TW201838732A - Cooling device for hot-rolled steel sheet, and method of cooling hot-rolled steel sheet - Google Patents

Abstract

An object is to improve evenness of temperature in a rolling direction and a plate width direction of a hot-rolled steel sheet by properly cooling the bottom face of the hot-rolled steel sheet after finish rolling in a hot rolling step. A cooling device for a hot-rolled steel sheet that cools a bottom face of a hot-rolled steel sheet being transported on transporting rolls after finish rolling in a hot-rolling step, wherein a whole area of a bottom face in a steel plate transporting zone in a plate width direction, and cooling zone that is demarcated by predetermined length in a rolling direction are defined as a whole cooling zone, the cooling device comprising: a width division cooling zone that is each of plural cooling zones obtained by dividing the whole cooling area in the plate width direction; a division cooling face that is each of cooling zones obtained by dividing the width division cooling zone in a rolling direction; at least one coolant nozzle out from which a coolant jets on to a respective bottom face of the division cooling face; a switching device that switches the coolant jetting out from the coolant nozzle between on to and off from the division cooling face; a width direction thermometer that measures temperature distribution in the plate width direction; and a controller that controls operation of the switching device based on a result of measurement with the width direction thermometer.

Description

 Cooling device for hot rolled steel sheet and cooling method for hot rolled steel sheet  

The present invention relates to a cooling device for cooling a lower surface of a hot-rolled steel sheet conveyed on a conveying roller after refining rolling in a hot rolling step, and a cooling method using the cooling device.

With the recent reduction in the weight of automobiles, the demand for high-tensile steel sheets in hot-rolled steel sheets has increased, and the quality required for hot-rolled steel sheets has increased. In particular, in recent years, it is not only high-strength, but also excellent workability such as press formability and hole expandability, and distribution difference of mechanical properties such as tensile strength and workability. It is controlled within the established range throughout the entire field of steel sheets.

However, at the time of cooling after refining rolling, uneven temperature distribution sometimes occurs in the sheet width direction of the hot-rolled steel sheet for various reasons. As a specific example, a non-uniform temperature distribution in a rib shape extending in the rolling direction of the hot-rolled steel sheet in the sheet width direction may be mentioned. There are several reasons for this, for example, after the refining rolling, before entering the cooling, it is caused by the scale remaining during the process of removing the scale which is performed before the refining rolling and the refining rolling. ; the lubricating material dispersed and residued during refining rolling is distributed in the width direction of the plate; the inconsistency of the cooling water spray disposed between the machines of the refining rolling mill; and the factors of the heating furnace Caused. Further, even after the refining rolling and entering the cooling process, there is a case where uneven temperature distribution occurs due to poor maintenance of the cooling device.

However, one of the reasons for the significant influence on the characteristics of such a final product in the manufacture of hot-rolled steel sheets is the coiling temperature. Therefore, in order to improve the quality of the steel sheet, it is important to improve the uniformity (consistency) of the coiling temperature in the entire field of the steel sheet. The "winding temperature" as used herein refers to the temperature of the steel sheet immediately before the winding of the steel sheet immediately after the cooling process after the refining rolling.

In the cooling step of spraying the cooling water on the high-temperature steel sheet of 800 ° C to 900 ° C after the refining rolling, the vapor generated by the boiling of the water film is stable during the period when the steel sheet temperature is approximately 600 ° C or higher. Cover the surface of the steel plate. Therefore, although the cooling capacity by the cooling water becomes small, it is relatively easy to achieve uniform cooling of the steel sheet in an all-round manner.

However, especially since the steel sheet temperature is lower than about 550 ° C, as the temperature of the steel sheet is lowered, the amount of vapor generated is also reduced. As a result, the vapor film originally covering the surface of the steel sheet begins to crack, and the distribution of the vapor film becomes a transition boiling region which changes with time and space. As a result, the unevenness of cooling increases, and it is easy to rapidly increase the unevenness of the temperature distribution of the steel sheet in the sheet width direction and the rolling direction. Therefore, it is difficult to control the temperature of the steel sheet, and it is difficult to terminate the cooling process at the desired coiling temperature of the entire steel sheet.

On the other hand, in order to manufacture a product having two excellent characteristics of strength and workability, it is effective to reduce the coiling temperature to a low temperature range of 500 ° C or lower. Therefore, it is very important to control the unevenness of the coiling temperature distribution in the entire steel sheet including the distribution in the sheet width direction and the long axis direction with respect to the target temperature within a predetermined range. of. Based on this point of view, there have been many inventions to date, which are inventions for controlling the coiling temperature.

Most of these inventions relate to countermeasures and technical solutions for uneven cooling that occur in response to factors of the cooling device itself. In particular, in the hot-rolled steel sheet, uneven cooling in the width direction of the sheet due to the cooling water sprayed on the upper surface side of the steel sheet on the steel sheet causes a significant problem, and various countermeasures have been proposed. In addition, many inventions can be seen, the technical subject of which is to reduce: for reasons other than the cooling device, especially because of the uneven temperature in the width direction of the plate and in the direction of the long axis before cooling. Uneven cooling due to distribution, or unevenness in surface properties such as roughness of the steel sheet surface and thickness of the scale. In particular, in the case where the coiling temperature falls in the low temperature range, the uneven temperature distribution before cooling will cause the vapor film to collapse and enter the migration boiling zone to be quenched in the low temperature portion, thereby generating: the temperature after cooling. The deviation is a problem that is more enlarged than the temperature deviation on the inlet side of the cooling device. In addition, due to the inconsistent surface properties, the effect will be similar. In the place where the surface roughness is large or where the thickness of the scale is large, the vapor film first collapses, and after cooling, it also occurs: The temperature deviation is increased to a temperature deviation of several times on the inlet side of the cooling device.

As a countermeasure against uneven cooling which occurs due to the temperature difference before cooling and the inconsistency in surface properties, it is preferable to make these inconsistent properties become very strong by applying a certain technical means before cooling. small. In fact, there have been many inventions about this aspect of the countermeasures. However, in such a large-scale manufacturing facility of a hot-rolled steel sheet manufacturing line, productivity and cost are also important. Even though there are countermeasures that can be used to improve the temperature and surface properties of the pre-cooling, it is difficult to completely implement the cooling before the actual implementation of the cost balance in order to achieve integrity. The countermeasure for improving the heterogeneity reaches a level that can completely eliminate the problem after cooling. In addition, there are many reasons why the heterogeneity of surface traits has not yet been solved, and there are cases where fundamental solutions have not yet been found.

Therefore, another technical solution for treating the heterogeneity before cooling is to selectively limit the amount of cooling to the low temperature portion or to increase the cooling rate for the high temperature portion according to the temperature distribution information before or during cooling. A technical solution whereby the temperature distribution after cooling is uniformized. Further, according to the following description, it is also considered that the temperature distribution after cooling can be made uniform. That is, the inconsistency of the surface properties of the scale or the like is not grasped based on the temperature distribution information before cooling. However, for the temperature distribution during cooling, the influence of the inconsistency in the surface properties of the scale or the like is often manifested. Therefore, it is considered that the temperature distribution is measured at an appropriate timing, that is, at a point in time before the collapse of the vapor film is actually progressing to cause a fatal uneven temperature distribution, and the amount of cooling is controlled based on the information. , the temperature distribution after cooling can be uniformized.

Therefore, the invention shown below has been proposed so far.

For example, the technical solution disclosed in Patent Document 1 is a method of cooling a steel sheet by a spray range control device which is provided with an injection valve having an opening and closing valve that can be opened and closed according to a pilot pressure. In the spray head formed of the nozzle, a control cylinder for supplying a pilot pressure capable of starting (ON) or stopping (OFF) the opening and closing valves of the respective injection nozzles is provided, which is rotated by the variable steering motor. The position of the piston rod moving on the screw to control the internal pressure of the control cylinder, thereby controlling the spray range of the cooling water sprayed by the spray nozzle. The steel plate cooling method is characterized by a plurality of nozzles. Among the injection nozzles, an edge guard, or a front end mask and a tail end mask are formed by adjusting a precession pressure to be sent to an opening/closing valve of a predetermined injection nozzle.

The cooling device for a steel pipe disclosed in Patent Document 2 includes an injection device and a bucket for injecting a fluid to a cooling water sprayed toward the steel pipe to change the flow direction of the cooling water so as not to be sprayed. The direction of the steel pipe; and the bucket is used to receive the cooling water after the flow direction is changed by the spraying device.

The cooling device for a hot-rolled material disclosed in Patent Document 3 includes a circular tubular head having a slit capable of ejecting a plate-like water flow, and a width adjusting body formed with a width of a water flow that can be ejected upward The direction end portion is a recess that gradually blocks the flow of water toward the center in the width direction, and is rotatable concentrically with the head.

Further, the technical solution disclosed in Patent Document 4 is that, in the cooling device, a plurality of nozzles for adding a coolant to the hot-rolled steel sheet are disposed along the width direction on both sides of the upper surface and the lower surface of the hot-rolled steel sheet. These nozzles are controlled to add a coolant to a location where a particularly high temperature is detected. In such a cooling device, a plurality of temperature sensors are also disposed in the width direction, and the temperature sensors can detect the temperature distribution in the width direction of the hot-rolled steel sheet, and can be based on the temperature sensor. A signal to control the amount of coolant ejected from the nozzle.

In the cooling device, a plurality of cooling water jets in which a plurality of cooling water supply nozzle groups are linearly arranged are disposed above and in the width direction of the hot-rolled steel sheet, and are used according to the cooling device. The temperature distribution sensed by the temperature distribution sensor in the width direction of the panel is sensed to control the flow rate of the cooling water. Specifically, in these cooling water jets, an opening and closing control valve is provided, and the cooling water is controlled by an opening and closing control valve.

 [Previous Technical Literature]    [Patent Literature]  

Patent Document 1: Japanese Patent Laid-Open No. Hei 7-314028

Patent Document 2: Japanese Unexamined Publication No. SHO 58-81010

Patent Document 3: Japanese Patent Publication No. 62-25049

Patent Document 4: Japanese Patent Publication No. 2010-527797

Patent Document 5: Japanese Patent Laid-Open No. Hei 6-71328

For hot-rolled steel sheets, the conveying speed of the steel sheets (the winding speed) is very fast, and the speed is as high as several meters/second to twenty meters/second. Therefore, in order to switch the cooling water from the cooling water nozzle and stop the injection of the cooling water before and after the cooling in the rolling direction as described above, it is necessary to minimize the response time of the switching and the high speed. Ground control.

In addition, in order to solve the uneven temperature distribution in the plate width direction of the steel sheet before cooling and during cooling, it is necessary to start the switching of the cooling water from the cooling water nozzles arranged in the width direction of the plate and stop the switching of the cooling water. The cooling water nozzles are individually switched at high speed in units of a plurality of cooling water nozzles. However, the above-described response time of the cooling device used in the cooling process of the conventional hot-rolled steel sheet is about 1 second to 3 seconds. Therefore, between the response times, the hot rolled steel sheet has been transported by ten meters to several tens of meters. Therefore, in particular, in view of the uneven temperature distribution of the steel sheet which changes in the rolling direction at a pitch of about 10 m or less, the uneven temperature distribution after cooling cannot be sufficiently suppressed.

