot finish rolling mill row (11) and is conveyed on the conveying rolls (12, 12, ...). Is a steel plate cooling device (20) provided with a plurality of cooling nozzles (21c, 21c, ..., 22c, 22c, ...) provided so as to be capable of cooling the cooling nozzle, Cooling water can be jetted toward the portion through which the steel plate passes provided on the lower surface side, and an upper surface guide (30) is provided on the upper surface side. ...) inflow holes (32, 32, ...) through which cooling water injected from the cooling nozzles should pass, outflow holes (33, 33, ...) for discharging cooling water injected from the cooling nozzles , and the upper surface side of the upper surface guide The drainage passage forming part (3 , 35, and ...), provided with inflow hole arrays (32A only inflow hole in the width direction of the steel sheet is arranged, 32A, ...) and the outflow hole rows only outlet hole in the width direction of the steel sheet are arranged ( 33A, 33A, ...) is formed, and the above-described problem is solved by providing a steel plate cooling device in which inflow hole rows and outflow hole rows are alternately arranged in the direction in which the steel plate passes .

  Here, “cooling water” is cooling water as a cooling medium, and does not need to be so-called pure water, and means water that may contain impurities inevitably mixed, such as industrial water. To do.

  The invention according to claim 2 is the steel sheet cooling device (20) according to claim 1, wherein a backflow prevention piece (33p, 33p,...) Is erected on the edge of the outflow hole (33, 33,...). It is characterized by being.

  The invention according to claim 3 is the steel sheet cooling device (20) according to claim 1 or 2, and faces the outflow holes (33, 33, ...) in the drainage passage forming portions (35, 35, ...). The rectifying pieces are provided with rectifying pieces (36, 36,...).

  The invention according to claim 4 is the steel plate cooling device (20) according to any one of claims 1 to 3, wherein the inflow holes (33, 33, ...) are provided with cooling nozzles (21c, 21c, ...). ) Is substantially similar to the cross-sectional shape of the cooling water jet jetted from (1).

  Here, the “substantially similar” means that the shape of the inflow hole is formed so as to correspond to the cross-sectional shape of the cooling water jet without strictly requiring the similar shape.

  The invention according to claim 5 is the steel sheet cooling device (20) according to any one of claims 1 to 4, wherein the cooling nozzles (21c, 21c, ...) are flat spray nozzles. To do.

According to a sixth aspect of the present invention, in the steel sheet cooling device (20) according to any one of the first to fifth aspects, a lower surface guide (40) is provided on the lower surface side, and the lower surface guide is disposed on the lower surface side. Of cooling water jetted from the cooling nozzles (22c, 22c,...) And outlet holes (43, 42,...) Through which the cooling water should pass through so that the cooling water can fall down and be discharged. 43,..., And the inflow holes of the lower surface guide and the outflow holes of the lower surface guide are alternately arranged in the moving direction of the steel plate (1).

  The invention according to claim 7 is a steel plate comprising: the final stand (11g) in the hot finish rolling mill row (11); and the steel sheet cooling device (20) according to any one of claims 1 to 6. The said subject is solved by providing the manufacturing apparatus (1) of a hot-rolled steel plate characterized by providing in order in the conveyance direction.

  The invention according to claim 8 is the final stand (11g) in the hot finish rolling mill (11), the steel sheet cooling device (20) according to any one of claims 1 to 6, and cooling water. The said subject is solved by providing the manufacturing apparatus (1) of the hot-rolled steel sheet characterized by providing the draining means (13) which drains the water of this in order in the conveyance direction of a steel plate (1).

  The invention described in claim 9 is the hot-rolled steel sheet manufacturing apparatus (1) according to claim 7 or 8, wherein the cooling nozzle (21c, 21c, ..., 22c, 22c, ...) provided in the cooling device (20). Among these, the nozzle arranged on the uppermost process side is arranged inside the housing of the final stand.

  Here, the “inside of the housing” means a position on the upper process side than the outer surface of the housing (the outer surface on the lower process side in the steel sheet conveyance direction).

  The invention described in claim 10 is the hot-rolled steel sheet manufacturing apparatus (1) according to any one of claims 7 to 9, wherein the cooling nozzle (21c, 21c, ..., 22c provided in the cooling device (20) is provided. , 22c,..., At least the cooling water injection port of the cooling nozzle closest to the final stand (11g) is directed to the steel plate to be positioned at the work roll (11gw, 11gw) outlet of the final stand. And

  Invention of Claim 11 uses the manufacturing apparatus (1) of a hot-rolled steel sheet of any one of Claims 7-10, and the final stand (11g) in a hot finish rolling mill row (11). The said subject is solved by providing the manufacturing method of the hot-rolled steel plate characterized by including the process of processing the steel plate rolled by this.

  According to the present invention, in a hot-rolled steel sheet production line, it is possible to guide a steel sheet to be passed through, and a cooling device that can appropriately drain even when a high-density, large amount of cooling water is supplied. A manufacturing apparatus and a manufacturing method can be provided. As a result, as described above, rapid cooling after rolling can be further promoted, and a steel plate with good mechanical performance can be produced.

It is the figure which showed typically a part of manufacturing apparatus of the hot rolled sheet steel which concerns on one embodiment. It is the figure expanded paying attention to the part in which the cooling device is arrange | positioned among FIG. It is a figure explaining arrangement | positioning of the cooling nozzle in this embodiment, and its injection form. It is a figure explaining an upper surface guide. It is an example explaining the other example of the outflow hole of an upper surface guide. It is a figure explaining the flow of the cooling water by an upper surface guide. It is the figure which showed the other example of the upper surface guide. It is the figure which showed other example of another form of the upper surface guide. It is a figure explaining a lower surface guide. It is an example explaining the other example of the outflow hole of a lower surface guide. It is a figure explaining the flow of the cooling water by a lower surface guide. It is a figure explaining the other form of a lower surface guide. It is a figure explaining the upper surface guide in an Example. It is a figure explaining the lower surface guide in a reference example. It is a figure showing the collision pressure of the jet which is a result of a reference example.

