JP4903920B1 - Steel plate cooling device and method for cooling steel plate - Google Patents

Abstract

The steel sheet cooling device includes a plurality of restraining roll pairs for restraining and passing the steel sheet; and an upper portion having a plurality of spray nozzle rows disposed between the restraining roll pairs so as to face each other with the steel sheet interposed therebetween. A plurality of spray nozzle rows arranged in the plate passing direction of the steel plate, and each spray nozzle row arranged in the width direction of the steel plate. Each spray nozzle row is relatively downstream with an upstream spray nozzle row group on the relatively upstream side when viewed along the plate passing direction. The number of spray nozzles belonging to the upstream spray nozzle row group is less than the number of spray nozzles belonging to the downstream spray nozzle row group.
[Selection] Figure 9

Description

The present invention relates to a cooling device that cools a steel plate obtained by hot rolling while horizontally restraining it with a restraining roll and a method for cooling the steel plate.
This application claims priority based on Japanese Patent Application No. 2010-164522 filed in Japan on July 22, 2010 and Japanese Patent Application No. 2010-234715 filed in Japan on October 19, 2010, The contents are incorporated here.

  The hot-rolled steel sheet after finish rolling in hot rolling is cooled to a predetermined temperature while being transported after being restrained by restraining rolls after the finish rolling mill. Between each restraining roll pair, a plurality of spray nozzles that inject cooling water onto the upper and lower surfaces of the cooling device, for example, the hot steel plate, are arranged, and the hot steel plate is cooled by the cooling water. In hot rolling of hot steel sheets, the cooling mode after finish rolling is an important factor that determines the mechanical properties, workability, and weldability of the steel sheet, and the hot steel sheet is uniformly cooled to a predetermined temperature. It is important to do.

  However, when the hot steel sheet is cooled with the cooling water as described above, it is difficult to uniformly cool the hot steel sheet under the influence of the on-board water staying on the hot steel sheet, particularly on the upper surface side of the hot steel sheet. That is, the on-board water on the hot steel plate is discharged in the width direction of the hot steel plate, but the on-board water and the water jet of cooling water injected on the hot steel plate interfere with each other. Thereby, a cooling water becomes non-uniform | heterogenous in the width direction of a hot-steel plate.

  Therefore, Patent Document 1 discloses a cooling method that allows the water jet to sufficiently reach the upper surface of the thermal steel sheet by adjusting the collision area of the water jet from the spray nozzle or adjusting the spread angle of the water jet. Has been. In the case of this method, sufficient cooling capacity can be secured and the hot steel sheet can be cooled uniformly.

  Here, in the hot rolling, the cooling capacity required for the cooling device differs depending on the type and application of the steel plate. Therefore, it is desired that the cooling device can uniformly cool the hot steel sheet as described above and can select a wide cooling capacity control range.

  Under this circumstance, for example, when the required cooling capacity is low, that is, when the amount of cooling water sprayed onto the hot steel sheet is small, the nozzle load pressure of the spray nozzle becomes small. This makes it difficult to ensure the area of the collision portion of the water jet from the spray nozzle on the hot steel plate (hereinafter referred to as “spray pattern”). For this reason, in the cooling method described in Patent Document 1, when the amount of cooling water is small, the water jet from the spray nozzle is affected by the water on the plate, and it is difficult to cool the hot steel plate uniformly.

  Therefore, Patent Document 2 discloses a cooling device that has spray nozzles having different amounts of cooling water to be sprayed and uses the spray nozzles according to the required cooling capacity (cooling water amount). However, when cooling the upper surface of the hot steel plate, if the difference in the amount of cooling water ejected from each spray nozzle is large, the water jet with a large amount of cooling water from the spray nozzle affects the water jet with a small amount of cooling water, The cooling water is not uniform in the width direction of the hot steel sheet. In addition, when spray nozzles having different amounts of cooling water are used simultaneously, nonuniform cooling occurs. Therefore, the conditions for applying this cooling device are limited, and the cooling capacity range may not be sufficiently expanded.

  Patent Document 3 discloses a cooling device including an air / water spray nozzle that ejects two fluids (air and cooling water) in order to ensure a spray pattern. However, the air-water spray nozzle requires an air compressor, air piping, and the like for supplying air, and the manufacturing cost of the cooling device increases. Moreover, since the nozzle structure of the air / water spray nozzle is complicated and easily clogged, the maintenance cost is increased in addition to the manufacturing cost of the cooling device. Further, the pressure control between air and water is complicated, and it is difficult to keep the air / water ratio constant, and the cooling capacity changes depending on the air / water ratio. As described above, the cooling device has a problem that it is difficult to accurately control the cooling capacity because there are too many influence factors.

Japanese Unexamined Patent Publication No. 2006-82115 Japanese Unexamined Patent Publication No. 2007-301568 Japanese Unexamined Patent Publication No. 2006-219732

  The present invention has been devised in view of the above-described problems, and when cooling a hot-rolled steel sheet after hot rolling, a steel sheet cooling apparatus that uniformly cools the steel sheet while controlling the cooling capacity over a wide range. And it aims at provision of the cooling method of a steel plate.

The present invention employs the following means in order to solve the above problems and achieve the object.
That is,
(1) A steel sheet cooling device according to an aspect of the present invention includes a plurality of restraint roll pairs for restraining and passing a steel sheet; and disposed opposite to each other with the steel sheet interposed between the restraint roll pairs. An upper cooling device and a lower cooling device having a plurality of spray nozzle rows, wherein the plurality of spray nozzle rows are arranged along the plate passing direction of the steel plate, and each spray nozzle row is A plurality of the same spray nozzles arranged in the width direction of the steel plate; when viewed along the plate passing direction, each spray nozzle row is a group of upstream spray nozzle rows relatively upstream And the downstream spray nozzle row group relatively downstream; the number of the spray nozzles belonging to the upstream spray nozzle row group is the spray nozzle belonging to the downstream spray nozzle row group Rather less than the number of the the total number of columns of each spray nozzle rows, the ratio of the number of columns of spray nozzle rows belonging to the upstream spray nozzle row group, the maximum injection quantity of each spray nozzle of the spray nozzle array Is an integer ratio that is the same as or close to the ratio of the minimum injection amount .

( 2 ) The steel plate cooling device according to ( 1 ) further includes a control unit that controls cooling water sprayed from the plurality of spray nozzle rows toward the steel plate; sprayed toward the steel plate. When the total amount of water is equal to or greater than the maximum spray amount of the upstream spray nozzle row group, the cooling water is jetted from both the upstream spray nozzle row group and the downstream spray nozzle row group, When the amount of water is smaller than the maximum injection amount of the upstream spray nozzle row group, the control unit controls the injection of the cooling water so that the cooling water is injected only from the upstream spray nozzle row group. Preferably.

( 3 ) The steel sheet cooling device according to ( 2 ) above is supplied to the water supply header; a water supply header that supplies the cooling water to the upstream spray nozzle row group and the downstream spray nozzle row group; A flow control valve that adjusts the flow rate of the cooling water; a first control valve that controls permission or prohibition of the supply of the cooling water supplied from the water supply header to the upstream spray nozzle row group; and the water supply header And a second control valve that controls permission or prohibition of supply of the cooling water supplied to the downstream spray nozzle row group.