The technique disclosed in Patent Document 1 is arranged in the plate width direction: a nozzle having an opening and closing valve that is opened and closed by a pilot pressure is provided. Further, the range of the leading pressure required to supply the injection for shutting off the cooling water can be selected within a range set in advance in the sheet width direction, and the injection of the cooling water can be selectively stopped. Thereby, it is possible to control the start or stop of the injection of the cooling water corresponding to the edge of the steel sheet and the low temperature portion of the step end.

However, the response time of the start/stop of the cooling water injection depends on the moving speed of the piston rod. According to the technique disclosed in Patent Document 1, since the piston link is moved by the rotation of the screw, the amount of movement is small, and it is difficult to control the start/stop of about three times or more in one second. Therefore, there is still a limit to using it for a non-uniform temperature distribution corresponding to a small pitch (for example, 10 meters or less).

Further, in the technique disclosed in Patent Document 2, it is possible to change the direction of the flow of the cooling water for cooling the steel pipe to a state in which cooling is not performed, but it is not possible to target the steel sheet simply by using the switching technique. Temperature control is performed at any position in the width direction of the board.

The technique disclosed in Patent Document 3 is to rotate the barrier plate so that the cooling water flow does not impinge on the end portion of the steel sheet, but it is also impossible to perform temperature control for any position in the plate width direction of the steel sheet.

Further, the cooling device described in Patent Document 4 discloses that the amount of the coolant discharged from the nozzle is controlled in the width direction of the sheet. However, it is not specifically disclosed which method is used for control. The amount of coolant. In the ninth drawing of Patent Document 4, it is disclosed that the nozzles are arranged side by side in the width direction of the plate. However, it is not disclosed that the coolant is utilized on the upstream side of the pipe connected to the nozzle. What way to control it. For example, in the case where the pipe connected to the nozzle is not filled with the coolant, the responsiveness when the coolant is added from the nozzle is poor, simply by controlling the amount of the coolant. Because the conveying speed of the steel plate is very fast, up to several meters/second to twenty-two meters/second, if it is in order to cope with the uneven temperature distribution of the steel plate before and after cooling in the long axis direction, When the cooling water nozzle starts to inject the cooling water and stops the injection of the cooling water to control the amount of the cooling water that hits the steel plate, switching from the state in which the cooling water is being injected to the stop of the injection and from the state in which the cooling water is stopped is switched to the start of the injection. The time required, that is, the response time, must be shortened as much as possible and must be controlled at high speed.

Further, Patent Document 4 discloses a technique for controlling the amount of coolant in the width direction of the sheet, but does not disclose a technique for controlling the coolant in the rolling direction. In this case, it is difficult to suppress the uneven temperature distribution in the form of a rib extending toward the rolling direction of the hot-rolled steel sheet. Further, the upper surface is provided with the presence of water on the upper surface of the steel sheet, and the temperature in the sheet width direction of the hot-rolled steel sheet cannot be sufficiently controlled. In view of the above, the cooling device described in Patent Document 4 cannot sufficiently uniform the temperature in the sheet width direction of the hot-rolled steel sheet, and there is still room for improvement.

The cooling device described in Patent Document 5 has the same problems as the above-described Patent Document 4. In other words, the cooling water is controlled by the opening and closing control valve. For example, when the piping connected to the nozzle is not filled with the cooling water at any time, the responsiveness is poor. Further, although a plurality of cooling water jets are provided in the width direction of the plate, only one is provided in the rolling direction, and it is impossible to control the temperature in the rolling direction for the hot rolled steel sheet, and it is difficult to suppress the uneven temperature in the form of a rib. distributed.

In addition, in the cooling device of Patent Document 5, cooling water is sprayed on the upper surface of the hot-rolled steel sheet to be cooled. However, since the upper surface is covered with water on the upper surface of the steel sheet, the hot rolling cannot be sufficiently controlled. The plate width direction temperature of the steel sheet. Moreover, if the water on the upper surface of the steel sheet cannot be properly removed, the temperature distribution sensor cannot be used for accurate temperature measurement, and there is room for improvement in temperature control.

In view of the above-described reasons, in the conventional cooling device and the cooling method, it is still difficult to achieve uniformity in the rolling direction of the hot-rolled steel sheet and the temperature in the sheet width direction.

Moreover, the material properties of the high tensile steel sheet are greatly affected by the cooling. Compared with conventional steel, the high tension steel plate has a greater influence on the characteristics of the final product. Therefore, for the conventional steel, even if it is not regarded as a problem, the uneven temperature distribution is for the high tensile steel plate. The intensity has a big impact. Therefore, in the manufacture of high-tensile steel sheets, it is necessary to control cooling with higher precision than when manufacturing conventional steel materials. In the technique proposed in the related art, the technique of controlling the cooling temperature of the steel sheet by using the cooling water supplied from the upper surface side of the steel sheet is, for example, the following problem.

(1) The cooling water supplied from the upper surface side of the steel sheet will be retained on the upper surface of the steel sheet after impacting the upper surface of the steel sheet to become the upper surface water of the steel sheet. If the cooling water is supplied from the upper surface side, especially when the steel sheet temperature is lowered to a temperature lower than 550 ° C, not only the place where the cooling water is hit, but also the upper surface water of the steel sheet is cooled. For high tensile steel sheets, this effect is particularly large, so that the uneven temperature distribution becomes larger as compared with conventional steel.

(2) The cooling water supplied from the upper surface side of the steel sheet flows over the upper surface of the steel sheet, and a part of it flows toward the sheet width direction of the steel sheet. This water flowing in the width direction of the plate interferes with the cooling water supplied from the upper surface side of the steel sheet. Therefore, it is difficult to accurately control the temperature in the sheet width direction of the steel sheet by the cooling water supplied from the upper surface side.

(3) If it is desired to control the cooling temperature with high precision by using the cooling water supplied from the upper surface side of the steel sheet, it is necessary to remove the surface water of the steel sheet by using a water removal device. In order to make it easier to increase the accuracy of the temperature measurement, the thermometer must be placed in a location that is not easily affected by the water removal equipment, that is, it must be placed at a position separated from the cooling water nozzle for jetting the cooling water in the rolling direction. . As a result, the time from when the temperature has been measured to when the water hits the steel sheet becomes long, and the temperature change during this time becomes large, so that the control accuracy of the cooling temperature is lowered.

As described above, conventional techniques for controlling the cooling temperature in the sheet width direction of the steel sheet by using the cooling water supplied from the upper surface side of the steel sheet are difficult to achieve: high precision required for manufacturing a high tensile steel sheet. Temperature control in the width direction of the board.

The present invention has been developed in view of the above-described circumstances, and an object thereof is to enhance the heat by appropriately cooling the lower surface of the hot-rolled steel sheet after the refining rolling in the hot rolling step. The uniformity (consistency) of the rolling direction of the rolled steel sheet and the temperature in the sheet width direction.

A cooling device for a hot-rolled steel sheet according to a first aspect of the present invention is characterized in that, after the refining rolling in the hot rolling step, the cooling device for cooling the lower surface of the hot-rolled steel sheet conveyed on the conveying roller is characterized In order to provide the entire field in the width direction of the lower surface of the steel sheet conveying field and the cooling area defined by the predetermined length in the rolling direction, the total cooling area is in the above-mentioned board. a cooling zone obtained by dividing into a plurality of width directions, that is, a cooling zone in a width direction; a cooling zone obtained by dividing a widthwise divided cooling zone into a plurality of rolling directions in a rolling direction, that is, dividing a cooling surface; At least one cooling water nozzle for injecting cooling water to each lower surface of the divided cooling surface; for switching the cooling water sprayed from the cooling water nozzle into a switching device for impact and non-impact with the divided cooling surface; a width direction thermometer for temperature distribution in the width direction of the plate; a control device for controlling the operation of the switching device according to the measurement result of the width direction thermometer .

In the case of "impact and non-impact on the divided cooling surface from the cooling water sprayed from the cooling water nozzle", "the impact on the divided cooling surface" means that the lower surface of the hot-rolled steel sheet exists in the split cooling. In the case of the surface, the cooling water is sprayed so that the cooling water impacts the lower surface of the hot-rolled steel sheet. On the other hand, "non-impacting the divided cooling surface" means that the cooling water does not impinge on the lower surface of the hot-rolled steel sheet when the lower surface of the hot-rolled steel sheet exists on the divided cooling surface.

In the cooling device for a hot-rolled steel sheet according to the first aspect, the cooling water nozzle system may be provided with one or more corresponding cooling water nozzles for each of the divided cooling surfaces.

In the cooling device for the hot-rolled steel sheet according to the first aspect, the number of the cooling water nozzles disposed on the two divided cooling surfaces adjacent to each other may be different from each other in the rolling direction.

In the cooling device for the hot-rolled steel sheet according to the first aspect, the divided cooling surfaces included in the widthwise divided cooling belt may have different lengths in the rolling direction in the rolling direction.

In the cooling device for the hot-rolled steel sheet according to the first aspect, the length of the cooling surface in the rolling direction may be set to be a multiple of the length between the conveying rollers.

In the cooling device for the hot-rolled steel sheet according to the first aspect, the arrangement of the plurality of cooling water nozzles in the sheet width direction may be arranged such that the center of the cooling water nozzle adjacent in the sheet width direction is The distance between them is all equal distance.

In the cooling device for the hot-rolled steel sheet according to the first aspect, a plurality of cooling water nozzles for cooling the same divided cooling surface are disposed, and the switching device is integrated: for switching a plurality of the same divided cooling surfaces The cooling water nozzle can simultaneously control the impact of the cooling water on the same split cooling surface and the non-impact switching control system.

In the cooling device for the hot-rolled steel sheet according to the first aspect, the switching device can be configured to include a pipe through which the cooling water supplied to the cooling water nozzle flows, a water supply head for supplying the cooling water, and a cooling device; The drain head or drainage area where the water is drained; between the water supply head and the drain head or the drain area, a valve for switching the flow direction of the cooling water is performed.

At this time, the valve may be a three-way valve, and the three-way valve may be disposed on the side in the width direction of the conveying roller and at the same height as the front end of the cooling water nozzle.

In the cooling device for a hot-rolled steel sheet according to the first aspect, the switching device includes a pipe through which cooling water supplied to the cooling water nozzle flows, a water supply head for supplying cooling water, and a cooling device for cooling a drainage area where water is drained; a mechanism for changing an injection direction of the cooling water sprayed from the cooling water nozzle; and when the injection direction is changed, a blocking mechanism may be performed such that the cooling water does not impinge on the divided cooling surface; It is also possible to switch so that the cooling water impacts and non-impacts on the lower surface of the divided cooling surface by a mechanism for changing the direction in which the cooling water is sprayed.

