JP3294138B2 - Hot rolling equipment and hot rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling equipment and a hot rolling method for thick plates and strips, and more particularly, to preventing narrowing of a rear end portion of a strip when rolling a thin strip. It was done.

[0002]

2. Description of the Related Art In a general strip hot rolling mill, a heating device (heating furnace) is provided downstream of a lump mill or a casting device (for example, a continuous slab casting device), and a heating furnace is provided at an outlet line of the heating furnace. There is provided a reverse type rough rolling mill in which slabs are continuously rough-rolled to make steel strips (sheet bars). On the downstream side of the rough rolling mill, a finishing rolling mill for finish rolling the roughly rolled strip is continuously arranged, and on the downstream side of the finishing rolling mill, a strip (finished strip) that has been finish-rolled and cooled. Is disposed in a coil form. As the finish rolling mill, a tandem rolling mill in which a plurality of rolling mills (for example, 7 stands) are arranged, or a reversible rolling mill having a coiler furnace on the front surface and the rear surface with a rolling roll interposed therebetween is used.

In a continuous casting apparatus, for example, a thickness of 250 mm and a width of 18
After the slab of 00 mm is discharged and cut into a predetermined length, the slab is heated and kept in a heating furnace. The slab that has exited the heating furnace is rolled to a thickness of 30 mm to 50 mm in multiple stages (e.g., 6 stages) by reverse rolling by a roughing mill to form a steel strip and sent to a finishing mill. In the finishing mill, the strip is rolled to a thickness of about 1.2 mm by rolling in multiple stages or rolling multiple times.
It is wound on a winder through a cooling run-out table.

[0004]

In the above-mentioned hot rolling equipment, when a finishing mill in which a plurality of stands of rolling mills are arranged is used, the rear end portion of the steel strip has a plurality of stands of finishing mills. When rolling through any of the rolling mills, the rear end meanders in the width direction of the strip because the steel strip is fed at a high speed, and the steel sheet is broken by a collision with a side guide, etc.
A so-called narrowing occurs. In particular, when the rolling mill on the subsequent stage where the sheet thickness becomes thinner passes through, the narrowing of the steel strip is likely to occur due to the low rigidity of the steel strip. Is reduced, so that narrowing is likely to occur. When rolling is performed by biting the rear end portion of the strip that has been drawn, the rolling roll of the rolling mill is flawed, and the rolling roll may be cracked or broken. For this reason, when the rolling roll has a flaw, it is necessary to immediately change the rolling roll assembly, and the number of times of reassembling per hour increases, thereby increasing the downtime of the apparatus.

In recent years, high-speed rolls using high-speed tool steel as a material for the roll surface have been used for the rolls of finishing mills in order to extend the life of the rolls and reduce the number of refills per hour. ing. But,
Since high-speed rolls have large thermal expansion and cause meandering of the steel strip, narrowing is more likely to occur,
High speed rolls are expensive and develop quickly when cracks occur. For this reason, at present, it is not possible to use a high-speed roll as the final roll of the finish rolling mill.

[0006] Even when a reversible rolling mill having a coiler furnace on the front surface and the rear surface with a rolling roll interposed therebetween is used, if the steel strip is rolled and thinned, the rear end portion has a front coiler furnace. If the pinch roll or the rear-side coiler furnace pinch roll passes through the tail, the rear end portion meanders in the width direction of the sheet, and narrowing is likely to occur. Therefore, the same problem as in the case where a finishing mill in which a plurality of rolling mills are arranged in a row is used.

[0007] In the hot rolling equipment for thick plates, the reversing rolling mill of one or two reversible rolling mills is not provided until the occurrence of narrowing as in the hot rolling equipment for steel strips. When the part is removed, the rear end of the thick plate is not restrained as in the finish rolling mill of the strip hot rolling equipment, so that the rear end of the thick plate meanders in the width direction. As a result, there is a problem that the high-speed roll having a large thermal expansion and causing the meandering of the thick plate cannot be further used.

The present invention has been made in view of the above circumstances, and provides a hot rolling equipment and a hot rolling method capable of preventing the occurrence of meandering at the rear end of a rolled material without affecting the sheet thickness. The purpose is to do.

[0009]

In order to achieve the above object, a hot rolling apparatus according to the present invention comprises a light rolling mill for lightly reducing the steel strip by driving a reduction driving means to an outlet side of a finishing mill. The machine is arranged, and comprises a load detection means for detecting the load of the light reduction roll when the steel strip is rolled down, based on the detection information of the load detection means, so that the load of the light reduction roll is constant. Control means for controlling the driving of the screw-down driving means to adjust the screw-down force of the light pressure-roller is provided.