( 4 ) Moreover, the steel sheet cooling device according to one aspect of the present invention includes a plurality of restraining roll pairs for restraining and passing the steel plates; and facing each other with the steel plates sandwiched between the restraining roll pairs. An upper cooling device and a lower cooling device, each having a plurality of spray nozzle rows, wherein the plurality of spray nozzle rows are arranged along a sheet passing direction of the steel plate, and each spray nozzle row is A plurality of the same spray nozzles arranged in the width direction of the steel plate; when viewed along the plate passing direction, each spray nozzle row is relatively upstream. A group of rows and a group of downstream spray nozzles relatively downstream; the number of spray nozzles belonging to the upstream spray nozzle row group includes the splines belonging to the downstream spray nozzle row group. Less than the number of Nozuru; a first water supply header for supplying the cooling water to the upstream spray nozzle row group, and the second water supply header for supplying the cooling water to the downstream spray nozzle row group, the first water supply A first flow rate adjusting valve for adjusting a flow rate of the cooling water supplied to the header; a second flow rate adjusting valve for adjusting a flow rate of the cooling water supplied to the second water supply header; and the plurality of spray nozzle rows. A control unit for controlling cooling water sprayed from the steel plate toward the steel plate; when the total water amount to be sprayed toward the steel plate is equal to or greater than the maximum spray amount of the upstream spray nozzle row group Is that the cooling water is injected from both the upstream spray nozzle row group and the downstream spray nozzle row group, while the total water amount is equal to the maximum injection amount of the upstream spray nozzle row group. Remote if small, so as to inject the cooling water from only the upstream spray nozzle row group, the control unit controls the injection of the cooling water.

( 5 ) In the steel sheet cooling device according to any one of (1) to ( 4 ), the adjacent intervals in the plate passing direction of the spray nozzle rows belonging to the upstream spray nozzle row group are It is preferable that the adjacent intervals in the plate passing direction of the spray nozzle rows belonging to the downstream spray nozzle row group are the same.

( 6 ) In the steel sheet cooling device according to any one of (1) to ( 4 ), it is preferable that the adjacent intervals of the spray nozzle rows in the plate passing direction are all the same.

By the way, when the total amount of cooling water sprayed on the upper surface of the steel plate is less than the maximum water amount of the upstream spray row group, the amount of water on the steel plate is small, and the water on the plate is moved in the plate passing direction of the steel plate as the steel plate moves. That is, it is discharged to the downstream side of the steel sheet and does not stay so much on the upstream side. For this reason, the cooling water sprayed to the upstream side of the steel plate is not affected by the water on the plate, and the steel plate can be cooled uniformly.
In such a case and when the on-board water on the steel plate stays on the side of the restraining roll opposite to the steel plate, ( 7 ) the steel plate according to any one of (1) to ( 4 ) above When the maximum spray amount is sprayed from the upstream spray nozzle row group, the cooling device moves toward the upstream position along the plate passing direction with respect to the area of the plate water that stays on the steel plate. The upstream spray nozzle row group may be arranged so that the cooling water is jetted from the side spray nozzle row group.

( 8 ) When cooling the steel sheet using the steel sheet cooling device according to any one of ( 2 ) to ( 4 ), the total water amount to be sprayed toward the steel sheet is the upstream spray. When it is equal to or greater than the maximum spray amount of the nozzle row group, the cooling water is jetted from both the upstream spray nozzle row group and the downstream spray nozzle row group, while the total water amount is the upstream spray nozzle row. When the injection amount is smaller than the maximum injection amount of the group, the control unit may control the injection of the cooling water so that the cooling water is injected only from the upstream spray nozzle row group.

( 9 ) The method for cooling a steel sheet according to ( 8 ) above, wherein the area of the on-board water that stays on the steel sheet when the cooling water is injected from the upstream spray nozzle row group at a maximum injection amount. The upstream spray nozzle row group is disposed at a position upstream of the region along the plate passing direction so that the cooling water is jetted from the upstream spray nozzle row group. Also good.

  According to the present invention, it is possible to perform uniform cooling with a smaller cooling nozzle number, a smaller number of nozzle rows, and even a smaller flow rate control valve with a wide cooling capacity range. In addition, since the equipment configuration is simple and there is only one type of nozzle, it is possible to reduce equipment construction costs and maintenance costs.

It is a side view which shows the outline of a one part structure of the hot rolling equipment which has a cooling device concerning 1st Embodiment of this invention. It is explanatory drawing which shows the outline of a structure in the longitudinal cross-sectional view of the upper cooling device of the cooling device. It is explanatory drawing which shows the outline of a structure in the horizontal sectional view of the upper cooling device of the cooling device. It is explanatory drawing which showed a mode that cooling water was injected from the spray nozzle of the cooling device. It is the graph which showed the relationship between the nozzle load pressure and spray angle of the spray nozzle of the cooling device. It is the graph which showed the relationship between the nozzle load pressure of the spray nozzle of the cooling device, and the amount of cooling water. It is explanatory drawing which showed the relationship between the nozzle load pressure of the spray nozzle of the cooling device, and the amount density of the cooling water supplied from the upper cooling device. It is explanatory drawing which shows a mode that a steel plate is cooled when the required cooling capacity is high. It is explanatory drawing which shows a mode that a steel plate is cooled when the cooling capacity requested | required is low. It is explanatory drawing in case cooling water is injected only from a downstream spray nozzle row group. It is a graph which shows the cooling rate in each position of the width direction of the steel plate cooled using the cooling device. It is a side view which shows the whole cooling device concerning the 2nd Embodiment of this invention. It is a perspective view which shows typically the nozzle header of the cooling device. It is a top view which shows arrangement | positioning of the cooling water spray nozzle attached to the nozzle header of the cooling device. It is a graph which shows the relationship between the feed water density from a small flow nozzle header and a large flow nozzle header, and nozzle feed water pressure.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described. FIG. 1 shows a schematic configuration of a part of a hot rolling facility having a cooling device 1 according to the present embodiment.

In the hot rolling facility, as shown in FIG. 1, a finish rolling mill 2, a hot straightening device 3, and a cooling device 1 are provided in this order in the sheet passing direction of a steel plate (hot steel plate) H. Yes. The rolling mill 2 hot-rolls the steel sheet H discharged from a heating furnace (not shown) and rolled by a rough rolling mill (not shown). The hot straightening device 3 straightens the shape of the steel plate H after finish rolling. The cooling device 1 cools the steel sheet H after hot correction to a predetermined temperature, for example, 350 ° C. Thus, the steel sheet H rolled by the finish rolling mill 2 is corrected by the hot straightening device 3 and then cooled by the cooling device 1 during conveyance.
It should be noted that a layout that corrects after cooling, that is, the hot straightening device 3 may be provided on the downstream side (rear side) of the cooling device 1. Alternatively, the hot straightening device 3 may be provided on both the upper side and the lower side across the steel plate H of the cooling device 1.

The cooling device 1 includes a plurality of restraining roll pairs 10, an upper cooling device 11 and a lower cooling device 12, and a control unit 5.
The plurality of constraining roll pairs 10 includes a constraining roll 10a disposed above the steel plate H and a transporting roll 10b disposed below. The restraining roll 10a and the transporting roll 10b are arranged in the horizontal direction along the plate passing direction of the steel plate H, and cause the steel plate H to pass through. Each constraining roll pair 10 is composed of two constraining rolls arranged vertically. The steel plate H is conveyed in a state of being sandwiched between the upper and lower restraining rolls. The lower restraining roll may be referred to as a transport roll.
Further, the steel roll H is sandwiched between the restraining roll 10a and the transport roll 10b.

  An upper cooling device 11 that cools the upper surface side of the steel plate H and a lower cooling device 12 that cools the lower surface side of the steel plate H are respectively disposed between the adjacent pair of restraining rolls 10 and 10. Specifically, the upper cooling device 11 and the lower cooling device 12 are disposed to face each other with the steel plate H interposed therebetween. With this configuration, the cooling device 1 can cool the upper and lower surfaces of the steel plate H. Further, the upper cooling device 11 and the lower cooling device 12 have a plurality of spray nozzle rows 21. This spray nozzle row 21 is arranged along the plate passing direction of the steel plate H, and each spray nozzle row 21 has a plurality of identical spray nozzles 20 arranged in the width direction of the steel plate H. .

  The lower cooling device 12 is provided with a plurality of spray nozzles, for example, full cone spray nozzles (not shown) arranged side by side in the sheet passing direction and the width direction of the steel plate H. Although the full cone nozzle of the lower cooling device 12 is not shown, the discharge water amount is slightly larger than the full cone spray nozzle of the upper cooling device 11 shown in FIG. Cooling water is sprayed onto the steel plate H from the full cone spray nozzle, and the steel plate H is cooled from the lower surface side by a water jet of cooling water.