In the cooling device for a hot-rolled steel sheet according to the first aspect, the width direction thermometer is provided in at least one of the upstream side in the rolling direction of the total cooling field and the downstream side in the rolling direction, and is divided and cooled in each width direction. Both have settings. At this time, the width direction thermometer may be disposed on the lower surface side of the steel sheet conveying field.

A method for cooling a hot-rolled steel sheet according to a second aspect of the present invention is characterized in that, after the refining rolling in the hot rolling step, the cooling method for cooling the lower surface of the hot-rolled steel sheet conveyed on the conveying roller is characterized by : The entire field in the width direction of the lower surface of the steel sheet conveying field and the cooling area defined by the predetermined length in the rolling direction are regarded as the total cooling field; the total cooling area is divided into a plurality of sheets in the width direction of the sheet In each of the obtained cooling fields, the cooling zone is divided as a width direction; the cooling zone obtained by dividing the cooling zone in the rolling direction into a plurality of rolling zones is used as a divided cooling surface; and the width of the hot rolled steel plate is measured. The temperature distribution in the direction; according to the measurement result of the temperature distribution, for each of the divided cooling surfaces, the cooling water from the cooling water nozzle is controlled to impact and non-impact the hot-rolled steel sheet in the width direction of the plate and in the rolling direction, respectively. .

In the second aspect, the same divided cooling surface may be provided with a plurality of cooling water nozzles for spraying the cooling water, and the plurality of cooling water nozzles are integrated and controlled simultaneously: from the plurality of cooling waters The impact of the cooling water of the nozzle on the hot-rolled steel sheet existing on the same split cooling surface and the non-impact.

In the second aspect, the water supply head through which the cooling water supplied to the cooling water nozzle flows, the water supply head for supplying the cooling water, and the drainage head or the drainage for draining the cooling water may be provided. a valve for switching the flow direction of the cooling water between the water supply head and the drain head or the aforementioned drainage area; controlling the opening and closing of the valve according to the measurement result of the temperature distribution in the width direction of the hot-rolled steel sheet For each of the divided cooling surfaces, the cooling water of the cooling water nozzle is separately controlled to impact and non-impact on the hot-rolled steel sheet in the width direction of the sheet and in the rolling direction.

The above-mentioned valve is a three-way valve, and may be directed to: a cooling head that does not want to use cooling water from a cooling water nozzle to cool the lower surface of the hot-rolled steel sheet, so that the cooling water from the cooling water nozzle is not impacted. To the extent of the lower surface of the hot-rolled steel sheet and the manner of continuously spraying water to control the opening degree of the three-way valve; for the purpose of using the cooling water from the cooling water nozzle to cool the water supply head of the lower surface of the hot-rolled steel sheet, The opening of the three-way valve is controlled such that the cooling water from the cooling water nozzle impinges on the lower surface of the hot-rolled steel sheet.

According to the present invention, it is possible to increase the uniformity of the temperature in the rolling direction and the sheet width direction of the hot-rolled steel sheet by appropriately cooling the lower surface of the hot-rolled steel sheet after the refining rolling in the hot rolling step. Sex (consistency).

1‧‧‧Bullet

2‧‧‧Hot rolled steel plate

10‧‧‧ hot rolling equipment

11‧‧‧heating furnace

12‧‧‧Width direction rolling mill

13‧‧‧Rough Rolling Mill

14‧‧‧Refining Rolling Mill

15‧‧‧Upside cooling unit

16‧‧‧Bottom cooling unit

17‧‧‧Bottom width direction control cooling device

18‧‧‧Transport roller

19‧‧‧Winding device

20‧‧‧Cooling water nozzle

21‧‧‧ middle head

23‧‧‧Pipe

24‧‧‧Three-way valve

25‧‧‧Water supply head

26‧‧‧Drain head

27‧‧‧Control device

30‧‧‧Upstream temperature measuring device

31‧‧‧Downstream temperature measuring device

32‧‧‧radiation heat thermometer

33‧‧‧Fiber

34‧‧‧Nozzles

35‧‧‧Water storage tank

40‧‧‧ spray holes

117‧‧‧Bottom width direction control cooling device

125‧‧‧Guideboard

125a‧‧‧jet

125c, 125d‧‧‧ water retaining plate

126, 226, 326‧‧‧ Cooling water travel direction changing device

127‧‧‧ gas nozzle

128‧‧‧ gas manifold

129‧‧‧ valve

130‧‧‧ gas nozzle

227, 327‧‧‧ nozzle adapter

228, 328‧‧‧ pneumatic cylinder

229‧‧‧Fixed shaft

230,331‧‧‧link front axle

231, 332‧‧‧ piston connecting rod

232‧‧‧ tube

329‧‧‧jet deflecting plate

330‧‧‧Rotary axis

Fig. 1 is an explanatory view showing a schematic configuration of a hot rolling facility 10.

Fig. 2 is a perspective view showing a schematic configuration of the lower width direction control cooling device 17 of the first embodiment.

Fig. 3 is a side view showing a schematic configuration of the lower width direction control cooling device 17 of the first embodiment.

Fig. 4 is a plan view showing a schematic configuration of the lower width direction control cooling device 17 of the first embodiment.

Fig. 5 is an explanatory view for explaining an example of the divided cooling surface A3.

Fig. 6 is an explanatory view focusing on dividing the cooling zone A2 in the width direction.

Fig. 7 is an explanatory view for explaining the divided cooling surface A3 of another example.

Fig. 8 is an explanatory view for explaining the divided cooling surface A3 of another example.

FIG. 9 is an explanatory view for explaining the arrangement of the divided cooling surface A3, the arrangement of the cooling water nozzles 20, and the arrangement of the temperature measuring devices 30 and 31 in the lower width direction control cooling device 17 of the first embodiment.

Fig. 10 is an arrangement example of the divided cooling surface A3 and the cooling water nozzle 20.

Fig. 11 is an arrangement example of the divided cooling surface A3 and the cooling water nozzle 20.

Fig. 12 is an arrangement example of the divided cooling surface A3 and the cooling water nozzle 20.

Fig. 13 is an arrangement example of the divided cooling surface A3 and the cooling water nozzle 20.

Fig. 14 is an explanatory diagram for explaining an example of the form of the temperature measuring device 30.

Fig. 15 is an explanatory view for explaining an example of the form of the cooling water nozzle 20.

Fig. 16 is an explanatory view for explaining the configuration of the lower side width direction control cooling device 17 without the intermediate head 21.

Fig. 17 is an explanatory diagram for explaining the configuration of the cooling water traveling direction changing device 126.

Fig. 18 is another explanatory diagram for explaining the configuration of the cooling water traveling direction changing means 126.

Fig. 19 is an explanatory diagram for explaining the configuration of the cooling water traveling direction changing means 226.

Fig. 20 is another explanatory diagram for explaining the structure of the cooling water traveling direction changing means 226.

Fig. 21 is an explanatory diagram for explaining the configuration of the cooling water traveling direction changing means 326.

Fig. 22 is another explanatory diagram for explaining the configuration of the cooling water traveling direction changing means 326.

Fig. 23 is a view showing a part of the surface temperature distribution of the upper surface of the steel sheet of Comparative Example 1.

Fig. 24 is a view showing a part of the temperature distribution on the upper surface of the steel sheet of Example 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the specification and the drawings, the same reference numerals are given to the components that have substantially the same functional configurations, and the repeated description thereof will be omitted.

 [First form]  

1 is an explanatory view for explaining a schematic configuration of a manufacturing apparatus (hereinafter referred to as "hot rolling equipment") 10 of a hot-rolled steel sheet including the cooling device of the first embodiment.

In the hot rolling facility 10, the heated billet 1 is continuously rolled by being sandwiched by rollers from above and below, and is rolled to a plate thickness of at least 1 mm to be taken up as a hot-rolled steel sheet 2. The hot rolling facility 10 is provided with a heating furnace 11 for heating the billet 1 and a width direction rolling mill 12 for rolling the billet 1 heated in the heating furnace 11 in the width direction of the sheet; a rough rolling mill 13 which is rolled in the direction of the width of the sheet by rolling in the vertical direction to form a coarse blank; and a refining rolling mill 14 for continuously refining the rough billet to obtain a predetermined thickness; The hot-rolled steel sheet 2 subjected to the hot-rolled refining and rolling by the refining rolling mill 14 is cooled by the cooling water, the cooling devices 15, 16, and 17; and the hot-rolled steel sheet 2 cooled by the cooling devices 15, 16, and The coil winding device 19 is taken up in a coil shape. Among the cooling devices 15, 16, and 17, the upper cooling device 15 is disposed above the steel sheet conveying area, and the lower cooling device 16 and the lower width direction control cooling device 17 are disposed below the steel sheet conveying region.

In the heating furnace 11, a process of heating the billet 1 carried from the outside through the loading port to a predetermined temperature is performed. When the heating process in the heating furnace 11 is completed, the billet 1 is conveyed to the outside of the heating furnace 11, passes through the width direction rolling mill 12, and is then moved to the rolling process performed by the rough rolling mill 13.

The conveyed billet 1 is rolled by a rough rolling mill 13 to form a rough blank (thin steel sheet) having a thickness of about 30 mm to 60 mm, and then conveyed to the refining rolling mill 14.

The refining rolling mill 14 rolls the conveyed rough blank to a plate thickness of several mm to obtain the hot-rolled steel sheet 2. The hot-rolled steel sheet 2 that has been rolled is conveyed by the transport rollers 18 (refer to Figs. 2 to 4), and sent to the upper cooling device 15, the lower cooling device 16, and the lower width direction. The cooling device 17 is controlled.

The hot-rolled steel sheet 2 is cooled by the upper side cooling device 15, the lower side cooling device 16, and the lower width direction control cooling device 17, and then wound up in a coil shape (steel tape roll shape) by the winding device 19.

The configuration of the upper cooling device 15 is not particularly limited, and a known cooling device can be applied. For example, the upper side cooling device 15 may have a plurality of cooling water nozzles that spray cooling water from the upper side of the steel sheet conveying area toward the upper surface of the steel sheet conveying area. As the cooling water nozzle system, for example, a slit lamination nozzle or a tube lamination nozzle or the like can be used. In view of the viewpoint of ensuring the cooling capacity, it is preferable that the upper side cooling device 15 is provided. However, if there is no shortage of cooling, the upper side cooling device 15 is not necessarily required to be disposed, but it is usually necessary.

The lower side cooling device 16 cools the steel sheet conveying area from the lower side of the steel sheet conveying area that is conveyed on the conveying roller 18 of the output roller path toward the lower surface of the steel sheet conveying area. The configuration of the cooling device is not particularly limited, and a known cooling device can be applied.

Next, a configuration of the lower width direction control cooling device 17 will be described. Fig. 2 is a perspective view schematically showing a part of the structure of the lower width direction control cooling device 17, and Fig. 3 is a schematic view showing a part of the structure of the lower width direction control cooling device 17, from the plate width direction (Y FIG. 4 is a plan view showing a part of the structure of the lower width direction control cooling device 17 as viewed from above in the vertical direction (Z direction).

