TWI445581B - Manufacturing apparatus of hot-rolled steel sheet and manufacturing method of hot-rolled steel sheet - Google Patents

Description

Manufacturing apparatus of hot rolled steel sheet and method of manufacturing hot rolled steel sheet

The present invention relates to a method for producing a hot-rolled steel sheet and a method for producing a hot-rolled steel sheet. More specifically, the steel sheet having a high temperature after being rolled by a hot-rolling finishing machine is sprayed with cooling water to water-cool the steel sheet. When the hot-rolled steel sheet is produced, the temperature of the steel sheet after the cooling is stopped can be accurately controlled.

The use of a steel material such as an automobile or a structural material is excellent in mechanical properties such as strength, workability, and toughness, and it is effective to comprehensively improve the mechanical properties and to refine the steel structure. Therefore, many methods for obtaining steel having fine texture have been explored. By the miniaturization of the structure, it is possible to obtain a high-strength hot-rolled steel sheet having excellent mechanical properties even if the amount of addition of the alloying elements is reduced.

It is known that as a method of miniaturizing a structure, in a particularly late stage of the hot rolling finishing treatment, rolling at a high rolling ratio is performed, the Worthfield iron particles are refined, and the rolling strain is accumulated on the steel sheet, thereby achieving: The fineness of the ferrite iron obtained after rolling. Further, from the viewpoint of suppressing the recrystallization or recovery of the Worthite iron and promoting the deformation of the ferrite and iron, it is effective to cool the steel sheet to 600 to 750 ° C in a short time as much as possible after rolling. That is to say, next to the hot rolling finishing, a cooling device which can be cooled more quickly than in a conventional manner is provided, and it is preferable to rapidly cool the rolled steel sheet. In order to rapidly cool the rolled steel sheet in this manner, in order to improve the cooling capacity, it is effective to increase the amount of cooling water per unit area of the steel sheet, that is, to increase the water density.

On the other hand, it is not necessary to rapidly cool as quickly as possible, and in order to achieve the desired metal structure, it is necessary to control the temperature of the steel sheet at the time of stopping the rapid cooling to a predetermined temperature in order to achieve the desired metal structure. Thereby, the desired steel sheet structure can be obtained, and the quality of the large number of steel sheets produced can be made more stable.

Here, the temperature at the time of rapid cooling is stopped, and the following is described as the rapid cooling stop temperature. The rapid cooling stop temperature is described in more detail below. The temperature distribution in the thickness direction of the steel sheet during rapid cooling is rapidly taken away by the rapid cooling to become a transition state in which the surface temperature is lower than the center temperature. When the rapid cooling is stopped in this state, the heat of the center portion is diffused to the surface portion and uniformized as time passes. The rapid cooling stop temperature is the temperature of the steel sheet in the state after the homogenization, and is substantially the same as the value of the surface temperature of the steel sheet measured by the radiation thermometer after a certain period of time has elapsed after the rapid cooling is stopped.

Patent Document 1 describes a method for producing a hot-rolled steel sheet, which is changed to another hot rolling condition different from a predetermined hot rolling condition during the hot rolling treatment, and the hot rolling treatment is continued, according to the other The hot rolling conditions and the measured values of the temperature of the steel sheet on the inlet side of the water-cooling device can be obtained by setting the winding temperature of the steel sheet as a target value, and determining the cooling conditions for the water-cooling device, and based on the other hot rolling conditions, The measured value of the temperature of the steel sheet on the inlet side of the water-cooling device is set by correcting the set value of the cooling condition of the water-cooling device. Thereby, the temperature of the steel sheet after rolling can be controlled to the target temperature.

Therefore, Patent Document 1 proposes a cooling method in which a rapid cooling device is provided on the outlet side of the hot rolling finishing machine, and a thermometer is provided between the finishing rolling mill and the rapid cooling device.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-246409

As described above, since the method of performing rapid cooling as soon as possible after the hot rolling finishing is effective, it is preferable to cool immediately after the work rolls of the final pedestal of the hot rolling finishing machine. That is, the cooling water is sprayed on the steel sheets existing inside the casing of the final pedestal of the hot rolling finishing machine to be cooled.

However, when this cooling is performed, the temperature of the steel sheet cannot be measured between the finishing rolling mill and the cooling device. Therefore, the control of the cooling water cannot be performed as described in Patent Document 1.

Therefore, the present invention has been made in view of the above problems, and an object of the invention is to provide a method for producing a hot-rolled steel sheet and a method for producing a hot-rolled steel sheet, which can be carried out even if a cooling device capable of cooling from a finishing rolling mill is disposed. Cooling control.

The following description is directed to the present invention. Although the symbols attached to the drawings are enclosed in parentheses for the sake of easy understanding, the present invention is not limited thereto.

The invention described in claim 1 is a manufacturing apparatus (10) for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine train (11); and a final pedestal (11g) disposed in the hot-rolling finishing machine train. An exit side, at least partially disposed in the final pedestal, an immediate rapid cooling device (20) capable of injecting cooling water, and a final pedestal inlet side temperature measuring device (45) configured to measure the surface temperature of the steel plate on the inlet side of the final pedestal a steel sheet speed measuring means (47) capable of measuring the speed of the steel sheet on the inlet side of the final pedestal; and the surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring means, and the steel sheet speed measuring means The rapid cooling stop temperature prediction device (51) for calculating the rapid cooling stop predicted temperature and the rapid cooling stop predicted temperature and the target rapidity by calculating the steel plate speed and the water supply amount or the water supply pressure of the rapid cooling device The immediate rapid cooling control device (52) for correcting the water supply amount or the water supply pressure of the rapid cooling device immediately after the cooling stop temperature is uniform.

The invention according to the second aspect of the invention is a method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus (10) for producing a hot-rolled steel sheet according to the first aspect of the invention, which will eventually The measured value of the steel sheet temperature on the inlet side of the pedestal (11g) is the initial value, and the rapid cooling stop predicted temperature is calculated based on the surface temperature of the steel sheet and the water supply amount of the rapid cooling device (20) or the water supply pressure, so that the rapid cooling is stopped. The predicted temperature is in accordance with the target rapid cooling stop temperature to correct the water supply amount or the water supply pressure of the immediately rapid cooling device.

The invention described in claim 3 is a manufacturing apparatus (10) for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine train (11); and a final pedestal (11g) disposed in the hot-rolling finishing machine train. An exit side, at least partially disposed in the final pedestal, an immediate rapid cooling device (20) capable of injecting cooling water, and a final pedestal inlet side temperature measuring device (45) configured to measure the surface temperature of the steel plate on the inlet side of the final pedestal An immediate rapid cooling device outlet side temperature measuring device (48) capable of measuring the surface temperature of the steel sheet on the outlet side of the rapid cooling device, and a steel plate speed measuring means capable of measuring the speed of the steel plate on the inlet side of the final pedestal (47); Calculated based on the surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, the steel sheet speed measured by the steel sheet speed measuring means, and the water supply amount or the water supply pressure of the rapid cooling device immediately a rapid cooling stop temperature predicting device (51) that rapidly stops the predicted temperature; and before the front end portion of the steel plate passes the immediate rapid cooling device, By correcting the rapid cooling stop predicted temperature and the target rapid cooling stop temperature, the water supply amount or the water supply pressure of the rapid cooling device is corrected immediately, and immediately after the rapid cooling device is passed through the front end portion of the steel plate, the rapid cooling is performed immediately. The immediate rapid cooling control device that corrects the water supply amount of the rapid cooling device, the water supply pressure, or the speed of the steel plate immediately after the target steel plate temperature measuring device matches the target rapid cooling stop temperature (52) .

The invention according to the fourth aspect of the invention is a method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus (10) for producing a hot-rolled steel sheet according to claim 3, in the steel sheet Before the front end portion passes the rapid cooling device (20), the steel plate temperature measurement value at the inlet side of the final pedestal (11g) is used as an initial value, and is calculated based on the surface temperature of the steel plate and the water supply amount or the water supply pressure of the rapid cooling device. The rapid cooling stops the predicted temperature so that the rapid cooling stop predicted temperature coincides with the target rapid cooling stop temperature to correct the water supply amount or the water supply pressure of the immediate rapid cooling device; after the front end portion of the steel plate passes the rapid cooling device immediately, The amount of water supply to the rapid cooling device, the water supply pressure, or the speed of the steel sheet is corrected so that the measured value of the rapid cooling device outlet side temperature measuring device (48) immediately matches the target rapid cooling stop temperature.

