JP6460071B2 - Steel plate top surface cooling device and top surface cooling method - Google Patents

Description

  The present invention relates to a steel plate top surface cooling device and a top surface cooling method capable of uniformly cooling the top surface of a steel plate in the width direction even when a steel plate having a wide variety of plate widths is targeted.

  A steel plate, such as a hot-rolled steel plate, is manufactured in an installation as shown in FIG. Specifically, the slab is heated in a heating furnace, the primary scale is removed by a descaling device, the slab is rolled by a hot rolling mill (rough rolling mill and finish rolling mill), and then in a cooling facility on a runout table. Controlled cooling of the steel sheet is performed by water cooling or air cooling. The cooling performed on the run-out table is performed to control the precipitates and transformation structure of the steel sheet to obtain a desired material such as strength and elongation. However, when the temperature distribution along the width direction of the steel plate after cooling (also simply referred to as “width direction”) becomes non-uniform, the strength, elongation, and other materials vary in the width direction, and a predetermined material is locally applied. There are things you can't get.

  Hot-rolled steel sheets are often cooled by using a tubular nozzle (laminar nozzle) on the upper surface and spray nozzles on the lower surface, and are generally unsatisfactory in the width direction due to cooling by the laminar nozzle on the upper surface. It is said that a uniform temperature distribution occurs.

An example of the arrangement of laminar nozzles in the upper surface cooling device for hot-rolled steel sheets is shown in FIG. FIG. 2 is a front view seen from the front in the transport direction. Laminar nozzle (simply called “nozzle” in the figure)
When cooling the upper surface of the steel sheet using the steel sheet, as shown in FIG. 2, the cooling provided along the width direction perpendicular to the longitudinal direction of the steel sheet (front and back direction of the paper surface, simply referred to as “longitudinal direction”) A plurality of nozzles are attached to the header along the width direction, and cooling water is sprayed simultaneously from each nozzle.

  However, since the cooling water that has reached the upper surface of the steel sheet forms a water flow from the central portion in the width direction toward the end in the width direction (edge portion), the amount of passing water increases toward the edge portion. Therefore, the vicinity of the edge portion of the steel plate is more easily cooled than the central portion in the width direction, and the central portion of the steel plate becomes high temperature and both edge portions become low temperature.

  Patent document 1 is mentioned as literature which disclosed the technique which prevents the overcooling of the edge part of such a steel plate. The technique disclosed in Patent Document 1 will be described with reference to FIG. In Patent Document 1, a shielding plate is disposed above the edge portion of a steel plate having a large temperature drop, and cooling water sprayed from nozzles disposed above the edge portion among a plurality of nozzles disposed in the width direction is blocked. By doing so, it is disclosed to prevent overcooling of the edge portion. Moreover, in the technique of patent document 1, the shielding board is moved to the steel plate width direction based on the magnitude | size of the board width of a steel plate. A plurality of such methods are disclosed in addition to Patent Document 1.

  Patent Document 2 describes a cooling device that can control the flow and shielding of cooling water for individual nozzles. Specifically, a flapper and a swinging device (for example, a pneumatic cylinder) that swings the flapper are used. When the cooling water is shielded, the flapper is directly under the nozzle, and the water flow from the nozzle is shielded by this and flows into the gutter and is then discharged out of the system. As described above, a technique for preventing overcooling of an edge portion of a steel sheet by blocking a nozzle that injects cooling water to the edge portion of the steel sheet is known.

JP-A-61-86022 Patent 3305550

  As described above, the method of Patent Document 1 moves the shielding plate above the edge portion where the temperature is likely to be lowered, and shields the cooling water sprayed from the nozzle above the edge portion, thereby overpassing the edge portion. This is to prevent cooling. In this method, it is necessary to move the shielding plate in the width direction according to the plate width of the steel plate. As a drive mechanism for moving the shielding plate, a wire, a screw, an air cylinder or the like is used. For example, a general hot-rolled steel plate has a minimum plate width of 600 mm and a maximum plate width of about 2400 mm, and the plate width difference is 1800 mm. In this case, it is necessary to move the shielding plates at both edges by a long distance of 900 mm at the maximum. In the case of a line for manufacturing a steel plate having a plate width exceeding 5000 mm, such as a thick steel plate, the moving distance of the shielding plate is further increased. For example, in the case of a thick steel plate having a minimum plate width of 1500 to 2000 mm and a maximum plate width of 4000 to 5500 mm, the plate width difference is about 2000 to 4000 mm, so the moving distance of the shielding plate is also 1000 to 2000 mm on one side. Each time it gets bigger.