The lower width direction control cooling device 17 in the present embodiment is substantially a switching device including a cooling water nozzle 20, an intermediate head 21, a pipe 23, a water supply head 25, a three-way valve 24, and a drain head 26; The devices 30, 31 and the control device 27 are constructed.

The lower width direction control cooling device 17 is used for cooling control of the divided cooling surface A3 in which the lower surface of the steel sheet conveying region to be described later, that is, the total cooling area A1 is divided. Fig. 5 to Fig. 8 show an explanatory diagram thereof. Fig. 5 to Fig. 8 are explanatory views for explaining the division of the cooling surface A3. 5 to 8 are views when the hot rolling facility 10 is viewed from the Z direction, and the positional relationship between the total cooling area A1 and the conveying roller 18 which will be described later is shown. Further, in the fifth to eighth drawings, the conveying roller 18 is indicated by a broken line for the sake of convenience of explanation.

In the present embodiment, the field in which the hot-rolled steel sheet 2 produced by the hot rolling facility 10 can be transported on the output roller is referred to as "the steel sheet conveying field". The term "steel sheet conveying field" is a field defined by the maximum sheet thickness x maximum sheet width of a hot-rolled steel sheet that can be produced, and is a three-dimensional field (three-dimensional field) extending in the rolling direction. Therefore, in the "rolling steel sheet field", in the rolling direction, the area on the output roller path from the outlet side end of the refining rolling mill to the time before the reeling machine is occupied.

In the lower surface of the "steel plate conveyance field", the lower width direction control cooling device 17 is a field to be cooled, that is, an area defined by the entire length in the plate width direction and the predetermined length in the rolling direction. It is called "Total Cooling Area A1".

"The entire field in the width direction of the sheet" means a field in which the hot rolled steel sheet 2 can exist on the conveying roller 18. The "predetermined length in the rolling direction" means at least a length of at least one pitch between the rollers in the rolling direction of the conveying roller 18. The "length of one pitch between the rollers in the rolling direction" means the distance between the axes of the adjacent conveying rollers in the rolling direction. The length of the "predetermined length in the rolling direction" is not particularly limited, but it is preferably 20 m or less based on the viewpoint of equipment cost. The specific length can be appropriately determined by controlling the cooling ability of the cooling device 17 and the predicted state of the uneven temperature distribution of the hot-rolled steel sheet 2 in the lower width direction.

Each of the cooling areas obtained by dividing the total cooling area A1 into a plurality of sheets in the sheet width direction is referred to as "width-direction divided cooling belt A2". Fig. 6 shows an example in which the steel sheet conveying area A1 is divided into six widthwise divided cooling belts A2. In the example shown in FIG. 6, in order to make the technique easy to understand, the widthwise divided cooling zone A2 is arranged in six in the plate width direction. However, the number of divisions is not limited thereto. The number (the number of divisions) of the cooling zone A2 divided in the width direction in the sheet width direction is not particularly limited, and may be divided into at least one cooling water nozzle 20 corresponding to each of the widthwise divided cooling zones A2.

The length in the width direction of the cooling zone A2 in the width direction is the length in which the length in the width direction of the plate transporting area A1 is divided by the number of divisions. The length in the width direction of the cooling zone A2 in the width direction is not particularly limited, and may be suitably set to 50 mm or 100 mm.

Each of the cooling collars obtained by dividing the cooling zone A2 in the width direction in the rolling direction is referred to as "divided cooling surface A3". The length in the width direction of the divided cooling surface A3 is the same as the length in the width direction of the cooling zone A2 in the width direction, and the length in the rolling direction of the divided cooling surface A3 is divided into the rolling direction length of the cooling zone A2 in the width direction. The length after the number is divided.

The length of the divided cooling surface A3 in the rolling direction is not particularly limited, and a suitable setting can be made. The length of the divided cooling surface A3 shown in Fig. 5 in the rolling direction is set to be the same length as one pitch between the rollers of the conveying roller 18 in the rolling direction. Further, the example shown in Fig. 7 is set to have a length of two pitches between the rollers in the rolling direction of the conveying roller 18. In this manner, the length of the divided cooling surface A3 in the rolling direction may be set to a length that is an integral multiple of the pitch between the rollers in the rolling direction of the conveying roller 18.

Further, the lengths of the plurality of divided cooling surfaces A3 arranged adjacently in the rolling direction are not necessarily the same in the rolling direction, and may be different from each other. For example, in the manner shown in Fig. 8, the length of the divided cooling surface A3 in the rolling direction may be gradually increased from the upstream side to the downstream side as follows: the conveying roller 18 is in the rolling direction. One pitch, two pitches, four pitches, eight pitches, and 16 pitches between the rollers.

In the following description, as shown in Fig. 9, the length of the rolling direction is set to a length of four times the distance between the rollers in the rolling direction of the conveying roller 18, and the divided cooling surface A3 is An example is given for explanation.

In the present embodiment, as shown in Fig. 9, the length of the divided cooling surface A3 in the rolling direction is four times the pitch between the rollers in the rolling direction of the conveying roller 18. However, as described above, the divided cooling surface A3 of another form can also be applied.

The cooling water nozzle 20 is a cooling water nozzle that sprays cooling water from the lower side of the steel sheet conveying area of the output roller to the lower surface of the steel sheet conveying area, and is provided with a plurality of cooling water nozzles 20. Various types of known nozzles can be used for the cooling water nozzle 20, and such a nozzle is, for example, a tube lamination nozzle. Further, the cooling range of the cooling water nozzle 20 in the width direction of the plate is set to be equal to or smaller than the length in the width direction of the cooling split surface A3 so as to prevent the impact range of the cooling water from cooling the split surface A3 from entering other cooling sections. Face A3.

The arrangement of the cooling water nozzles 20 for dividing the cooling surface A3 in the present embodiment is also shown in Fig. 9. In Fig. 9, the cooling water nozzle 20 is indicated by the symbol "●". At least one cooling water nozzle 20 is disposed for each of the divided cooling surfaces A3.

In the cooling water nozzle 20 of the present embodiment, four cooling water nozzles 20 are disposed on one divided cooling surface A3 in a plan view seen from above in the steel sheet conveying region. In the present embodiment, when the four cooling water nozzles 20 are viewed in a plan view, they are disposed between the adjacent conveying rollers 18 and arranged in the rolling direction. The number and arrangement of the cooling water nozzles 20 disposed in each of the divided cooling surfaces A3 are not particularly limited, and may be one or plural. The adjacent divided cooling faces A3 and the number and arrangement of the cooling water nozzles 20 may be set to be different from each other.

In addition, when the amount of water and the flow rate discharged from the cooling water nozzle 20 are set in the same manner by the respective cooling water nozzles 20 in the sheet width direction and the rolling direction, and the cooling capacity is set to be the same, it is easier to control. Further, the number of cooling water nozzles 20 provided in each of the cooling partition faces A3, the amount of discharged water, and the discharge flow rate are arranged in the same manner at the same position in the rolling direction, and are arranged in the plate width. When the cooling ability of each divided cooling surface A3 in the direction is set to be the same, it is easier to control.

In addition, the cooling water nozzles 20 having the same discharge water amount and the discharge flow rate attached to the divided cooling surface A3 disposed in the sheet width direction are disposed such that the distance between the centers of the cooling water nozzles 20 adjacent to each other in the sheet width direction is All are equally equidistant. In this way, uniform cooling in the width direction of the board can be performed with higher precision.

Further, even if the cooling capacity of the cooling water nozzle 20 and the cooling capacity of the discharge flow rate are different in the sheet width direction and the rolling direction, the control device 27 can perform the control.

In the present embodiment, the divided cooling surface A3 is arranged in two in the rolling direction (X direction), and six in the sheet width direction (Y direction). The cooling water nozzles 20 having the same amount of discharged water and the same discharge flow rate are arranged in the rolling direction and the plate width direction, respectively.

In the ninth aspect, the divided cooling surface A3 of the present embodiment and the arrangement of the cooling water nozzles 20 belonging to the present embodiment are shown. However, the present invention is not limited thereto, and various combinations may be made. Figures 10 through 13 list various examples. Each of the cooling water nozzles here uses the same amount of discharged water and flow rate, and is set to have the same cooling capacity.

In the example shown in Fig. 10, the length of the divided cooling surface A3 in the rolling direction is set to a length of one pitch between the rollers of the conveying roller 18 in the rolling direction, and each divided cooling surface A3 is Each is assigned a cooling water nozzle 20.

In the example shown in Fig. 11, the length of the divided cooling surface A3 in the rolling direction is set to a length of one pitch between the rollers of the conveying roller 18 in the rolling direction, and each divided cooling surface A3 is Two cooling water nozzles 20 are assigned to each. The two cooling water nozzles 20 may be arranged in the rolling direction or in the plate width direction. Further, it may be arranged such that, in the manner shown in Fig. 11, a shift is formed in the rolling direction and in the sheet width direction.

In the example shown in Fig. 12, the length of the divided cooling surface A3 in the rolling direction is set to the length of the two pitches between the rollers of the conveying roller 18 in the rolling direction, and each divided cooling surface A3 Each of the four cooling water nozzles 20 is assigned.

In the example shown in Fig. 13, the length of the divided cooling surface A3 in the rolling direction is set to be one from the upstream side, sequentially between the rollers in the rolling direction of the conveying roller 18. The length of the pitch, the length of the two pitches, the length of the four pitches, the length of the eight pitches, etc. are changed, and the two divided cooling faces A3 adjacent in the rolling direction are assigned to the two The number of cooling water nozzles 20 that divide the cooling surface A3 is also different.

The intermediate head 21 functions as a part of the switching device in this embodiment, and is a water supply head for supplying cooling water to the cooling water nozzle 20. In the present embodiment, as can be seen from Figs. 2 to 4, the intermediate head 21 is a tubular member extending in the rolling direction, and a plurality of cooling water nozzles 20 are provided in the rolling direction. Therefore, the injection and the stop of the cooling water from the cooling water nozzles 20 disposed in one intermediate head 21 can be simultaneously controlled. The illustrated example is an example in which four cooling water nozzles 20 are arranged in the rolling direction for one intermediate head 21, but the number of cooling water nozzles 20 is not limited thereto.

Further, the intermediate head 21 is arranged in a one-to-one manner corresponding to the divided cooling surface A3. In this way, the switching control of the injection and the stop of the cooling water can be performed for each of the divided cooling surfaces A3.

In the present embodiment, since the two divided cooling faces A3 are provided in the rolling direction, two intermediate heads 21 are also provided in the rolling direction, and the number of the intermediate heads 21 is made to match the number of the divided cooling faces A3. Just change it as appropriate.

The three-way valve 24 is a member that functions as a part of the switching device in this embodiment. That is, the three-way valve 24 is a main member for switching the cooling water sprayed by the cooling water nozzle 20 into a switching device that performs impact and non-impact on the lower surface of the steel sheet conveying field.

The three-way valve 24 of the present embodiment is a split type valve that can switch the water from the water supply head 25 to the guide pipe 23 to be supplied to the intermediate head 21 and the cooling water nozzle 20, or to the drain head 26. Further, in the present embodiment, the drain head 26 is used as a portion for draining, but is not particularly limited to such a form.