The invention according to claim 5 is an apparatus (110) for manufacturing a hot-rolled steel sheet, comprising: a hot-rolling finishing machine train (11); and a final pedestal (11g) disposed in the hot-rolling finishing machine train. An exit side, at least partially disposed in the final pedestal, an immediate rapid cooling device (20) capable of injecting cooling water; and a cooling device disposed closer to the outlet side than the immediate rapid cooling device, that is, a thermal cycle cooling device (40); a final pedestal inlet side temperature measuring device (45) that can measure the surface temperature of the steel sheet on the inlet side of the final pedestal; and a steel sheet speed measuring means (47) that can measure the speed of the steel sheet on the inlet side of the final pedestal; The surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, the steel sheet speed measured by the steel sheet speed measuring means, the water supply amount of the rapid cooling device, the water supply pressure, and the water supply amount of the thermal cycle cooling device. Calculating a rapid cooling stop predicted temperature and a winding predicted temperature, a rapid cooling stop temperature and a winding temperature predicting device (151); and stopping the rapid cooling The predicted temperature and the measured temperature is wound, the stop temperature and the coiling temperature uniform manner as rapidly cooling target, is corrected immediately or rapidly water supply water pressure of the cooling device immediately rapidly cooled thermocycler cum cooling control means (152).

The invention according to claim 6 is a method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus (110) for hot-rolled steel sheet according to claim 5, which will eventually The measured value of the steel sheet temperature on the inlet side of the pedestal (11g) is calculated as an initial value based on the surface temperature of the steel sheet, the water supply amount of the rapid cooling device (20), the water supply pressure, and the water supply amount of the thermal cycle cooling device (40). The rapid cooling stop predicted temperature and the predicted winding temperature are corrected so that the rapid cooling stop predicted temperature and the winding predicted temperature match the target rapid cooling stop temperature and the winding temperature, and the amount of water supplied to the rapid cooling device or The water supply pressure and the amount of water supplied to the thermal cycle cooling device are corrected.

The invention according to claim 7 is an apparatus (110) for manufacturing a hot-rolled steel sheet, comprising: a hot-rolling finishing machine train (11); and a final pedestal (11g) disposed in the hot-rolling finishing machine train. An exit side, at least partially disposed in the final pedestal, an immediate rapid cooling device (20) capable of injecting cooling water; and a cooling device disposed closer to the outlet side than the immediate rapid cooling device, that is, a thermal cycle cooling device (40); A final pedestal inlet side temperature measuring device (45) capable of measuring the surface temperature of the steel sheet on the inlet side of the final pedestal; and an immediate rapid cooling device outlet side temperature at which the surface temperature of the steel sheet on the outlet side of the rapid cooling device can be measured immediately a measuring device (48); a steel sheet speed measuring means (47) capable of measuring the speed of the steel sheet on the inlet side of the final pedestal; and a surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, by the steel plate The speed of the steel plate measured by the speed measuring means, the water supply amount of the rapid cooling device, the water supply pressure, and the water supply amount of the thermal cycle cooling device are calculated to calculate the urgency. a rapid cooling stop temperature and a winding temperature predicting device (151) for cooling the predicted temperature and the predicted winding temperature, and a rapid cooling stop predicted temperature and a predicted winding temperature before the tip end portion of the steel sheet is immediately passed through the rapid cooling device. Correction of the amount of water supplied to the rapid cooling device, the water supply pressure, and the amount of water supplied to the thermal cycle cooling device, in accordance with the target rapid cooling stop temperature and the winding temperature, and immediately after the rapid cooling device is passed through the front end portion of the steel plate. By immediately changing the temperature measured by the rapid cooling device outlet temperature measuring device to the target rapid cooling stop temperature, the water supply amount of the rapid cooling device, the water supply pressure, or the speed of the steel plate is corrected, and the winding prediction is made. The temperature is immediately synchronized with the target winding temperature, and the immediate rapid cooling and thermal cycle cooling control device (152) for correcting the water supply amount of the thermal cycle cooling device is corrected.

The invention according to claim 8 is a method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by a manufacturing apparatus (110) of the hot-rolled steel sheet according to claim 7, in the steel sheet Before the front end portion passes the rapid cooling device (20) immediately, the steel plate temperature measurement value at the inlet side of the final pedestal is used as an initial value, based on the surface temperature of the steel plate, and immediately the water supply amount of the rapid cooling device or the water supply pressure, and the thermal cycle cooling device. (40) The amount of the water supply is calculated, and the rapid cooling stop predicted temperature and the winding predicted temperature are calculated so that the rapid cooling stop predicted temperature and the winding predicted temperature are corrected in accordance with the target rapid cooling stop temperature and the winding temperature. Immediately, the water supply amount or the water supply pressure of the rapid cooling device is corrected, and the water supply amount of the thermal cycle cooling device is corrected; after the front end portion of the steel plate is immediately cooled by the rapid cooling device, the temperature is measured by the immediate cooling device outlet side temperature measuring device (48). The temperature of the rapid cooling device is corrected in the same manner as the target rapid cooling stop temperature. The amount of water, the water supply pressure, or the speed of the steel sheet is corrected, and the amount of water supplied to the heat cycle cooling device is corrected so that the winding predicted temperature coincides with the target winding temperature.

According to the apparatus for producing a hot-rolled steel sheet according to the present invention and the method for producing a hot-rolled steel sheet, even if a cooling device capable of cooling from the finishing rolling mill is disposed, high-precision cooling control of the steel sheet can be performed.

The above-described effects and advantages of the present invention will be understood from the description of the embodiments described below. Hereinafter, the present invention will be described based on the embodiments shown in the drawings. However, the invention is not limited by the embodiment.

1 is a conceptual diagram for explaining a manufacturing apparatus 10 (hereinafter referred to as "manufacturing apparatus 10") of the hot-rolled steel sheet according to the first embodiment. In Fig. 1, the steel sheet 1 is conveyed from the left side (upstream side, inlet side) to the right side (downstream side, outlet side) of the paper surface, and the paper surface is vertically oriented. Here, the passing line is shown by a broken line. The upstream side (inlet side) / downstream side (outlet side) direction is described as a passing direction, and the direction orthogonal to the direction of the steel plate which penetrated is the steel plate width direction. In the drawings, for the sake of easy viewing, the repeated reference numerals are omitted.

As shown in Fig. 1, the manufacturing apparatus 10 includes a hot rolling finishing machine array 11, conveying rollers 12, 12, ... a pinch roller 13, a winding device 14, an immediate rapid cooling device 20, and a thermal cycle cooling device. 40. Further, the manufacturing apparatus 10 is provided with a final pedestal inlet side temperature measuring device 45 and a plate thickness measuring device 46 on the inlet side of the final pedestal 11g of the hot rolling finishing machine row 11. In addition, the steel plate speed measuring means 47 is provided in the final pedestal 11g, and immediately after the pinch roller 13 is provided on the outlet side of the rapid cooling device 20, the immediate rapid cooling device outlet side temperature measuring device 48 is provided, and is wound. The device 14 is previously provided with a winding temperature measuring device 49 and has a cooling control device 50. Although the illustration and description are omitted, the hot-rolling finishing machine row 11 is placed closer to the inlet side, and a heating furnace, a rough rolling mill, or the like is disposed, and the conditions for entering the steel sheet of the hot rolling finishing machine row 11 are prepared. .

The hot rolled steel sheet is manufactured substantially in the following manner. That is, it is taken out from the heating furnace, rolled into a coarse bar of a predetermined thickness by a rough rolling mill, and rolled in a hot rolling finishing machine row 11 to a predetermined thickness. Then, it is rapidly cooled in the rapid cooling device 20 at once. At this time, the controlled cooling process is performed by the cooling control device 50. Then, it is cooled by the heat transfer cooling device 40 to a predetermined winding temperature by the pinch roller 13, and is wound into a coil shape by the winding device 14. The detailed manufacturing method will be described later.

