JP2007203369A - Cooling facility and cooling method of steel plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling facility and a cooling method which can uniformly cool a steel plate at a high cooling rate when feeding cooling water on a top side of the hot steel plate. <P>SOLUTION: The cooling facility is provided with upper headers 21a, 21b connected to upper nozzles 22a, 22b for ejecting rod-shaped cooling water 23a, 23b of the water volume density of ≥4 m<SP>3</SP>/m<SP>2</SP>min above a hot steel plate 10. The upper nozzles 22a, 22b are arranged opposite to each other in the conveying direction of the hot steel plate 10 so that the angles θ1, θ2 of depression formed between the rod-shaped cooling water 23a, 23b and the hot steel plate 10 are 30-60°. Cooling water is fed on a top surface of the steel plate 10 while passing the steel plate 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steel sheet cooling facility and a cooling method.

  In the process of manufacturing steel sheets by hot rolling, it is common to supply cooling water or air cooling to control the rolling temperature. Recently, however, the structure has been refined by obtaining a high cooling rate. The development of technology to increase the strength of steel sheets is thriving.

  For example, there is a technique described in Patent Document 1 as a technique for cooling a steel sheet by supplying cooling water. This is to raise and lower a slit nozzle unit that sprays cooling water in the direction of steel sheet conveyance, and it is said that a wide range of cooling rates can be secured by using it together with a separately provided laminar nozzle and spray nozzle. Yes.

Moreover, there exists a technique described in patent document 2 as another technique which cools a steel plate by supplying cooling water. This is because the header having slit-shaped nozzles is inclined to face and inject film-like cooling water, and a partition plate is provided to fill the cooling water between the steel plate and the partition plate to obtain a high cooling rate. Yes.
JP-A-62-260022 JP 59-144513 A

  However, the techniques described in Patent Documents 1 and 2 have major problems in ensuring cooling uniformity and equipment costs.

  That is, in the technique described in Patent Document 1, the slit nozzle unit must be brought close to the steel plate, and when the steel plate with the tip or tail end warped is cooled, the steel plate collides with the slit nozzle unit, May be damaged, or the steel plate may not be able to move, causing the production line to stop or the yield to decrease. Therefore, it is conceivable that when the tip and tail ends pass, the lifting mechanism is operated to retract the slit nozzle unit upward. In this case, the leading and trailing ends are not sufficiently cooled, and the desired material is obtained. It becomes impossible. Furthermore, there is a problem that the equipment cost for providing the lifting mechanism is increased.

  In the technique described in Patent Document 2, the cooling water is not filled between the steel plate and the partition plate unless the nozzle is brought close to the steel plate. When the nozzle is brought close to the steel plate, similarly to the technique described in Patent Document 1, inconvenience occurs when cooling the steel plate with the tip and tail ends warped.

  Furthermore, in the techniques described in Patent Documents 1 and 2, it is assumed that a slit-like nozzle is used. However, if the jet outlet is not always maintained in a clean state, the cooling water does not form a film. For example, as shown in FIG. 13, when the foreign matter 60 adheres to the jet nozzle of the slit nozzle 52 and clogging occurs, the cooling water film 53 is broken. Further, in order to keep the cooling water in the injection region (in the cooling region), it must be injected at a high pressure. However, if the film-like cooling water 53 is injected at a high pressure, the balance of the injection pressure becomes worse and the cooling water There was a problem that the film 53 was easily broken. If the cooling water film 53 is not formed well, the cooling water leaks in the upstream or downstream direction of the injection region, and it stays on the steel plate 10 to partially cool the steel plate 10 and cause temperature unevenness. There is. Although there is a technique for removing the cooling water staying on the upper surface of the steel plate 10 by side spraying or the like, there is a problem that when the amount of cooling water is large, it cannot be completely eliminated and temperature unevenness is caused.

  The present invention has been made in view of the above circumstances, and in the case of supplying cooling water to the upper surface of a hot steel plate, the steel plate can be cooled uniformly and stably at a high cooling rate. An object of the present invention is to provide a cooling facility and a cooling method.

  In order to solve the above problems, the present invention has the following features.

[1] A header connected to a nozzle for injecting bar-shaped cooling water having a water amount density of 4 m ³ / m ² min or more is provided above the steel sheet, and the depression angle between the bar-shaped cooling water and the steel sheet is 30 ° to 60 °, The cooling equipment for steel sheets, wherein the nozzles are arranged so as to face each other in the conveying direction of the steel sheets.

  [2] The steel sheet cooling equipment according to [1], wherein the nozzles are arranged in five or more rows in the steel plate conveyance direction, and the bar-shaped cooling water is injected at a speed of 8 m / s or more.

  [3] The injection direction of the rod-shaped cooling water is set so that 0 to 35% of the actual injection length in the rod-shaped cooling water injection direction is the length of the component that goes to the outside in the steel plate width direction perpendicular to the conveyance direction component of the steel plate. The steel sheet cooling equipment according to [1] or [2], wherein the steel sheet cooling equipment is provided.