  The above-mentioned operation and gain of the present invention will be clarified from the following embodiments for carrying out the invention. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a diagram schematically showing a part of a steel plate cooling device 20 according to one embodiment and a hot-rolled steel plate manufacturing device 10 including the cooling device 20. In FIG. 1, the steel sheet 1 is conveyed from the left side (upstream side, upper process side) to the right side (downstream side, lower process side) of the paper surface, and the vertical direction of the paper surface is the vertical direction. The upstream side (upper process side) / downstream side (lower process side) direction may be described as the passing plate direction, and the direction of the plate width of the steel plate to be passed is the direction perpendicular to this direction. May be described. In the drawings, repeated reference numerals may be omitted for easy viewing.

  As shown in FIG. 1, a hot-rolled steel plate manufacturing apparatus 10 includes a hot finish rolling mill row 11, a cooling device 20, transport rolls 12, 12,. Although illustration and explanation are omitted, a heating furnace, a rough rolling mill row, and the like are arranged upstream from the hot finish rolling mill row 11 to adjust the conditions of the steel sheet for entering the hot finish rolling mill row 11. ing. On the other hand, another cooling device and a winder are provided on the downstream side of the pinch roll 13, and various facilities for shipping as a steel plate coil are arranged.

  A hot-rolled steel sheet is generally manufactured as follows. That is, the rough bar extracted from the heating furnace and rolled to a predetermined thickness by a roughing mill is continuously rolled to a predetermined thickness by the hot finish rolling mill row 11 while the temperature is controlled. Thereafter, it is rapidly cooled in the cooling device 20. Here, the cooling device 20 is installed in the final stand 11g of the hot finish rolling mill row 11 so as to be as close as possible to the rolling roll from the inside of the housing 11gh that supports the rolling roll. And it passes through the pinch roll 13, is cooled to a predetermined winding temperature by another cooling device, and is wound up in a coil shape by a winder.

  The hot-rolled steel sheet manufacturing apparatus 10 (hereinafter sometimes simply referred to as “manufacturing apparatus 10”) includes the hot finish rolling mill row 11 as described above. In this embodiment, seven rolling mills (11a, 11b, 11c,..., 11g) are arranged in parallel along the sheet passing direction. Each of the rolling mills 11a, 11b,..., 11g is a rolling mill that constitutes a so-called stand, and can satisfy conditions such as thickness, mechanical properties, and surface quality required for the final product. Thus, the rolling reduction is set.

  Next, the cooling device 20 will be described. FIG. 2 is an enlarged view of a portion of FIG. 1 where the cooling device 20 is provided. FIG. 2A is an enlarged view so that the entire cooling device 20 appears, and FIG. 2B is a view paying attention to the vicinity of the final stand 11g. The cooling device 20 includes upper surface water supply means 21, 21, ..., lower surface water supply means 22, 22, ..., upper surface guides 30, 30, ..., lower surface guides 40, 40, ....

The upper surface water supply means 21, 21,... Are means for supplying cooling water to the upper surface side of the steel plate 1, and are provided in a plurality of rows in the cooling headers 21 a, 21 a,. , And cooling nozzles 21c, 21c,... Attached to the tips of the conduits 21b, 21b,.
In the present embodiment, the cooling header 21a is a pipe extending in the direction orthogonal to the sheet passing direction, that is, the rear / front direction in FIG. 2, and such cooling headers 21a, 21a,. Has been.
The conduit 21b is a plurality of thin pipes branched from the respective cooling headers 21a, and the open ends thereof are directed to the upper surface side of the steel plate. A plurality of conduits 21b, 21b,... Are provided in a comb shape along the tube length direction of the cooling header 21a, that is, in the steel plate width direction.

A cooling nozzle 21c, 21c,... Is attached to the tip of each conduit 21b, 21b,. The cooling nozzles 21c, 21c,... Of the present embodiment are flat type spray nozzles capable of forming a fan-shaped cooling water jet (for example, a thickness of about 5 mm to 30 mm). FIG. 3 schematically shows a collision mode of the cooling water jet formed on the steel plate surface by the cooling nozzles 21c, 21c,. In FIG. 3, the white circles represent the positions immediately below the cooling nozzles 21c, 21c,. Moreover, the collision position and shape of a cooling water jet are typically represented by a thick line. FIG. 3 shows the sheet passing direction and the sheet width direction together.
As can be seen from FIG. 3, in this embodiment, the adjacent nozzle rows are arranged so that the positions in the plate width direction are shifted, and the so-called staggered pattern is used so that the adjacent nozzle rows have the same position in the plate width direction. It is an array. Thereby, the collision area of the jet flow in the plate width direction of the steel plate to be conveyed is made uniform every time it passes through the nozzle row, and it becomes possible to reduce cooling unevenness in the plate width direction of the steel plate.

In the present embodiment, the cooling nozzle is arranged so that the cooling water jet can pass at least twice over all positions in the steel plate width direction on the steel plate surface. That is, the point D with the steel plate to be passed moves along the straight arrow in FIG. At that time, the nozzle row A (A1, A2) twice, the nozzle row B twice (B1, B2), the nozzle row C twice (C1, C2), and so on. The jet from the nozzle belonging to the row collides twice. Therefore, between the cooling nozzle interval P _W , the cooling water jet collision width L, and the torsion angle β,
L = 2P _W / cos β
The cooling nozzle was arranged so that Here, the passage is made twice, but the present invention is not limited to this, and the passage may be made three times or more.
In addition, from the viewpoint of achieving uniform cooling performance in the steel plate width direction, the cooling nozzles were twisted in directions opposite to each other in the nozzle bands adjacent in the sheet passing direction.

Here, in the present embodiment, in the adjacent nozzle bands as described above, the embodiment in which the cooling nozzles are twisted in the opposite directions has been described, but this is not necessarily limited to this, and all are in the same direction. It may be in a twisted form. Further, the twist angle (β above) is not particularly limited, and can be appropriately determined from the viewpoint of required cooling capacity, accommodation of equipment arrangement, and the like.
In the present embodiment, the nozzle rows adjacent in the sheet passing direction are arranged in a staggered pattern from the viewpoint of the advantages described above, but the present invention is not limited to this, and the cooling nozzles are linear in the sheet passing direction. It may be in a parallel form.