The manufacturing device 10 will be described in detail below. Fig. 2 is a view showing an enlarged view of a portion in which the immediate rapid cooling device 20 is disposed in the first drawing. Fig. 2(a) is an enlarged view showing the entire immediate cooling device 20, and Fig. 2(b) is a view further focusing on the vicinity of the final pedestal 11g.

The hot rolling finishing machine row 11 is a rolling mill 11a, ..., 11f, 11g which are arranged in parallel along the passing direction. Each of the rolling mills 11a, ..., 11f, and 11g is a rolling mill that constitutes a so-called pedestal, and the rolling conditions such as the reduction ratio are set to meet the thickness, mechanical properties, surface quality, and the like required for the final product. conditions of. Here, the pressing ratio of each pedestal is set to match the performance of the steel plate to be manufactured. From the point of view of high-pressure rolling, the Worthfield iron particles are fined, and the rolling strain is accumulated in the steel sheet, and the ferrite iron particles obtained after rolling are finely refined, in the final pedestal. That is, the pedestal 11g must have a higher pressing ratio, that is, a lowering ratio of 15 to 50%, than the usual rolling.

Each of the rolling mills of the pedestal has a pair of work rolls 11aw, 11aw, ..., 11fw, 11fw, 11gw, 11gw which are actually pressed and pressed down, and one which is arranged such that the outer circumferences are in contact with each other of the work rolls Pair of support rolls 11ab, 11ab, ..., 11fb, 11fb, 11gb, 11gb. The rolling mill includes a work roll and a support roll on the inner side to form an outer casing of the rolling mill for supporting the casings 11ah, ..., 11fh, and 11gh of the rolling rolls. The casing has upright portions 11gr and 11gr that are opposed to each other, and the upright portions 11gr and 11gr are erected so as to sandwich the steel sheet 1 that passes through in the width direction of the steel sheet.

Here, the distance L1 between the axial center of the work roll 11gw indicated by L1 and the outlet side end surface of the housing upright portion 11gr in Fig. 2(a) is larger than the radius r1 of the work roll 11gw. Then, at a portion corresponding to the difference, that is, L1 - r1, a part of the cooling device 20 can be rapidly cooled as will be described later. That is, a part of the immediate rapid cooling device 20 can be disposed to be inserted inside the casing 11gh.

The conveyance rollers 12, 12, ... are roll sets in which the steel sheets 1 are conveyed in the passing direction.

The pinch roller 13 is also provided as a water removal function, and is provided on the outlet side of the immediate rapid cooling device 20. Thereby, it is possible to prevent the cooling water sprayed in the rapid cooling device 20 from flowing out toward the outlet side of the steel sheet 1. Further, the undulation of the steel sheet 1 on the rapid cooling device 20 is prevented immediately, and in particular, the penetration of the steel sheet 1 can be improved at a point before the front end of the steel sheet 1 is bitten into the winding device 14. Here, the upper roll 13a among the rolls of the pinch rolls 13 can be moved up and down as shown in Fig. 2(a).

The winding device 14 is a device that winds a rolled steel sheet into a coil shape. The winding device 14 can be applied to a conventional construction.

Immediately, as shown in Fig. 2 (a) and Fig. 2 (b), the rapid cooling device 20 is provided with upper water supply means 21, 21, ..., lower water supply means 22, 22, ..., upper guides 25, 25 , ..., and the following guides 30, 30, ....

The upper water supply means 21, 21, ... are means for supplying cooling water to the upper surface side of the steel sheet 1, and include cooling headers 21a, 21a, ...; and a plurality of rows provided in each of the cooling headers 21a, 21a, ... The ducts 21b, 21b, ...; and the cooling nozzles 21c, 21c, ... attached to the tips of the ducts 21b, 21b, ....

The cooling header 21a is a pipe extending in the width direction of the steel sheet, and the cooling headers 21a, 21a, ... are arranged side by side in the passing direction.

The ducts 21b, 21b, ... are a plurality of thin pipes which are branched from the respective cooling headers 21a, and the opening ends thereof face the upper surface side of the steel sheet 1. The ducts 21b, 21b, ... are disposed in the tube length direction of the cooling header 21a, that is, in the width direction of the steel sheet, and have a comb shape.

Cooling nozzles 21c, 21c, ... are attached to the tips of the respective ducts 21b, 21b, .... The cooling nozzles 21c and 21c of the present embodiment are flat type spray nozzles that can form a fan-shaped cooling water jet (for example, a thickness of about 5 mm to 30 mm). In the third and fourth figures, a schematic diagram of the cooling water jet formed on the surface of the steel sheet by the cooling nozzles 21c, 21c, ... is shown. Figure 3 is a perspective view. Fig. 4 is a view schematically showing an impact pattern when the jet collides against the surface of the steel sheet. In Fig. 4, the white circle shows the position immediately below the cooling nozzles 21c, 21c, ..., and the thick line shows the collision position and shape of the cooling water jet. In Figs. 3 and 4, the passing direction is displayed together with the sheet width direction. "..." in Fig. 4 means that the description of the white circle and the thick line is omitted for easy viewing.

In the present embodiment shown in FIGS. 3 and 4, the adjacent nozzle rows are arranged such that the positions of the cooling nozzles 21c, 21c, ... in the width direction of the steel sheet are shifted, and the adjacent nozzle rows are arranged. The cooling nozzles 21c, 21c, ... have the same position in the width direction of the steel sheet, and are arranged in a so-called staggered arrangement.

In the present embodiment, all the positions in the width direction of the steel sheet surface of the steel sheet surface are disposed so that the cooling nozzles 21c, 21c, ... are disposed so that the cooling water jet can pass through at least twice for one nozzle row. That is, the point ST of the steel plate that has passed through moves along the straight arrow of Fig. 4. At this time, in the nozzle row A twice (A1, A2), the nozzle row B twice (B1, B2), the nozzle row C twice (C1, C2) ..., in each nozzle column to be from the nozzle column The jet of the nozzle collided twice. Therefore, the cooling nozzles 21c, 21c, ... are arranged such that the interval P _W between the cooling nozzles 21c, 21c, ..., the collision width L of the cooling water jet, and the torsion angle β are established:

L=2P _W /cosβ

Relationship. Although the present embodiment is passed twice, it is not limited thereto, and it may be made to pass three times or more. From the viewpoint of achieving uniformity of cooling ability in the width direction of the steel sheet, the nozzle rows adjacent in the passing direction are twisted in opposite directions to each other in the nozzle nozzles 21c, 21c, ....

The "uniform cooling width" for the cooling of the steel sheet is determined by the arrangement of the nozzles. This represents the nature of the nozzle group that is arranged to allow the conveyed steel sheet to be uniformly cooled in the width direction of the steel sheet. Specifically, it is generally the same as the width of the largest steel sheet that can be manufactured in the steel plate manufacturing apparatus. Specifically, it is, for example, the size indicated by RH in Fig. 4 .

In the present embodiment, the adjacent nozzle rows have been described as being configured to twist the cooling nozzles 21c, 21c, ... in mutually opposite directions, and are not necessarily limited thereto, and may be all twisted in the same direction. Type. The torsion angle (the above-mentioned β) is not necessarily limited, and may be appropriately determined from the viewpoints of required cooling capacity, storage of equipment, and the like.

In the present embodiment, from the viewpoint of the above-described advantages, the nozzle rows adjacent in the passing direction are arranged in a staggered manner, and the present invention is not limited thereto, and the cooling nozzles may be arranged in a straight line in the passing direction. The type on the top.

The position where the upper water supply means 21 is provided, in particular, the position where the cooling nozzles 21c, 21c, ... are to be disposed, is not particularly limited, but is preferably arranged after the final pedestal 11g of the hot rolling finishing machine row 11 The inner side of the casing 11gh of the final pedestal 11g is as close as possible to the work roll 11gw of the final pedestal 11g. By disposing in this manner, the steel sheet 1 after the rolling performed by the hot rolling finishing machine row 11 can be rapidly cooled, and the front end portion of the steel sheet 1 can be stabilized and guided to the cooling device 20. In the present embodiment, as shown in Fig. 2, the cooling nozzles 21c, 21c, ... close to the work rolls 11gw are disposed close to the steel sheet 1.