In order to achieve the above object, the hot rolling equipment of the present invention comprises a heating device for heating a slab cast by a casting device, and rough-rolls the slab heated by the heating device. A rough rolling mill is formed downstream of the heating device, and a rolling mill having a plurality of stands is arranged in a row to finish-roll the rough-rolled strip to a predetermined thickness. A downstream mill is disposed downstream of the rough rolling mill, and a downcoiler for winding the strip steel that has been subjected to finish rolling into a coil is disposed downstream of the finishing rolling mill, and among the rolling mills of the finishing rolling mill, A light reduction rolling mill provided with a pair of light reduction rolls for lightly reducing the strip by driving the reduction drive means on the exit side of the rolling roll of the final stand rolling mill is arranged when the strip is reduced. Load for detecting the load of the light reduction roll Control means for controlling the driving of the screw-down driving means to adjust the rolling force of the light-rolling roll so that the load of the light-rolling roll becomes constant based on the detection information of the load-detecting means. It is characterized by having.

[0011] While the steel strip that has been subjected to hot rough rolling is lightly reduced by a light reduction rolling mill on the exit side of a rolling roll of a final stand rolling mill, hot finishing is sequentially performed to a required plate thickness by a plurality of rolling mills. To roll. When the rear end of the strip passes through the rolling roll of the rolling mill in front of the final stand, the strip is sandwiched between the rolling roll of the final stand rolling mill and the light rolling roll to prevent the occurrence of drawing. . The rolling force of the light rolling roll is controlled based on the detection information of the load detecting means so that the load is constant, and does not affect the thickness of the strip.

In order to achieve the above object, the hot rolling equipment of the present invention comprises a heating device for heating a slab cast by a casting device, and rough-rolls the slab heated by the heating device. A rough rolling mill is formed on the downstream side of the heating device to form a strip, and the reversible finish rolling mill for finishing rolling to a predetermined thickness by reciprocating the rough-rolled strip is passed several times. Arranged downstream of the reversible finishing mill, a downcoiler arranged downstream of the reversible finishing mill is disposed on the downstream side of the reversible finishing mill, and a down coiler for winding the strip-rolled steel strip in a coil shape is disposed downstream of the rolling mill. A light reduction rolling mill for lightly reducing the strip by a pair of light reduction rolls by driving the reduction drive means is provided, and a load detection means for detecting a load of the light reduction roll when the strip is reduced is provided. , Detection of the load detecting means Distribution load of the soft reduction rolls is characterized by comprising a control means for adjusting the rolling force of the control to the soft reduction rolls the driving of the pressure driving means to be constant on the basis of.

The hot rough-rolled strip is hot finish-rolled while being lightly reduced by a light reduction rolling mill downstream of a rolling roll of a reversible finishing mill, and the strip is reciprocated through a plurality of times. Finish rolling to a predetermined thickness. When the rear end of the steel strip falls off, the steel strip is sandwiched between two rolls of a reversible finishing mill and a light reduction roll to prevent the narrowing. The rolling force of the light rolling roll is controlled based on the detection information of the load detecting means so that the load becomes constant, and does not affect the thickness of the strip.

In order to achieve the above object, the hot rolling equipment according to the present invention comprises a reversible type in which a slab heated in a heating furnace is reciprocated a plurality of times to finish-roll a slab having a predetermined thickness. A finish rolling mill is provided, and a light reduction rolling mill for lightly reducing the strip by a pair of light reduction rolls is arranged on the downstream side of the rolling roll of the reversible finishing rolling mill by driving a reduction driving means, Load detecting means for detecting the load of the light pressure roll when the pressure reduction is performed, and controlling the driving of the pressure driving means such that the load of the light pressure roll becomes constant based on the detection information of the load detection means. And a control means for adjusting the rolling force of the light rolling roll.

In order to achieve the above object, a hot rolling facility according to the present invention comprises a shear for cutting a slab having a thickness of 100 mm or less manufactured by a medium or thin slab continuous casting apparatus into a predetermined length. A heating furnace for heating the cut slab, a finishing mill in which a plurality of stands of rolling mills are arranged in a row, and the heated slab is finish-rolled into a steel strip having a predetermined thickness. A down coiler that winds the strip in a coil form, and a light rolling mill that is disposed downstream of the rolling rolls of the reversible finishing rolling mill and that drives the reduction driving means to lightly reduce the strip by a pair of light reduction rolls. Load detecting means for detecting the load of the light reduction roll when the steel strip is reduced, and the reduction driving means such that the load of the light reduction roll is constant based on the detection information of the load detection means. No drive Control to the is characterized in that a control means for adjusting the rolling force of the soft reduction rolls.