  The position where the upper surface water supply means 21 is provided, in particular, the position where the cooling nozzles 21c, 21c,... Should be arranged is not particularly limited, but immediately after the final stand 11g in the hot finish rolling mill row 11, the final It is preferable that the stand 11g is arranged as close as possible to the work roll 11gw of the final stand 11g from the inside of the housing 11gh. By arranging in this way, the steel plate 1 immediately after rolling by the hot finish rolling mill row 11 can be rapidly cooled, and the tip of the steel plate 1 can be stably guided to the cooling device 20. In this embodiment, the cooling nozzle 21c close | similar to the work roll 11gw is arrange | positioned close to the steel plate 1 so that FIG.

  Further, the injection direction of the cooling water injected from the cooling water injection ports of the respective cooling nozzles 21c, 21c,... Is basically the vertical direction, while the injection of the cooling water from the cooling nozzle closest to the work roll 11gw of the final stand 11g. Is preferably inclined in the direction of the work roll 11gw rather than vertical. As a result, it is possible to further shorten the time from when the steel sheet 1 is crushed by the final stand 11g to when the cooling is started, and to make the time for recovering the rolling strain accumulated by rolling almost zero. Therefore, a steel sheet having a finer structure can be produced.

  The lower surface water supply means 22, 22,... Are means for supplying cooling water to the lower surface side of the steel plate 1, and are provided in a plurality of rows in the cooling headers 22 a, 22 a,. , And cooling nozzles 22c, 22c,... Attached to the tips of the conduits 22b, 22b,. The lower surface water supply means 22, 22,... Are provided opposite to the upper surface water supply means 21, 21,..., And are substantially the same as the upper surface water supply means 21, 21,. The description is omitted here.

  Next, the upper surface guide 30 will be described. FIG. 4 conceptually shows the upper surface guide 30. FIG. 4A is a view as seen from above the cooling device 20 and is partially cut away. FIG. 4B is a view from the side. 4, the positions of the cooling nozzles 21c, 21c,... And the position of the steel plate 1 are also shown.

  The upper surface guide 30 includes a plate-shaped guide plate 31 and drainage passage forming portions 35, 35,... Disposed on the upper surface side of the guide plate 31.

The guide plate 31 is a plate-like member and is provided with inflow holes 32, 32,... And outflow holes 33, 33,.
The inflow holes 32, 32, ... are provided at positions corresponding to the cooling nozzles 21c, 21c, ..., and the shape thereof also corresponds to the shape of the jet. Therefore, the inflow holes 32, 32,... Are arranged in parallel in the steel plate width direction to form an inflow hole array 32A, and the inflow hole arrays 32A, 32A,. Here, the shape of the inflow hole is not particularly limited, and it may be formed so that the jet flow from the cooling nozzle does not hit the guide plate as much as possible. Specifically, depending on the characteristics of the jet of the cooling nozzle used, 10% or more of the amount of cooling water ejected from one cooling nozzle 21c per unit time does not collide with the guide plate 31 of the upper surface guide 30. It is preferable that the shape passes. Further, from the viewpoint of efficiently providing the inflow holes 32, 32,... In a limited space, the opening shape of the inflow holes is substantially similar to the transverse cross-sectional shape of the cooling water jet (cross section orthogonal to the ejection direction axis). It is preferable.

On the other hand, the outflow holes 33, 33,... Are rectangular holes, and a plurality of the holes are juxtaposed in the steel plate width direction to form an outflow hole array 33A. , The part of the guide plate 31 remains between the outflow holes 33, 33,... Prevents the steel sheet conveyed from entering the outflow holes 33, 33,. It becomes. The outflow hole arrays 33A, 33A,... Are arranged between the inflow hole arrays 32A, 32A,.
That is, in the guide plate 31, the inflow hole rows 32A and the outflow hole rows 33A are alternately arranged along the plate passing direction.

  Here, the parallel rectangles as described above have been described as a preferable opening shape of the outflow holes 33, 33,. Thereby, a large opening area can be obtained efficiently in a limited space. However, the present invention is not limited to this, and it is only necessary that an appropriate amount of drainage can be secured and the steel plate can be prevented from being caught. That is, the opening shape of the outflow hole is not limited to the above-described rectangle, and examples thereof include a circle and a trapezoid. And a steel plate penetration | invasion prevention means becomes a shape corresponding to the said opening shape. For example, when the outflow hole has a trapezoidal shape having an upper base and a lower base in the plate passing direction, the steel plate intrusion preventing means can be formed in a parallelogram shape inclined from the plate passing direction.

  FIG. 5 shows a modification of the outflow hole. In the upper surface guide 30 ′ of the modified example of FIG. 5, only the outflow hole 33 ′ is different and the other parts are the same as those of the upper surface guide 30 described above. . One inflow hole 33 ′ of the upper surface guide 30 ′ is one long hole 33 </ b> A ′ in the width direction, and a net member 33 </ b> B ′ is stretched here. The outflow hole can also be formed by this. The so-called fineness of the mesh 33B ′ is preferably a mesh of 5 mm × 5 mm or more from the viewpoint that the influence of the flow of cooling water is small and foreign substances such as dust are hardly clogged.

Further, out of the edges of the outflow holes 33, 33,..., Backflow prevention pieces 33p, 33p,. These backflow prevention pieces 33p, 33p,... Are provided to prevent water that has entered the outflow holes 33, 33,... From flowing back from the outflow holes 33, 33,. By providing the backflow prevention pieces 33p, 33p,..., A larger amount of drainage can be secured, and drainage performance can be improved.
In this embodiment, the backflow prevention pieces 33p and 33p are erected substantially in parallel, but the backflow prevention pieces may be erected so that the upper end side is narrower than the lower end. Thereby, the flow-path cross-sectional area between the backflow prevention piece and the piece (35a, 35c) by which the drainage passage formation part mentioned later is erected can be ensured widely.