Further, the injection direction of the cooling water sprayed from the cooling water injection ports of the respective cooling nozzles 21c, 21c, ... is substantially in the vertical direction, and on the other hand, the cooling nozzle closest to the work rolls 11gw and 11gw of the final pedestal 11g. The ejection of the cooling water by 21c, 21c, ..., 22c, 22c, ... is preferably in the direction of the work rolls 11gw and 11gw more in the vertical direction. Thereby, the time from the pressing of the steel sheet 1 to the final pedestal 11g to the start of cooling can be further shortened, and the time for returning the rolling strain accumulated by rolling can be made substantially zero. Thus, a steel sheet having a finer structure can be produced.

The water supply means 22, 22, ... are means for supplying cooling water to the lower surface side of the steel sheet 1, and include cooling headers 22a, 22a, ...; and a plurality of conduits 22b provided in the respective cooling headers 22a, 22a, ... 22b, ...; and cooling nozzles 22c, 22c, ... attached to the tips of the ducts 22b, 22b, .... The water supply means 22, 22, ... are disposed to face the above-described upper water supply means 21, 21, ..., and the cooling water is sprayed in the same direction, but is substantially the same as the upper water supply means 21, 21, ..., and thus the description thereof is omitted here. .

As shown in Fig. 3, when the water supply amount to the upper water supply means 21, 21, ... is corrected, the water supply amount adjusting means 21g provided at the water supply flow path 21e of the cooling headers 21a, 21a, ... receives The water supply amount correction command from the immediate rapid cooling control device 52 (refer to Fig. 1) corrects the appropriate water supply amount. When the water supply pressure is corrected, the water supply amount adjusting device 21g provided at the water supply flow path 21e toward the cooling headers 21a, 21a, ... receives the water supply pressure correction command from the immediate rapid cooling control device 52, by The water supply amount is corrected by the pressure value measured by the pressure sensor 21f attached to the cooling headers 21a, 21a, ..., in accordance with the pressure value of the next command, thereby correcting the appropriate water supply pressure.

On the other hand, when the water supply amount and the water supply pressure to the lower water supply means 22, 22, ... are corrected, they are also the same as the upper water supply means 21, 21, ....

Next, returning to Fig. 2, the above guides 25, 25, ... will be described. The upper guides 25, 25, ... are plate-shaped members disposed between the upper water supply means 21 and the conveyed steel plate 1, and are disposed such that when the front end of the steel plate 1 is passed, the front end of the steel plate 1 is not stuck. To the conduits 21b, 21b, ... or the cooling nozzles 21c, 21c. On the other hand, the upper guides 25, 25, ... are provided with inflow holes through which the jet flow from the upper water supply means 21 passes. Thereby, the jet flow from the upper water supply means 21 is passed through the upper guides 25, 25, ... to reach the upper surface of the steel sheet 1, and appropriate cooling can be performed. The shape of the upper guide 25 used herein is not particularly limited, and a conventional upper guide can be used.

The upper guides 25, 25, ... are arranged as shown in Fig. 2. In the present embodiment, three upper guides 25, 25, 25 are used, which are arranged side by side in the passing direction. Any of the upper guides 25, 25, 25 is disposed to correspond to the height direction position of the cooling nozzles 21c, 21c, .... That is, in the present embodiment, the upper guide 25 which is closest to the work roll 11gw of the final pedestal 11g is disposed so as to be inclined such that the end portion on the final pedestal 11g side is lower and the other end side is higher. The other two upper guides 25, 25 are arranged to have a predetermined spacing from the passing surface (through the line) and substantially parallel to the passing surface (through the line).

The lower guide 30 is a plate-shaped member disposed between the lower water supply means 22 and the steel sheet 1 to be conveyed. Thereby, it is possible to prevent, in particular, when the steel sheet 1 passes through the manufacturing apparatus 10, the foremost end of the steel sheet 1 is caught by the lower water supply means 22, 22, ... or the conveyance rollers 12, 12, . On the other hand, the lower guide 30 is provided with an inflow hole through which the jet flow from the lower water supply means 22 passes. Thereby, the jet flow from the lower water supply means 22 is passed through the lower guide 30 to reach the lower surface of the steel sheet 1, and appropriate cooling can be performed. The shape of the lower guide 30 used herein is not particularly limited, and a conventional lower guide can be used.

The lower guide 30 is arranged as shown in Fig. 2. In the present embodiment, four lower guides 30, 30, ... are used to be disposed between the respective conveyance rollers 12, 12, and 12. Any of the lower guides 30, 30, ... is disposed so as not to be too low in height with respect to the upper end portions of the conveyance rollers 12, 12, ....

In the present embodiment, an example in which the lower guide 30 is provided will be described, and the lower guide may not necessarily be provided.

In the supply of the cooling water as described above, the specific amount of the supplied water is appropriately determined depending on the cooling heat of the steel sheet required, and is not particularly limited. However, as described above, since the rapid cooling after rolling is effective from the viewpoint of the fineness of the steel sheet structure, it is preferable to supply the cooling water having a high water density. The water density of the supplied cooling water is, for example, 10 m ³ /(m ² ‧ minutes) to 25 m ³ /(m ² ‧ minutes) from the viewpoint of the fineness of the steel sheet structure described above. The water density can be used for a single side of the steel sheet with a larger water density. The cooling capacity is preferably 600 ° C / sec or more in a steel plate having a thickness of 3 mm.

Returning to Fig. 1, the description will be continued for the manufacturing apparatus 10. The thermal cycle cooling device 40 is a water-cooled cooling device disposed after the pinch roller 13, and is used to cool the steel sheet 1 to a winding temperature. Similarly to the immediate rapid cooling device 20, the thermal cycle cooling device 40 is provided with an upper water supply means and a lower water supply means, and is configured to cool the steel sheet 1 from both upper and lower surfaces.

The upper water supply means of the thermal cycle cooling device 40 is means for supplying cooling water to the upper surface side of the steel sheet 1. Here, a commonly used cooling means can be used. Here, for example, a tube layer cooling device is provided, which device is provided with a laminar flow nozzle.

The lower water supply means of the thermal cycle cooling device 40 is means for supplying cooling water to the lower surface side of the steel sheet 1, and a commonly used cooling means can be used here. Here, for example, a spray cooling device including a "tapered spray nozzle" for forming a conical jet is provided.

The final pedestal inlet side temperature measuring device 45 is used to measure the surface temperature of the steel sheet 1 on the inlet side of the final pedestal 11g of the hot rolling finishing machine row 11 as shown in Fig. 1 . In the manufacturing apparatus 10 of the present embodiment as shown in Fig. 1, one final pedestal inlet side temperature measuring device 45 is provided on the upper surface side or the lower surface side of the steel sheet, and a plurality of final pedestal inlet side temperature measuring units may be provided. Device. At this time, one of them is placed on the top and the other is preferably placed below. As a result, the initial value of the temperature distribution in the thickness direction of the plate used for the rapid cooling stop temperature prediction described later can be asymmetrically distributed, and the prediction can be improved with high accuracy.

The final pedestal inlet side temperature measuring device 45 may be any type of device as long as it can measure the surface temperature of the steel sheet 1, and is not limited to a specific type of structure. In the present embodiment, it is considered that it is possible to use cooling water between the pedestals of the finishing rolling mill train 11, and it is preferable to use a so-called water column thermometer in order to measure the measurement error caused by the cooling water sprayed here. The water-column thermometer is known as a radiation thermometer disposed at a position facing the steel sheet 1 and used between the steel sheet 1 and the radiation thermometer, as disclosed in Japanese Laid-Open Patent Publication No. 2006-010130. A water column forming means is formed as a water-hydraulic column of the optical waveguide. By detecting the emitted light from the surface of the steel sheet 1 by the radiation thermometer through the water column, the surface temperature of the steel sheet 1 can be measured with high accuracy.

The measurement results of the surface temperature of the steel sheet 1 by the pedestal inlet side temperature measuring device 45 are input to the cooling control device 50 to be described later.