It is also possible to replace the three-way valve 24 of the present embodiment by providing two on-off valves (in a broad sense, a valve for opening and closing the flow of the fluid, also referred to as an ON/OFF valve), which can also be performed with the three-way The same control of the valve.

In the present embodiment, a three-way valve 24 is disposed corresponding to an intermediate head 21, and is disposed between a water supply head 25 for supplying cooling water and a drain head 26 for discharging cooling water. However, the present invention is not limited thereto, and a three-way valve 24 may be disposed to correspond to the form of the plurality of intermediate heads 21. In this way, a plurality of intermediate heads 21 can be integrated and controlled simultaneously.

Further, in the illustrated example, although the two water supply heads 25 and the two drain heads 26 are separately provided, the number of the water supply heads 25 and the drain heads 26 is not limited thereto, and for example, one may be separately provided.

The inside of the pipe 23 is filled with cooling water at any time by the three-way valve 24. As a result, when the cooling water is caused to impinge on the lower surface (divided cooling surface A3) of the steel sheet conveying direction, that is, when the lower surface of the hot-rolled steel sheet 2 is cooled, the indication from the occurrence of the opening of the three-way valve 24 can be shortened. The time until the cooling water is sprayed from the cooling water nozzle 20 can improve the responsiveness. In addition, the responsiveness of the three-way valve 24 to opening and closing is preferably within 0.5 seconds. The three-way valve 24 can use, for example, a solenoid valve.

Further, the three-way valve 24 is preferably disposed at the same height as the front end of the cooling water nozzle 20. More specifically, it is preferable that the portion of the three-way valve 24 that is connected to the pipe 23 is provided at the same height position as the front end of the cooling water nozzle 20. As a result, the front end of the cooling water nozzle 20 and the front end of the pipe 23 are at the same height, so that the inside of the pipe 23 can be filled with the cooling water at any time. Even if, for example, the sealing of the three-way valve 24 is not complete enough and a certain amount of cooling water leaks, the inside of the piping 23 can be filled with the cooling water, which makes it more responsive.

The three-way valve 24 is preferably provided on the side in the plate width direction with respect to the conveying roller 18. Although it is also conceivable to provide the three-way valve 24 under the transport roller 18, for example, the space below the transport roller 18 is limited, and it is difficult to provide a plurality of three-way valves 24. Further, it is also difficult to perform maintenance on the three-way valve 24 below the conveying roller 18. Based on this point of view, if the three-way valve 24 is provided on the side in the plate width direction with respect to the conveying roller 18 in this manner, the degree of freedom in setting the three-way valve 24 can be improved. It can also be easily repaired and maintained.

The upstream side temperature measuring device 30 is disposed at a position on the lower surface side of the steel sheet conveying field, and can be used as a width direction thermometer for measuring the temperature of the hot-rolled steel sheet 2 on the upstream side in the rolling direction of the total cooling area A1.

It is preferable that the upstream side temperature measuring device 30 is disposed so as to divide the cooling zone A2 in the width direction. Therefore, in the illustrated example, six upstream temperature measuring devices 30 are arranged in the plate width direction. The temperature on the upstream side of the divided cooling zone A2 in each width direction (that is, the temperature before being cooled) was measured. In this way, the temperature in the entire plate width direction of the hot-rolled steel sheet 2 on the upstream side of the lower width direction control cooling device 17 can be measured.

The downstream side temperature measuring device 31 is disposed at a position on the lower surface side of the steel sheet conveying field, and can be used as a width direction thermometer for measuring the temperature of the hot-rolled steel sheet 2 on the downstream side in the rolling direction of the total cooling area A1.

The downstream temperature measuring device 31 is preferably disposed so as to divide the cooling zone A2 in the width direction. In the illustrated example, six downstream temperature measuring devices 31 are arranged in the plate width direction to enable measurement of cooling. The temperature of the cooling zone A2 is divided in the respective width directions. In this way, the temperature in the entire plate width direction of the hot-rolled steel sheet 2 on the downstream side in the rolling direction of the cooling device 17 in the lower width direction can be measured.

The control device 27 is a device that controls the operation of the switching device based on the result of one or both of the measurement results of the upstream temperature measuring device 30 and the measurement results of the downstream temperature measuring device 31. Therefore, the control device 27 includes a circuit for calculating an operation in accordance with a predetermined program and a computer, and the circuit and the computer are electrically connected to the upstream temperature measuring device 30, the downstream temperature measuring device 31, and the switching device.

Specifically, the temperature of the hot-rolled steel sheet 2 conveyed on the output roller after the refining and rolling is measured by the upstream temperature measuring device 30. This measurement result is sent to the control device 27, and the amount of cooling required to uniformize (conformize) the temperature of the hot-rolled steel sheet 2 for each of the divided cooling surfaces A3 is calculated.

Then, based on the calculation result, the control device 27 performs feedforward control on the opening and closing of the three-way valve 24. In other words, the control device 27 controls the opening and closing of the three-way valve 24 for each divided cooling surface A3 to achieve the cooling amount required to uniformize the temperature of the hot-rolled steel sheet 2, and performs execution for each divided cooling surface A3. The cooling water sprayed from the cooling water nozzle 20 is subjected to impact or non-impact control of the lower surface of the hot-rolled steel sheet 2.

Further, since the divided cooling surface A3 is arranged in the sheet width direction and the rolling direction, the control device 27 can control the temperature in both the sheet width direction and the rolling direction, and can accurately rotate the hot rolled steel sheet 2 The temperature is uniform.

Further, feedforward control is useful in order to reduce the uneven temperature distribution of the hot-rolled steel sheet 2 extending in the rolling direction, and based on this viewpoint, feedforward control is performed by using the upstream side temperature measuring device 30. The temperature in the sheet width direction of the hot-rolled steel sheet 2 can be made more uniform.

However, it is not limited to the feedforward control, and the feedback control of the opening and closing of the three-way valve 24 may be performed based on the measurement result of the downstream side temperature measuring device 31. In other words, the control device 27 performs calculation using the measurement result of the downstream temperature measuring device 31, and based on the calculation result, controls the opening and closing times of the three-way valve 24 for each cooling split surface A3. In this way, for each of the divided cooling surfaces A3, control can be performed to impinge or non-impact the cooling water to the lower surface of the steel sheet conveying field.

The lower width direction control cooling device 17 is selectively executable to perform feedforward control on the three-way valve 24 in accordance with the measurement result of the upstream side temperature measuring device 30 or in accordance with the measurement result of the downstream side temperature measuring device 31. The three-way valve 24 performs feedback control.

In addition, this feedback control can also be applied to the correction control of the feedforward control result. In this way, the lower width direction control cooling device 17 can be collectively executed: the feedforward control is performed on the three-way valve 24 in accordance with the measurement result of the upstream side temperature measuring device 30; and the measurement is performed in accordance with the downstream side temperature measuring device 31. As a result, feedback control is performed for the three-way valve 24.

Further, if only one of the feedforward control and the feedback control is executed, one of the upstream temperature measuring device 30 or the downstream temperature measuring device 31 may be omitted.

Further, the lower width direction control cooling device 17 is provided with the three-way valve 24 in the intermediate head 21, and the three-way valve 24 is disposed at the same height as the front end of the cooling water nozzle 20, so that it can be installed inside the piping 23 at any time. Filled with cooling water. Therefore, when the opening and closing of the three-way valve 24 is controlled in accordance with the temperature measurement result of the upstream temperature measuring device 30 and/or the downstream temperature measuring device 31, the cooling water sprayed from the cooling water nozzle 20 can be controlled to control the cooling water sprayed from the cooling water nozzle 20. The responsiveness has become extremely good.

Further, in order to make the inside of the pipe 23 more reliably filled with the cooling water, it is also possible to provide the cooling water from the cooling water nozzle 20 at any time. That is, in order to prevent the cooling water from the cooling water nozzle 20 from impinging on the intermediate head 21 of the divided cooling surface A3, the opening degree of the three-way valve 24 is controlled, so that the cooling water from the cooling water nozzle 20 is not It will hit the extent of dividing the cooling surface A3 and continuously discharge the water. On the other hand, in order to allow the cooling water from the cooling water nozzle 20 to impinge on the intermediate head 21 of the divided cooling surface A3, the cooling water from the cooling water nozzle 20 can be caused to impinge on the divided cooling surface A3. The opening of the three-way valve 24 is controlled. In this case, the inside of the pipe 23 can be surely filled with the cooling water, thereby ensuring responsiveness.

In the side width direction direction control cooling device 17, the configuration of the upstream side temperature measuring device 30 and the downstream side temperature measuring device 31 is not particularly limited as long as it can measure the temperature of the hot rolled steel sheet 2. For the limitation, it is preferable to use a temperature measuring device disclosed in, for example, Japanese Patent No. 3818501. Fig. 14 is an explanatory view showing a schematic configuration of the upstream temperature measuring device 30.

The upstream side temperature measuring device 30 has a radiant heat thermometer 32 for measuring the temperature of the hot rolled steel sheet 2; the front end is disposed at a position opposed to the steel sheet conveying field (hot rolled steel sheet 2), and the rear end is connected to the radiant heat thermometer 32. An optical fiber 33; a nozzle 34 used as a water column forming portion for spraying a water column between the steel sheet conveying field and the front end of the optical fiber 33, and a water storage tank for supplying water to the nozzle 34; 35. The upstream temperature measuring device 30 measures the lower surface temperature of the hot-rolled steel sheet 2 by receiving the radiant light from the lower surface (hot-rolled steel sheet 2) of the steel sheet conveying region by the radiant heat thermometer 32 passing through the water column.

Here, in general, the cooling water from the cooling water nozzle 20 is present on the lower surface of the steel sheet conveying field. Therefore, if a general thermometer is used, a measurement error caused by the cooling water will occur. Therefore, in order to set the thermometer, it is necessary to provide a section in which the cooling water can be emptied and there is no cooling water in the rolling direction (for example, a water-free section of several meters).

On the other hand, in the upstream temperature measuring device 30, the radiant heat thermometer 32 transmits the radiation light through the water column from the nozzle 34. Therefore, the water column can be used to suppress the influence of the cooling water, and the cooling water can be reduced. Measurement error. Therefore, it is not necessary to provide a section in which no cooling water exists, and the upstream side temperature measuring device 30 can be brought close to the cooling water nozzle 20 on the most upstream side. Therefore, it can improve responsiveness. Further, in order to ensure sufficient responsiveness, the distance between the upstream side temperature measuring device 30 and the cooling water nozzle 20 on the most upstream side is preferably within 5 meters, and more preferably within 1 meter.

Further, since the hot-rolled steel sheet 2 will meander on the output roller, if the distance between the upstream side temperature measuring device 30 and the most upstream side cooling water nozzle 20 is too long, there will be a result that the hot-rolled steel sheet 2 is in the sheet width. The temperature measurement position in the direction is inconsistent with the cooling position. In this case, in particular, in the vicinity of the end portion in the width direction of the hot-rolled steel sheet 2, there is a concern that it is not cooled.