As shown in FIG. 4B, the drainage passage forming portions 35, 35,... Are members that have a concave cross section surrounded by the pieces 35a, 35b, 35c and extend in the steel plate width direction. The drainage passage forming portion 35 is disposed so as to cover the concave opening from the upper surface side of the guide plate 31 toward the guide plate 31. At this time, it covers so that a part of upper surface of the guide plate 31 and the outflow hole row | line | column 33A may be included between opening part, ie, piece 35a and piece 35c. Further, there is a predetermined interval between adjacent drainage passage forming portions 35, 35,..., And inflow hole rows 32A, 32A,... And cooling nozzles 21c, 21c,.
Further, on the outflow hole row 33A side of the piece 35b facing the outflow hole row 33A, a rectifying piece 36 is provided at a position directly above the outflow hole row 33A. The shape of the rectifying piece 36 is preferably a shape that can be rectified so as to separate the drainage impinging on the piece 35b toward the bottom surface of the drainage passage provided with the backflow prevention pieces 33p, 33p as described later. For example, an inverted triangle, a trapezoid, a wedge shape, and other protruding shapes can be considered.

  Here, the heights of the drainage passage forming portions 35, 35,... Are not particularly limited, but when the inner diameter of the conduits 21b, 21b,. It is preferable that it is the range of these. This is because if the conduits 21b, 21b,... Are longer than 20d, the pressure loss is undesirably increased, and if it is shorter than 5d, the injection from the cooling nozzle may be unstable.

  The upper surface guide 30 as described above is arranged as shown in FIG. In this embodiment, three upper surface guides 30, 30, and 30 are used, and these are arranged in parallel in the plate passing direction. All of the upper surface guides 30, 30, 30 are arranged so as to correspond to the height direction positions of the cooling nozzles 21c, 21c,. That is, in the present embodiment, the upper surface guide 30 close to the final stand 11g is disposed so as to be inclined so that the end on the final stand 11g side is low and the other end side is high. The other two upper surface guides 30, 30 are arranged substantially parallel to the passage plate surface at a predetermined interval from the passage plate surface.

By such an upper surface guide 30, it is possible to eliminate a problem that the front end portion is caught by a cooling nozzle or the like when the steel plate front end portion is passed, which is a basic function of the upper surface guide 30.
Furthermore, according to the upper surface guide 30, it becomes possible to appropriately discharge a large amount of cooling water supplied to the upper surface side of the steel plate. First, the cooling water supplied by the upper surface water supply means 21, 21,... Cools the steel sheet, and then a part of the cooling water flows in the width direction of the steel sheet and falls downward to be drained. However, if the amount and density of the supplied cooling water are large, the drainage does not catch up and the accumulated water is formed thick. On the other hand, the upper surface guide 30 can keep the accumulated water thin by providing a further drainage passage. Details are as follows.

FIG. 6 shows a diagram for explanation. In FIG. 6, the reference numerals are omitted for the sake of clarity, but the corresponding reference numerals in FIG. 4B can be referred to. When the cooling water supply density and the cooling water supply amount are so high that the drainage from the width direction of the steel plate cannot catch up, the water flow from the cooling nozzles 21c, 21c,. In such a case, the cooling water sprayed on the upper surface of the steel plate 1 also moves forward and backward and collides as shown by the arrow R in FIG. When such a collision occurs, the cooling water changes its direction, moves upward as indicated by an arrow S, passes through the outflow holes 33, 33,..., And collides with the piece 35b of the drainage passage forming portion 35. At this time, the piece 35b is provided with the wedge-shaped rectifying piece 36 as described above, and the direction of the cooling water is changed as indicated by the arrow T. At this time, the rectifying piece 36 suppresses the resistance of the direction change to be low, and it is performed reliably and efficiently.
As a result, the cooling water that has reached the upper surface side of the guide plate 31 moves in the back / front direction of the paper in FIG. At this time, since the backflow prevention pieces 33p and 33p are provided at the edge of the outflow hole 33, the cooling water is prevented from returning from the outflow hole 33 again.

As described above, the provision of the additional drainage means can suppress the stagnant water even when the cooling water supplied to the upper surface side has a large amount and a high water density. In addition, the holes for supplying the cooling water are separated from the holes for discharging, and the cooling water used for cooling due to the structure as described above collides with the cooling water that has started moving because of drainage. It can be suppressed. Thereby, water supply / drainage is performed smoothly, the accumulated water can be thinned, and the cooling efficiency can be increased.
Thus, it becomes possible to suppress the uneven cooling in the width direction of the steel sheet to be small by suppressing smooth drainage and staying water. Thereby, the steel plate which has uniform quality can be obtained. As for the cooling unevenness, the temperature unevenness in the width direction of the cooling water is preferably within ± 30 ° C.

  In this embodiment, the outflow holes 33, 33,... Included in one outflow hole row 33A are arranged over the entire width direction of the steel plate of the upper surface guide 30, but the present invention is not limited to this. For example, such an outflow hole may be provided only in the vicinity of the central portion in the width direction of the steel plate, where the accumulated water tends to be thick.

In draining the cooling water that has reached the upper surface of the guide plate 31 from both ends in the width direction of the guide plate 31, a configuration for further improving the drainage may be added. For example, the following can be mentioned.
Of the upper surface side of the guide plate 31, the center in the plate width direction may be formed high, and the inclination may be provided so as to become lower toward both ends in the width direction. According to this, drainage easily moves to both ends of the guide plate 31 due to the height difference, and smooth drainage can be promoted.
Moreover, it is easy to introduce cooling water into the drainage passage forming part by installing a pump or the like and forcibly draining or by making the inside of the drainage passage forming part have a negative pressure, and the drainage performance may be further improved.
Further, the upper surface guide itself is formed so as to be movable in the vertical direction, and the upper surface guide 30 is moved downward within a range that does not affect the plate so as to press against the staying water, forcing the cooling water into the drainage passage forming portion. It is good also as a structure to guide.

  Further, in the inflow holes 33, 33,... Provided in the guide plate 31 and both ends in the width direction, chamfering or rounding may be performed on the edge portion (edge) (the edge is formed in an arc shape). . Thereby, the catch of the steel plate passed through can be reduced or the smooth flow of cooling water can be promoted.