The plate thickness measuring device 46, as shown in Fig. 1, is in hot rolling finishing The inlet side of the final pedestal 11g of the row 11 is used to measure the thickness of the steel sheet 1. The plate thickness measuring device 46 may be any type of device as long as it can measure the thickness of the steel plate 1, and is not limited to a specific type device. However, considering that the thickness of the steel sheet 1 is less than 30 mm, an X-ray thickness gauge is suitable from the viewpoint of measurement accuracy of the thickness range and the like.

The measurement result of the plate thickness of the steel plate 1 by the plate thickness measuring device 46 is input to the cooling control device 50 mentioned later.

As shown in Fig. 1, the steel sheet speed measuring means 47 is provided in the final pedestal 11g of the hot rolling finishing machine row 11, and measures the speed of the steel sheet 1 on the inlet side of the final pedestal 11g. The steel sheet speed measuring means 47 may be any structure as long as it can measure the speed of the steel sheet 1. In the present embodiment, the speed of the steel sheet 1 is obtained by multiplying the forward slip by the peripheral speeds of the work rolls 11gw and 11gw. The result of measuring the speed of the steel sheet 1 by the steel sheet speed measuring means 47 is input to the cooling control device 50 which will be described later.

The rapid cooling device outlet side temperature measuring device 48 is a device for measuring the temperature of the steel sheet immediately on the outlet side of the rapid cooling device 20, and the winding temperature measuring device 49 is a device for measuring the temperature of the steel sheet before the winding device 14. The immediate rapid cooling device outlet side temperature measuring device 48 and the winding temperature measuring device 49 may be any type of sensor as long as it is a device capable of measuring the surface temperature of the steel sheet 1, and is not limited to a specific type device.

The cooling control device 50 has a structure including a rapid cooling stop temperature prediction device 51 and an immediate rapid cooling control device 52.

The rapid cooling stop temperature prediction device 51 is based on the measured value (FT') of the surface temperature of the steel sheet 1 input from the final pedestal inlet side temperature measuring device 45 on the inlet side of the final pedestal 11g, and from the plate thickness measuring device 46. The measured value of the plate thickness of the input steel sheet 1 and the measured value of the conveyance speed of the steel sheet 1 input from the steel sheet speed measuring means 47 include rapid cooling by the rapid cooling device 20 using the heat conduction model of the steel sheet 1. The prediction calculation of the rapid cooling stop temperature is performed to obtain the rapid cooling stop predicted temperature. A detailed example of the contents of the calculation performed here will be described in detail later.

Immediately after the rapid cooling control device 52 reaches the final pedestal inlet side temperature measuring device 45 until reaching the immediate rapid cooling device outlet side temperature measuring device 48, that is, immediately after the front end of the steel plate 1 passes rapidly Immediately before the cooling device 20, the cooling control device 52 is rapidly cooled, and it is determined whether or not the target rapid cooling stop temperature is equal to the rapid cooling stop predicted temperature calculated by the rapid cooling stop temperature predicting device 51, and if not, Then, the amount of cooling water of the rapid cooling device 20 is controlled immediately.

After the front end of the steel sheet 1 has reached the immediate rapid cooling device outlet side temperature measuring device 48, that is, the front end of the steel sheet 1 passes through the rapid cooling device 20 immediately, so that the target rapid cooling stop temperature and the immediate rapid cooling device outlet are provided. At least one of the cooling water amount and the steel sheet speed of the rapid cooling device 20 is controlled so that the measured temperatures of the side temperature measuring devices 48 match.

By the manufacturing apparatus 10 having the above configuration, it is possible to manufacture a hot-rolled steel sheet having a predetermined structure which is controlled to a desired rapid cooling stop temperature.

Next, an example of a method of manufacturing a hot-rolled steel sheet using the manufacturing apparatus 10 will be described. The amount of water supply to the rapid cooling device 20 is changed immediately, and the rapid cooling stop predicted temperature coincides with the target rapid cooling stop temperature.

The surface temperature, the plate thickness, and the speed of the steel sheet 1 on the inlet side of the final pedestal 11g reaching the hot rolling finishing machine row 11 are determined by the final pedestal inlet side temperature measuring device 45, the plate thickness measuring device 46, and the steel plate speed. Determined by means 47. The rapid cooling stop temperature predicting device 51 calculates the inlet side temperature of the final pedestal 11g from the temperature, the plate thickness, the speed, the specific heat of the steel sheet, the density, and the like by the equation (1). The equation (1) is the temperature drop amount ΔT ₁ from the final pedestal inlet side temperature measuring device 45 to the final pedestal 11g, which is caused by air cooling.

[Mathematical formula 1]

Here, σ is the Stefan Boltzmann constant (W/m ² ‧K ⁴ ), ε is the emissivity of the steel sheet 1, c is the specific heat of the steel sheet 1 (J/kg‧K), and ρ is the steel sheet 1 Density (kg/m ³ ), h1 is the plate thickness (m) before the final pedestal 11g, and α _A is the thermal conductivity (W/m ² ‧K) due to air cooling. T _S1 is the surface temperature (° C.) of the steel sheet 1 in this section, and T _A is the temperature (° C.). t ₁ is the time (seconds) through which the interval passes.

Next, the temperature at the exit side of the rolling stand is calculated from the temperature of the work roll 11gw of the final pedestal 11g, the contact time with the work roll 11gw, the rolling torque, and the like by the equations (2) and (3). The equation (2) is the temperature drop amount ΔT ₂ due to the contact between the steel sheet 1 of the final pedestal 11g and the work roll 11gw.

[Mathematical formula 2]

Here, c is the specific heat (J/kg‧K) of the steel sheet 1, ρ is the density (kg/m ³ ) of the steel sheet 1, and λ is the thermal conductivity (w/m‧K) of the steel sheet 1. h ₂ is the plate thickness (m) after the final pedestal 11g, t _R is the time (s) at which the steel sheet 1 is in contact with the work roll 11gw of the final pedestal 11g, and T _S2 is the surface temperature of the steel sheet 1 in contact with the work roll 11gw ( °C), and T _R is the temperature of the work roll 11gw.

On the other hand, the equation (3) is an expression indicating the temperature increase amount ΔT ₃ due to the rolling of the final pedestal 11g.

[Mathematical expression 3]

Here, c is the specific heat of the steel sheet 1 (J/kg‧K), ρ is the density (kg/m ³ ) of the steel sheet 1, η is the processing heat efficiency, and G is the rolling torque (N‧ m). r is the diameter (m) of the work roll 11 gw, w is the plate width (m) of the steel plate, and h ₂ is the plate thickness (m) after the final pedestal 11 g.

Next, from the temperature of the outlet side of the final pedestal 11g, the temperature immediately before the rapid cooling of the apparatus 20 is predicted. At this time, it is necessary to set the amount of cooling water of the rapid cooling device 20 at once. Therefore, specifically, temperature prediction is performed as follows. In other words, the amount of water supplied from all the headers 21a, 21a, ..., 22a, 22a, ... of the rapid cooling device 20 is tentatively set to the minimum amount of water including zero (air-cooling), and the formula (4), Sub-(5) is performed: the temperature prediction calculation of the steel sheet from the final pedestal exit to the immediate rapid cooling device 20. The equation (4) is the temperature drop amount ΔT _4L due to water cooling, and the equation (5) is the temperature drop amount ΔT _4A due to air cooling.

[Mathematical formula 4]

[Mathematical expression 5]

Here, σ is the Stefan Boltzmann constant (W/m ² ‧K ⁴ ), ε is the emissivity (-) of the steel sheet 1, and c is the specific heat of the steel sheet 1 (J/kg‧K), ρ is The density of the steel sheet 1 (kg/m ³ ). α _A is the thermal conductivity (W/m ² ‧ K) of the air-cooling portion, α _R is the thermal conductivity (W/m ² ‧ K) due to the water cooling of the rapid cooling device 20, and h ₂ is the plate after the final pedestal 11 g Thickness (m). T _S4L is the surface temperature (° C.) of the steel sheet 1 in the water-cooled portion of the rapid cooling device 20 immediately, and T _S4A is the surface temperature (° C.) of the steel sheet 1 in the air-cooled portion of the rapid cooling device 20 immediately, and T _A is the temperature (° C.). , T _L is the cooling water temperature (°C). t _4L is the time (seconds) at which the rapid cooling device 20 immediately passes through the water-cooling portion, and t _4A is the time (seconds) at which the rapid cooling device 20 passes through the air-cooled portion immediately.