  When the moving distance of the shielding plate is increased, there are problems that the equipment cost for installation and maintenance of the equipment increases and the operation of the drive mechanism becomes unstable. For example, in the case of a drive mechanism using an air cylinder, it is necessary to increase the length of one stroke, so the installation space for the drive mechanism becomes very large, and the equipment cost for installation and maintenance is excessive. In addition, the operational stability is not good. Moreover, in the drive mechanism using a wire, a screw, etc., there is a problem that the drive mechanism is wetted by steam generated when the cooling water collides with the upper surface of the steel plate, and a failure due to rust occurs. There is also. In this case, a larger drive mechanism is required as the moving distance is longer, and the equipment cost for inspection / replacement of the failed drive mechanism is increased accordingly. Further, if the moving distance is large, the operation frequently becomes unstable due to a slight defect caused by rust or the like. In addition, when the moving distance of the shielding plate is increased, it is difficult to finely adjust the moving distance, and it is difficult to strictly control the opening / closing (ON / OFF) of a specific nozzle.

  The method of Patent Document 2 needs to provide a flapper and a swinging device that swings the flapper for each nozzle, and there is a problem that the equipment cost increases. For example, when the upper surface of a general hot-rolled steel sheet having a plate width of 600 to 2400 mm (plate width difference: 1800 mm) is cooled using an apparatus having a laminar nozzle pitch of 100 mm as shown in FIG. Since it is necessary to individually control ON / OFF for every 10 nozzles (20 nozzles in total) and it is necessary to install a flapper and a swing device corresponding to each nozzle, the equipment cost increases. Furthermore, since the flapper and the swing device itself are bulky, it may be physically difficult to provide the flapper and the swing device corresponding to each nozzle. Such a problem becomes prominent particularly when minute nozzles are arranged at a short pitch. Specifically, in the case of a conventional facility in which the nozzle pitch is 50 mm, the inner diameter of the nozzle is 16 mm, and the outer diameter is 22 mm, considering the size of the flapper and the swing device, the flapper and the swing corresponding to each nozzle. It is difficult to secure a space for arranging the moving devices in the width direction.

  The present invention solves the above-mentioned problem and can cope with the case where the minute nozzles are arranged at a short pitch while keeping the moving distance of the shielding plate short, and prevents overcooling at the edge portion of the steel plate. It is an object of the present invention to provide a steel plate top surface cooling device and a top surface cooling method capable of ensuring a high quality steel plate with little variation.

Means of the present invention are as follows.
[1] A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed, the nozzle being arranged in the width direction of the steel plate and spraying cooling water onto the top surface of the steel plate, and disposed below the nozzle, And a drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate, the opening having a dimension in the longitudinal direction of the steel plate, The upper surface cooling device of the steel plate which becomes small as it goes to the edge part of a direction.
[2] The steel plate upper surface cooling device according to [1], wherein the shielding plate is provided with a weir plate at least on an edge of the opening in the forward direction of the edge of the opening.
[3] The shielding plate is inclined downward toward both ends in the steel plate width direction, and the inclination angle of the shielding plate is 1 ° or more and 30 ° or less of the steel plate according to [1] or [2]. Top surface cooling device.
[4] The steel plate top surface cooling device according to any one of [1] to [3], wherein the driving mechanism is installed outside an end surface of the shielding plate in the steel plate width direction.
[5] The nozzles are provided in a plurality of rows along the longitudinal direction of the steel plate, and the shielding plate includes a plurality of rows of opening portions corresponding to the nozzle rows in the longitudinal direction of the steel plate [1] to [4]. The upper surface cooling apparatus of the steel plate as described in any one of to.
[6] A method of cooling the upper surface of a steel sheet using the upper surface cooling apparatus for a steel sheet according to any one of [1] to [5], wherein the length of the steel plate of the shielding plate depends on the width of the steel sheet A method of cooling the upper surface of a steel plate that displaces the position in the direction.
[7] When the opening of the shield plate is aligned at one end in the longitudinal direction of the steel plate and the other end is arranged at a different position, and the plate width of the steel plate increases, The steel sheet upper surface cooling method according to [6], wherein the shielding plate is moved backward to one end side when the steel plate is advanced toward the end side and the plate width of the steel plate is reduced.
[8] The drive mechanism can displace the shielding plate discontinuously in units of stroke with a predetermined distance as one stroke, and by displacing the shielding plate by one stroke, The method for cooling the upper surface of a steel sheet according to [6] or [7], wherein the shielding pattern can be changed by one level, and the shielding pattern can be changed by at least three levels according to the plate width of the steel sheet.