  As shown in FIGS. 2 and 3, the upper cooling device 11 has a plurality of spray nozzles for injecting cooling water onto the upper surface of the steel sheet H, and in this embodiment, a full cone spray nozzle 20. The full cone spray nozzle 20 can inject a conical water jet as shown in FIG.

  As shown in FIGS. 2 and 3, the plurality of full cone spray nozzles 20 form a nozzle row in the width direction of the steel plate H, and the nozzle rows are arranged in a plurality of rows in the plate passing direction. For example, in FIG.2 and FIG.3, the spray nozzle row | line | column 21 arrange | positioned along with 9 rows is comprised. A plurality of spray nozzles 20 are arranged in the width direction of the steel sheet H in each of the spray nozzle rows 21a to 21i. That is, the plurality of full cone nozzles 20 are arranged in a staggered manner in a horizontal sectional view. With this configuration, the cooling water sprayed from the full cone spray nozzle 20 is sprayed onto the upper surface of the steel plate H.

  As shown in FIGS. 2 and 3, the nine spray nozzle rows 21a to 21i are spray nozzle rows 21a to 21a in which each spray nozzle row 21 is relatively upstream when viewed along the plate passing direction. 21c and the spray nozzle rows 21d to 21i on the downstream side. Specifically, it is grouped into two spray nozzle row groups 22 and spray nozzle row groups 23 arranged in the plate passing direction of the steel plate H. Hereinafter, the spray nozzle row group disposed on the upstream side of the steel plate H (upstream side of the steel plate H) is referred to as the upstream spray nozzle row group 22, and the spray disposed on the downstream side of the steel plate H (downstream side of the steel plate H). The nozzle row group is referred to as a downstream spray nozzle row group 23. As described above, the upstream spray nozzle row group 22 is composed of, for example, three spray nozzle rows 21a to 21c, and the downstream spray nozzle row group 23 is composed of, for example, six spray nozzle rows 21d to 21i. Yes. A method of setting the number of spray nozzle rows 21a to 21i in the upstream spray nozzle row group 22 and the downstream spray nozzle row group 23 will be described later. The arrangement position of the upstream spray nozzle row group 22 will also be described later.

  Each full cone spray nozzle 20 is connected to one end of a supply pipe 24 that supplies cooling water to the full cone spray nozzle 20. The supply pipe 24 extends vertically upward from the full cone spray nozzle 20, and the other end of the supply pipe 24 is disposed in a nozzle box 30 capable of storing cooling water.

  The interior of the nozzle box 30 is partitioned into two storage chambers 31 and 32. In the upstream storage chamber 31 disposed on the upstream side of the steel plate H, the supply pipe 24 of the full cone spray nozzle 20 of the upstream spray nozzle row group 22 is accommodated. Further, in the downstream storage chamber 32 arranged on the downstream side of the steel plate H, the supply pipe 24 of the full cone spray nozzle 20 of the downstream spray nozzle row group 23 is accommodated. In each of the storage chambers 31 and 32, cooling water is always stored up to the position of the other end of the supply pipe 24. Thus, when cooling water is supplied from the header 40 described later to the storage chambers 31 and 32, the cooling water is immediately supplied to the full cone spray nozzle 20 via the supply pipe 24. Therefore, the reaction of the upper cooling part 11 becomes quick, and the steel plate H can be cooled appropriately. Even when cooling is not performed, the cooling water stored in the storage chambers 31 and 32 can prevent the nozzle box 30 from being damaged by heating (from the hot steel plate).

A supply header 40 for supplying cooling water to the nozzle box 30 (upstream spray nozzle row group 22 and downstream spray nozzle row group 23) is disposed above (upstream side) the nozzle box 30. A flow rate adjustment valve 41 is provided above (upstream) the supply header 40. By opening / closing the flow rate adjusting valve 41, the cooling water flows through the supply header 40, and the flow rate of the cooling water supplied to the supply header 40 is adjusted (controlled). A pipe 42 communicating with the supply header 40 is connected to the upstream storage chamber 31. An on / off control valve (first control valve) 43 is provided in the pipe 42, and the on / off control valve 43 supplies cooling water from the supply header 40 to the upstream storage chamber 31 (upstream spray nozzle row group 22). Permit or prohibit (on / off or valve opening / closing) is controlled. Similarly, a pipe 44 communicating with the supply header 40 is also connected to the downstream storage chamber 32. An on / off control valve (second control valve) 45 is provided in the pipe 44, and the on / off control valve 45 supplies cooling water from the supply header 40 to the downstream storage chamber 32 (downstream spray nozzle array group 23). Permit or prohibit (on / off or valve opening / closing) is controlled.
The flow rate adjustment valve 41, the on / off control valve 43, and the on / off control valve 45 are connected to the control unit 5. The control unit 5 controls the cooling water sprayed from the plurality of spray nozzle rows 21 toward the steel plate H.

Further, as shown in FIG. 2, the spray nozzle rows 21 belonging to the upstream spray nozzle row group 22 have the same adjacent interval a in the plate passing direction, and each spray nozzle belonging to the downstream spray nozzle row group 23. It is preferable that the adjacent space | interval b in the plate passing direction of the row | line | column 21 is the same. Furthermore, the spray nozzle row 21c disposed on the most downstream spray nozzle row group 23 side of each spray nozzle row 21 belonging to the upstream spray nozzle row group 22, and each spray nozzle belonging to the downstream spray nozzle row group 23 It is preferable that the adjacent space | interval c with the spray nozzle row | line | column 21d arrange | positioned at the most upstream spray nozzle row group 22 side of the row | line | column 21 is equal to the adjacent space | interval a and the adjacent space | interval b. That is, it is preferable that the adjacent intervals of the spray nozzle rows 21 in the plate passing direction are all the same.
Furthermore, it is preferable that the adjacent intervals e in the width direction of the steel plates of each spray nozzle row 21 are all the same.

  In the upper cooling device 11 having the above configuration, first, the required amount of cooling water is determined from the cooling rate required for the steel sheet H and the cooling stop temperature. The flow rate adjustment valve 41 is controlled by the control unit 5 so that the cooling water amount of the cooling water is supplied, and the flow rate of the cooling water supplied to the supply header 40 is adjusted. At this time, the controller 5 determines whether both the on / off control valves 43 and 45 are opened or only the on / off control valve 43 is opened, as will be described later. At this time, when the required amount of cooling water is larger than the maximum amount of water in the upstream spray row group 22, both the on / off control valves 43 and 45 are opened by the control unit 5, while the required amount of cooling water is increased in the upstream spray row. When it is less than the maximum amount of water in the group 22, only the on / off control valve 43 is opened by the control unit 5. Then, for example, the cooling water is supplied from the supply header 40 to the upstream storage chamber 31 by opening the on / off control valve 43. The cooling water in the upstream storage chamber 31 is injected to the steel sheet H through the supply pipe 24 and the full cone spray nozzle 20 of the upstream spray nozzle row group 22. Similarly, for example, by opening the on / off control valve 45, the cooling water is supplied from the supply header 40 through the outlet storage chamber 32, the supply pipe 24 of the downstream spray nozzle array group 23, and the full cone spray nozzle 20. Is injected into. As described above, in the upper cooling device 11, the injection of the cooling water is controlled for each of the spray nozzle row groups 22 and 23.

  Next, the method for setting the number of spray nozzle rows 21a to 21i in the spray nozzle row groups 22 and 23 and the arrangement position of the upstream spray nozzle row group 22 will be described below. It explains together.