On the other hand, according to the present aspect, the upstream side temperature measuring device 30 can be brought close to the cooling water nozzle 20 on the most upstream side, so that the temperature measurement position and the cooling position of the hot-rolled steel sheet 2 in the sheet width direction can be surely made. Consistently, moderate cooling of the hot rolled steel sheet 2 is possible.

Further, the configuration of the downstream temperature measuring device 31 is also the same as that of the upstream temperature measuring device 30, and the same effects as those of the upstream temperature measuring device 30 described above can be obtained.

The three-way valve 24 is provided in the intermediate head 21, and when the number of the cooling water nozzles 20 in the intermediate head 21 is small, the controllability of the cooling water sprayed to the hot-rolled steel sheet 2 can be improved. On the other hand, if the number of the cooling water nozzles 20 is reduced, it is necessary to increase the number of the three-way valves 24 corresponding to the number of cooling water nozzles 20, which will result in an increase in equipment cost and operating cost. Therefore, the number of the cooling water nozzles 20 can be set in consideration of the balance point of these factors.

When the cooling water is impacted on the split cooling surface A3, if a small amount of cooling water is used, the length of the rolling direction of the total cooling area A1 becomes long. Therefore, it is preferable to spray the cooling water from the cooling water nozzle 20 at a large water density of, for example, 1 m ³ /m ² /min or more.

As shown in Fig. 15, the front end of the cooling water nozzle 20 in the cooling device 17 may be controlled in the lower width direction, and a plurality of injection holes 40 for injecting cooling water may be provided. The plurality of injection holes 40 are arranged at equal intervals in the projection direction in the sheet width direction (Y direction). For example, if a large flow rate of cooling water is ejected from a single injection hole of the cooling water nozzle 20, there is only one place in the plate width direction of the hot-rolled steel sheet 2 to cause the cooling water to impact, so that it is easy to produce a rib-like shape. Uniform temperature distribution. On the other hand, by providing a plurality of injection holes 40, the impact pressure of the cooling water on the divided cooling surface A3 can be reduced. Therefore, the uneven temperature distribution of the rib shape can be more reliably suppressed, and the temperature in the width direction of the hot rolled steel sheet 2 can be made more uniform.

In the above embodiment, the intermediate head 21 is provided. However, the present invention is not limited to this embodiment, and a configuration in which the intermediate head 21 is not provided may be employed. Fig. 16 is a plan view schematically showing a configuration of the lower width direction control cooling device 17 of this type. Fig. 16 is a view corresponding to Fig. 4, although the three-way valve 24 is connected to each of the cooling water nozzles 20. However, for the sake of easy understanding, the three-way valve 24 and the water supply are provided in Fig. 16. The disclosure of the head 25 and the drain head 26 is omitted.

In the embodiment shown in Fig. 16, each of the cooling water nozzles 20 is connected to a pipe (not shown), and a three-way valve is provided in this pipe. The three-way valve is provided between a water supply head for supplying cooling water to the piping and a drain head for discharging cooling water. In this manner, the configuration of one three-way valve for one cooling water nozzle 20 can achieve the same effect as that obtained by the above-described form. In this case, the method of thinking about the divided cooling surface A3 is also the same as that of the lower width direction control cooling device 17.

The lower width direction control cooling device 17 in the example shown in Fig. 1 is disposed on the upstream side of the lower side cooling device 16, but the arrangement position of the lower width direction control cooling device 17 is not limited to this. example.

If the lower width direction control cooling device 17 is disposed on the upstream side of the lower side cooling device 16 as shown in the example of Fig. 1, it can be removed from the hot rolled steel sheet 2 at the beginning of the cooling process. The uneven temperature distribution. On the other hand, if the lower width direction control cooling device 17 is disposed in the middle of the lower side cooling device 16, even if the cooling of the upper side cooling device 15 and the lower side cooling device 16 is uneven, the cooling may not be removed. Uniform temperature distribution caused by uniformity.

Further, if the lower width direction control cooling device 17 is disposed on the downstream side of the lower side cooling device 16, the uneven temperature distribution of the coiling temperature can be reduced.

Therefore, depending on the position of the lower side width direction of the lower side cooling device 16 to control the cooling device 17, the effect is different. Therefore, it is appropriate to determine the cost depending on the steel type and equipment cost. Just configure the location. Further, it is preferable to set the upstream, middle, and downstream of the lower side cooling device 16 based on the viewpoint of minimizing the uneven temperature distribution.

 [Second form]  

In the second aspect, the lower width direction control cooling device 117 is disposed in place of the lower width direction control cooling device 17 of the hot rolling facility 10, in which the cooling water traveling direction changing devices 126, 226, and 326 are disposed. Since the plate 125 is in place of the three-way valve 24 of the switching device of the first aspect, it has a drainage area, but does not have a drain head. The same configuration as in the first embodiment can be applied to the configuration of the other portions. Therefore, the same reference numerals are given to the same as in the first embodiment, and the description thereof will be omitted.

FIG. 17 and FIG. 18 are explanatory diagrams for explaining an example of a switching device including the cooling water traveling direction changing device 126 in the switching device according to the second aspect, which is disposed between the conveying rollers 18. The periphery of the cooling water nozzle 20 is shown as a focus.

The switching device of this example has a guide plate 125 and a cooling water traveling direction changing device 126.

The guide plate 125 is a plate-like member disposed between the intermediate head 21 and the divided cooling surface A3. The guide plate 125 is designed to have sufficient strength to withstand the extent to which the hot-rolled steel sheet 2 is not damaged by the front end of the hot-rolled steel sheet 2 when it travels through the sheet. The guide plates 125 are at least disposed between respective adjacent transport rollers 18. As a result, the front end of the hot-rolled steel sheet 2 at the time of traveling through the sheet can be prevented from being caught in the cooling water nozzle 20, the intermediate head 21, and the conveying roller 18.

Further, the guide plate 125 is provided with an injection port 125a through which the cooling water sprayed from the cooling water nozzle 20 passes when the gas is not ejected from the cooling water traveling direction changing means 126. In this way, the cooling water sprayed from the cooling water nozzle 20 can be caused to impinge on the divided cooling surface A3 by the guide plate 125 to perform appropriate cooling. Further, a drain hole through which the drain can pass can be provided in the guide plate 125.

The distance between the upper surface of the guide plate 125 and the divided cooling surface A3 is not particularly limited, and for example, it can be set to about 20 mm.

Further, the guide plate 125 has, in addition to the ejection opening 125a, a horizontal piece 125b which is formed in parallel with the rolling direction, and water blocking plates 125c and 125d which are provided downward from the lower surface of the horizontal piece 125b. The water flap 125c is provided on the side of the injection port 125a more than the water stop plate 125d.

The water deflectors 125c and 125d are used to prevent the cooling water sprayed from the cooling water nozzles 20 from impinging on the horizontal piece 125b and then splashing toward the side of the injection port 125a when the cooling water traveling direction changing means 126 injects the gas. . Further, the water-blocking plates 125c and 125d can also prevent the cooling water from the injection port 125a from being blown to the side of the steel sheet conveying area by the influence of the airflow of the injected gas, and impinging on the divided cooling surface A3.

Further, when the cooling water traveling direction changing means 126 is injecting gas, the water stop plate 125d can prevent the cooling water sprayed from the cooling water nozzle 20 from hitting the horizontal piece 125b and then splashing toward the side of the cooling water nozzle 20. Further, it also has a function of preventing it from interfering with the jet of cooling water sprayed from the cooling water nozzle 20. The water flap 125d is provided so as not to obstruct the flow of the cooling water jetted from the cooling water nozzle 20 and the gas flow of the gas injected from the cooling water traveling direction changing means 126.

When the length of the water-blocking plate 125c is too long, the cooling water jet directly impacts, and the amount of cooling water splashed from the injection port 125a toward the steel plate conveying area side increases. Therefore, it is set to 10 mm or more and 30 mm or less. The degree is appropriate.

On the other hand, the length of the water-blocking plate 125d is preferably set to a length sufficient to prevent the above-described interference phenomenon, and is preferably set to be 50 mm or more and 150 mm or less.

The cooling water traveling direction changing means 126 is means for injecting a gas from the cooling water sprayed from the cooling water nozzle 20 to change the traveling direction of the cooling water. The cooling water traveling direction changing device 126 includes a gas nozzle 127, a gas branch pipe 128, a valve 129, and a gas nozzle 130.

The gas ejected from the gas nozzle 130 can change the traveling direction of the cooling water ejected from the cooling water nozzle 20, whereby the cooling water can be controlled to be impacted and non-impacted on the divided cooling surface A3.

More specifically, the gas nozzles 130 are respectively connected to the gas head 127 via the gas branch pipe 128, and are supplied with a gas (for example, air) of a predetermined pressure from the gas head 127. A valve 129 is attached to the middle of the gas branch pipe 128.

Valve 129 controls gas nozzle 130 to initiate gas injection and stop gas injection based on signals from control unit 27. Such a valve is, for example, a solenoid valve. Further, for the cooling water nozzles 20 belonging to one divided cooling surface A3, the gas nozzles 130 are arranged in accordance with the number of the cooling water nozzles 20, so that the cooling water impact can be controlled for each of the divided cooling surfaces A3. The impact reaches the lower surface of the steel sheet conveying field.

The gas nozzle 130, as seen from Figs. 17 and 18, is disposed in the vicinity of the cooling water nozzle 20. The gas is ejected from the gas nozzle 130 at an angle inclined by 15 degrees or more and 30 degrees or less in the vertical direction, so that the traveling direction of the cooling water jet can be effectively changed as long as the gas flow rate is small.

The gas nozzle 130 is preferably a flat type gas nozzle which can form a fan-shaped jet which is less likely to be attenuated even if the distance from the nozzle is farther. At this time, if the diffusion angle of the fan-shaped jet jetted from the gas nozzle 130 is too large, the attenuation of the impact force when striking the jet of the cooling water becomes large, and therefore, it is preferable to adjust so that the jetted The fan-shaped jet just covers the entire width of the cooling water jet.

As shown in Fig. 17, when the valve 129 is closed and the gas is not ejected from the gas nozzle 130, the cooling water sprayed from the cooling water nozzle 20 is impacted to the split cooling surface A3 through the injection port 125a. The hot rolled steel sheet 2 can be cooled. Further, in Fig. 17, the flow direction of the cooling water sprayed from the cooling water nozzle 20 is indicated by a black triangular arrow indicated at the front end of the solid line.

On the other hand, Fig. 18 is a schematic view showing the same manner as in Fig. 17, showing a state in which gas is ejected from the gas nozzle 130. In Fig. 18, the flow direction of the gas ejected from the gas nozzle 130 is indicated by a black triangular arrow indicated at the leading end of the broken line.

As a specific aspect of the valve 129 being operated so as not to block the cooling water from hitting the split cooling surface A3, the cooling water can be made by changing the traveling direction of the cooling water jet flow. The jet of cooling water jetted from the nozzle 20 does not impinge on the split cooling surface A3.