  In the present invention, since it is possible to displace the shielding plate along the longitudinal direction of the steel plate, even if the steel plate having a large plate width difference is to be cooled, the shielding plate corresponding to the plate width of the steel plate is used. The travel distance is small. Therefore, equipment cost can be suppressed, the displacement operation of the shielding plate can be stabilized, and ON / OFF of individual nozzles can be strictly controlled.

  Moreover, in this invention, even if it is a case where a micro nozzle is arrange | positioned with a short pitch, the installation space of the equipment for controlling ON / OFF of a nozzle can be restrained.

  In the present invention, it is possible to more reliably manufacture a high-quality steel sheet having the above-described effects and having less material variation.

FIG. 1 is a schematic diagram showing a hot rolling line. FIG. 2 is a front view of the steel sheet upper surface cooling device viewed in the longitudinal direction. FIG. 3 is a front view of the steel sheet upper surface cooling device disclosed in Patent Document 1 as seen in the longitudinal direction. FIG. 4 is a side view of a steel plate top surface cooling device. FIG. 5 is a schematic diagram showing an example of the arrangement of nozzles in the steel sheet upper surface cooling apparatus. FIG. 6 is a plan view showing an example of the shielding plate used in the present invention. FIG. 7 is a plan view showing another example of the shielding plate used in the present invention. FIG. 8 is a plan view showing another example of the shielding plate used in the present invention. FIG. 9 is a plan view showing an example of a shielding plate and a drive mechanism used in the present invention. FIG. 10 is a plan view of an example of the shielding plate used in the present invention when the shielding plate is displaced along the longitudinal direction. FIG. 11 is a plan view showing an example of a shielding plate used in the present invention, which is provided with a plurality of openings in the longitudinal direction. FIG. 12 is a plan view showing an example of a shielding plate in which steel plates having different plate widths can be cooled by different opening rows. FIG. 13 is a perspective view illustrating an example of a shielding plate provided with a dam plate. FIG. 14: is the front view which looked at the upper surface cooling apparatus of the steel plate which has the inclined shielding board facing the longitudinal direction.

  First, an example of the shielding plate used in the present invention will be described with reference to FIG. The shielding plate used in the present invention is a plate-like member provided between the nozzle and the steel plate. FIG. 6 is a plan view showing the shielding plate and the positions of the nozzles provided on the shielding plate and arranged in the steel plate width direction. The length of the shielding plate in the steel plate width direction is preferably larger than the distance between the left end nozzle and the right end nozzle so as to cover all the nozzles for one row. The shielding plate has an opening that penetrates the front surface and the back surface thereof. The cooling water sprayed from the nozzle descends through the opening and reaches the upper surface of the steel plate. In addition, the nozzle for 1 row arranged in the width direction may be called a nozzle row.

  The opening is formed such that the dimension in the longitudinal direction of the steel sheet becomes smaller as it goes toward the end in the width direction of the steel sheet. For example, in the example of FIG. 6, the opening has a rectangular plane, and a plurality of openings are provided in the width direction of the steel plate. In each opening, the dimension (length) in the longitudinal direction of the steel sheet is the same along the width direction. Further, when comparing a plurality of openings, the dimension in the longitudinal direction of the steel sheet is smaller as the opening is located on the end side in the width direction. Thus, at least a part of the opening (in each opening in the example of FIG. 6), the dimension in the longitudinal direction may be substantially equal along the width direction.

  The shape of the opening is not limited to a rectangular shape in plan view as shown in FIG. For example, in the example of FIG. 7, the four corners of the rectangle are chamfered in an R shape except for the opening at the center in the width direction. In the example of FIG. 8, the shape of the opening is a rectangle, pentagon, trapezoid, or triangle from the center in the width direction toward the end.

  6 to 8, a plurality of openings are provided, but only one opening corresponding to all nozzles for one row is provided (for example, each opening in FIGS. 6 to 8 communicates in the width direction). Embodiment). However, from the viewpoint of securing the strength of the shielding plate, it is preferable to provide the plurality of openings separately. For example, in FIG. 8, a narrow reinforcing member is interposed between the openings in order to ensure the strength of the shielding plate.