  [4] 40 to 60% of the total number of nozzles arranged in the width direction of the steel sheet is the number of nozzles for injecting rod-shaped cooling water having a component directed to the outer side of the steel sheet width direction perpendicular to the conveying direction component of the steel sheet. The steel sheet cooling equipment according to any one of [1] to [3] above.

  [5] Number of nozzles for injecting rod-shaped cooling water having a component facing outward in one of the steel sheet width directions perpendicular to the conveying direction component of the steel plate, and the number of nozzles for injecting rod-shaped cooling water having a component facing outward in the other side Nozzles are arranged in the width direction of the steel sheet so that the two are equal to each other. The steel sheet cooling equipment according to any one of [1] to [4], wherein

  [6] The above-mentioned [1] to [5], wherein a plate-like or curtain-like shield is provided above the innermost row of rod-like cooling water and / or stagnant cooling water that jets oppositely. The steel sheet cooling equipment according to any one of the above.

  [7] In the above [6], the lowermost end of the shielding object provided above the rod-shaped cooling water in the innermost row that jets oppositely is a position 300 to 500 mm above the upper surface of the hot steel plate. The steel sheet cooling equipment described.

[8] A header connected to a nozzle for injecting bar-shaped cooling water having a water amount density of 4 m ³ / m ² min or more is provided above the steel sheet, and the depression angle between the bar-shaped cooling water and the steel sheet is 30 ° to 60 °, A cooling method for a steel sheet, wherein cooling is performed by arranging the nozzles so as to face each other in a conveying direction of the steel sheet.

  [9] The method for cooling a steel sheet according to [8], wherein five or more rows of the nozzles are arranged in the conveying direction of the steel sheet, and the rod-shaped cooling water is injected at a speed of 8 m / s or more.

  [10] The injection direction of the rod-shaped cooling water is set so that 0 to 35% of the actual injection length in the rod-shaped cooling water injection direction becomes the length of the component that goes to the outside in the steel plate width direction perpendicular to the conveyance direction component of the steel plate. The method for cooling a steel sheet according to [8] or [9], wherein the steel sheet is cooled.

  [11] 40 to 60% of the total number of nozzles arranged in the width direction of the steel sheet is the number of nozzles for injecting rod-shaped cooling water having a component directed to the outer side of the steel sheet width direction perpendicular to the conveying direction component of the steel sheet. The method for cooling a steel sheet according to any one of [8] to [10], wherein:

  [12] Number of nozzles for injecting rod-shaped cooling water having a component facing outward in one side of the steel sheet width direction perpendicular to the conveying direction component of the steel plate, and number of nozzles for ejecting rod-shaped cooling water having a component facing outward in the other side The method for cooling a steel sheet according to any one of [8] to [10], wherein the nozzles are arranged in the width direction of the steel sheet so that the two are equal.

  [13] Any of the above [8] to [12], wherein a plate-like or curtain-like shielding object is provided above the innermost row of rod-like cooling water and / or stagnant cooling water to be opposedly jetted The cooling method of the steel plate as described in 2.

  [14] The above-mentioned [13], wherein the lowermost end of the shield provided above the innermost row of rod-shaped cooling water that is jetted oppositely is positioned 300 to 500 mm above the upper surface of the hot steel plate. Cooling method for steel sheet.

  By using the present invention, the steel sheet can be uniformly cooled to the target temperature at a high cooling rate. As a result, a high quality steel plate can be manufactured.

  Embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
Drawing 1 is an explanatory view of the cooling equipment of the steel plate in the 1st embodiment of the present invention.

  The cooling facility according to the first embodiment is a passage-type cooling facility installed on a hot rolling line for steel plates, and includes one or a plurality of cooling units 20 shown in FIG. The cooling unit 20 supplies a pair of upper headers (first upper header 21 a and second upper header 21 b) for supplying cooling water toward the upper surface of the steel plate 10, and supplies cooling water toward the lower surface of the steel plate 10. Two lower headers 31 are provided. In FIG. 1, reference numeral 13 denotes a table roller.

  A plurality of rows of circular tube nozzles 22a and 22b (here, six rows in the conveying direction of the steel plate 10) are attached to the first upper header 21a and the second upper header 21b, respectively. The circular tube nozzle (first upper nozzle) 22a and the circular tube nozzle (second upper nozzle) 22b of the second upper header 21b are opposed to each other in the conveying direction of the steel plate 10 by rod-shaped cooling water 23a, 23b supplied from each. Are arranged to be. That is, the first upper nozzle 22a ejects the rod-shaped cooling water 23a at an inclination angle (injection angle) of θ1, and the second upper nozzle 22b injects the rod-shaped cooling water 23b at an inclination angle (injection angle) of θ2. .

  Therefore, the region sandwiched between the positions where the cooling water from the circular tube nozzles in the row farthest from the upper header (outermost row) collides with the steel plate 10 is the cooling region.