In the hot rolling equipment according to the present invention, the control means stores the target load of the light reduction roll and compares the target load with the actual load detected by the load detection means. And a function of controlling the driving of the screw-down driving means so as to adjust the screw-down force of the light screw-down roll so that the actual load becomes the target load.

The hot rolling method of the present invention for achieving the above object is a hot rolling method for finish rolling a slab heated by a heating device into a rolled material having a predetermined thickness.
The rolled material is lightly reduced with a constant load by a pair of light reduction rolls on the downstream side of the rolling rolls of the finishing mill.

[0018]

FIG. 1 is a side view of a schematic configuration of a hot rolling facility according to a first embodiment of the present invention, and FIG. 2 is a finishing mill having a plurality of rolling mills arranged in a row. FIG. 3 shows a side cross-sectional state of the final stand of the finishing mill.
FIG. 4 shows a state viewed from the line IV-IV in FIG.

As shown in FIG. 1, a slab 2 manufactured by a continuous casting device (not shown) is heated and kept in a heating furnace 6. A reverse type rough rolling mill R ₁ , R ₂ , R ₃ is provided continuously to the outlet line of the heating furnace 6.
A finishing mill F is provided continuously to the outlet lines of R ₁ , R ₂ and R ₃ . A cooling device 7 is provided continuously to the finishing mill F,
The strip 14 finished and rolled by the finishing mill F is cooled by the cooling device 7.
And then wound up in a coil shape by the winder 8.

As shown in FIGS. 1 and 2, the finishing mill F
Is a rolling mill F ₁ having a plurality of stands (seven stands in the illustrated example).
To F ₆ are arrayed, with rolling rolls (work rolls) 11 soft reduction rolling mill 13 on the exit side a pair of soft reduction rolls 12 made of ceramics of the rolling mill F ₆ is the final stand are arranged I have. Since the light pressure roll 12 is made of ceramic, the influence of heat on the steel strip 14 can be eliminated. It should be noted that the material of the light pressure roll 12 is not limited to ceramic, and other materials such as carbon steel can be used.

As shown in FIG. 3, the work roll 11 of the rolling mill F ₇ and the light rolling roll 12 of the light rolling mill 13 are supported by a common housing 15. That is, the work roll 11 is supported by the housing 15 via the work roll chock 16, and a rolling-down force acts on the work roll 11 by the backup roll 17. The backup roll 17 is supported by the housing 15 via a backup roll chock 18, and the upper backup roll chock 18 is supported by the housing 15 via a rolling-down cylinder 19. A load cell 25 is provided between the lower backup roll chock 18 and the housing 15, and the load of the work roll 11 is detected by the load cell 25.

A pair of light pressure rolls 12 are supported on the housing 15 via a light pressure roll chock 20. The upper light pressure roll chock 20 is supported by the housing 15 via a light pressure cylinder 21 as a pressure drive means. I have. In addition, a load cell 22 as a load detecting means is provided between the lower light pressure roll chock 20 and the housing 15. When the light reduction cylinder 21 is driven, the strip 14 is lightly reduced on the exit side of the work roll 11 by the light reduction roll 12.
The load 2 is detected by the load cell 22.

As shown in FIG. 4, the left and right light pressure roll chocks 20 have light pressure reduction cylinders 21 and load cells 22.
Are provided. The detection information of the left and right load cells 22 is input to a control device 23 as a control means, and the left and right light pressure reduction cylinders 21 are controlled by the control device 23 via a servo valve 24 connected to a hydraulic pressure source.
2 are independently driven so that the load of the second is constant.

A rolling method using the above-mentioned hot rolling equipment will be described. From the thick slab continuous casting apparatus 1, for example, the thickness 25
A slab 2 having a width of 0 mm and a width of 1800 mm is discharged, cut into a predetermined length by a plate cutting device 5, and then heated and maintained in a heating furnace 6. The slab 2 coming out of the heating furnace 6 is subjected to rough rolling mills R ₁ , R
_{In the} reverse rolling by ₂ , for example, it is sequentially rolled in 6 stages
It is made into a 35 mm steel strip 14 and sent to a finishing mill F. The strip 14 sent to rough rolled by the finishing mill F, finishing mill work rolls 11 of the rolling mill F ₇ is the last stand of the F
While being lightly reduced by a pair of light reduction rolls 12 on the output side,
It is the thickness of the rolling mill F ₁ to F 7 phase rolling for example 1.2mm in by ₇ of the finishing rolling mill F. The steel strip 14 rolled to a predetermined thickness is sent to a winder 8 through a cooling run-out table 7, and is wound around a coil by the winder 8.