  Also, in FIGS. 6 to 8, the positions of one end in the longitudinal direction (lower end in the example in the figure) are aligned, and the positions of the other end (upper end in the example in the figure) are different. Are arranged as follows. The position of the other end part is located at the other end part side (upper side in the example in the figure) of the shielding plate in the steel plate longitudinal direction as the center part in the width direction, and the one end part in the steel plate longitudinal direction of the shielding plate as the end part in the width direction. It is located on the side (lower side in the example in the figure). Although the details will be described later, by arranging the openings in this way, when the shielding plate is retracted (displaced downward in the example in the figure), the nozzles are sequentially shielded from the nozzles on the end side in the width direction. When the nozzle is advanced (displaced upward in the example shown in the figure), the nozzles are sequentially opened from the nozzle in the center in the width direction. Therefore, it becomes easy to control ON / OFF of the nozzles arranged in the width direction. In addition, the position of the one end part of each opening part does not need to be exactly the same, and may shift | deviate slightly.

  Next, a drive mechanism for displacing the shielding plate will be described with reference to FIG.

  The shielding plate is displaced along the longitudinal direction of the steel plate by the drive mechanism. The shielding plate can be displaced both forward and backward. Note that either the forward direction or the backward direction of the shielding plate coincides with the conveying direction of the steel plate. As the drive mechanism, devices such as an electric drive type, a pneumatic drive type, a hydraulic drive type, and a wire drive type can be adopted.

  The drive mechanism is preferably installed outside the end faces of the shielding plate in the steel plate width direction (left and right surfaces of the rectangular shielding plate in FIG. 9). As a result, it is possible to prevent the drive mechanism from getting wet with steam or the like reflected from the upper surface of the steel plate, to prevent the drive mechanism from being deteriorated by rust or the like, and to further stabilize the operation of the drive mechanism. One drive mechanism may be attached on one side in the width direction with respect to one shielding plate, or a total of two drive mechanisms may be attached on both sides in the width direction as shown in FIG.

  The drive mechanism can move the shielding plate discontinuously in units of strokes with a predetermined distance as one stroke, or can continuously adjust the moving distance of the shielding plate. Below, the aspect which moves a shielding board per stroke using FIG. 10 is demonstrated. In FIG. 10, the drive mechanism is not shown.

  In FIG. 10, (a) is an initial state, and the shielding plate is gradually displaced in the backward direction toward (b) to (d). Specifically, the position of the nozzle is relatively displaced upward by displacing the shielding plate downward in the figure. In FIG. 10A, all the nozzles in one row are located above the opening, and the cooling water of all the nozzles can be injected toward the upper surface of the steel plate (ON state). FIG. 10B shows a state in which the shielding plate is retracted by one stroke (L). Thus, the cooling water from the pair of nozzles at both ends in the width direction is shielded by the plate portion (OFF state), and the shielding pattern of the nozzle row is changed by one level. The shielding pattern refers to a combination pattern of nozzles in the ON state and nozzles in the OFF state in the nozzle row.

  Next, in FIG. 10C, the shielding plate is further retracted by one stroke (L) from (b). Accordingly, the second nozzle from the end in the width direction, which was in the ON state in (b), is in the OFF state in (c). FIG. 10D shows a state in which the shielding plate is displaced by seven strokes (7L), and all the nozzles other than the central six nozzles are in a shielding state. Although omitted in FIG. 10, between the state of (c) and the state of (d), the shielding plate moves back by one stroke (total displacement: 3L to 6L), thereby causing an end in the width direction. The left and right nozzles on the part side are turned off one by one.

  When cooling a steel material having a relatively wide plate width, as many nozzles as possible are turned on as shown in FIG. On the other hand, when cooling a steel material with a narrow plate width, the nozzles on the width direction end side are turned off according to the plate width as shown in FIGS. Adjust so that the nozzle for the width is turned on. In addition, as an example, it is preferable to adjust the displacement of the shielding plate so that the nozzle located within 100 mm from the end face in the width direction of the steel plate toward the central portion in the width direction is turned off.

  As described above, in order to change the shielding pattern of the nozzle row by displacing the shielding plate by one stroke, the displacement amount (L) of the shielding plate for one stroke is changed in the longitudinal direction of the adjacent opening. It is preferable to substantially match the difference in length.