  At that time, the first upper header 21a and the second upper header 21b are arranged so that the injection line of the rod-like cooling water 23a from the first upper nozzle 22a and the injection line of the rod-like cooling water 23b from the second upper nozzle 22b do not intersect. If it arrange | positions to some extent, the water film of the staying cooling water 24 as shown in FIG. 1 will be formed stably. As a result, the cooling water from the circular tube nozzles in the row closest to the upper header (innermost row) is jetted toward the water film of the staying cooling water 24, and the other rod-like shape is mutually attached. It is preferable because the cooling water 23a and 23b are not broken. And if the interval between the positions where the cooling water from the circular tube nozzles in the innermost row collides with the steel plate 10 is called the staying area length, if the staying area length is within 1.5 m, the staying cooling Since the rate at which water cools the steel plate 10 is relatively small, it is possible to prevent the cooling method from changing greatly when the leading edge or the rearmost end of the steel plate 10 passes in an unsteady state.

  FIGS. 3A and 3B show examples of the arrangement of the circular tube nozzles 22a and 22b attached to the upper headers 21a and 21b. As described above, the circular tube nozzles 22 a and 22 b are arranged in six rows in the conveying direction of the steel plate 10. Moreover, it is attached so that cooling water can be supplied to the full width of the passing steel plate 10 in the plate width direction. In addition, although two upper headers are provided here, one header that is integrated with these may be provided, and the circular tube nozzles 22a and 22b may be arranged thereon.

  On the other hand, with respect to the lower header 31, here, two lower headers 31 are arranged, and circular nozzles 32 are attached to each of the lower headers 31. The cooling water is supplied to the entire width of the steel plate 10 to be performed.

And the cooling unit 20 supplies cooling water with the water density of 4 m < ³ > / m < ² > min or more from the upper headers 21a and 21b toward the upper surface of the steel plate 10, and is similarly 4 m from the lower header 31 toward the lower surface of the steel plate 10. Cooling water is supplied at a water density of ³ / m ² min or more.

Here, the reason why the water density is set to 4 m ³ / m ² min or more will be described. The staying cooling water 24 shown in FIG. 1 is formed to be blocked by the rod-shaped cooling waters 23a and 23b to be supplied. At this time, if the water density is small, damming itself cannot be performed, and if the water density becomes larger than a certain amount, the amount of the staying cooling water 24 that can be dammed increases, and the cooling water discharged from the end of the plate width The amount of the cooling water supplied is balanced and the retained cooling water 24 is kept constant. In the case of a thick steel plate, the general plate width is ^{2 to 5} m, and if it is cooled with a water density of 4 m ³ / m ² min or more, the retained cooling water can be kept constant at these plate widths, A desired amount of temperature drop can be obtained while passing the steel plate 10.

The larger the water density is 4 m ³ / m ² min or more, the more control rolled material that eliminates the waiting for cooling. For example, if the water density is small, the waiting for cooling can be solved only with a rolled material having a thin plate thickness. However, if the water density is increased, the waiting for cooling can be solved even for a rolled material having a certain thickness. However, the effect of shortening the cooling waiting time for increasing the water volume gradually decreases as the water density increases, so the water density takes into account the shortening effect such as the cooling waiting time and the equipment cost. It is preferable to determine. A more preferable water density is 4 to 10 m ³ / m ² min.

In this cooling unit 20, the rod-shaped cooling water 23a ejected from the first upper nozzle 22a and the rod-shaped cooling water 23b ejected from the second upper nozzle 22b are 4 m ³ so as to face each other in the conveying direction of the steel plate 10. Since the cooling water is supplied at a large water amount density of / m ² min or more, the stagnant cooling water 24 on the upper surface of the steel plate 10 is about to move in the conveying direction of the steel plate 10, and the injected rod-like cooling water 23a, 23b I dam up myself. Thereby, a stable cooling region can be obtained, and uniform cooling can be performed.

  Note that the cooling water sprayed from the upper nozzles 22a and 22b is, for example, a rod-shaped cooling water instead of a film-shaped cooling water using a slit nozzle. This is because the power to dam is large. In addition, when the film-like cooling water is injected obliquely, the water film near the steel sheet becomes thin and becomes more fragile as the distance from the steel sheet to the nozzle increases.

  Incidentally, the rod-shaped cooling water of the present invention refers to cooling water that is injected from a circular (including elliptical or polygonal) nozzle outlet. In addition, the rod-shaped cooling water of the present invention is not a spray-like jet or a film-like laminar flow, but the cross section of the water flow from the nozzle outlet to the steel plate is maintained in a substantially circular shape, and is continuous and straight. Refers to water cooling water.