In the temperature prediction value obtained by the rapid cooling device 20 obtained in this manner, the amount of cooling water that matches the target rapid cooling stop temperature is obtained using a convergence calculation means such as a dichotomy. The amount of cooling water calculated by the rapid cooling stop temperature predicting device 51 is sent to the immediate rapid cooling control device 52, and the immediate rapid cooling device 20 issues a command for letting the obtained set water amount flow out.

As a method of matching the temperature of the steel sheet 1 immediately after the passage of the rapid cooling device 20 with the target rapid cooling stop temperature, in addition to adjusting the amount of cooling water, the same effect can be obtained by adjusting the water supply pressure to the immediate rapid cooling device 20.

According to the above method, the amount of cooling water or the water supply pressure of the rapid cooling device 20 can be appropriately adjusted so that the rapid cooling stop predicted temperature predicted by the rapid cooling stop temperature predicting device 51 and the target rapid cooling stop temperature are matched. The rapid cooling stop temperature is controlled with high precision.

After the tip end of the steel sheet 1 reaches the immediate rapid cooling device outlet side temperature measuring device 48, the target rapid cooling stop temperature is immediately synchronized with the measured temperature of the rapid cooling device outlet side temperature measuring device 48, and the cooling control device is immediately cooled. By performing the feedback control of the amount of cooling water or the water supply pressure of the rapid cooling device 20, the rapid cooling stop predicted temperature predicted by the rapid cooling stop temperature predicting device 51 can be corrected to cover the steel plate. The rapid cooling stop temperature is controlled over a full length of 1 and with high precision.

In the above-described example, by adjusting the amount of cooling water or the water supply pressure of the rapid cooling device 20 immediately, the rapid cooling stop predicted temperature coincides with the target temperature, and the cooling water amount or the water supply pressure of the rapid cooling device 20 is immediately controlled to be constant. The rapid cooling stop temperature can also be controlled by adjusting the rolling speed. Since the response characteristics of the rolling motor for adjusting the rolling speed are higher than those of the valve which adjusts the cooling capacity of the cooling device in general, the rolling speed of the rolling speed is high, so the method of adjusting the rolling speed is stopped for rapid cooling. The temperature control performance is better. However, in order to adjust the rolling speed, it is necessary to adjust the rolling speeds of all the hot rolling finishing machines 11 together, and the ease of the rolling technique is high.

In the method of adjusting the amount of cooling water, the method of adjusting the rolling speed by immediately increasing the amount of cooling water of the rapid cooling device 20 after the front end of the steel sheet reaches the immediate rapid cooling device outlet side temperature measuring device 48 is described. The rolling speed is feedback-controlled so that the measured temperature of the immediately rapid cooling device outlet-side temperature measuring device 48 coincides with the target rapid cooling stop temperature. Specifically, if the measured temperature is higher than the target, the rolling speed is adjusted toward the low speed side, and if it is lower, it is adjusted toward the high speed side.

Fig. 5 is a conceptual view for explaining a manufacturing apparatus 110 (hereinafter referred to as "manufacturing apparatus 110") of the hot-rolled steel sheet according to the second embodiment, and is a view corresponding to the first drawing. In the manufacturing apparatus 110, the cooling control apparatus 150 is different from the manufacturing apparatus 10, and other structures are common, and the same reference numerals are given to the common structures, and the description thereof is omitted.

The cooling control device 150 is configured to include a rapid cooling stop temperature and winding temperature prediction device 151, and an immediate rapid cooling and thermal cycle cooling control device 152.

The rapid cooling stop temperature and the winding temperature prediction device 151 is based on the measured value (FT') of the surface temperature of the steel sheet 1 input from the final pedestal inlet side temperature measuring device 45 on the inlet side of the final pedestal 11g, and the plate thickness measuring device. The measurement value of the plate thickness of the steel plate 1 input from the steel plate 1 and the measured value of the conveyance speed of the steel plate 1 input from the steel plate speed measuring means 47 are performed, and the rapid cooling device 20 and the thermal cycle cooling using the heat conduction model of the steel plate 1 are performed. Each of the predicted values is obtained by predictive calculation of the rapid cooling stop temperature and the winding temperature by the device 40. An example of the operation content will be described in detail later.

Immediately after the rapid cooling and thermal cycle cooling control device 152, from the front end of the steel sheet 1 to the final pedestal inlet side temperature measuring device 45 until the immediate rapid cooling device outlet side temperature measuring device 48 is reached, the immediate rapid cooling and thermal cycle The cooling control device 152 determines whether the target rapid cooling stop temperature and the rapid cooling stop predicted temperature calculated by the rapid cooling stop temperature and the winding temperature prediction device 151 match each other, and if they do not match, the control is immediately performed. The amount of cooling water of the rapid cooling device 20. Immediately after the tip end of the steel sheet 1 reaches the immediate rapid cooling device outlet side temperature measuring device 48, the target rapid cooling stop temperature is given and the measured temperature of the rapid cooling device outlet side temperature measuring device 48 is immediately matched. The amount of cooling water of the rapid cooling device 20 and/or the speed of the steel sheet 1.

Immediately after the front end of the steel sheet 1 reaches the winding temperature measuring device 49, the immediate rapid cooling and hot cycle cooling control device 152 determines the target winding temperature to be given. Whether or not the winding predicted temperature calculated by the rapid cooling stop temperature and winding temperature prediction device 151 coincides, and if not, controls the amount of cooling water of the thermal cycle cooling device 40. After the leading end of the steel sheet 1 reaches the winding temperature measuring device 49, the amount of cooling water of the thermal cycle cooling device 40 is controlled so that the target winding temperature is set to match the measured temperature of the winding temperature measuring sensor 49. At least one of the speeds of the steel sheets 1.

By the manufacturing apparatus 110 having the above configuration, the desired rapid cooling stop temperature and the winding temperature are controlled, and a hot-rolled steel sheet having a predetermined structure can be produced.

Next, an example of a method of manufacturing a hot-rolled steel sheet using the manufacturing apparatus 110 will be described. In this example, the amount of water supply to the rapid cooling device 20 and the thermal cycle cooling device 40 is changed, and the rapid cooling stop predicted temperature and the predicted winding temperature are matched to the target rapid cooling stop temperature and the target winding temperature, respectively.

The surface temperature, the plate thickness, and the speed of the steel sheet 1 reaching the inlet side of the final pedestal 11g are measured by the final pedestal inlet side temperature measuring device 45, the plate thickness measuring device 46, and the steel sheet speed measuring means 47, respectively. The rapid cooling stop temperature and winding temperature prediction device 151 calculates the inlet side temperature of the final pedestal 11g based on the temperature, the plate thickness, the speed, and the like by the above formula (1).

Next, the temperature at the exit side of the rolling stand is calculated from the work roll temperature of the final pedestal 11g, the contact time with the roll, the rolling torque, and the like by the above equations (2) and (3).

Next, from the temperature of the outlet side of the final pedestal 11g, the temperature immediately before the rapid cooling of the apparatus 20 is predicted. At this time, it is necessary to set the amount of cooling water of the rapid cooling device 20 at once. Therefore, specifically, temperature prediction is performed as follows. In other words, the amount of water supplied from all the headers 21a, 21a, ..., 22a, 22a, ... of the rapid cooling device 20 is tentatively set to the minimum amount of water including zero (air cooling), and the above formula (4) is used. The equation (5) is performed by calculating the temperature of the steel sheet 1 from the final pedestal outlet to the immediately rapid cooling device 20.

In the temperature prediction value obtained by the rapid cooling device 20 obtained in this manner, the amount of cooling water that matches the target rapid cooling stop temperature is obtained using a convergence calculation means such as a dichotomy. The amount of cooling water calculated by the rapid cooling stop temperature and the winding temperature prediction device 151 is sent to the immediate rapid cooling and thermal cycle cooling control device 152, and the immediate cooling device 20 is issued with a command to cause the determined set water amount to flow out. .