In setting the number of the spray nozzle rows 21a to 21i and the arrangement position of the upstream spray nozzle row group 22, first, the characteristics will be described using the full cone spray nozzle 20 used in an embodiment described later as an example. . The rated maximum load pressure of the full cone nozzle 20 is 0.3 MPa.
The injection angle α of the water jet from the full cone spray nozzle 20 shown in FIG. 4 depends on the nozzle load pressure of the full cone spray nozzle 20. FIG. 5 shows the result of investigation by the inventors on this point. The horizontal axis in FIG. 5 indicates the nozzle load pressure, and the vertical axis indicates the change rate of the injection angle. Referring to FIG. 5, it can be seen that when the nozzle load pressure is about 0.04 MPa (dotted line in FIG. 5) or less, the rate of change of the spray angle of the full cone spray nozzle 20 decreases rapidly. This indicates that when the nozzle load pressure is 0.04 MPa or less, it is not possible to secure a so-called spray pattern, which is an area where the water jet from the full cone spray nozzle 20 collides with the steel plate H. Therefore, in order to cool the steel plate H appropriately, it turns out that the nozzle load pressure of the full cone spray nozzle 20 is 0.04 MPa or more. In this embodiment, the nozzle load pressure is 0.04 MPa or more, but this is only an example.

  In addition, the inventors investigated the amount of cooling water of the full cone spray nozzle 20 necessary for securing the nozzle load pressure of 0.04 MPa or more, that is, for securing the spray pattern. The result is shown in FIG. The horizontal axis in FIG. 6 indicates the nozzle load pressure, and the vertical axis indicates the cooling water amount of the full cone spray nozzle 20. Referring to FIG. 6, it was found that the range of the cooling water amount that secures the spray pattern is a range in which the ratio of the maximum water amount and the minimum water amount of the full cone spray nozzle 20 is approximately 3: 1.

  Here, cooling of the steel plate H using the upper cooling device 11 of the cooling device 1 will be described. FIG. 7 shows the relationship between the nozzle load pressure of the full cone spray nozzle 20 and the water density of the cooling water supplied from the upper cooling device 11. The water density indicates the amount of cooling water per unit area of cooling water sprayed on the steel plate H between the pair of restraining rolls 10a and 10b arranged with the steel plate H interposed therebetween. Therefore, hereinafter, the water density or the cooling water quantity may be described, but both are synonymous.

  As described above, in the hot rolling, the cooling capacity required for the cooling device 1, that is, the required cooling water amount (water density) varies depending on the type and application of the steel plate H. For example, when the required amount of cooling water is larger than the maximum amount of water in the upstream spray row group 22 (the range of the solid line on the upper side in the graph of FIG. 7), in order to secure this high water amount density, for example, as shown in FIG. Cooling water is jetted onto the upper surface of the steel plate H from both the side spray nozzle row group 22 and the downstream spray nozzle row group 23. In this case, since the amount of cooling water is larger than the maximum amount of water in the upstream spray row group 22, the on-board water 50 staying on the steel plate H spreads over the entire upper surface of the steel plate H between the pair of restraining rolls 10 and 10. Specifically, since the on-board water 50 and the cooling water sprayed from the upstream spray nozzle row group 22 and the downstream spray nozzle row group 23 are forcibly stirred over the entire surface of the steel plate H, the steel plate H Is uniformly cooled at least in the width direction of the steel plate H. Therefore, in order to avoid the influence of the on-plate water 50, it is necessary to secure the spray pattern of each full cone spray nozzle 20. That is, as described above, the nozzle load pressure of the full cone spray nozzle 20 needs to be 0.04 MPa or more. In the graph of FIG. 7, in the range of the upper solid line, such nozzle load pressure can be ensured, and the steel sheet H can be cooled appropriately.

On the other hand, as shown in FIG. 7, when the required amount of cooling water (water density) decreases, the nozzle load pressure of the full cone spray nozzle 20 also decreases. For example, when the water density required in FIG. 7 is about 0.55 m ³ / m ² / min or less, that is, when it is less than the maximum water quantity of the upstream spray row group 22, the upstream spray nozzle row group 22 and the downstream spray nozzle. If cooling water is supplied from both of the row groups 23, it becomes impossible to secure a nozzle load pressure of 0.04 MPa in each full cone spray nozzle 20.

Therefore, the cooling water is sprayed onto the upper surface of the steel sheet H only from the upstream spray nozzle row group 22 and the cooling water injection from the downstream spray nozzle row group 23 is stopped. Here, when the required water density is a water density of about 0.55 m ³ / m ² / min or less (the range of the solid line on the lower side in the graph of FIG. 7), that is, the maximum water quantity of the upstream spray train group 22. When the amount is smaller, the on-board water 50 on the steel plate H becomes small as shown in FIG. 9, and the on-board water 50 flows in the plate passing direction of the steel plate H, that is, downstream of the steel plate H as the steel plate H moves. Therefore, the injection of the cooling water from the downstream spray nozzle row group 23 is stopped as described above. Thereby, as shown in the graph of FIG. 7, the upper solid line shifts to the lower solid line, and the nozzle load pressure of the full cone spray nozzle 20 in the upstream spray nozzle row group 22 rapidly increases. Therefore, the spray pattern of the full cone spray nozzle 20 can be ensured, and the steel plate H can be cooled appropriately.

  When stopping the injection of the cooling water from the downstream spray nozzle row group 23 in this way, the number of rows (9 rows) of all the spray nozzle rows 21a to 21i and the upstream spray nozzle row as in the present embodiment. Most preferably, the ratio of the number of the spray nozzle rows 21a to 21c of the group 22 (three rows) is the ratio of the maximum water amount to the minimum water amount of the full cone spray nozzle 20, that is, the above-described 3: 1. For example, when the number of spray nozzle rows 21 in the upstream spray nozzle row group 22 is 4 or more, the nozzle load pressure of each full cone spray nozzle 20 is when the number of rows in the upstream spray nozzle row group 22 is 3. Smaller than Then, when the required amount of cooling water is further reduced, a spray pattern can be secured when the number of upstream spray nozzle array groups 22 is 3, but the number of upstream spray nozzle array groups 22 is less. In the case of four or more rows, the spray pattern may not be secured. That is, when the number of upstream spray nozzle row groups 22 is 4 or more, the range of water density that can secure the spray pattern and cool the steel plate H appropriately is the number of upstream spray nozzle row groups 22. It becomes narrower than the range of the water density in the case of three rows. Incidentally, in the present embodiment, the ratio of the controllable maximum water density to the minimum water density, that is, the cooling capacity control range is as wide as 9: 1. On the other hand, when the number of rows of the upstream spray nozzle row group 22 is two or less, the amount of cooling water to be sprayed from each full cone spray nozzle 20 exceeds the maximum amount of water, and the required water amount density cannot be ensured. Therefore, as described above, the ratio between the number of all the spray nozzle rows 21a to 21i and the number of the spray nozzle rows 21a to 21c of the upstream spray nozzle row group 22 is the maximum water amount and the minimum amount of the full cone spray nozzle 20. Most preferably, it is an integer ratio that is the same as or close to the ratio to the amount of water.

  In the present embodiment, since the ratio of the maximum water amount to the minimum water amount of the full cone spray nozzle 20 is 3: 1, the number of rows of all the spray nozzle rows 21a to 21i and the upstream spray nozzle row group 22 Although the ratio of the number of spray nozzle rows 21a to 21c to the number of rows is 3: 1, the ratio of the number of spray nozzle rows is not limited to this. As described above, if the ratio of the number of spray nozzle rows is the ratio of the maximum water amount and the minimum water amount of the spray nozzle, the ratio of the number of spray nozzle rows can be set to various values. For example, when the spray nozzle used for the cooling device is changed and the ratio of the maximum water amount to the minimum water amount is, for example, 7: 3, the number of rows of all spray nozzle rows (7 rows) and the spray nozzles of the upstream spray nozzle row group The ratio of the number of columns (3 columns) is also set to 7: 3.