  At that time, the injection angle θ1 of the first upper nozzle 22a and the injection angle θ2 of the second upper nozzle 22b are preferably set to 30 ° to 60 °. If the injection angles θ1 and θ2 are smaller than 30 °, the first upper nozzle 22a and the second upper nozzle 22b must be separated from each other, the equipment length becomes longer, and the vertical direction of the rod-shaped cooling waters 23a and 23b This is because the velocity component becomes small, the collision with the steel plate 10 becomes weak, and the cooling capacity decreases. On the other hand, when the injection angles θ1 and θ2 are larger than 60 °, the conveying direction speed component of the rod-shaped cooling water 23a and 23b becomes small, the force for damming the cooling water becomes weak, and the cooling water flows out of the cooling region and becomes large. This is because temperature unevenness occurs. The injection angle θ1 and the injection angle θ2 are not necessarily equal. Further preferable injection angles θ1 and θ2 are 40 ° to 50 °.

  Moreover, in order to make rod-like cooling water sprayed from each nozzle row act like a wall that dams up the cooling water that leaks outward in the conveying direction, the more nozzle rows are better, the faster the jet speed is better. . Specifically, if the nozzle rows are at least 5 rows in the conveying direction of the steel plate and the injection speed is 8 m / s or more, the force for blocking the cooling water is sufficient. The upper limit of the number of nozzle rows may be appropriately determined depending on the size of the steel sheet to be cooled, the conveyance speed, the target temperature drop amount, and the like. In addition, when the injection speed exceeds 30 m / s, the pressure loss increases, causing the problem of increased wear on the inner surface of the nozzle, and the equipment cost also increases.

  And in order to ensure that the nozzle is not clogged and the injection speed of the cooling water is ensured, the inner diameter of the nozzle may be in the range of 3 to 8 mm. Further, in order to prevent the cooling water from flowing out from the gap between the rod-shaped cooling waters, the interval between the nozzles adjacent to each other on the imaginary line drawn in the plate width direction may be within 10 times the nozzle inner diameter.

  (A) of FIG. 3 shows an arrangement in which six rows are provided in the carrying direction with an interval between adjacent nozzles of 40 mm, and (b) is four rows in the carrying direction in which the interval between adjacent nozzles is 40 mm. An example of an arrangement in which two rows in which the interval between adjacent nozzles is 20 mm is provided in the transport direction is shown.

  Further, in order to prevent the upper nozzles 22a and 22b from being damaged by warpage of the steel plate 10, the positions of the tips of the upper nozzles 22a and 22b are preferably separated from the pass line. Is dispersed and becomes rod-shaped, and the action of blocking the cooling water is lost. Therefore, the distance between the tip of the upper nozzles 22a and 22b and the pass line is preferably 500 mm to 1800 mm.

  Moreover, as shown in FIGS. 4 and 5, the injection of the rod-shaped cooling water 23a, 23b is performed so that 0 to 35% of the velocity component in the injection direction of the rod-shaped cooling water 23a, 23b becomes the velocity component toward the outside in the steel plate width direction. When the direction is set, the cooling water sprayed from the upper nozzles 22a and 22b onto the upper surface of the steel plate 10 merges and quickly drops from the width end of the steel plate 10 as shown by an arrow A in FIGS. Compared with the case where the rod-shaped cooling water 23a, 23b does not have a component toward the outer side in the width direction of the steel sheet, the accumulated cooling water 24 can be dammed up and drained with a low pressure and a small amount of water. It is preferable when designing a general facility. A more preferable range is 10 to 35%. By the way, if it exceeds 35%, it takes equipment cost to prevent scattering of the cooling water in the plate width direction, and the vertical component of the rod-shaped cooling water becomes small, and the cooling capacity is lowered.

  Further, 40 to 60% of the total number of nozzles arranged in the width direction of the steel sheet is the number of nozzles for injecting rod-shaped cooling water having a component directed to the outside of one side in the steel sheet width direction perpendicular to the conveying direction component of the steel sheet. preferable. If the number of nozzles facing one outside is 60% or more of the whole and the cooling water discharge from the end of the plate is biased, the rod-shaped cooling water will be used as the stagnant cooling water when the thickness of the stagnant cooling water increases. This is because there is a possibility that unevenness in temperature in the width direction may occur because the dams cannot be stopped. Moreover, it is also because the equipment cost for preventing this will become high when splashed water increases extremely on the outer side of one side.

  By the way, as shown in FIG. 4, even if nozzles that spray without facing the width direction outside are installed in the central portion of the plate width, the number thereof is within 20% of the whole, and the remaining number of nozzles facing both outsides is almost the same. If equal, the accumulated cooling water is discharged smoothly. It is most suitable for draining off the retained cooling water.

  Here, the setting of the injection direction of the rod-shaped cooling water will be specifically described with reference to FIG. FIG. 6 shows the injection direction of the rod-shaped cooling water. The angle formed by the rod-shaped cooling water injection line and the steel plate (substantial dip angle) is β, the dip angle with respect to the transport direction is θ, and the steel plate width direction is outward. The angle (outward angle) is shown as α. And, 0 to 35% of the velocity component in the jet direction of the rod-shaped cooling water is a velocity component that goes outward in the steel plate width direction, which means that the steel plate width perpendicular to the conveyance direction with respect to the cooling water jet substantial length L It means that the ratio Lw / L (width direction speed component ratio) of the length Lw of the direction component is 0 to 35%. Table 1 shows the calculation results when the nozzle ejection height h is 900 mm and the dip angle θ with respect to the conveying direction is 45 ° and 50 °. The width direction velocity component ratio is 0 to 35% when the dip angle θ with respect to the transport direction is 45 °, the outward angle α is 0 to 25 °, and when the dip angle θ with respect to the transport direction is 50 °, the outward angle α is 0 to 0%. This is the case of 30 °.