  The material of the guide plate 31 can be a general material having strength and heat resistance required as a guide, and is not particularly limited. However, for the purpose of reducing scratches and the like on the steel plate when the steel plate to be passed through contacts with the guide plate 31, a material such as a resin that is softer than the steel plate is used in a portion where the problem of strength and heat resistance does not occur. May be.

FIG. 7 shows a view corresponding to FIG. 4B among the upper surface guides 130, 130 ′ of another form. FIG. 7A shows the upper surface guide 130 and FIG. 7B shows the upper surface guide 130 ′. Here, members common to the upper surface guide 30 are denoted by the same reference numerals, and description thereof is also omitted.
In the upper surface guide 130, drainage passage forming portions 135, 135,... Are formed separately from the guide plate 31. Therefore, in the drainage passage forming portions 135, 135,..., The pieces 35a, 35a,... And the backflow prevention pieces 33p, 33p,... Are connected by the bottom plates 135d, 135d,. The pieces 33p, 33p,... Are connected by bottom plates 135e, 135e,. Such an upper surface guide 130 may be used.
In the upper surface guide 130 ′, the backflow prevention pieces 133 p ′, 133 p ′,... Extend to the upper surface side of the guide plate 31.

FIG. 8 shows a view corresponding to FIG. 4B among the upper surface guides 230 and 230 ′ of still another embodiment. FIG. 8A shows the upper surface guide 230 and FIG. 8B shows the upper surface guide 230 ′. Here, members common to the upper surface guides 30 and 130 are denoted by the same reference numerals, and description thereof is also omitted.
Also on the upper surface guide 230, drainage passage forming portions 235, 235,... Are formed separately from the guide plate 31. Therefore, in the drainage passage forming portions 235, 235, ..., the pieces 35a, 35a, ... are connected to the backflow prevention pieces 233p, 233p, ... by the bottom plates 235d, 235d, ..., and the pieces 35c, 35c, ... are backflow prevention pieces. 233p, 233p,... Are connected by bottom plates 235e, 235e,... To form the bottom of the drainage passage. Further, the backflow prevention pieces 233p, 233p,... Extend on the upper surface side of the guide plate 31. In the upper surface guide 230, in addition to the cooling nozzles 21c, 21c,... Between the guide plate 31 and the drainage passage forming portions 235, 235,..., Headers 21a, 21a,. Yes. Such an upper surface guide 230 may be used.

  In the upper surface guide 230 ′, the drainage passage forming portions 235 and 235 adjacent to each other in the upper surface guide 230 are formed as one drainage passage forming portion 235 ′. This also ensures the drainage path indicated by T ′ in FIG. According to this, it becomes possible to increase the flow path cross-sectional area of the drainage channel (T ′).

  Next, the lower surface guide 40 will be described. FIG. 9 conceptually shows the lower surface guide 40. FIG. 9A shows a view of the cooling device 20 as viewed from above. FIG.9 (b) is the figure seen from the side surface side. 9, the positions of the cooling nozzles 22c, 22c,... And the position of the steel plate 1 are also shown.

  The lower surface guide 40 includes a plate-shaped guide plate 41 and a water supply / drainage passage forming member 45 disposed on the lower surface side of the guide plate 41.

The guide plate 41 is a plate-like member and has inflow holes 42, 42,... And outflow holes 43, 43,.
The inflow holes 42, 42,... Are provided at positions corresponding to the cooling nozzles 22c, 22c,. Therefore, the inflow holes 42, 42,... Are arranged in parallel in the steel plate width direction to form an inflow hole array 42A, and the inflow hole arrays 42A, 42A,. It is preferable that one corresponding inflow hole 42 is provided for one cooling nozzle 22c. As a result, the water supply and drainage can be appropriately separated to enable smoother drainage.
Although the opening shape of the inflow holes 42, 42,... Is not particularly limited, in order for the cooling water to efficiently pass through here, the jet flow from the cooling nozzles 22c, 22c,. It is preferably formed so as not to exist. Specifically, depending on the characteristics of the jet of the cooling nozzle used, 10% or more of the amount of cooling water ejected from one cooling nozzle 22c per unit time does not collide with the guide plate 41 of the lower surface guide 40. It is preferable that the shape passes through.
Further, from the viewpoint of efficiently providing the inflow holes 42, 42,... In a limited space, the opening shape of the inflow holes 42, 42,... Is a cross-sectional shape of the cooling water jet (a cross-sectional shape orthogonal to the ejection direction axis). ) Is preferably substantially similar.

On the other hand, the outflow holes 43, 43,... Are rectangular holes, and a plurality of the holes are juxtaposed in the steel plate width direction to form an outflow hole array 43A. When the guide plate 41 is partially left between the outflow holes 43, 43,..., The leading end of the steel sheet to be conveyed is prevented from entering the outflow holes 43, 43,. It becomes. The outflow hole arrays 43A, 43A,... Are arranged between the inflow hole arrays 42A, 42A,.
That is, in the guide plate 41, the inflow hole rows 42A and the outflow hole rows 43A are alternately arranged along the plate passing direction.

The size (Lg) of the outflow holes 43, 43, ... in the plate direction is not particularly limited as long as appropriate drainage is possible, but for example, it may be formed so as to satisfy the following expression (1). it can.
α · W · H ≦ (Lg · W−N · Lg · Wg) / 2 (1)
Here, W is the size of the plate width method of the lower surface guide 40, H is the distance between the upper surface of the lower surface guide 40 and the lower surface of the steel plate 1 to be passed, and Wg is the size of the steel plate intrusion prevention means 43s in the plate width direction. , N represents the number of steel plate intrusion prevention means 43s arranged in the plate width direction. α is a coefficient, and in the reference example (see also FIG. 14) shown later, α = 0.5 was an appropriate value.
According to this, the right side of the equation (1) represents the total opening area of the outflow holes 43, 43,..., And the left side is the cooling water while reaching the outflow holes 43, 43,. The flow path cross-sectional area of the moving passage (between the upper surface of the lower surface guide 40 and the lower surface of the steel plate 1) is represented. And the drainage resistance can be kept small by making the total opening area of the outflow holes 43, 43,... On the right side equal to or larger than the area determined from the channel cross-sectional area on the left side.