The valve 129 is operated to receive a signal from the control device 27, whereby the gas from the gas nozzle 130 can be ejected toward the cooling water jet that is being ejected from the cooling water nozzle 20. As a result, the cooling water jet that is being ejected from the cooling water nozzle 20 will be redirected by the airflow to change direction. As a result, the cooling water will hit the lower surface of the guide plate 125, and therefore, the cooling water will not pass through the injection port 125a. In this way, the impact of the cooling water on the divided cooling surface A3 can be blocked, and the cooling of the hot-rolled steel sheet 2 can be stopped.

Here, the control of the switching device executed by the control device 27 can be similarly executed by the lower width direction control cooling device 17 of the first embodiment.

According to the present aspect, the cooling water that is blocked by the switching device and is prevented from being hit by the split cooling surface A3 does not hit the split cooling surface A3. Therefore, it is not necessary to separately prepare a container such as a bucket for recycling. The cooling water that divides the cooling surface A3 to impact is divided. Therefore, the switching device of the second aspect can be easily installed even in a narrow space between adjacent transport rollers 18.

In addition, the switching device of the second embodiment does not control the ON/OFF mode of the cooling water injection from the cooling water nozzle 20, but maintains a state in which a certain amount of cooling water is injected from the cooling water nozzle 20, and controls: The cooling water sprayed from the cooling water nozzle 20 is sprayed, and the hot-rolled steel sheet 2 is subjected to impact and non-impact. Further, as a control mechanism for controlling the impact of the cooling water jet and the non-impact, the mechanism for operating the shutter is not mechanically operated, but the cooling water traveling direction changing device 126 is turned ON/OFF. In a manner, the gas nozzle 130 is controlled to perform gas injection, thereby controlling the impact of the cooling water on the split cooling surface A3 and non-impact.

19 and 20 are diagrams schematically showing a part of the lower width direction control cooling device 117 according to the modification of the second embodiment. Fig. 19 is a view corresponding to Fig. 17, and Fig. 20 is a view corresponding to Fig. 18.

The lower width direction control cooling device 117 illustrated in Figs. 19 and 20 applies a switching device using the cooling water traveling direction changing device 226 instead of the cooling water traveling direction changing device 126 of the switching device. Therefore, the cooling water traveling direction changing device 226 will be described here.

The cooling water traveling direction changing device 226 includes a nozzle adapter 227 and a pneumatic cylinder 228. The nozzle adapter 227 is attached to the cooling water nozzle 20. Further, the nozzle adapter 227 is mounted to be rotatable about the fixed shaft 229. The fixed shaft 229 is fixed by a support member (not shown) so that the position does not shift. Further, the nozzle adapter 227 is rotatably coupled to the piston link 231 of the pneumatic cylinder 228 via the link front end shaft 230 and by the link front end shaft 230.

Therefore, by operating the pneumatic cylinder 228, the cooling water nozzle 20 can be tilted. In other words, in the posture of the cooling water nozzle 20 shown in Fig. 19, the cooling water can be sprayed upward in the vertical direction, and by operating the pneumatic cylinder 228, as shown in Fig. 20 The cooling water nozzle 20 is inclined at a predetermined angle with respect to the vertical direction.

The nozzle adapter 227 is attached to each of the cooling water nozzles 20, and the pneumatic cylinder 228 is attached to each of the nozzle adapters 227. The operation of the pneumatic cylinder 228 can be performed by a solenoid valve (not shown). The solenoid valve receives the signal from the control device 27 to open and close, whereby the direction of the cooling water nozzle 20 can be controlled via the pneumatic cylinder 228 to be oriented in the vertical direction as described above or in a direction oblique to the vertical direction. One of the poses.

As shown in Fig. 19, when the cooling water nozzle 20 is controlled to face the vertical direction, the cooling water jet will be impacted on the divided cooling surface A3 through the injection port 125a provided in the guide plate 125. On the other hand, as shown in Fig. 20, when the cooling water nozzle 20 is controlled to be inclined to the vertical direction, the direction of the jet of the cooling water jet will vary according to the inclination of the cooling water nozzle 20. Therefore, the cooling water is only impacted on the lower surface of the guide plate 125, and the split cooling surface A3 is not impacted.

Therefore, the electromagnetic valve receives the signal from the control device 27 to operate, thereby changing the posture of the cooling water nozzle 20, changing the direction of the cooling water being sprayed from the cooling water nozzle 20, and switching to: can be blocked The posture in which the cooling water is impinged on the divided cooling surface A3; and the posture in which the cooling water is impinged on the divided cooling surface A3 is not blocked.

Further, the intermediate head 21 and the nozzle adapter 227 are connected by a flexible pipe (for example, a rubber pipe or the like) 232, and even if the cooling water nozzle 20 is inclined as described above, it is also possible to have flexibility. The tube 232 is deformed to absorb the deviation of the relative position of the two.

The angle at which the cooling water nozzle 20 is tilted must be adjusted so that almost all of the cooling water jets impinge on the lower surface of the guide plate 125. On the other hand, in order to shorten the response time, it is preferable to set the inclination angle of the cooling water nozzle 20 to be smaller. Based on these viewpoints, it is preferable to design such that when the cooling water nozzle 20 is inclined by 5 degrees or more and 10 degrees or less with respect to the vertical direction, almost all of the cooling water jets are caused to impinge under the guide plate 125. surface.

21 and 22 are views schematically showing a part of the lower width direction control cooling device 117 according to another modification of the second aspect. Fig. 21 is a view corresponding to Fig. 17, and Fig. 22 is a view corresponding to Fig. 18.

In the switching device illustrated in FIGS. 21 and 22, the cooling water traveling direction changing device 326 is used instead of the cooling water traveling direction changing device 126. Therefore, the cooling water traveling direction changing device 326 will be described here.

The cooling water traveling direction changing device 326 includes a nozzle adapter 327, a pneumatic cylinder 328, and a jet deflecting plate 329. The nozzle adapter 327 is attached to the cooling water nozzle 20. Further, the jet deflecting plate 329 is attached to the nozzle adapter 327 so as to be rotatable around the rotating shaft 330. Further, the jet deflecting plate 329 is rotatably coupled to the piston link 332 of the pneumatic cylinder 328 via the link distal end shaft 331 and by the link distal end shaft 331.

Therefore, by actuating the pneumatic cylinder 328, the jet flow can be tilted toward the plate 329. That is, when in the posture of the jet flow deflecting plate 329 shown in Fig. 21, the jet deflecting plate 329 is located at a position that is incapable of impacting the cooling water sprayed from the cooling water nozzle 20, by actuating the pneumatic cylinder 328, The jet deflecting plate 329 can be inclined at a predetermined angle with respect to the vertical direction as shown in Fig. 22, so that the cooling water sprayed from the cooling water nozzle 20 can be caused to impinge on the jet deflecting plate 329.

The nozzle adapter 327 is attached to each of the cooling water nozzles 20, and the pneumatic cylinders 328 are attached to the respective nozzle adapters 327. The operation of the pneumatic cylinder 328 can be performed by a solenoid valve (not shown). The solenoid valve receives the signal from the control device 27 to open and close, whereby the direction in which the jet flow is deflected toward the plate 329 via the pneumatic cylinder 328 can be controlled to be in the vertical direction as described above or to be tilted in the vertical direction. One of the directions.

As shown in Fig. 21, if the jet deflecting plate 329 is controlled to be in the vertical direction, the jet of cooling water will impinge on the split cooling surface A3 through the injection port 125a provided in the guide plate 125. On the other hand, as shown in Fig. 22, if the jet deflecting plate 329 is controlled to be inclined in the vertical direction, the cooling water sprayed from the cooling water nozzle 20 will be bent by the jet deflecting plate 329. As a result, the direction of the jet of the cooling water jet changes, and thus impinges on the lower surface of the guide plate 125, so that the cooling water does not hit the split cooling surface A3.

In this manner, the solenoid valve receives the signal from the control unit 27 to actuate, thereby changing the posture of the jet deflecting plate 329, thereby changing the direction of the cooling water sprayed from the cooling water nozzle 20, and switching to: blocking the cooling water The posture of the split cooling surface A3 is impinged; and the posture in which the cooling water hits the split cooling surface A3 is not blocked.

The inclination angle of the jet deflecting plate 329 must be adjusted so that almost all of the cooling water jet impinges on the lower surface of the guide plate 125. On the other hand, in order to shorten the response time, it is preferable to set the inclination angle of the jet deflecting plate 329 as small as possible. Based on these viewpoints, it is preferable to design such that when the jet deflecting plate 329 is inclined by about 5 degrees to 10 degrees with respect to the vertical direction, the jet deflecting plate 329 can be used to change the direction to spray almost all of the cooling water. It is preferable to impinge on the lower surface of the guide plate 125.

The above is an example of a cooling water traveling direction changing device of three types. Among these three forms, if the direction of the cooling water jet is changed by injecting gas, it is not necessary to provide a mechanism such as a movable portion and a pneumatic cylinder. Therefore, compared with the conventional method, it is of course undoubted that even if it is compared with the above-described method of using the jet deflecting plate and the method of tilting the cooling water nozzle, the device can be miniaturized, so even a narrow space It can also be easily set up. Further, it is not necessary to provide a mechanism such as a movable portion and a pneumatic cylinder, and thus, it is more advantageous in terms of durability. On the other hand, it is also considered that the consumption of gas (air) may become unfavorable in terms of cost, but if the cooling water jet is completely blocked or the direction is largely changed as compared with the conventional method, The angle required to change the direction of the cooling water jet flow is only a small amount, so that the amount of gas (air) required can be greatly reduced as compared with the conventional method, and as a result, the air compressor can be reduced. Set up fees and operating costs.

In the case of using the above-described jet deflecting plate, it is only necessary to slightly change the direction of the cooling water jet flow, and the force applied to the jet deflecting plate is only 10 compared with the case where the cooling water jet is completely blocked or largely changed in direction. % to 20% (×sin θ times, θ is the angle of change of the direction of the cooling water jet). Therefore, the punching load that is repeatedly received can be greatly reduced, so that the strength required for the movable portion of the device can be reduced. In this way, the weight can be greatly reduced, the thrust required for the pneumatic cylinder can be reduced, and the required cylinder diameter can be reduced. It also reduces air consumption and therefore reduces operating costs. In addition, the punching load applied by the pneumatic cylinder during the reciprocating motion can be lightly reduced, and the durability can be greatly improved as compared with the conventional method.

In the above description of the second aspect, the direction of controlling the jet of the cooling water and the form of the non-impact divided cooling surface A3 are changed by changing the direction of the jet of the cooling water sprayed from the cooling water nozzle 20. . However, the second embodiment is not limited to this form, and may be, for example, moving the guide sheet in the rolling direction or changing the direction of the jet of the cooling water sprayed from the cooling water nozzle. The movement of the plates in the rolling direction is combined to control the impact of the cooling water jet and the non-impact to the split cooling surface.