  And FIG. 4 mentioned above is a top view which shows an example at the time of installing upper nozzle 22a, 22b based on the above. Here, the rod-shaped cooling water from the nozzle in the center in the steel sheet width direction has an outward angle α of 0 °, and the outward angle α gradually increases as the nozzle installation position goes outward in the steel sheet width direction. Moreover, each nozzle is installed so that the position at which the rod-shaped cooling water collides with the steel plate is at equal intervals (for example, 60 mm pitch) in the steel plate width direction.

  Moreover, FIG. 5 mentioned above is a top view which shows the other example at the time of installing upper nozzle 22a, 22b based on the above. Here, the outward angle α of the cooling water jet is constant (for example, 20 °), and the nozzles are arranged so that the positions where the rod-shaped cooling water collides with the steel sheet are equally spaced (for example, 60 mm pitch) in the steel sheet width direction. It is installed. At that time, in the vicinity of the center in the width direction of the steel plate, nozzles that spray toward both the left and right sides must be installed, so that the hole for attaching the nozzle can be machined toward the outside in the width direction of one steel plate. Nozzle row (for example, a nozzle row having an injection velocity component in the upward direction in FIG. 5) and nozzle row (for example, an injection velocity component in the downward direction in FIG. Nozzles with nozzles) are alternately shifted in the transport direction by a predetermined interval (for example, 20 mm), and nozzles for injecting rod-shaped cooling water having a component directed outward in one of the steel plate width directions perpendicular to the steel plate transport direction component The number and the number of nozzles for injecting rod-shaped cooling water having a component facing the other side are made equal.

  If the outward angle α is increased, draining with a smaller amount of water becomes possible, but as shown in FIG. 5, the range in which the nozzle density increases near the center of the steel sheet width direction widens. The outward angle α may be determined in consideration of the ability of the pump that supplies water to the header, the thickness of the piping, and the like so that a uniform flow rate distribution can be obtained in the steel plate width direction.

  And it is preferable to provide a waterproof wall, a drain outlet, etc. in the both outer sides of the above cooling facilities. This is because it is effective to prevent the cooling water from leaking out of the facility or being scattered inside the facility to become new accumulated water.

  However, when the outward angle α exceeds 30 °, it is not preferable because it costs equipment costs to prevent scattering of the cooling water, and the vertical component of the rod-shaped cooling water becomes small and the cooling capacity is lowered.

  In the above-described embodiment, one or more cooling units 20 having a pair of upper headers 21a and 21b as shown in FIG. 1 are provided. 2, as shown in FIG. 2, it is possible to provide intermediate headers 21c between the pair of upper headers 21a and 21b, and the number thereof may be any number.

Thus, in this embodiment, the upper headers 21a and 21b connected to the upper nozzles 22a and 22b for injecting bar-shaped cooling water having a water density of 4 m ³ / m ² min or more are provided above the thermal steel plate 10, The upper nozzles 22a and 22b are arranged so that the slant angles θ1 and θ2 formed by the rod-shaped cooling waters 23a and 23b and the hot steel plate 10 are 30 ° to 60 ° and face each other in the conveying direction of the hot steel plate 10, and the steel plate 10 Since cooling water is supplied to the upper surface of the steel sheet 10 while passing, the steel sheet is cooled uniformly and stably at a high cooling rate to a target temperature by installing it in a hot rolling line for thick steel sheets and thin steel sheets. be able to. As a result, a high quality steel plate can be manufactured.

(Second Embodiment)
In said 1st Embodiment, when the speed of the rod-shaped cooling water 23a, 23b injected from the opposing upper nozzles 22a, 22b is high, for example, when it is 10 m / s or more, the rod-shaped cooling water 23a, 23b is a steel plate. After hitting 10, they collide with each other and scatter upward. If the scattered cooling water falls on the stagnant cooling water 24, there is no problem. However, as shown in FIG. 11, when the scattered cooling water 25 splashes obliquely upward and falls on the rod-shaped cooling waters 23a and 23b, the scattered cooling water. 25 may leak from the gap between the rod-shaped cooling waters 23a and 23b, and complete draining may not be possible. In particular, when the staying area length L is within 200 mm, the problem is likely to occur. Further, when the cooling water injection speed is high, the scattered cooling water 24 may jump over the upper headers 21 a and 21 b and fall on the steel plate 10.