[0025] Therefore, when the rear end portion of the strip 14 is the work roll 11 of the rolling mill F ₅ short of the final stand was Shirinuke,
Strip 14 at two positions of the work rolls 11 and soft reduction rolls 12 of the rolling mill F ₇ of the final stand is held. As a result, the rear end of the steel strip 14 having a thickness of 1.2 mm does not meander, and the occurrence of narrowing can be prevented. For this reason, there is no possibility that the work roll 11 will be scratched, and the work roll 11 will not be cracked or broken, and the number of work roll assembly replacements per time can be reduced to reduce the downtime of the apparatus. . In addition, since there is no possibility that the work roll 11 may be damaged, it is possible to use a high-speed roll for the work roll 11 of the final rolling mill of the finishing mill F, thereby further reducing downtime.

In the above-described hot rolling equipment, a rolling mill
Load output side of the soft reduction rolls 12 of the work roll 11 of the F ₇ are detected lateral independently by the load cell 22, the detection information (the actual load value) of the load cell 22 is input to the control unit 23. The control device 23 compares the target load value with the load value detected by the load cell 22. If the actual load value is large, the servo valve 24 reduces the light reduction force.
The right and left light reduction cylinders 21 are driven via the servo valve 24 so that the light reduction force is increased when the actual load value is small. That is, the load of the light reduction roll 12 is controlled to be always constant at the load target value for each of the left and right sides.

[0027] Thus, the thickness of the finishing mill F of the final stand in a rolling mill F ₇ is to a predetermined thickness using a steel band 14, without having to change the soft reduction of the soft reduction rolls 12, light It is possible to eliminate the influence of the pressing roll 12 on the thickness accuracy. Further, since the left and right soft reduction cylinder 21 is driven independently, even if the thickness in the width direction of the rolling mill F ₇ strip 14 is rolled in a different, soft reduction rolls 12 in accordance with the thickness The light reduction force is adjusted, and there is no possibility that the light reduction rolling mill 13 may meander.

In the above-mentioned hot rolling equipment, the strip steel 14 subjected to the hot rough rolling is applied to the rolling mill at the final stand of the finishing mill F.
While being soft reduction by exit side of the soft reduction rolling mill 13 of the rolling rolls 11 of the F _7, it is finish rolling between successive heat required thickness by the rolling mill F ₁ to F ₇ of a plurality of stands. Then, when the rear end portion of the strip 14 has Shirinuke rolling rolls 11 of the rolling mill F ₅ in front of the final stand, strip rolling roll 11 of the rolling mill F ₇ of the final stand and at two places in soft reduction rolls 12 Steel 14
Is pinched. For this reason, the narrowing of the rear end portion of the steel strip 14 is prevented from occurring. Further, since the rolling force of the light reduction roll 12 is controlled based on the detection information of the left and right load cells 22 so that the load is constant, the light reduction roll 12 affects the thickness of the steel strip 14 and the running state. Has no effect.

Further, in the above embodiment, since the pair of low pressure rolls 12 are formed of ceramics having a low thermal conductivity (including ceramic sprayed), the heat of the steel strip 14 is not easily transmitted to the low pressure roll 12 and the roll temperature is low. Is less likely to rise, so there is an advantage that the roll temperature is not required and the sheet temperature does not decrease. In particular, in this embodiment, the exit side of the final stand rolling mill F ₇ will form adding the pair of soft reduction rolls 12, usually of the material of the soft reduction, if roll strip requiring cooling 14
Although the temperature on the outlet side is lowered, it can be prevented because it is made of ceramics. .

Further, in the above embodiment, since a pair of soft reduction rolls 12 on the outlet side of the final stand rolling mill F _7, conventionally, it can be shortened previously tail end length of the plate which has been rolled with no tension In addition, the thickness accuracy and the shape of the plate at the end of the tail end can be improved.
That is, conventionally, the strip is rolled in a state where sufficient tension is not applied at the start of the finish rolling in the final strip rolling mill of the strip or until the end of the strip is wound up by the winder. In this embodiment, the thickness reduction of the strip 14 is always performed during the finish rolling because the thickness reduction control of the strip 14 by the light reduction roll 12 is performed in the present embodiment. Even before the steel strip is wound by the winder 8, the strip steel 14 is maintained in a state where a sufficient tension is applied to the steel strip 14, and the thickness of the steel strip 14 is controlled from immediately after the start of the finish rolling to immediately before the end thereof. Has an effect that the shape control can be stably performed.