Further, in the above description of the first aspect and the second aspect, the number of switching devices that can actuate to cause the cooling water to impinge on the divided cooling surface by using the control device is exemplified; The shape of the number of cooling water nozzles for the cooling water that divides the cooling surface of the second embodiment. However, the present invention is not limited to this embodiment, and in addition to controlling the number of switching devices and the number of cooling water nozzles, for example, a form of controlling the flow rate of the cooling water sprayed from the cooling water nozzle may be employed. The flow rate of the cooling water can be controlled using a flow regulating valve. In this case, the flow regulating valve can be placed between the intermediate head and the switching device.

If a spray nozzle is used as the cooling water nozzle, it is also possible to produce a structure in which the distance between the tip end of the spray nozzle and the steel sheet can be changed. In this way, the impact pressure of the cooling water jet that impacts the steel sheet can be controlled, so that the cooling temperature can be easily controlled.

 [Examples]  

Hereinafter, the effects of the present invention will be described with reference to examples and comparative examples. However, the invention is not limited to such an embodiment.

<Example 1>

In the verification effect, the lower width control cooling device 17 shown in Fig. 2 was used as the cooling device of the first embodiment. On the other hand, the cooling device of Comparative Example 1 does not use the lower width direction control cooling device 17, but uses the conventional lower side cooling device 16.

The conditions at the time of this verification are as follows.

The working conditions of Example 1 were set such that the steel sheet width was 1300 mm, the sheet thickness was 3.2 mm, the steel sheet conveying speed was 600 mpm, the temperature before cooling was 900 ° C, and the target coiling temperature was 550 °C. The lower width control cooling device uses the switching device of the first aspect. The apparatus shown in Fig. 4 has two intermediate heads in the rolling direction, and four cooling water nozzles are disposed in each of the intermediate heads. In contrast, in the first embodiment, the rolling direction is provided in the rolling direction. Four intermediate heads, each with two cooling water nozzles. The cooling length in the rolling direction was the same as in Fig. 4, and the distance between the conveying rollers of 8 parts was used, and the response speed including the three-way valve and the piping system was 0.2 second. Further, the water amount density of the sprayed cooling water was set to 2 m ³ /m ² /min. The installation position of the cooling device is controlled in the lower width direction, and is selected on the side close to the winding device (the downstream side of the lower cooling device).

On the other hand, in the working conditions of Comparative Example 1, there was no cooling control function in the sheet width direction, and the water amount density of the injected cooling water was set to 0.7 m ³ /m ² /min.

Fig. 23 is a view showing an example of taking out a part of the temperature distribution on the upper surface of the steel sheet of Comparative Example 1. In Fig. 23, in order to make the display of the temperature distribution easier to understand, in particular, only the distribution on the lower temperature side than the required temperature is displayed in a shading manner (the same applies to Fig. 24 shown later). The light-colored portion means a portion which is -30 ° C or more and -15 ° C or less in comparison with a desired temperature; and a thick black portion indicates a portion which is lower than -30 ° C as compared with a desired temperature. As can be seen from Fig. 23, in Comparative Example 1, a wide low temperature portion p was formed in the central portion in the sheet width direction. Further, the rib-shaped low temperature portions q1 and q2 extending in the rolling direction are also generated.

According to Comparative Example 1, the standard temperature deviation was 23.9 °C. The standard temperature deviation was obtained from the measurement results by the infrared temperature image measuring device, and the front end and the trailing end of the steel sheet were each removed by 10 m, and all the measurement points of the steel sheet temperature after 50 mm at both ends were removed.

Fig. 24 is a view showing an example of taking out a part of the temperature distribution on the upper surface of the steel sheet of Example 1. As can be seen from Fig. 24, in the first embodiment, each of the low temperature portions p, q1, and q2 is smaller than Comparative Example 1.

According to Example 1, the standard temperature deviation was 8.8 °C. Therefore, according to the present invention, it is understood that the temperature in the sheet width direction of the hot-rolled steel sheet can be uniformized (conformized).

<Example 2>

The working conditions were the same as in the first embodiment, and the cooling length in the rolling direction of the lower width direction control cooling device was the same as in the first embodiment, and the length of the distance between the conveying rollers of eight parts was employed. The lower width direction control cooling device is a switching device of the second aspect, and the cooling water traveling direction changing device is a cooling water traveling direction changing device 126. As shown in Fig. 10, one switching is performed on one divided cooling surface A3. Device. The response speed is 0.18 seconds. The amount of water of the sprayed cooling water was 2 m ³ /m ² /min. The installation position of the lower width direction control cooling device is provided on the side close to the winding device (the downstream side of the lower side cooling device).

According to Example 2, the temperature distribution on the entire steel sheet of the hot-rolled steel sheet after cooling was obtained in the same manner as in Fig. 24, and the standard temperature deviation was 8.6 °C.

Claims (16)

 A cooling device for a hot-rolled steel sheet, which is characterized in that, after the refining rolling in the hot rolling step, the cooling device for cooling the lower surface of the hot-rolled steel sheet conveyed on the conveying roller is characterized in that The entire field in the width direction of the lower surface of the steel sheet conveying field and the cooling field defined by the predetermined length in the rolling direction are regarded as the total cooling field, and the total cooling field is divided into plural numbers in the width direction of the aforementioned plate. a cooling zone obtained by dividing each of the cooling zones, that is, a cooling zone in the width direction; a cooling zone obtained by dividing the widthwise divided cooling zone into a plurality of the rolling directions, that is, dividing the cooling surface; At least one cooling water nozzle for injecting cooling water on each of the lower surfaces of the cooling surface; for switching the cooling water sprayed from the cooling water nozzle into an impact and non-impact switching device with the divided cooling surface; a width direction thermometer for temperature distribution in the width direction of the plate; controlling the foregoing according to the measurement result of the width direction thermometer described above Converting means actuating the control means.    The cooling device for hot-rolled steel sheets according to the first aspect of the invention, wherein the cooling water nozzles are provided with one or more corresponding cooling water nozzles for each of the divided cooling surfaces.    The cooling device for hot-rolled steel sheets according to the first or second aspect of the invention, wherein the number of the cooling water nozzles disposed in the two divided cooling surfaces adjacent to each other is in the rolling direction The upper lines are different from each other.    The cooling device for a hot-rolled steel sheet according to any one of the first aspect, wherein the divided cooling surfaces included in the widthwise divided cooling belt have respective rolling directions The lengths are different from each other in the rolling direction.    The cooling device for hot-rolled steel sheets according to any one of the first aspect, wherein the length of the divided cooling surface in the rolling direction is a multiple of the length between the conveying rollers.    The apparatus for cooling a hot-rolled steel sheet according to any one of the preceding claims, wherein the arrangement of the plurality of cooling water nozzles in the width direction of the sheet is configured to: The distances between the centers of the aforementioned cooling water nozzles adjacent in the plate width direction are all equal distances.    A cooling device for a hot-rolled steel sheet according to any one of the preceding claims, wherein the plurality of cooling water nozzles for cooling the same divided cooling surface are disposed, and The switching device system is configured to switch between a plurality of the cooling water nozzles of the same divided cooling surface and a cooling and non-impact switching control system for the same divided cooling surface, and simultaneously control.    The cooling device for a hot-rolled steel sheet according to any one of the first to seventh aspect, wherein the switching device includes: a cooling water that is supplied to the cooling water nozzle a water supply head for supplying cooling water; a drain head or a drainage area for draining the cooling water; and a flow direction between the water supply head and the drain head or the drainage area for switching the cooling water valve.    A cooling device for a hot-rolled steel sheet according to the invention of claim 8, wherein the valve is a three-way valve disposed on a side of a width direction of the conveying roller and is the same as the cooling water The front end of the nozzle is the same height.    The cooling device for a hot-rolled steel sheet according to any one of the above-mentioned claims, wherein the switching device includes a cooling water supplied to the cooling water nozzle. a water supply head for supplying cooling water; a drainage area for draining the cooling water; a mechanism for changing an injection direction of the cooling water sprayed from the cooling water nozzle; when the injection direction is changed, The blocking mechanism may be blocked so that the cooling water does not impinge on the divided cooling surface; and the switching may be performed by a mechanism for changing the spraying direction of the cooling water to cause the cooling water to perform the lower surface of the divided cooling surface Impact and non-impact.    The cooling device for a hot-rolled steel sheet according to any one of the preceding claims, wherein the width direction thermometer is provided on the upstream side of the rolling direction in the total cooling field and is rolled. At least one of the downstream sides of the direction is provided, and a cooling belt is provided in each of the aforementioned width directions.    The cooling device for hot-rolled steel sheets according to claim 11, wherein the width direction thermometer is disposed on a lower surface side of the steel sheet conveying field.    A method for cooling a hot-rolled steel sheet, which is a cooling method for cooling a lower surface of a hot-rolled steel sheet conveyed on a conveying roller after refining rolling in a hot rolling step, characterized in that the steel sheet is conveyed under the field The entire field in the width direction of the surface of the surface and the cooling area defined by the predetermined length in the rolling direction are regarded as the total cooling field; each cooling obtained by dividing the total cooling area into a plurality of the width direction of the aforementioned plate In the field, the cooling zone is divided as a width direction; the cooling zone obtained by dividing the widthwise divided cooling zone into a plurality of the rolling direction is used as a divided cooling surface; and the hot rolled steel sheet is measured in the width direction of the plate. The temperature distribution on the upper portion; the cooling water from the cooling water nozzle is controlled for the hot-rolled steel sheet for each of the divided cooling surfaces in the width direction of the sheet and in the rolling direction, respectively, according to the measurement result of the temperature distribution. Impact and non-impact.    The method for cooling a hot-rolled steel sheet according to claim 13, wherein the plurality of divided cooling surfaces are provided with a plurality of cooling water nozzles for spraying the cooling water, and the plurality of the cooling water nozzles are integrated The cooling water nozzles are simultaneously controlled: the impact of the cooling water from the plurality of cooling water nozzles on the hot-rolled steel sheets existing on the same divided cooling surface, and non-impact.    The method of cooling a hot-rolled steel sheet according to the above-mentioned item, wherein the cooling water supplied through the cooling water nozzle is provided to supply cooling water. a water supply head; a drain head or a drainage area for draining the cooling water; a valve for switching a flow direction of the cooling water between the water supply head and the drain head or the drainage area; according to the hot-rolled steel sheet The opening and closing of the valve is controlled as a result of measurement of the temperature distribution in the width direction of the sheet, and the cooling water is separately controlled in the width direction of the sheet and in the rolling direction for each of the divided cooling surfaces. The cooling water of the nozzle impacts and non-impacts on the aforementioned hot rolled steel sheet.    The method for cooling a hot-rolled steel sheet according to claim 15, wherein the valve is a three-way valve; and the cooling water of the cooling water nozzle is not used to cool the lower surface of the hot-rolled steel sheet. The water supply head controls the opening degree of the three-way valve so that the cooling water from the cooling water nozzle does not hit the lower surface of the hot-rolled steel sheet and continuously sprays water; The water supply head that cools the lower surface of the hot-rolled steel sheet by the cooling water from the cooling water nozzle controls the water surface by impinging the cooling water from the cooling water nozzle against the lower surface of the hot-rolled steel sheet. The opening of the three-way valve.