  On the other hand, in the cooling facility according to the second embodiment, instead of the cooling unit 20 of FIG. 1 used in the first embodiment, a side view in FIG. 7 and an AA arrow in FIG. As shown in the view, a cooling unit 40 in which shielding plates 26a and 26b are added above the rod-shaped cooling water in the innermost row is used.

  As a result, even when the scattered cooling water 25 is scattered obliquely upward, the falling scattered cooling water 25 is blocked by the shielding plates 26a and 26b, and does not fall on the rod-shaped cooling water 23a and 23b. To fall into. Therefore, it becomes possible to drain water accurately.

  The shield plates 26a and 26b can be moved up and down by the cylinders 27a and 27b. The shield plates 26a and 26b are used only when manufacturing the products that require the shield plates 26a and 26b. Just keep it.

  Incidentally, when using the shielding plates 26 a and 26 b, it is preferable that the lowermost ends of the shielding plates 26 a and 26 b be positioned 300 to 500 mm above the upper surface of the steel plate 10. In other words, if the steel plate 10 is positioned at least 300 mm above the upper surface of the steel plate 10, it will not collide even if a steel plate with a warp at the tip or tail end enters. However, if the height of the steel plate 10 is increased beyond 500 mm, the scattered cooling water 25 cannot be sufficiently shielded.

  Further, instead of the shielding plates 26a and 26b in FIGS. 7 and 8, shielding curtains 28a and 28b having a light and smooth surface may be used as shown in FIG. The shielding curtains 28a and 28b are normally in a suspended state and are lifted along the rod-shaped cooling water in the innermost row when the injection of the rod-shaped cooling water 23a and 23b is started. At that time, since the rod-shaped cooling water 23a and 23b are jetted vigorously, the flow is not disturbed.

  Furthermore, as described above, when the cooling water injection speed is fast and the scattered cooling water jumps over the upper headers 21a and 21b and falls on the steel plate 10, the upper header as shown in FIG. You may use the shielding board 29 which straddles 21a and the upper header 21b, and is located above the staying cooling water 24. FIG. By using such a shielding plate 29, it is possible to accurately shield the scattered cooling water that jumps over the upper headers 21a and 21b and falls on the steel plate 10. In addition, the scattered cooling water hitting the shielding plate 29 is effective because it scatters the scattered cooling water to be scattered in the lateral direction and falls onto the staying cooling water 24 together.

  Example 1 of the present invention will be described below.

  FIG. 12 is a diagram showing a hot rolling line for thick steel plates used in Example 1 of the present invention and a conveyance pattern there.

  The thick steel plate hot rolling line includes a heating furnace 11, a reversible rolling mill 12, a first cooling device 14, a hot leveler 15, and a second cooling device 16.

  And conveyance pattern A performs accelerated cooling after finish rolling, and after carrying out rough rolling and finish rolling the slab extracted from heating furnace 11 by reversible rolling machine 12, and making plate thickness 25mm, Through the hot leveler 15, the second cooling device 16 performs accelerated cooling with a temperature drop of 150 ° C.

  Moreover, the conveyance pattern B performs temperature adjustment cooling before controlled rolling, and after the slab extracted from the heating furnace 11 is rough-rolled by the reversible rolling machine 12 to have a plate thickness of 60 mm, the first cooling is performed. The apparatus 14 performs the adjustment cooling with a temperature drop of 80 ° C., and then performs low temperature finish rolling, that is, controlled rolling.

Based on the first embodiment described above, the cooling unit 20 shown in FIG. 1 is replaced with 1 unit for the first cooling facility 14 and 6 units for the second cooling facility 16 under the above. It installed and the conveyance pattern A and the conveyance pattern B were conveyed. At that time, the upper nozzles 22a and 22b have a nozzle tip height position of 1.2 m from the table roller, an arrangement shown in FIG. 3A, a nozzle inner diameter of 6 mm, and a water amount density of 6 m ³ / m ^2. min, the injection angles θ1 and θ2 of the rod-shaped cooling water were 45 °, and the injection speed was 8 m / s.

  Further, as Invention Example 2, in the nozzle arrangement shown in FIG. 5, the height position of the nozzle tip, the nozzle inner diameter, the water density, the injection angles θ1, θ2, and the injection speed are the same as in Example 1, and the rod-shaped cooling water is used. 1 unit of cooling units and 6 units of second cooling facility 16 were installed in the first cooling facility 14 and the transport pattern A and transport pattern B were transported.

  In the inventive examples 1 and 2, the position where the rod-shaped cooling water collides with the steel plate was set to a 60 mm pitch in the steel plate width direction.

  On the other hand, as Comparative Example 1, the first cooling facility 14 and the second cooling facility 16 were changed to conventional conventional shower cooling devices, and the transport pattern A and the transport pattern B were transported.

  Further, as Comparative Example 2, the first cooling facility 14 and the second cooling facility 16 are the cooling devices described in Patent Document 2 that inject film-like cooling water so as to face each other. Carried.