  The material of the guide plate 41 can be a general material having strength and heat resistance required as a guide, and is not particularly limited. However, for the purpose of reducing scratches and the like on the steel plate when the steel plate to be passed through contacts with the guide plate 41, a material such as a resin that is softer than the steel plate is used in a portion where the problem of strength and heat resistance does not occur. May be.

  In the inflow holes 42, 42,..., And the outflow holes 43, 43,... Provided in the guide plate 41, chamfering or rounding is performed on the edge portions (edges). May be. Thereby, the catch of the steel plate passed through can be reduced or the smooth flow of cooling water can be promoted.

  Here, as a preferable opening shape of the outflow holes 43, 43,. Thereby, a large opening area can be obtained efficiently in a limited space. However, the present invention is not limited to this, and it is only necessary that an appropriate amount of drainage can be secured and the steel plate can be prevented from being caught. That is, the opening shape of the outflow hole is not limited to the above-described rectangle, and examples thereof include a circle and a trapezoid. And a steel plate penetration | invasion prevention means becomes a shape corresponding to the said opening shape. For example, when the outflow hole has a trapezoidal shape having an upper base and a lower base in the plate passing direction, the steel plate intrusion preventing means can be formed in a parallelogram shape inclined from the plate passing direction.

  FIG. 10 shows a modified example of the outflow hole. The lower surface guide 40 ′ of the modified example of FIG. 10 is the same as the lower surface guide 40 except that the outflow hole 43 ′ is different. Therefore, the same portions are denoted by the same reference numerals, and description thereof is omitted. . One inflow hole 43 ′ of the lower surface guide 40 ′ is one long hole 43 </ b> A ′ in the width direction, and a net member 43 </ b> B ′ is stretched here. This also makes it possible to form an outflow hole. The so-called fineness of the mesh 43B 'is preferably a mesh of 5 mm x 5 mm or more from the viewpoint that there is little influence on the flow of the cooling water and that clogging of foreign matters such as dust does not easily occur.

  Returning to FIG. 9, the water supply / drainage passage forming member 45 will be described. The water supply / drainage passage forming member 45 is a pair of plate-like members 45a provided so as to hang down from the lower surface side of the guide plate 41 in the boundary portion between the inflow hole row 42A and the outflow hole rows 43A, 43A adjacent thereto. 45b is formed. Therefore, inflow holes 42, 42,... Are arranged between the upper ends of the pair of plate members 45a, 45b. And the outflow holes 43, 43, ... and the steel plate intrusion prevention means 43s, 43s, ... are arranged at the upper end between the adjacent water supply / drainage passage forming members 45, 45.

  In this embodiment, as can be seen from FIG. 9B, the steel plate intrusion prevention means 43s, 43s,... Of the guide plate 41 are formed slightly thick on the lower surface side. The upper ends of the plate-like members 45a and 45b are attached to the lower surface of the guide plate 41 and the thickly formed side surfaces of the steel plate intrusion prevention means 43s and 43s by welding.

  In the present embodiment, the form attached by welding has been described, but it may be a fixing means such as a screw or fixing by an adhesive, and is not particularly limited. In addition, although the guide plate 41 and the water supply / drainage channel forming member 45 are integrated here, they are not necessarily integrated. However, since the water supply / drainage channel forming member is a member that forms the water supply channel and the water drainage channel, it is preferable that there is no gap that communicates as much as possible. explained.

  Moreover, the space | interval of the lower end part (lower end part of plate-shaped member 45a, 45b) is formed narrow, and the cooling nozzle 22c is arrange | positioned here. As a result, between the adjacent water supply / drainage passage forming members 45, 45, as shown by V in FIG. Such a shape is preferably formed to match the shape of the jet water from the cooling nozzles 22c, 22c,.

  The lower surface guide 40 as described above is arranged as shown in FIG. In this embodiment, four lower surface guides 40, 40,... Are used and arranged between the transport rolls 12, 12, 12. All of the lower surface guides 40, 40,... Are arranged at a height that does not become too low with respect to the upper ends of the transport rolls 12, 12,.

Such a lower surface guide 40 can eliminate a problem that the steel plate tip is caught between the transport rolls 12 and 12, which is a basic function of the lower surface guide 40.
Furthermore, according to the lower surface guide 40, it becomes possible to appropriately discharge a large amount of cooling water supplied to the lower surface side of the steel plate. Details are as follows.

FIG. 11 shows an explanatory diagram. In FIG. 11, the reference numerals are omitted for the sake of clarity of the drawing, but the corresponding elements can be referred to the reference numerals of FIG. 9.
The cooling water sprayed from the cooling nozzle 22c passes between the plate-like members 45a and 45b, reaches the lower surface of the steel plate 1 from the inflow hole 42, and cools the steel plate 1 (FIG. 11 (b)). Thereafter, the cooling water moves on the upper surface of the guide plate 41 in the direction indicated by the straight arrow in FIG. 11A and drops downward from the outflow holes 43 and 43 as indicated by the straight arrow in FIG. Drained.

Thus, not only the hole for water supply and the hole for drainage are separated, but also the water passage for water supply and the drainage channel for drainage are separated, so that the cooling water used for cooling Collisions with the drainage can be prevented. Thereby, water supply / drainage is performed smoothly, stagnant water can be suppressed, and cooling efficiency can be increased. In particular, since the cooling nozzles 22c, 22c,... Are located directly below the water supply / drainage passage forming member 45, the passage for drainage extends to the vicinity of the right and left of the cooling nozzles 22c, 22c,. The influence on… can be suppressed.
In the lower surface guide, 80% or more of the cooling water supplied by the lower surface water supply means is preferably drained from the outflow hole. Thereby, very high cooling efficiency is securable.
In addition, it is possible to suppress the cooling unevenness in the width direction of the steel sheet to be small by suppressing the smooth drainage and the staying water. Thereby, the steel plate which has uniform quality can be obtained. As for the cooling unevenness, the temperature unevenness in the width direction of the cooling water is preferably within ± 30 ° C.