When the ratio between the maximum water amount and the minimum water amount of the full cone spray nozzle 20 is not expressed as an integer ratio, the number of rows of all the spray nozzle rows 21 a to 21 i and the spray nozzle row 21 a of the upstream spray nozzle row group 22. The ratio of the number of rows of ~ 21c may be set to an integer ratio that approximates the ratio of the maximum water amount and the minimum water amount of the full cone spray nozzle 20. Specifically, the ratio of the maximum water volume when the minimum water volume is 1 is rounded off to the integer. For example, when the ratio of the maximum water amount to the minimum water amount is, for example, 1: 3.1, it can be set to 1: 3 by rounding off the decimal point of 3.1. The integer ratio between the maximum water amount and the minimum water amount of the full cone spray nozzle 20 obtained in this way may be set to the approximate integer ratio.
It is not preferred that there is an uncontrollable water density range between the maximum water density and the minimum water density. Accordingly, the ratio of the number of spray nozzle rows of the upstream spray nozzle row group 22 to the number of rows of all spray nozzle rows may be approximated to be smaller than the ratio of the maximum water amount and the minimum water amount of the spray nozzle. preferable.
In the present invention, it is not necessary to provide an upper limit for the ratio of the number of spray nozzle rows. However, even if the nozzle load pressure is increased to, for example, about 0.7 MPa, the ratio of the maximum water amount to the minimum water amount is about 4 and may be 4 or less. If necessary, the upper limit may be 3.5, 3 or 2.5.

  In addition, as described above with reference to FIG. 9, the on-board water 50 may flow and stay on the downstream side of the steel plate H depending on the required amount of cooling water. In this case, the upstream spray nozzle row group 22 is preferably arranged so that the cooling water sprayed from the upstream spray nozzle row group 22 does not interfere with the on-board water 50. Specifically, when the maximum spray amount is sprayed from the upstream spray nozzle row group 22, toward the upstream side position along the plate passing direction from the region of the plate water 50 staying on the steel plate H, It is preferable that the upstream spray nozzle row group 22 is arranged so that the cooling water is jetted from the upstream spray nozzle row group 22.

Further, the inventors have intensively studied the range where the on-board water 50 exists on the steel plate H when the cooling water is injected only from the upstream spray row group 22. Specifically, first, in a state where the steel plate H is stationary, the cooling water having the maximum water amount W in the upstream spray row group 22 is injected from the upper cooling device H to the steel plate H, and the plate at the center in the plate width direction is injected. The height hc of clean water was derived from experiments. Next, when cooling water having the same water density W is sprayed on the steel plate H that has been passed at the plate passing speed Ls, an experiment is conducted on the range in which the cooling water spreads as the plate water 50 to the steel plate H as shown in FIG. went. And the height distribution on the steel plate H of the plate water 50 was assumed to be a secondary distribution in the width direction. As a result, it was found that the range X ₀ where the on-board water 50 shown in FIG. 9 exists is represented by the following formula (1). The range X ₀ is the distance from the center of the constraining roll pair 10 on the downstream side of the steel sheet H to the end of the plate clean water 50. Moreover, the board water height hc in Formula (1) shows the height of the board water 50 in the center of the width direction of the steel plate H, and is represented by the following formula (2).

However, _{X 0:} horizontal extent of the plate clean water 50 (m), hc: height of the plate clean water 50 in the plate width direction center of the case steel H is in a quiescent state (m), S: constraining roll pair 10 10, center-to-center distance (m), Ls: plate speed of steel plate H (m / min)
In the above formula (1), “29.4” is a constant having a dimension of (m / min ² ).

Where W: density of cooling water sprayed from the upper cooling device 11 (m ³ / m ² / min), B: width of the steel plate H (m)
In the above formula (2), “0.04” is a constant having a dimension of (m ^(−1/3) / min ^(2/3) ).

As described above, the range X ₀ where the on-board water 50 exists on the steel plate H is calculated by the above formula (1). The position of the upstream end of the range X ₀ is present the plate clean water 50 is substantially the same as the position of the upstream end of the example downstream spray nozzle row group 23 as shown in FIG. The upstream spray nozzle row group 22 is located at a position where the water jet of the cooling water jetted from the downstream spray nozzle row 21c does not interfere with the plate water 50, that is, the downstream end of the water jet is on the downstream side. It is arranged in the center range X ₀ or more away from the constraining roll pair 10. Thereby, since the upstream spray nozzle row group 22 injects the cooling water in a place where there is almost no on-plate water 50, the region of the steel plate H to which the injected cooling water hits is uniformly cooled. That is, since the flowing direction of the on-board water 50 is the same as the passing direction of the steel plate H, the on-board water 50 is not much stirred. Thus, the steel plate H can be cooled uniformly by suppressing the stirring of the on-plate water 50.

  According to the above embodiment, injection of the cooling water to the upper surface of the steel plate H is controlled for each of the spray nozzle row groups 22 and 23. For example, when the required cooling capacity is high, that is, when the required amount of cooling water is larger than the maximum amount of water in the upstream spray row group 22 (in the range of the upper solid line in the graph of FIG. 7), first, by the flow control valve 41 Cooling water whose flow rate is controlled is supplied to the supply header 40. Then, both of the on / off control valves 43 and 45 are opened, and cooling water is sprayed onto the upper surface of the steel plate H from all the spray nozzle row groups 22 and 23. In this case, since the nozzle load pressure of the full cone spray nozzle 20 is high, even if the plate water 50 stays on the steel plate H, the spray pattern of each full cone spray nozzle 20 can be secured, and the plate water 50 as a whole. Therefore, the steel plate H can be uniformly cooled. Therefore, the steel plate H can be uniformly cooled to a predetermined temperature.

  On the other hand, for example, when the required cooling capacity is low, that is, when the required amount of cooling water is smaller than the maximum amount of water in the upstream spray row group 22 (the lower solid line range in the graph of FIG. 7), first, the flow rate adjustment The flow rate of the cooling water is controlled by the valve 41, and this cooling water is supplied to the supply header 40. Then, only the on / off control valve 43 is opened, for example, the cooling water is injected onto the upper surface of the steel plate H only from the upstream spray nozzle row group 22 of the steel plate H, and the cooling water is injected from the downstream spray nozzle row group 23 of the steel plate. To stop. In this case, the nozzle load pressure of the full cone spray nozzle 20 is high, and the amount of cooling water sprayed onto the steel sheet H can be set to a predetermined amount while maintaining the spray pattern. Further, the plate water 50 on the steel plate H becomes a small amount, and the plate water 50 flows in the plate passing direction of the steel plate H as the steel plate H moves, that is, on the downstream side of the steel plate H. For this reason, the cooling water sprayed to the upstream side of the steel plate H is not influenced by the plate water 50, and the steel plate H can be cooled uniformly. Therefore, the steel plate H can be uniformly cooled to a predetermined temperature. As described above, according to the present embodiment, the steel sheet H can be uniformly cooled to a predetermined temperature while controlling the cooling capacity over a wide range.

Here, an inconvenience when cooling water is injected only from the downstream spray nozzle row group 23 will be described.
In this case, as shown in FIG. 10, the on-board water 50 flows upstream from the injection region. Since the flow direction of the plate water 50 is opposite to the plate passing direction of the steel plate H, an irregular flow occurs in the plate water 50, and the cooling of the steel plate H is performed in the width direction or the longitudinal direction on the upstream side of the injection region. It becomes uneven. Therefore, it is not preferable to inject cooling water only from the downstream spray nozzle row group 23.

  Next, an advantage of arranging the same full cone spray nozzle 20 in all the spray nozzle rows 21a to 21i will be described. In this case, the cooling capacity of all the full cone spray nozzles 20 in the upper cooling device 11 is the same. As described above, when spray nozzles having different cooling capacities are used, the cooling water is not uniform with respect to the steel sheet H. In the present embodiment, the cooling water sprayed from the full cone spray nozzle 20 affects each other. Since the feeding can be suppressed, the cooling water does not become uneven with respect to the steel sheet H. For this reason, the injection of the cooling water is controlled for each of the upstream spray nozzle array group 22 and the downstream spray nozzle array group 23, so that it is also applicable when the required cooling capacity is high or low, or at the boundary of the cooling capacity. it can. Therefore, the cooling capacity control range can be selected over a wide range. In addition, since the cooling capability of all the full cone spray nozzles 20 is the same, there exists an effect that control of the full cone spray nozzle 20 at the time of cooling the steel plate H becomes easy.