  In each case, after cooling (after sufficiently recuperating), the steel plate width direction temperature was continuously measured using a radiation thermometer, and the temperature distribution on the upper surface of the steel plate was examined. The temperature variation (difference between the highest temperature and the lowest temperature) in the stationary part excluding the cutting edge, the tail edge, and the width direction plate edge was defined as temperature unevenness and compared. The size of the temperature unevenness almost corresponded to the variation in mechanical properties of the product such as tensile strength. The production efficiency and the yield were compared on the basis of Comparative Example 1.

  The results are shown in Table 2.

  First, Comparative Example 1 is shower cooling, and due to the influence of cooling water staying on the steel plate, temperature unevenness is 80 ° C. in conveyance pattern A (accelerated cooling after finish rolling), and conveyance pattern B (temperature adjustment before controlled rolling). In cooling, the temperature was 40 ° C., and the strength variation of the product was large.

  Next, in Comparative Example 2, since the nozzle had to be brought close to the steel plate, the equipment might be damaged when the warpage of the steel plate occurred. Since the steel plate that collided with the equipment did not become a product, the yield of the product decreased compared to Comparative Example 1. In addition, since it took a considerable amount of time to repair the damaged equipment, the production efficiency also declined. Further, since the film-like cooling water is supplied, foreign matter adheres to the nozzle outlet and the film-like cooling water is not formed, and the cooling water may not be dammed in the injection region (in the cooling region). Therefore, due to the influence of the cooling water staying on the steel plate, the temperature unevenness becomes 80 ° C. in the conveyance pattern A (accelerated cooling after finish rolling), and 40 ° C. in the conveyance pattern B (temperature adjustment cooling before control rolling). The intensity variation was also large.

  On the other hand, in Example 1 of the present invention, the height position of the nozzle tip was increased to 1.2 m, so that the equipment was not damaged even if the steel plate was warped, and the yield was not reduced by trouble. Efficiency has improved. Furthermore, since the rod-shaped cooling water was jetted at high speed while facing the cooling water, the cooling water could be completely dammed in the cooling region, and the temperature unevenness could be suppressed to an extremely low value of 8 to 15 ° C.

  Further, in Invention Example 2, the cooling water sprayed from the upper nozzles 22a and 22b onto the upper surface of the steel plate 10 merges and quickly falls from the width end of the steel plate 10 as indicated by the arrow A in FIG. The stagnant cooling water 24 can be dammed up and drained with a smaller amount of water than when there is no orientation angle α, and the temperature unevenness was suppressed to a very low value of 6 to 12 ° C., and cooling was possible uniformly. Furthermore, since the cooling water could be dammed even if the flow rate and pressure were slightly reduced, the equipment did not require so much pressure and a large amount of water, and an economical equipment design could be performed.

  From the above results, the effectiveness of the present invention was confirmed.

  In the hot rolling line for thick steel plates shown in FIG. 12, based on the second embodiment, the cooling unit 40 shown in FIG. 7 or FIG. One unit was installed in the facility 16 to cool the steel plate. At that time, the injection angles θ1 and θ2 of the rod-shaped cooling water were 45 °, and the injection speed was 12 m / s. Moreover, the residence area length L was set to 0 mm.

  And the example 3 of this invention is a case where the cooling unit 40 provided with the shielding plates 26a and 26b shown in FIG. 7 is used. At that time, the shielding plates 26a and 26b were set to be positioned 50 mm above the rod-shaped cooling water in the innermost row. And the distance ((delta) in FIG. 7) of the conveyance direction with the position where the rod-shaped cooling water of the innermost row | line | column collides with the steel plate 10 was made into 100 mm.

  In addition, Example 4 of the present invention is a case where the cooling unit 40 including the shielding curtains 28a and 28b shown in FIG. 9 is used. At that time, the conveyance direction distance (δ in FIG. 9) between the position of the lowermost end of the shielding curtains 28a and 28b lifted by the injection of the rod-shaped cooling water and the point where the rod-shaped cooling water in the innermost row collides with the steel plate 10 is 100 mm. It was made to become.

  As a result, both the inventive examples 3 and 4 were able to accurately prevent the scattered cooling water 25 that collided with the steel plate 10 and scattered upward from falling onto the rod-shaped cooling waters 23a and 23b. Thereby, the uniformity of cooling was able to be maintained.