  Here, the minimum stroke (minimum value of L) required for shifting the shielding pattern by one level is equal to the inner diameter of the nozzle in the case of a circular laminar nozzle. In this case, if the dimension in the longitudinal direction of the opening located at the extreme end in the width direction is substantially equal to the inner diameter of the nozzle, and the difference in the dimension in the longitudinal direction of adjacent openings is also substantially equal to the inner diameter of the nozzle. Good. For example, consider a case where the inner diameter of the nozzle is 16 mm, the pitch of the nozzles in the width direction is 100 mm, and the upper surface of a steel plate having a plate width of 600 to 2400 mm is cooled by the nozzle row arranged as shown in FIG. The total number of nozzles in a row is 25, and the five nozzles located in the center are collectively controlled ON / OFF by one opening. For the other nozzles, the nozzles at the symmetrical positions are subjected to ON-OFF control by the openings having the same shape and size. Similarly to FIG. 6, the length of the opening in the longitudinal direction is shortened by L from the opening at the center in the width direction toward the opening at the end in the width direction. In this case, by retracting the shielding plate by one stroke along the longitudinal direction, the 10 sets of nozzles on the left and right in the width direction are turned from the ON state to the OFF state one by one in order from the end in the width direction. A total of 11 levels of shielding patterns are formed by the ON state-OFF state of these 10 sets of nozzles. The central five nozzles corresponding to the minimum plate width are always in the ON state. It should be noted that the amount of displacement for one stroke can be appropriately adjusted according to the injection flow rate of the nozzle, the distance between the nozzle tip and the shielding plate, and the like.

  As described above, the number of strokes required to form the 11-level shielding pattern is 10, and the maximum displacement amount of the shielding plate is calculated as 160 mm by 10 × inner diameter (16 mm). The amount of displacement of the shielding plate in the present invention can be much shorter than that of the prior art that displaces the shielding plate in the width direction as disclosed in Patent Document 1 and the like. Therefore, the installation space can be reduced, the shielding plate can be stably operated, and ON / OFF of each nozzle can be reliably controlled.

  Further, in the present invention, even when the nozzles are installed in the width direction at a short pitch (for example, 50 mm), it is not necessary to move the shielding plate in the width direction. Is possible.

  As described above, in the present invention, even when steel plates having a wide variety of plate widths are targeted, ON / OFF control of individual nozzles can be performed with a short moving distance of the shielding plate. Therefore, even for steel plates having a wide variety of plate widths, it is possible to manufacture high-quality products with little variation in material.

  Further, it is preferable to provide at least three levels of the shielding pattern described above. Thereby, the shielding pattern corresponding to several board width can be prepared. In order to cope with a wide range of plate widths, it is more preferable to prepare a shielding pattern of 4 levels or more.

  In addition, ON / OFF control of a plurality of nozzle rows can be performed by a single shielding plate. In the example of FIG. 11, ON / OFF control of the upper and lower nozzle rows is made possible by a single shielding plate. In this case, since one shielding plate can be moved by one or two shielding mechanisms, the equipment space can be further reduced, and the equipment cost can be further suppressed.

  In the example of FIG. 11, the first nozzle row shown above and the second nozzle row shown below are controlled by the same kind of opening row. Specifically, each opening row has openings of the same size and shape arranged in the width direction with the same arrangement configuration. In such a case, by displacing one shielding plate, the first nozzle row and the second nozzle row can be controlled with the same shielding pattern.

  On the other hand, the first nozzle row and the second nozzle row can be controlled with different shielding patterns by different types of opening rows. In this case, the shape, size, or arrangement configuration of the opening that forms the first opening row, and the shape, size, or arrangement of the opening that constitutes the second opening row It only has to be different.

  In addition, by changing the types of the first row and the second row of opening portions, it is possible to make steel plates having different plate widths in the first row of nozzles and the second row of nozzles to be cooled. Thereby, the uniform cooling of the width direction is attained with respect to the steel plate provided with the plate | board width of a wider range. For example, in an apparatus in which a total of 10 nozzle rows are arranged in the longitudinal direction, when it is necessary to support cooling of the upper surface of a steel plate having a plate width in the range of 600 mm to 4200 mm, an opening that can handle a plate width of 600 to 2400 mm By arranging five patterns of patterns (pattern A) corresponding to 5 rows and 5 rows of opening patterns (pattern B) that can correspond to plate widths of 2400 to 4200 mm, the width of the steel plate with respect to a wide plate width of 600 to 4200 mm The direction can be cooled uniformly.

  FIG. 12 shows an example of the pattern A and pattern B of the opening. In FIG. 12, the number of nozzles is partially omitted. In the pattern A, a flat rectangular opening corresponding to a nozzle having a plate width of 600 mm is provided at the center in the width direction. In addition, a plurality of openings are provided outside the plate width 600 mm and inside 2400 mm so that the longitudinal dimension becomes smaller toward the end.