  Furthermore, the number of rows of all the spray nozzle rows 21a to 21i and the number of rows and ratios of the spray nozzle rows 21a to 21c of the upstream spray nozzle row group 22 are the ratios of the maximum water amount and the minimum water amount of each full cone spray nozzle 20. Is set to For this reason, when the required cooling capacity decreases, the injection of the cooling water from the downstream spray nozzle row group 23 can be stopped at an appropriate timing as described above. Therefore, the cooling capacity control range can be maximized while ensuring the required cooling capacity.

  Further, since the upstream spray nozzle row group 22 is arranged at a position where the water jet of the cooling water sprayed from the downstream spray nozzle row 21c does not interfere with the plate water 50, the upstream spray nozzle row group. The cooling water jetted from 22 is not affected by the on-board water 50. Moreover, the spray pattern of each full cone spray nozzle 20 can be secured as described above. Therefore, even when the required cooling capacity is low, the steel sheet H can be appropriately cooled.

  As described above, the steel plate H can be uniformly cooled in the present embodiment, but the inventors have verified this effect. Specifically, when the required amount of cooling water is smaller than the maximum amount of water in the upstream spray row group 22, the cooling water was sprayed onto the steel sheet H only from the upstream spray nozzle row group 22 as shown in FIG. 9.

  And the result of having measured the width direction distribution of the cooling rate from 750 degreeC to 600 degreeC at the time of cooling the steel plate H to 100 degrees C or less is shown in FIG. The horizontal axis in FIG. 11 indicates the position in the width direction of the steel plate H, and the vertical axis indicates the cooling rate at each position in the width direction of the steel plate H. Referring to FIG. 11, the cooling rate is substantially uniform in the width direction of the steel plate H, and it was confirmed that the steel plate H can be cooled uniformly.

[Second Embodiment]
Next, a cooling device according to a second embodiment of the present invention will be described.
12-15 is this 2nd Embodiment and has shown the steel plate cooling device. Hereinafter, the steel material is a thick plate, and the member and apparatus on the upper side of the steel plate will be described. In the following description, the description of the same members as those in the first embodiment is omitted.
In addition, the second embodiment is different in that a water supply header is provided for each of the upstream spray nozzle row group and the downstream spray nozzle row group, and a flow rate adjusting valve is provided for each of the water supply headers. This is different from the first embodiment.

The steel plate cooling device 100 includes an upper cooling device 111 and a lower cooling device 112. The upper cooling device 111 includes a small flow rate cooling unit (upstream spray nozzle row group) 110 and a large flow rate cooling unit (downstream spray nozzle row group) 130 as shown in FIG. The small flow rate cooling unit 110 and the large flow rate cooling unit 130 are disposed on the upper side of the steel plate H.
The small flow rate cooling unit 110 includes a small flow rate water supply header (first water supply header) 117. The small flow rate water supply header 117 supplies cooling water to the small flow rate cooling unit 110. The large flow rate cooling unit 130 includes a large flow rate water supply header (second supply header) 137. The large flow rate water supply header 137 supplies cooling water to the large flow rate cooling unit 130.
Further, the steel plate cooling apparatus 100 includes a flow rate adjusting valve (first flow rate adjusting valve) 114 that adjusts the flow rate of the cooling water supplied to the small flow rate water supply header 117, and the flow rate of the cooling water supplied to the large flow rate water supply header 137. And a flow rate adjustment valve (second flow rate adjustment valve) 134 for adjusting the pressure.
Further, the flow rate adjusting valves 114 and 134 are connected to a flow rate adjusting unit (control unit) 149. Further, flow path switching three-way valves 115 and 135 which are one of on / off control valves are connected to the flow rate adjusting unit 149.
The flow rate adjusting unit 149 controls opening and closing of the flow rate adjusting valves 114 and 134 and the flow path switching three-way valves 115 and 135, and controls the cooling water sprayed from the plurality of cooling water spray nozzles 126 toward the steel plate H.

The small flow rate water supply header 117 is connected to a cooling water tank (not shown) via a small flow rate cooling water supply pipe 112. A flow rate adjusting valve 114 and a flow path switching three-way valve 115 are attached to the small flow rate cooling water supply pipe 112. One outlet of the flow path switching three-way valve 115 is connected to a small flow rate water supply header 117 via a small flow rate cooling water supply pipe 112. Hereinafter, this direction switching is referred to as opening. The other outlet of the flow path switching three-way valve 115 is connected to a cooling water tank (not shown) via a return pipe (not shown). Hereinafter, this direction switching is referred to as closing.
Similarly, the large flow rate cooling unit 130 also includes a large flow rate cooling water supply pipe 132, a flow rate adjustment valve 134, and a flow path switching three-way valve 135.

  The flow control valve 114 of the small flow cooling unit 110 and the flow control valve 134 of the large flow cooling unit 130 are proportional to the ratio of the number of cooling water spray nozzles of the large flow cooling unit 130 to the number of cooling water spray nozzles of the small flow cooling unit 110. It is preferable to set the opening so as to achieve the supplied water density. Thereby, the amount of cooling water from the cooling water spray nozzle 126 of the small flow rate cooling unit 110 and the cooling water spray nozzle 146 of the large flow rate cooling unit 130 is maintained constant, and the steel sheet H can be uniformly cooled.

  The small flow cooling unit 110 includes a small flow nozzle header 122, and the large flow cooling unit 130 includes a large flow cooling water nozzle header 142. As shown in FIG. 13, a small flow rate nozzle water supply pipe 119 is connected to the small flow rate nozzle header 122, and a large flow rate nozzle water supply pipe 139 is connected to the large flow rate nozzle header 142. Further, a small flow cooling water spray nozzle 126 is attached to the small flow nozzle header 122, and a large flow cooling water spray nozzle 146 is attached to the large flow nozzle header 142.

  The small flow cooling water spray nozzle 126 and the large flow cooling water spray nozzle 146 are the same. Further, the intervals in the plate passing direction of the small flow cooling water spray nozzle 126 and the large flow cooling water spray nozzle 146 are equal. Further, the intervals in the plate passing direction of the cooling water spray nozzles 126 and 146 of the adjacent small flow rate cooling unit 110 and the large flow rate cooling unit 130 are also equal to the intervals in the plate passing direction of the other cooling water spray nozzles 126 and 146. Yes. As a result, the deviation in the amount of water on the plate is reduced, and the steel plate is uniformly cooled.

  As shown in FIG. 13, the small-flow-rate cooling water spray nozzle 126 penetrates the bottom plate 124 of the small-flow-rate nozzle header 122, the upper-end cooling water inlet 127 is located near the top plate 123, and the lower-end jet outlet 28 is the bottom plate. Projecting downward from 124. The large flow nozzle header 142 has the same structure as the small flow nozzle header 122, and the large flow cooling water spray nozzle 146 has the same structure as the small flow cooling water spray nozzle 126.

The distance g between the top plate 123 of the small flow rate nozzle header 122 and the cooling water inlet 127 of the small flow rate cooling water spray nozzle 126 and the top plate 143 of the large flow rate nozzle header 142 and the cooling water inlet 147 of the large flow rate cooling water spray nozzle 146. Is preferably 3 to 8 mm. When the gap g is less than 3 mm, the pressure applied to each cooling water inlet is not uniform, and water is likely to be discharged from the cooling water spray nozzle closest to the nozzle water supply pipes 119 and 139. Thereby, the difference in the amount of water sprayed from each spray nozzle 126, 146 may occur. On the other hand, if the interval g exceeds 8 mm, it takes too much time for the small flow nozzle header 122 and the large flow nozzle header 142 to be filled with water after the start of water injection. Furthermore, when the gap g exceeds 8 mm, water accumulated between the cooling water inlets 127 and 147 and the top plates 123 and 142 of the headers when water injection from the cooling water spray nozzles 126 and 146 is stopped. The water will droop from the cooling water spray nozzles 126 and 146 until they are all gone.
Further, on the upper side of the steel plate H, a small flow rate cooling unit 150 and a large flow rate cooling unit 170 on the lower side of the steel plate H similar to the small flow rate cooling unit 110 and the large flow rate cooling unit 130 are arranged. In the small flow cooling unit 150 and the large flow cooling unit 170, the gap g is the gap g between the bottom plate 64 of the small flow nozzle header 162 and the cooling water inlet 67 of the small flow cooling water spray nozzle 166, and the large flow nozzle header. This is the distance g between the bottom plate 184 of 182 and the cooling water inlet 187 of the large flow rate cooling water spray nozzle 186.