It is explanatory drawing of the cooling equipment which concerns on the 1st Embodiment of this invention. It is explanatory drawing of the other cooling equipment which concerns on the 1st Embodiment of this invention. It is the figure which showed the nozzle arrangement example of the upper header in the 1st Embodiment of this invention. It is the figure which showed an example of the setting of the injection direction of the upper nozzle in the 1st Embodiment of this invention. It is the figure which showed the other example of the setting of the injection direction of the upper nozzle in the 1st Embodiment of this invention. It is explanatory drawing about the setting of the injection direction of rod-shaped cooling water. It is explanatory drawing of the cooling equipment which concerns on the 2nd Embodiment of this invention. It is an AA arrow line view of FIG. It is explanatory drawing of the other cooling facility which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the other cooling facility which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating scattering cooling water. It is explanatory drawing of the hot rolling line and conveyance pattern of the thick steel plate in the Example of this invention. It is the figure which showed the trouble of the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steel plate 11 Heating furnace 12 Reversible rolling mill 13 Table roller 14 1st cooling equipment 15 Hot leveler 16 2nd cooling equipment 20 Cooling unit 21a 1st top header 21b 2nd top header 22a 1st top nozzle 22b 2nd top nozzle 23a Rod shape Cooling water 23b Bar-shaped cooling water 24 Stagnating cooling water 25 Spattering cooling water 26a Shield plate 26b Shield plate 27a Cylinder 27b Cylinder 28a Shield screen 28b Shield screen 29 Shield plate 31 Lower header 32 Lower nozzle 33 Rod-shaped coolant 40 Cooling unit 51 Cooling header 52 Slit nozzle 53 Cooling water film 60 Deposit

Claims (14)

The header which connected the nozzle which injects the rod-shaped cooling water of the water amount density of 4m < ³ > / m < ² > min or more above the steel plate is provided, and the depression angle which rod-shaped cooling water and the said steel plate make is 30 degrees-60 degrees, A steel sheet cooling facility, wherein the nozzles are arranged so as to face each other in the transport direction.   The said nozzle is arranged in 5 or more rows in the conveyance direction of a steel plate, and rod-shaped cooling water is injected at a speed | rate of 8 m / s or more, The cooling equipment of the steel plate of Claim 1 characterized by the above-mentioned.   The injection direction of the rod-shaped cooling water is set so that 0 to 35% of the actual injection length in the rod-shaped cooling water injection direction is the length of the component that goes to the outside in the steel plate width direction perpendicular to the conveyance direction component of the steel plate. The steel sheet cooling equipment according to claim 1, wherein the steel sheet cooling equipment is provided.   40 to 60% of the total number of nozzles arranged in the width direction of the steel sheet is the number of nozzles for injecting rod-shaped cooling water having a component directed to the outside of the steel sheet width direction perpendicular to the conveying direction component of the steel sheet. The steel sheet cooling equipment according to any one of claims 1 to 3.   The number of nozzles that eject rod-shaped cooling water having a component facing outward in one direction in the width direction of the steel sheet perpendicular to the conveying direction component of the steel sheet is equal to the number of nozzles ejecting rod-shaped cooling water having a component facing outward in the other side 5. The steel sheet cooling equipment according to claim 1, wherein the nozzles are arranged in the width direction of the steel sheet as described above.   The steel plate according to any one of claims 1 to 5, wherein a plate-like or curtain-like shielding object is provided above the innermost row of rod-like cooling water and / or stagnant cooling water to be opposedly jetted. Cooling equipment.   The bottom end of the shield provided above the rod-shaped cooling water in the innermost row that jets oppositely is a position 300 to 500 mm above the top surface of the steel plate. Steel sheet cooling equipment. The header which connected the nozzle which injects the rod-shaped cooling water of the water amount density of 4m < ³ > / m < ² > min or more above the steel plate is provided, and the depression angle which rod-shaped cooling water and the said steel plate make is 30 degrees-60 degrees, A cooling method for a steel sheet, wherein cooling is performed by arranging the nozzles so as to face each other in a conveying direction.   9. The steel sheet cooling method according to claim 8, wherein five or more rows of the nozzles are arranged in a conveying direction of the steel sheet, and the rod-shaped cooling water is sprayed at a speed of 8 m / s or more.   The injection direction of the rod-shaped cooling water is set so that 0 to 35% of the actual injection length in the rod-shaped cooling water injection direction is the length of the component that goes to the outside in the steel plate width direction perpendicular to the conveyance direction component of the steel plate. The steel sheet cooling method according to claim 8 or 9, wherein the steel sheet is cooled.   40 to 60% of the total number of nozzles arranged in the width direction of the steel sheet is the number of nozzles for injecting rod-shaped cooling water having a component directed to the outside of the steel sheet width direction perpendicular to the conveying direction component of the steel sheet. The method for cooling a steel sheet according to any one of claims 8 to 10.   The number of nozzles that eject rod-shaped cooling water that has a component facing outward in one direction in the width direction of the steel sheet perpendicular to the conveying direction component of the steel plate is equal to the number of nozzles that eject rod-shaped cooling water that has a component facing outward in the other side The method for cooling a steel sheet according to any one of claims 8 to 11, wherein the nozzles are arranged in the width direction of the steel sheet.   The method for cooling a steel sheet according to claim 5 or 6, wherein a plate-like or curtain-like shield is provided above the innermost row of bar-like cooling water and / or stagnant cooling water that is jetted oppositely.   14. The lowermost end of the shield provided above the innermost row of rod-shaped cooling water that jets oppositely is positioned 300 to 500 mm above the upper surface of the steel sheet. Cooling method for steel sheet.

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