As a method of matching the temperature of the steel sheet 1 immediately after the passage of the rapid cooling device 20 with the target rapid cooling stop temperature, in addition to adjusting the amount of cooling water, the same effect can be obtained by adjusting the water supply pressure to the immediate rapid cooling device 20.

In the present embodiment, the temperature before passing through the thermal cycle cooling device 40 is predicted from the measured temperature of the rapid cooling device outlet side temperature measuring device 48. At this time, it is necessary to set the amount of cooling water of the thermal cycle cooling device 40. First, the amount of water supplied from all the cooling headers in the thermal cycle cooling device 40 is tentatively set to the minimum amount of water including zero water (air cooling), and is performed using equations (6) and (7): from immediately The rapid cooling device outlet side temperature measuring device 48 calculates the temperature of the steel sheet 1 through the thermal cycle cooling device 40. The equation (6) is the temperature drop amount ΔT _5L due to water cooling, and the equation (7) is the temperature drop amount ΔT _5A due to air cooling.

[Mathematical expression 6)

[Mathematical expression 7]

Here, σ is the Stefan Boltzmann constant (W/m ² ‧K ⁴ ), ε is the emissivity (-) of the steel sheet 1, and c is the specific heat of the steel sheet 1 (J/kg‧K), ρ is The density of the steel sheet 1 (kg/m ³ ). α _A is the thermal conductivity (W/m ² ‧ K) of the air-cooling portion, α _L is the thermal conductivity (W/m ² ‧ K) due to water cooling of the thermal cycle cooling device 40, and h ₂ is the plate after the final pedestal 11 g Thickness (m). T _S5L is the surface temperature (° C.) of the steel sheet in the water-cooled portion of the thermal cycle cooling device 40, T _S5A is the surface temperature (° C.) of the steel sheet 1 in the air-cooled portion of the thermal cycle cooling device 40, and T _A is the temperature (° C.), T _L is the cooling water temperature (°C). t _5L is the time (seconds) at which the thermal cycle cooling device 40 passes through the water-cooled portion, and t _5A is the time (seconds) at which the thermal cycle cooling device 40 passes through the air-cooled portion.

Then, the temperature predicted value after the passage of the thermal cycle cooling device 40 is calculated, and the amount of cooling water of the thermal cycle cooling device 40 is obtained by using a convergence calculation means such as a dichotomy to match the target winding temperature. The amount of cooling water of the thermal cycle cooling device 40 calculated by the rapid cooling stop temperature and winding temperature prediction device 151 is sent to the immediate rapid cooling and thermal cycle cooling control device 152, and the thermal cycle cooling device 40 is issued. The instruction to set the amount of water flowing out.

By appropriately adjusting the amount of cooling water of the rapid cooling device 20 and the amount of cooling water of the thermal cycle cooling device 40 by the above method, the rapid cooling stop temperature and the winding temperature can be controlled with high precision.

Immediately after the front end of the steel sheet 1 reaches the rapid-cooling device outlet-side temperature measuring device 48, the chilling and cooling cycle control device 152 is rapidly cooled to allow the target rapid cooling stop temperature and the rapid-cooling device exit-side temperature measuring device 48. The method of measuring the temperature uniformity is performed: the feedback control of the amount of cooling water of the rapid cooling device 20 is immediately performed. After the leading end of the steel sheet 1 reaches the winding temperature measuring device 49, the hot and cold cycle cooling control device 152 is rapidly cooled to heat the target winding temperature in accordance with the measured temperature of the winding temperature measuring device 49. The amount of cooling water of the cooling device 40 is subjected to feedback control. With this, even if the rapid cooling stop temperature predicted by the rapid cooling stop temperature/winding temperature prediction device 151 and the predicted temperature of the winding predicted temperature are predicted, the full length of the steel sheet 1 can be covered and the rapid cooling stop temperature can be controlled with high accuracy. And winding temperature.

As described in the first embodiment, in the present embodiment, the amount of cooling water of the rapid cooling device 20 is made constant, and by adjusting the rolling speed, the measurement of the immediate cooling device outlet side temperature measuring device 48 can be performed. The rapid cooling stop temperature is controlled in such a manner that the temperature coincides with the target rapid cooling stop temperature.

In this case, if the rolling speed is controlled by feedback so that the measured temperature of the rapid cooling device outlet side temperature measuring device 48 coincides with the target temperature, the winding temperature is changed by changing the rolling speed. Then, the amount of cooling water of the thermal cycle cooling device 40 is fed back and forth by the rapid cooling and thermal cycle cooling control device 152 so that the measured temperature of the winding temperature measuring device 49 coincides with the target winding temperature.

The present invention is described with respect to the presently-executed and preferred embodiments, and the present invention is not limited to the embodiments disclosed in the specification, and is not inconsistent with the scope of the invention and The range of the idea can be appropriately changed, and the manufacturing apparatus of the hot-rolled steel sheet and the method of manufacturing the hot-rolled steel sheet accompanying the change must also be understood as being included in the technical scope of the present invention.

1. . . Steel plate

10. . . Hot rolled steel sheet manufacturing apparatus

11. . . Hot rolling finishing machine

11g. . . Final pedestal

11gh. . . case

11gr. . . (housing) standing portion (side wall)

11gw. . . Work roll

12. . . Transport roller

13. . . Pinch roller

14. . . Winding device

20. . . Immediate rapid cooling device

twenty one. . . Above water supply means

21a. . . Cooling header

21b. . . catheter

21c. . . Cooling nozzle

twenty two. . . Water supply means below

22a. . . Cooling header

22b. . . catheter

22c. . . Cooling nozzle

25. . . Upper guide

30. . . Following guide

40. . . Thermal cycle cooling device

45. . . Final pedestal inlet side temperature measuring device

46. . . Plate thickness measuring device

47. . . Steel plate speed measuring means

48. . . Immediate rapid cooling device outlet side temperature measuring device

49. . . Winding temperature measuring device

50. . . Cooling control device

51. . . Rapid cooling stop temperature prediction device

52. . . Immediately rapid cooling control

110. . . Manufacturing equipment for hot-rolled steel sheets (measurement method for steel sheet speed)

150. . . Cooling control device

151. . . Rapid cooling stop temperature and winding temperature prediction device

152. . . Immediate rapid cooling and thermal cycle cooling control device

Fig. 1 is a view schematically showing a part of a manufacturing apparatus of a hot-rolled steel sheet according to the first embodiment.

Fig. 2 is a view showing an enlarged view of a portion in which an immediate rapid cooling device is disposed in the first drawing. Fig. 2(a) is a view showing the entire rapid cooling device, and Fig. 2(b) is a view focusing on the vicinity of the final pedestal.

Fig. 3 is a perspective view for explaining a cooling nozzle of an immediate rapid cooling device.

Fig. 4 is a view for explaining the arrangement of the cooling nozzles of the immediate rapid cooling device.

Fig. 5 is a view schematically showing a part of a manufacturing apparatus of a hot-rolled steel sheet according to a second embodiment.

1. . . Steel plate

10. . . Hot rolled steel sheet manufacturing apparatus

11. . . Hot rolling finishing machine

11a,...,11f. . . Rolling mill

11g. . . Final pedestal

11aw, 11aw, ..., 11fw, 11fw. . . Work roll

11ab, 11ab, ..., 11fb, 11fb. . . Support roller

11ah,...,11fh. . . case

11gh. . . case

12. . . Transport roller

13. . . Pinch roller

14. . . Winding device

20. . . Immediate rapid cooling device

40. . . Thermal cycle cooling device

45. . . Final pedestal inlet side temperature measuring device

46. . . Plate thickness measuring device

47. . . Steel plate speed measuring means

48. . . Immediate rapid cooling device outlet side temperature measuring device

49. . . Winding temperature measuring device

50. . . Cooling control device

51. . . Rapid cooling stop temperature prediction device

52. . . Immediately rapid cooling control

Claims (8)