  FIG. 14 schematically shows the arrangement of the small flow cooling water spray nozzle 126 (166) and the large flow cooling water spray nozzle 146 (186). As shown in FIG. 14, a large number of small-flow-rate cooling water spray nozzles 126 (166) and large-flow-rate cooling water spray nozzles 146 (186) are arranged at regular intervals in the steel plate width direction and the steel plate conveyance direction, respectively. The small flow cooling water spray nozzle 126 (166) and the large flow cooling water spray nozzle 146 (186) have the same nozzle diameter, and the number of small flow cooling water spray nozzles is smaller than the number of large flow cooling water spray nozzles.

FIG. 15 shows the relationship between the water supply density (m ³ / m ² / min) and the nozzle water supply pressure (MPa).

  The spray pattern securing limit pressure is a nozzle water supply pressure (for example, 30 kPa) indicating whether or not a predetermined spray pattern determined by the nozzle can be secured. In order to cool the hot steel plate uniformly, the nozzle water supply pressure needs to be equal to or higher than the spray pattern securing limit pressure. For this reason, in cooling of the steel plate (steel material) H, the water supply density for obtaining a necessary cooling rate (determined by the components of the steel material and the material to be secured) is determined. This is a region where the nozzle water supply pressure is equal to or higher than the spray pattern securing limit pressure with reference to FIG. 15 and the water supply density, and water is supplied to both the small flow nozzle header 122 and the large flow nozzle header 142 or to one of them. The flow rate adjustment unit 149 determines whether to do this.

  Specifically, as shown in FIG. 15, if the determined water supply density is in the range of b to c, cooling water is supplied to both the small flow nozzle header 122 and the large flow nozzle header 142, and a to If it is in the range of b, the cooling water is supplied only to the small flow rate nozzle header 122. In addition, the flow rate control valves 114 and 134 adjust the spray water amount and the spray pressure from each nozzle through the small flow nozzle header 122 and the large flow nozzle header 142 so as to be constant.

  The steel plate cooling apparatus 100 includes a flow rate adjusting unit 149 on the upper surface side of the steel plate as shown in FIG. The flow rate adjusting unit 149 controls the cooling water sprayed toward the steel plate H from the small flow rate cooling water spray nozzle 126 and the large flow rate cooling water spray nozzle 146. In this flow rate adjusting unit 149, the cooling rate is determined from, for example, the component and mechanical characteristics (material) of the target steel plate by a host computer, and the zone water supply density is obtained from this cooling rate and the plate thickness of the target steel plate. Further, the flow rate adjusting unit 149 determines the zone water supply density and the nozzle header (both the large flow rate water supply header 137 and the small flow rate water supply header 117 or only the small flow rate water supply header 117) to be used from FIG.

  The zone water supply density and the nozzle header information to be supplied are input to the flow rate adjustment unit 149. Here, when the nozzle header information uses both the large flow rate water supply header 137 and the small flow rate water supply header 117, the water supply amount density ratio is further input to the flow rate adjustment unit 149. Then, the flow rate adjusting unit 149 determines the valve opening signal of the flow rate adjusting valves 114 and 134 and the flow path switching three-way valves 115 and 135 based on the input zone water supply density, nozzle header information, and water supply density ratio. And a signal for releasing the. When the nozzle header information uses only the large flow rate water supply header 137, the flow rate adjustment unit 149 closes the flow path switching three-way valve 115, opens the flow path switching three-way valve 135, and sets the flow rate control valve. A valve opening signal 134 is output. When the nozzle header information uses only the small flow rate water supply header 117, the flow rate adjustment unit 149 closes the flow path switching three-way valve 135, opens the flow path switching three-way valve 115, and sets the flow rate control valve. The valve opening signal 114 is output. The same applies to the flow rate adjustment unit (control unit) 189 on the lower surface side of the steel plate H.

  The cooling units 110 and 130 (upper cooling device 111) on the upper side of the steel plate have been described above, but the cooling units 150 and 170 (lower cooling device 112) on the lower side of the steel plate H have the same structure as the upper side. That is, the cooling water feed pipe 152, the feed water header 157, the nozzle feed pipe 159, the nozzle header 162, and the cooling water spray nozzle 166, and the cooling water feed pipe 172, the feed water header 177, the nozzle feed pipe 179, the nozzle header 182 and the cooling The water spray nozzle 186 has the same structure as the upper cooling device 111 on the upper side of the steel plate H. The flow rate adjusting valves 154 and 174, the flow path switching three-way valves 155 and 175, and the flow rate adjusting unit 189 also have the same structure as the upper cooling device 111 on the upper side of the steel plate H.

  Here, an example of the operation and operation of the steel plate cooling apparatus 100 configured as described above will be described.

Prior to accepting the rolled hot thick steel plate H, the steel sheet cooling device 100 supplies water at a zone water supply density (for example, 1.5 m ³ / m ² / min) in the cooling zone in which the steel plate cooling device 100 is disposed. The nozzle header information (for example, the large flow rate water supply header 137 and the small flow rate water supply header 117), and the feed amount density ratio (for example, 2.0) of the large flow rate cooling unit 130 to the small flow rate cooling unit 110 are It is input to the upper flow rate adjustment unit 189. As a result, the flow rate adjusting unit 149 supplies the water supply density of each of the small flow rate cooling unit 110 and the large flow rate cooling unit 130 (for example, the small flow rate cooling unit: 0.5 m ³ / m ² / min, the large flow rate cooling unit: 1 0.0 m ³ / m ² / min), the opening degree of the flow control valves 114 and 134 is determined based on the determined water supply density, and the flow control valves 114 and 134 are The opening degree information from which the water supply density is obtained is output. The flow rate adjusting valves 114 and 134 are activated when the opening degree information is input, and the opening degree corresponds to the information. As a result, the cooling water in the small flow rate cooling water supply pipe 112 sequentially passes through the small flow rate water supply header 117 and the small flow rate nozzle supply pipe 119 and flows into the small flow rate unit 122. Further, the cooling water in the large flow rate cooling water supply pipe 132 passes through the large flow rate water supply header 137 and the large flow rate nozzle supply pipe 139 in the same manner as described above and flows into the large flow rate unit 142. The cooling water fills the small flow unit 122 and the large flow unit 142 in a short time, and the cooling water is supplied from the small flow side cooling water spray nozzle 122 of the small flow unit 122 and the large flow side cooling water spray nozzle 146 of the large flow unit 142. Are injected almost simultaneously.

  In addition, the water supply amount density ratio output from the upper computer to the flow rate adjusting units 149 and 189 is calculated from the cooling zone water supply amount density. However, the water supply density ratio is preferably a water supply density ratio proportional to the number of nozzles of the large flow nozzle header 142 relative to the number of nozzles of the small flow nozzle header 122, or a value close thereto, but in any case both headers It is necessary to set the pressure in 122 and 142 to a value equal to or higher than the spray pattern securing limit pressure. Further, the lower cooling units 50 and 70 of the steel plate H are similarly adjusted.

  In the above state, the hot thick steel plate H is passed and cooling is started. When the hot thick steel plate H passes through the steel plate cooling device 100, the water injection stop information is input from the host computer to the flow rate adjusting unit 149. . As a result, by outputting a closing signal for the flow path switching three-way valves 115 and 135 from the flow rate adjusting unit 149, the flow path switching three-way valves 115 and 135 are closed and the water supply is stopped. Along with this, the injection of cooling water from the small flow rate side cooling water spray nozzle 122 and the large flow rate side cooling water spray nozzle 146 is immediately stopped.