  Moreover, in this embodiment, as mentioned above, the space | interval of the lower end part between plate-shaped member 45a, 45b which forms the channel | path of water supply is formed narrowly, and plate-shaped member 45a, 45b which forms the channel | path of drainage in connection with this. The lower end portion is formed with a wide interval. Thereby, the drainage channel is expanded, and the drainage is performed more smoothly.

  However, the plate-like member of the water supply / drainage channel forming member is not necessarily inclined in this manner, and may be suspended vertically downward. FIG. 12 shows a lower surface guide 40 'of the example. FIG. 12 is a view corresponding to FIG. 9, and is the same as the lower surface guide 40 except that the plate-like members 45 a ′ and 45 b ′ extend vertically downward. Such a lower surface guide may be used.

  Returning to FIG. 2, the description of the hot-rolled steel sheet manufacturing apparatus 10 will be continued. The conveying rolls 12, 12,... Are rolls that convey the steel plate 1 in the plate direction while being a table of the steel plate 1. As described above, the lower surface guides 40, 40,... Are arranged between the transport rolls 12, 12,.

  The pinch roll 13 also serves as a drainer and is provided on the downstream side of the cooling device 20. Thereby, it becomes possible to prevent the cooling water sprayed in the cooling device 20 from flowing out to the downstream side of the steel plate 1. Furthermore, the waviness of the steel plate 1 in the cooling device 20 can be suppressed, and in particular, the plate-passability of the steel plate 1 can be improved at the time before the tip of the steel plate 1 bites into the winder. Here, of the rolls of the pinch roll 13, the upper roll 13a is movable up and down as shown in FIG.

  As described above, in the hot-rolled steel sheet production line, without disturbing the movement (passing) of the steel sheet, a high water density, a steel sheet cooling device excellent in drainage even when a large amount of cooling water is supplied, A manufacturing apparatus can be provided. And it becomes possible to manufacture the hot rolled steel plate excellent in the mechanical characteristic by this.

In the drainage of the cooling water by the upper surface guide and the lower surface guide as described above, the specific drainage performance is appropriately determined depending on the required amount of cooling heat of the steel sheet and is not particularly limited. However, as described above, from the viewpoint of refinement of the steel sheet structure, rapid cooling immediately after rolling is effective, and therefore, it is preferable to supply cooling water having a high supply density. Therefore, the drainage in the upper surface guide and the lower surface guide only needs to ensure drainage performance corresponding to the supply amount and supply density of the cooling water. From the viewpoint of the refinement of the steel sheet, the supply density of the cooling water to be supplied can be 10 to 25 m ³ / (m ² · min). A higher supply density may be used.

In the present embodiment, the cooling device and the manufacturing apparatus provided with both the upper surface guide and the lower surface guide have been described as preferable modes. However, the present invention is not limited to this, and the upper surface guide is applied and the lower surface guide is conventionally used. May be used.
However, both the upper and lower surfaces can be efficiently cooled by the upper surface guide and the lower surface guide of this embodiment, and uneven cooling is less likely to occur.

A steel plate is manufactured as follows, for example, with the above-described hot-rolled steel plate manufacturing apparatus. That is, the jet of the cooling water in the cooling device 20 is stopped during the non-rolling time until the steel sheet is wound by the winder and rolling of the next steel sheet is started. Then, the pinch roll 13 on the downstream side of the cooling device 20 moves the upper roll 13a to a position higher than the upper surface guide 30 of the cooling device 20 during the non-rolling time, and thereafter, rolling of the next steel plate is started. The
A few seconds before the leading end of the next steel plate bites into the final stand 11g of the hot finish rolling mill row 11, the injection of cooling water from the cooling device 20 is started, and the cooling immediately after the leading end of the steel plate passes through the cooling device 20. The water injection pressure is controlled to be substantially a predetermined value. Moreover, immediately after the front-end | tip of the steel plate 1 passes the pinch roll 13, the upper side roll 13a is dropped and the pinch of the steel plate 1 is started.

By starting the injection of the cooling water before the front end of the steel plate 1 is conveyed into the cooling device 20, the length of the unsteady cooling part at the front end of the steel plate can be shortened, and the injected cooling is performed. Water can stabilize the plate-passability of the steel plate 1. That is, when the steel plate 1 floats and approaches the upper surface guide 30, the collision force that the steel plate 1 receives from the cooling water jets injected from the cooling nozzles 21 c, 21 c,. Force acts. Therefore, even when the steel plate 1 collides with the upper surface guide 30, the impact force is mitigated by the collision force received from the cooling water jet, and the frictional heat between the steel plate 1 and the upper surface guide 30 is reduced. It becomes possible to reduce the scratches generated on the steel sheet surface.
Therefore, if a hot-rolled steel sheet is manufactured by a hot-rolled steel sheet manufacturing apparatus provided with the cooling device 20 operated in this way on the downstream side of the hot finish rolling mill row 11, high-density, large-volume cooling water is used. It becomes possible to cool. That is, by manufacturing a hot-rolled steel sheet by such a manufacturing method, it becomes possible to manufacture a hot-rolled steel sheet having a refined structure.

  Further, the plate passing speed in the hot finish rolling mill row may be constant except for the plate start portion. Thereby, the steel plate with which mechanical strength was raised over the steel plate full length can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. In the example, an upper surface guide was manufactured as shown in FIG. 13 (FIG. 13 is a view corresponding to FIG. 4B), and the amount of drainage from the upper surface guide with respect to the total injection amount of the nozzle was measured. Here, the density of the amount of water sprayed from the nozzle was set to 20 m ³ / (m ² · min).

  As a result, 15% of the total injection amount from the nozzle provided on the upper surface of the steel plate could be discharged from the upper surface guide. As a result, it is possible to suppress an impediment to injection due to a backflow from the nozzle hole (inflow hole), and it is possible to reduce the thickness of the accumulated water.

  Next, an example of a test performed on the lower surface guide will be described as a reference example. In this reference example, the lower surface guide having the shape of the lower surface guide 40 described above was manufactured and the drainage property was examined.