A manufacturing apparatus for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine row; disposed at an outlet side of a final pedestal of the hot-rolling finishing machine row, at least partially disposed in the final pedestal, and capable of spraying cooling water immediately a rapid cooling device; a final pedestal inlet side temperature measuring device capable of measuring a surface temperature of the steel plate on the inlet side of the final pedestal; and a steel plate speed measuring means capable of measuring a speed of the steel plate on the inlet side of the final pedestal; The surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, the steel sheet speed measured by the steel sheet speed measuring means, and the water supply amount or the water supply pressure of the immediate rapid cooling device are calculated. The rapid cooling stop temperature prediction device that rapidly stops the predicted temperature; and corrects the immediate water supply amount or the water supply pressure immediately after the rapid cooling stop predicted temperature matches the target rapid cooling stop temperature. Cooling control unit. A method for producing a hot-rolled steel sheet is a method for producing a hot-rolled steel sheet by the apparatus for producing a hot-rolled steel sheet according to the first aspect of the invention, and the steel sheet temperature measurement value at the inlet side of the final pedestal is used as an initial value. The rapid cooling stop predicted temperature is calculated based on the surface temperature of the steel sheet and the water supply amount or the water supply pressure of the immediate rapid cooling device, so that the rapid cooling stop predicted temperature matches the target rapid cooling stop temperature. Correct the water supply or water supply pressure of the above-mentioned immediate rapid cooling device. A manufacturing apparatus for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine row; disposed at an outlet side of a final pedestal of the hot-rolling finishing machine row, at least partially disposed in the final pedestal, and capable of spraying cooling water immediately a rapid cooling device; a final pedestal inlet side temperature measuring device capable of measuring the surface temperature of the steel sheet on the inlet side of the final pedestal; and an immediate rapid cooling device configured to measure the surface temperature of the steel plate on the outlet side of the immediate rapid cooling device An exit side temperature measuring device; a steel sheet speed measuring means capable of measuring a speed of the steel sheet on the inlet side of the final pedestal; and a surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, a rapid cooling stop temperature predicting device that calculates a rapid cooling stop predicted temperature by the steel plate speed measured by the steel plate speed measuring means, and the water supply amount or the water supply pressure of the immediate rapid cooling device, and the immediate end portion of the steel plate Before the rapid cooling device, to make the above rapid cooling The amount of water supply or the water supply pressure of the immediate rapid cooling device is corrected so that the predicted temperature is equal to the target rapid cooling stop temperature, and the immediately preceding rapid cooling device is passed through the front end portion of the steel plate so as to be immediately idling The instantaneous rapid cooling control device that corrects the water supply amount of the rapid cooling device, the water supply pressure, or the speed of the steel plate immediately after the temperature measured by the cooling device outlet temperature measuring device matches the target rapid cooling stop temperature. A method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus for producing a hot-rolled steel sheet according to the third aspect of the invention, wherein the end portion of the steel sheet is passed through the immediate rapid cooling device The measured value of the steel sheet temperature on the inlet side of the pedestal is an initial value, and the predicted cooling cooling stop predicted temperature is calculated based on the surface temperature of the steel sheet and the water supply amount or the water supply pressure of the immediate rapid cooling device, so that the rapid cooling stop predicted temperature is set. Correcting the water supply amount or the water supply pressure of the immediate rapid cooling device in accordance with the target rapid cooling stop temperature; and passing the immediate rapid cooling device at the front end portion of the steel plate to cause the immediate rapid cooling device to exit The measured value of the side temperature measuring device corrects the water supply amount, the water supply pressure, or the speed of the steel sheet of the immediate rapid cooling device so as to match the target rapid cooling stop temperature. A manufacturing apparatus for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine row; disposed at an outlet side of a final pedestal of the hot-rolling finishing machine row, at least partially disposed in the final pedestal, and capable of spraying cooling water immediately a rapid cooling device; a cooling device disposed closer to the outlet side than the immediate rapid cooling device, that is, a thermal cycle cooling device; and a final pedestal inlet side temperature measuring device configured to measure a surface temperature of the steel plate on the inlet side of the final pedestal; a steel sheet speed measuring means capable of measuring the speed of the steel sheet on the inlet side of the final pedestal; and measuring the surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device by the steel sheet speed measuring means The rapid steel plate speed, the water supply amount of the rapid cooling device, the water supply pressure, and the water supply amount of the thermal cycle cooling device, and the rapid cooling stop temperature and the winding temperature prediction device for calculating the rapid cooling stop predicted temperature and the winding predicted temperature And stopping the predicted temperature and winding with the above rapid cooling The measured temperature, and the stop temperature and the coiling temperature consistent manner as the targets of the rapid cooling, rapid cooling apparatus immediately corrected amount of water or water pressure immediately rapidly cooling the cooling control means cum thermocycler. A method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus for producing a hot-rolled steel sheet according to the fifth aspect of the invention, wherein the steel sheet temperature measurement value at the inlet side of the final pedestal is an initial value. The rapid cooling stop predicted temperature and the winding predicted temperature are calculated based on the surface temperature of the steel sheet, the water supply amount of the immediate rapid cooling device, the water supply pressure, and the water supply amount of the thermal cycle cooling device, so that the rapid cooling stop is stopped. The predicted temperature and the predicted winding temperature are corrected so as to match the target rapid cooling stop temperature and the winding temperature, and the water supply amount or the water supply pressure of the immediate rapid cooling device is corrected, and the water supply amount of the thermal cycle cooling device is corrected. . A manufacturing apparatus for a hot-rolled steel sheet, comprising: a hot-rolling finishing machine row; disposed at an outlet side of a final pedestal of the hot-rolling finishing machine row, at least partially disposed in the final pedestal, and capable of spraying cooling water immediately a rapid cooling device; a cooling device disposed closer to the outlet side than the immediate rapid cooling device, that is, a thermal cycle cooling device; and a final pedestal inlet side temperature measuring device configured to measure a surface temperature of the steel plate on the inlet side of the final pedestal; An immediate rapid cooling device outlet-side temperature measuring device capable of measuring the surface temperature of the steel sheet on the outlet side of the immediate rapid cooling device; a steel plate speed measuring device capable of measuring the speed of the steel plate on the inlet side of the final pedestal; The surface temperature of the steel sheet measured by the final pedestal inlet side temperature measuring device, the steel sheet speed measured by the steel sheet speed measuring means, the water supply amount of the immediate rapid cooling device or the water supply pressure, and the above-described thermal cycle cooling device The amount of water supplied to calculate the rapid cooling stop prediction And a rapid cooling stop temperature and winding temperature prediction device for predicting the temperature of the winding; and the target of the rapid cooling stop prediction temperature and the winding prediction temperature before the front end portion of the steel sheet passes through the immediate rapid cooling device The rapid cooling stop temperature and the winding temperature are the same, and the water supply amount or the water supply pressure of the immediate rapid cooling device and the water supply amount of the thermal cycle cooling device are corrected; after the steel plate front end portion passes the immediate rapid cooling device, Correcting the water supply amount, the water supply pressure, or the speed of the steel sheet of the immediate rapid cooling device so that the temperature measured by the immediate rapid cooling device outlet side temperature measuring device matches the target rapid cooling stop temperature, and The immediate cooling cooling and thermal cycle cooling control device that corrects the water supply amount of the thermal cycle cooling device is adjusted so as to match the target winding temperature. A method for producing a hot-rolled steel sheet, which is a method for producing a hot-rolled steel sheet by the apparatus for producing a hot-rolled steel sheet according to claim 7, wherein the final portion of the steel sheet is passed through the immediate rapid cooling device The steel plate temperature measurement value on the inlet side of the pedestal is used as an initial value, and the rapid cooling stop prediction is calculated based on the surface temperature of the steel sheet, the water supply amount of the immediate rapid cooling device, the water supply pressure, and the water supply amount of the thermal cycle cooling device. The temperature and the predicted winding temperature are such that the rapid cooling stop predicted temperature and the predicted winding temperature are corrected so as to match the target rapid cooling stop temperature and the winding temperature, and the water supply amount of the immediate rapid cooling device or The water supply pressure is corrected, and the water supply amount of the heat cycle cooling device is corrected; after the front end portion of the steel sheet passes through the immediate rapid cooling device, the temperature measured by the immediate rapid cooling device outlet side temperature measuring device is used as the target Rapid cooling stop temperature consistent way The water supply amount of the immediate rapid cooling device, the water supply pressure, or the speed of the steel sheet is corrected, and the water supply amount of the heat cycle cooling device is corrected so that the predetermined winding temperature matches the target winding temperature.