  The above description is a case where the cooling water is injected from both the small flow unit 110 and the large flow unit 130. However, when the cooling water is injected only from the small flow unit 110, the cooling zone in which the steel plate cooling device 100 is disposed. , The nozzle header information (small flow rate water supply header 117) for supplying water is input from the host computer to the flow rate adjustment units 149 and 189. As a result, the opening degree of the flow rate adjustment valve 114 of the water supply target unit 110 is determined, and the flow rate adjustment valve 114 and the flow path switching three-way valve 115 are sent from the host computer to the flow rate adjustment units 149 and 189 in the same manner as described above. An operation signal is output.

The present invention is not limited to the first and second embodiments. That is,
(A) Although the embodiment has been described for a thick plate, the present invention can also be used for a thin plate and a shaped steel. In the case of a thick plate, it can also be used for roller quenching, which is a cooling facility after heat treatment.
(B) Although the flow rate adjusting units (control units) 149 and 189 are provided in the upper cooling device and the lower cooling device, one flow rate adjusting unit may control both the upper cooling device and the lower cooling device.
(C) In each of the above embodiments, a full cone nozzle has been described. However, in the present invention, other nozzle types may be used.
(D) In each of the above embodiments, the nozzle types and the number of rows of the upper cooling device and the lower cooling device may be different.

  As described above, the first and second preferred embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  INDUSTRIAL APPLICABILITY The present invention is useful when cooling a steel plate obtained by hot rolling while horizontally restraining it with a restraining roll.

H Steel plate 1 Cooling device 2 Finishing rolling mill 3 Hot straightening device 10a Restraining roll 10b Conveying roll 10 Restraining roll pair 11 Upper cooling device 12 Lower cooling device 20 Full cone spray nozzles 21a to 21i Spray nozzle row 22 Upstream spray nozzle row group 23 downstream spray nozzle array group 24 supply pipe 30 nozzle box 31 upstream storage chamber 32 downstream storage chamber 40 header 41 flow control valve 42 piping 43 on / off control valve 44 piping 45 on / off control valve 50 plate water 100 steel plate cooling device 110 , 150 Small flow cooling unit 112, 152 Small flow cooling water feed pipe 114, 154 Flow control valve 115, 155 Three-way valve for channel switching 117, 157 Small flow feed header 119, 159 Small flow nozzle feed pipe 122, 162 Small flow Nozzle header 12 6, 166 Small flow cooling water spray nozzles 130, 170 Large flow cooling units 132, 172 Large flow cooling water feed pipes 134, 174 Flow control valves 135, 175 Three-way valves 137, 177 High flow feed headers 139, 179 Large flow nozzle water supply pipe 142, 182 Large flow nozzle header 146, 186 Large flow cooling water spray nozzle 149, 189 Flow adjustment unit

Claims (9)

A plurality of restraining roll pairs for restraining the steel plate;
An upper cooling device and a lower cooling device having a plurality of spray nozzle rows arranged opposite to each other with the steel plate in between at a position between the pair of restraining rolls;
With
The plurality of spray nozzle rows are arranged along the sheet passing direction of the steel plate, and each spray nozzle row has a plurality of identical spray nozzles arranged in the width direction of the steel plate;
When viewed along the plate passing direction, each spray nozzle row is classified into an upstream spray nozzle row group relatively upstream and a downstream spray nozzle row group relatively downstream. Is;
The number of the spray nozzles belonging to the upstream spray nozzle row group is rather less than the number of said spray nozzles belonging to the downstream spray nozzle row group;
The ratio of the total number of the plurality of spray nozzle rows to the number of spray nozzle rows belonging to the upstream spray nozzle row group is the maximum injection amount and the minimum injection amount of each spray nozzle belonging to the spray nozzle row. An apparatus for cooling a steel sheet, characterized in that the ratio is an integer ratio that is the same as or close to the ratio . A control unit for controlling cooling water sprayed from the plurality of spray nozzle rows toward the steel plate;
When the total amount of water to be sprayed toward the steel sheet is equal to or greater than the maximum spray amount of the upstream spray nozzle row group, the cooling is performed from both the upstream spray nozzle row group and the downstream spray nozzle row group. While the water is injected, when the total water amount is smaller than the maximum injection amount of the upstream spray nozzle row group, the control unit is configured to inject the cooling water only from the upstream spray nozzle row group. Controlling the injection of the cooling water;
The steel sheet cooling device according to claim 1 . A water supply header for supplying the cooling water to the upstream spray nozzle row group and the downstream spray nozzle row group;
A flow rate adjustment valve for adjusting a flow rate of the cooling water supplied to the water supply header;
A first control valve that controls permission or prohibition of supply of the cooling water supplied from the water supply header to the upstream spray nozzle row group;
A second control valve that controls permission or prohibition of supply of the cooling water supplied from the water supply header to the downstream spray nozzle row group;
The steel sheet cooling device according to claim 2 , further comprising: A plurality of restraining roll pairs for restraining the steel plate;
An upper cooling device and a lower cooling device having a plurality of spray nozzle rows arranged opposite to each other with the steel plate in between at a position between the pair of restraining rolls;
With
The plurality of spray nozzle rows are arranged along the sheet passing direction of the steel plate, and each spray nozzle row has a plurality of identical spray nozzles arranged in the width direction of the steel plate;
When viewed along the plate passing direction, each spray nozzle row is classified into an upstream spray nozzle row group relatively upstream and a downstream spray nozzle row group relatively downstream. Is;
The number of spray nozzles belonging to the upstream spray nozzle row group is less than the number of spray nozzles belonging to the downstream spray nozzle row group;
A first water supply header for supplying cooling water to the upstream spray nozzle row group;
A second water supply header for supplying cooling water to the downstream spray nozzle row group;
A first flow rate adjustment valve for adjusting a flow rate of the cooling water supplied to the first water supply header;
A second flow rate adjustment valve for adjusting a flow rate of the cooling water supplied to the second water supply header;
A control unit for controlling cooling water sprayed from the plurality of spray nozzle rows toward the steel plate;
Further comprising:
When the total amount of water to be sprayed toward the steel sheet is equal to or greater than the maximum spray amount of the upstream spray nozzle row group, the cooling is performed from both the upstream spray nozzle row group and the downstream spray nozzle row group. While the water is injected, when the total water amount is smaller than the maximum injection amount of the upstream spray nozzle row group, the control unit is configured to inject the cooling water only from the upstream spray nozzle row group. Controlling the injection of the cooling water;
A steel sheet cooling device. The adjacent intervals in the plate passing direction of the spray nozzle rows belonging to the upstream spray nozzle row group are the same;
The adjacent intervals in the plate passing direction of the spray nozzle rows belonging to the downstream spray nozzle row group are the same;
The steel sheet cooling device according to any one of claims 1 to 4 , wherein the steel sheet cooling device is provided. The steel plate cooling device according to any one of claims 1 to 4 , wherein all adjacent intervals of the spray nozzle rows in the plate passing direction are the same. When spraying the maximum injection amount from the upstream spray nozzle row group,
The upstream spray nozzle so that the cooling water is jetted from the upstream spray nozzle row group toward the upstream position along the plate passing direction with respect to the area of the on-plate water staying on the steel plate. The row group is arrange | positioned, The cooling device of the steel plate of any one of Claims 1-4 characterized by the above-mentioned. When cooling the steel sheet using the steel sheet cooling device according to any one of claims 2 to 4 ,
When the total amount of water to be sprayed toward the steel sheet is equal to or greater than the maximum spray amount of the upstream spray nozzle row group, the cooling is performed from both the upstream spray nozzle row group and the downstream spray nozzle row group. When the total water amount is smaller than the maximum spray amount of the upstream spray nozzle row group while water is jetted, the control unit causes the cooling water to be jetted only from the upstream spray nozzle row group. Controlling the injection of the cooling water;
A method for cooling a steel sheet, comprising: An area of the on-board water that stays on the steel sheet when the cooling water is sprayed from the upstream spray nozzle array group at the maximum spray amount;
Disposing the upstream spray nozzle row group at a position upstream of the region along the plate passing direction so that the cooling water is injected from the upstream spray nozzle row group;
The method for cooling a steel sheet according to claim 8 .

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