  On the other hand, in the pattern B, a flat rectangular opening corresponding to a nozzle having a plate width of 2400 mm is provided at the center in the width direction, and the longitudinal dimension increases toward the end up to a width of 7200 mm on the outside. A plurality of openings are provided to be smaller.

  When cooling a steel plate having a plate width of 600 mm to 2400 mm, the upper surface of the steel plate is cooled by turning on an appropriate nozzle and turning off an appropriate nozzle in the pattern A. On the other hand, all the nozzles above the pattern B are turned off. On the other hand, when cooling a steel plate having a width of 2400 to 7200 mm, all the nozzles located above the opening of the pattern A are turned on (or turned off), and the nozzles located above the opening of the pattern B Of these, the upper surface of the steel sheet may be cooled by setting the appropriate nozzle to the ON state and the appropriate nozzle to the OFF state.

  Next, in the shielding plate that simply provided the opening in the plate member, the cooling water shielded by the shielding plate stays on the upper surface of the shielding plate, and the retained cooling water falls from the opening, The cooling of the steel sheet may become uneven. Therefore, it is preferable to install a weir plate at the edge portion of the opening of the shielding plate so that the cooling water staying on the upper surface of the shielding plate does not fall downward. As a result, it is possible to prevent the cooling capacity from fluctuating due to falling of the accumulated cooling water, and the steel sheet can be cooled more uniformly along the width direction.

  It is preferable that the dam plate is provided at least on the edge on the forward direction side of the shielding plate among the edges of the opening. Note that the forward direction of the shielding plate refers to a direction in which the nozzles are sequentially turned on from the width direction end portion when the shielding plate is displaced in that direction. Thus, the cooling water staying on the upper surface of the shielding plate even when a part of the nozzle is turned off by displacing the shielding plate in the backward direction (displace the nozzle relatively in the forward direction). Is prevented from falling from the opening. The barrier plate only needs to extend to the side where the nozzle is installed (upper side).

  A specific example will be described with reference to FIG. In FIG. 13, the shielding plate is retracted toward the right side of the drawing by a driving mechanism (not shown), and accordingly, the nozzle is sequentially turned off from the nozzle on the end side in the width direction. A dam plate is provided on the edge of the opening on the left side (forward direction side) of the drawing. Even when the shielding plate moves toward the right side (reverse direction side) of the drawing and a part of the nozzle is blocked, the cooling water sprayed from the blocked nozzle is blocked by the weir plate and falls to the opening. The water is drained in the width direction of the shielding plate. In the example of FIG. 13, the weir plate is provided only on the edge on the forward direction side of the shielding plate, but it is installed on the entire periphery of the opening and the edge of the shielding object in the forward and backward direction (forward direction side and backward direction side). It doesn't matter. In order to completely block the shielded cooling water, the height of the weir plate is preferably 20 mm or more, more preferably 40 mm or more. Also, if the height of the weir plate is too large, the distance from the steel plate pass line to the shielding plate becomes too short, and there is concern about collision with the steel plate, so the height of the weir plate should be 300 mm or less. good.

  In order to prevent cooling water from staying on the upper surface of the shielding plate, it is effective to incline the shielding plate downward toward the end in the width direction and drain the cooling water to the outside in the width direction. FIG. 14 shows a specific example. The inclination angle of the shielding plate refers to an angle formed between the surface of the shielding plate and a horizontal plane. In order to quickly discharge the cooling water, the inclination angle is preferably set to 1 ° or more. When the inclination angle is smaller than 1 °, the retention of the cooling water cannot be completely prevented, and the cooling in the width direction of the steel sheet becomes slightly non-uniform because the accumulated cooling water falls from the opening. There is. From the viewpoint of drainage, the inclination angle is more preferably 3 ° or more, and particularly preferably 5 ° or more. If the inclination angle is larger than 30 °, the distance from the pass line of the steel plate to the shield becomes too short and there is a concern about collision with the steel plate, so the inclination angle is preferably 30 ° or less. In addition, from the viewpoint of reducing the moving distance of the accumulated water until drainage and draining the water evenly on the left and right sides, the central part in the width direction is symmetrical as shown in FIG. It is preferable to make it.

  In the above description, the run-out cooling of the hot-rolled steel sheet has been mainly described. However, the present invention can be similarly applied to the controlled cooling of the thick steel sheet and the cooling during the rolling of the thick steel sheet and the hot-rolled steel sheet. is there.

(Example)
Examples of the present invention will be described below.