FIG. 14 shows the main dimensions of the bottom guide manufactured. That is, the size of the inflow hole in the plate passing direction was 115 mm, the size of the outflow hole in the plate passing direction was 45 mm, and the distance between the lower surface of the steel plate to be passed through and the lower surface guide upper surface was changed. The cooling water was supplied at a flow density of 15 m ³ / (m ² · min) by a flat spray nozzle. For reference, the case without the lower surface guide, which is considered to be the most excellent in drainage, is also shown.

  Here, by using a flat spray nozzle, it is possible to increase the area of the jet collision region having a high cooling capacity with a small number of nozzles. Further, compared to a slit jet nozzle that supplies a film-like jet in the plate width direction of the steel plate, it is easy to maintain a uniform jet in the plate width direction, so that the uniformity of cooling can be increased.

  Table 1 shows the results. The result was judged by whether the maintenance of the feed water was good. This is because if there is a problem with the drainage, good water supply cannot be performed, so that the appropriateness or inappropriateness of the drainage can be determined depending on whether or not the water supply is maintained.

  As can be seen from Table 1, by using the lower surface guide, it is possible to supply substantially the same amount of cooling water as when not using the lower surface guide corresponding to the case where drainage is the highest. Therefore, it was found that the lower surface guide has high drainage.

  Moreover, in FIG. 15, the result of having compared the collision pressure of the jet which collides with a steel plate is shown. FIG. 15 shows the relative value of 1.0 when the lower surface guide corresponding to the case where drainage is the highest is not used. Thus, according to the manufactured lower surface guide, it can be seen that even when the lower surface guide is provided, the collision pressure is substantially the same as when the lower surface guide is not provided. Therefore, it has been found that the lower surface guide can be supplied without attenuating the jet to the steel plate.

  While the invention has been described in connection with embodiments that are presently practical and preferred, the invention is not limited to the embodiments disclosed herein, The scope and the scope of the invention can be appropriately changed without departing from the gist or idea of the invention, and the steel sheet cooling apparatus, the hot-rolled steel sheet manufacturing apparatus, and the manufacturing method are also included in the technical scope of the present invention. Must be understood as encompassed by.

DESCRIPTION OF SYMBOLS 1 Steel plate 10 Manufacturing apparatus 11 Rolling machine row 11g Final stand 12 Transport roll 13 Pinch roll 20 Cooling device 21 Upper surface water supply means 21a Cooling header 21b Conduit 21c Cooling nozzle 22 Lower surface water supply means 22a Cooling header 22b Conduit 22c Cooling nozzle 30 Upper surface guide 31 Guide Plate 32 Inflow hole 32A Inflow hole row 33 Outflow hole 33A Outflow hole row 33p Backflow prevention piece 35 Drainage passage forming part 36 Rectification piece 40 Lower surface guide 41 Guide plate 42 Inflow hole 42A Inflow hole row 43 Outflow hole 43A Outflow hole row 45 Water supply / drainage passage Forming member 45a Plate member 45b Plate member

Claims (11)

A steel sheet cooling apparatus including a plurality of cooling nozzles arranged on the lower process side of the final stand of the hot finish rolling mill row and provided to be able to cool the steel sheet transported on the transport roll,
The cooling nozzle is provided on the upper surface side and the lower surface side of the portion through which the steel plate passes, and is capable of injecting cooling water toward the portion through which the steel plate passes,
An upper surface guide is provided on the upper surface side,
The upper surface guide is
An inflow hole through which the cooling water sprayed from the cooling nozzle on the upper surface side should pass,
An outlet hole for discharging the cooling water sprayed from the cooling nozzle ;
A drainage passage forming portion provided on the upper surface side of the upper surface guide and leading to the outflow hole ,
An inflow hole row in which only the inflow holes are arranged in the width direction of the steel plate, and an outflow hole row in which only the outflow holes are arranged in the width direction of the steel plate are formed, in the direction in which the steel plate passes. A steel sheet cooling apparatus in which the inflow hole rows and the outflow hole rows are alternately arranged .   The steel sheet cooling device according to claim 1, wherein a backflow prevention piece is provided upright at an edge of the outflow hole.   The steel plate cooling apparatus according to claim 1 or 2, wherein a piece of the drainage passage forming portion facing the outflow hole is provided with a rectifying piece.   The said inflow hole is a substantially similar shape to the cross-sectional shape of the cooling water jet injected from the said cooling nozzle, The cooling device of the steel plate of any one of Claims 1-3 characterized by the above-mentioned.   The said cooling nozzle is a flat spray nozzle, The cooling device of the steel plate of any one of Claims 1-4 characterized by the above-mentioned. A lower surface guide is provided on the lower surface side,
The lower surface guide has an inflow hole through which the cooling water sprayed from the cooling nozzle on the lower surface side should pass, and an outflow hole through which the cooling water should pass through so as to fall and be discharged.
The steel plate according to any one of claims 1 to 5 , wherein the inflow hole of the lower surface guide and the outflow hole of the lower surface guide are alternately arranged in a moving direction of the steel plate. Cooling system.   An apparatus for producing a hot-rolled steel sheet, comprising: a final stand in a hot finish rolling mill row; and the steel sheet cooling device according to any one of claims 1 to 6 in order in the conveying direction of the steel sheet.   It is equipped with the final stand in a hot finishing rolling mill row | line | column, the cooling device of the steel plate of any one of Claims 1-6, and the draining means which drains a cooling water in order in the conveyance direction of a steel plate. An apparatus for producing hot-rolled steel sheets.   The manufacturing apparatus of the hot-rolled steel sheet according to claim 7 or 8, wherein a nozzle arranged on an uppermost process side among cooling nozzles provided in the cooling device is arranged inside a housing of the final stand.   The cooling water injection port of the cooling nozzle closest to the final stand among the cooling nozzles provided in the cooling device is directed to a steel plate to be positioned at a work roll outlet of the final stand. Item 10. The apparatus for producing a hot-rolled steel sheet according to any one of Items 7 to 9.   A process of processing a steel sheet rolled at a final stand in a hot finish rolling mill using the hot-rolled steel sheet manufacturing apparatus according to any one of claims 7 to 10 is provided. A method of manufacturing a steel sheet.