  The rolling operation was performed using the hot rolling line shown in FIG. Specifically, after the slab having a thickness of 250 mm was reheated in a heating furnace, the primary scale was removed by a descaling apparatus, rolled to a thickness of 50 mm by a rough rolling mill, and rolled to a thickness of 15 mm by a finish rolling mill. Then, the steel plate was cooled with a run-out table and wound up with a coiler. The plate width that can be manufactured in this line was 600 mm at the minimum and 2400 mm at the maximum. In this example, three types of steel plates having a plate width of 600 mm, 1200 mm, and 2000 mm were cooled from 900 ° C. to 550 ° C. by a run-out table.

  In the runout table, the upper surface of the steel sheet was cooled by an upper surface cooling device equipped with a laminar nozzle, and the lower surface was cooled by a spray nozzle. The upper side laminar nozzle and the lower side spray nozzle can jet cooling water in the range of 2400 mm in length in the width direction so as to be cooled to the maximum plate width. The temperature distribution of the steel sheet before and after cooling is measured by a radiation thermometer.

  The distance from the laminar nozzle injection port to the upper surface of the steel sheet is 1500 mm, the inner diameter of the laminar nozzle is 16 mm, the pitch in the width direction of the laminar nozzle is 100 mm, and the flow rate per laminar nozzle is 30 L / min. .

  In inventive examples 2 and 3, a shielding plate was provided on the shielding plate, and in inventive examples 3 to 6, the shielding plate was inclined. The weir plate was provided only on the edge of the opening on the side of the forward direction of the shielding plate, and the inclination of the shielding plate was symmetrical on the left and right sides in the width direction as shown in FIG.

  As an example of the present invention, a shield plate provided with openings shown in FIG. 6 and drive mechanisms at both ends in the width direction of the shield plate were installed below the laminar nozzle to cool the upper surface of the steel plate. The shielding plate has a rectangular opening on the surface corresponding to five nozzles at the center in the width direction, and corresponds to one nozzle each so as to be symmetric toward the end in the width direction. A rectangular opening on the surface was provided. In addition, each opening was provided with the same position at one end and the other end being different by 20 mm. Therefore, the stroke (L) required to shut off the nozzles at both ends in the width direction one by one was 20 mm.

  On the other hand, as a comparative example, a similar experiment was performed under the condition that no shielding plate was provided between the nozzle and the steel plate.

  In order to obtain a predetermined material, the temperature deviation ΔT between the central portion in the width direction and the end portion in the width direction needs to be within 40 ° C., and in consideration of variations in manufacturing conditions, it is preferably within 30 ° C., more preferably Is more preferably within 20 ° C. When 40 ° C <ΔT, material failure occurs (x), and when 30 ° C <ΔT ≦ 40 ° C, the material and temperature uniformity satisfy the standard for the time being, but there is some variation in material (Δ), 20 ° C <ΔT ≦ 30 ° C. was evaluated as (◯) because both the material and temperature uniformity were good, and ΔT ≦ 20 ° C. was evaluated as (◎) because the material and temperature uniformity was very good. The results are shown in Table 1.

  In the present invention examples 1 to 6, since the shielding object having an opening having a smaller longitudinal dimension toward the end in the width direction is installed below the nozzle, ΔT is within 30 ° C. in any steel plate of any plate width. Therefore, it was possible to manufacture a high-quality steel sheet with little material variation. In particular, the inventive examples 2 and 3 are provided with a weir plate at the edge of the opening, so that the shielded cooling water is prevented from falling downward from the opening, and ΔT can be further reduced. It was. Further, in Examples 4 to 6 of the present invention, the shielding plate was inclined, and the amount of falling from the opening of the shielded cooling water was suppressed, and ΔT could be further reduced.

  On the other hand, in Comparative Example 1, since the shielding plate was not installed, the width direction end of the steel plate was not affected by the water flow to the width direction end formed by the cooling water that reached the upper surface of the steel plate at any plate width. Due to overcooling, a predetermined material could not be obtained.

Claims (10)

A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed,
A nozzle that is arranged in the width direction of the steel plate and injects cooling water onto the upper surface of the steel plate;
A shielding plate provided below the nozzle and provided with an opening through which cooling water can pass downward;
A drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate,
The size of the opening in the longitudinal direction of the steel sheet is getting smaller as it goes to the end in the width direction of the steel sheet ,
The shielding plate is inclined downward toward both ends in the steel plate width direction,
The upper surface cooling apparatus of the steel plate whose inclination-angle of the said shielding board is 1 degree or more and 30 degrees or less . A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed,
A nozzle that is arranged in the width direction of the steel plate and injects cooling water onto the upper surface of the steel plate;
A shielding plate provided below the nozzle and provided with an opening through which cooling water can pass downward;
A drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate,
The size of the opening in the longitudinal direction of the steel sheet is getting smaller as it goes to the end in the width direction of the steel sheet ,
The drive mechanism is a steel sheet upper surface cooling device installed outside an end face in the steel plate width direction of the shielding plate . Before SL drive mechanism, the upper surface cooling equipment of the steel sheet according to claim 1 which is installed outside the end surface in the steel plate width direction of the shielding plate. A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed,
A nozzle that is arranged in the width direction of the steel plate and injects cooling water onto the upper surface of the steel plate;
A shielding plate provided below the nozzle and provided with an opening through which cooling water can pass downward;
A drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate,
The size of the opening in the longitudinal direction of the steel sheet is getting smaller as it goes to the end in the width direction of the steel sheet ,
The nozzles are provided in a plurality of rows along the longitudinal direction of the steel plate,
The said shielding board is an upper surface cooling apparatus of the steel plate provided with the opening part row | line | column corresponding to each nozzle row | line | column along a steel plate longitudinal direction . The nozzles are provided in a plurality of rows along the longitudinal direction of the steel plate,
The steel plate upper surface cooling apparatus according to any one of claims 1 to 3 , wherein the shielding plate includes a plurality of rows of opening portions corresponding to the nozzle rows along a longitudinal direction of the steel plate. A steel plate top surface cooling method performed using the steel plate top surface cooling device according to any one of claims 1 to 5,
The upper surface cooling method of the steel plate which displaces the position in the steel plate longitudinal direction of a shielding board according to the board width of a steel plate. The opening of the shielding plate is aligned with the position of one end in the longitudinal direction of the steel plate, and the position of the other end is arranged differently,
When the plate width of the steel plate is increased, the shielding plate is advanced to the other end side,
The method for cooling the upper surface of a steel plate according to claim 6, wherein when the plate width of the steel plate is reduced, the shielding plate is retracted toward the one end side. A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed,
A nozzle that is arranged in the width direction of the steel plate and injects cooling water onto the upper surface of the steel plate
A shielding plate provided below the nozzle and provided with an opening through which cooling water can pass downward;
A drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate,
The opening is a method of cooling the upper surface of a steel sheet, using a steel sheet upper surface cooling device whose dimensions in the longitudinal direction of the steel sheet are smaller toward the end in the width direction of the steel sheet,
Depending on the plate width of the steel plate, the position of the shielding plate in the longitudinal direction of the steel plate is displaced ,
The opening of the shielding plate is aligned with the position of one end in the longitudinal direction of the steel plate, and the position of the other end is arranged differently,
When the plate width of the steel plate is increased, the shielding plate is advanced to the other end side,
A method for cooling the upper surface of a steel sheet in which the shielding plate is retracted toward one end when the width of the steel sheet is reduced . The drive mechanism can displace the shielding plate discontinuously in units of stroke, with a predetermined distance as one stroke,
By displacing the shielding plate by one stroke, the shielding pattern of the nozzle row in the steel plate width direction can be changed to another different kind of shielding pattern ,
The method for cooling the upper surface of a steel sheet according to any one of claims 6 to 8 , wherein at least the shielding pattern can be changed to three or more different shielding patterns according to the sheet width of the steel sheet. A steel plate top surface cooling device for cooling the top surface of a steel plate being conveyed,
A nozzle that is arranged in the width direction of the steel plate and injects cooling water onto the upper surface of the steel plate;
A shielding plate provided below the nozzle and provided with an opening through which cooling water can pass downward;
A drive mechanism for displacing the shielding plate along the longitudinal direction of the steel plate,
The opening is a method of cooling the upper surface of a steel sheet, using a steel sheet upper surface cooling device whose dimensions in the longitudinal direction of the steel sheet are smaller toward the end in the width direction of the steel sheet,
Depending on the plate width of the steel plate, the position of the shielding plate in the longitudinal direction of the steel plate is displaced,
By displacing the shielding plate by one stroke, the shielding pattern of the nozzle row in the steel plate width direction can be changed to another different kind of shielding pattern ,
A method for cooling the upper surface of a steel sheet, wherein at least the shielding pattern can be changed into three or more different shielding patterns according to the sheet width of the steel sheet.