[0031] Incidentally, the work roll of one front of the rolling mill F ₅ of the rear end is the final stand rolling mill F ₇ and between the strip 14 to the tip portion of the strip 14 is wound on the winder 8 The steel strip 14 is lightly supported by the light reduction roll 12 only when the roll 11 has been removed, so that the tension on the steel strip 14 is applied only immediately after the start of the finish rolling of the steel strip 14 and immediately before the end of the finish rolling of the steel strip 14. You may give.

Next, a hot rolling facility according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a side view of a finishing mill in a hot rolling facility according to a second embodiment of the present invention. The configuration other than the finish rolling mill is the same as that of the first embodiment shown in FIG.
The same members are denoted by the same reference numerals, and overlapping drawings and descriptions are omitted.

The finishing mill of the hot rolling equipment according to the second embodiment includes a reversible finishing mill 31 for reciprocating the rough-rolled steel strip 14 a plurality of times and finish rolling to a predetermined thickness. Has become. That is, a rolling mill 34 having a work roll 32 and a backup roll 33 is disposed downstream of the rough rolling mills R ₁ , R ₂ , R ₃ (see FIG. 1). On the upstream side (left side in the figure) of the rolling mill 34, the front coiler furnace pinch roll 3 is provided.
5 is arranged, and a rear-side koiler furnace pinch roll 36 is arranged downstream of the rolling mill 34 (right side in the figure).
Further, a front coiler furnace 37, a gate 38, and a guide 39 are disposed above the pass line S on the upstream side of the front coiler furnace pinch roll 35, and above the pass line S on the downstream side of the rear coiler furnace pinch roll 36. A rear coiler furnace 41, a gate 42, and a guide 43 are disposed at the rear side.

On the exit side (right side in the figure) of the work roll 32 of the rolling mill 34, a light rolling mill 13 having the same light rolling roll 12 as shown in FIGS. 1 to 4 is arranged. ing. Although not shown in FIG. 4, the light rolling mill 13 provided in this embodiment is also provided with the same light rolling cylinder, load cell, servo valve, and control device as those in the first embodiment, and is the same as described above. Further, the rolling force is controlled based on the detection information of the left and right load cells so that the load of the light rolling roll 12 becomes constant.

The steel strip 14 roughly rolled by the rough rolling mills R ₁ , R ₂ , R ₃ shown in FIG. 1 is passed through the front coiler furnace spin roll 35 and the first hot finishing is performed by the rolling mill 34. After rolling, the roll is advanced above the pass line S by the rear coiler furnace pinch roll 36 and the gate 42, and is wound by the rear coiler furnace 41 while being guided by the guide 43. Then, the steel strip 14 is rewound, and the guide 43,
Gate 42 and rear coiler furnace pinch roll 36
BR> to return to the pass line S, the rolling mill 34 is rotated in the reverse direction to perform the second hot finishing rolling.
, And is wound by the front coiler furnace 37 while being guided by the guide 39.

In this manner, the steel strip 14 is reciprocated through the rolling mill 34 a plurality of times to be rolled to a predetermined thickness (for example, 1.2 mm), passed through the rear coiler furnace pinch roll 36 and passed through the pass line S. It is advanced and sent to a winder through a cooling run-out table in the same manner as in the first embodiment, and is wound around a coil by the winder. Since the steel strip 14 is lightly reduced by the light reduction roll 12 on the exit side of the work roll 32 of the rolling mill 34, the steel strip 14 has a predetermined thickness and passes through the rear coiler furnace pinch roll 36 to advance the pass line S. At this time, even if the rear end of the strip 14 passes through the front coiler furnace pinch roll 35, the strip 14 is sandwiched between the work roll 32 and the light pressure roll 12. As a result, the rear end of the steel strip 14 having a thickness of, for example, 1.2 mm does not meander, and the occurrence of narrowing can be prevented.

Further, the load of the light reduction roll 12 is controlled so as to be always constant at the target load value for each of the left and right sides. The thickness does not fluctuate due to the light reduction of the light reduction roll 12, the influence of the light reduction roll 12 on the sheet thickness accuracy can be eliminated, and the rolled steel strip 14 can be eliminated.
Even if the thickness in the width direction is different, the light reduction force of the light reduction roll 12 is adjusted according to the thickness, and there is no possibility that the light reduction rolling mill 13 may meander. Therefore, similarly to the first embodiment, the rear end of the steel strip 14 is prevented from being drawn down, and the thickness and running state of the steel strip 14 are not affected by the light reduction roll 12.

Next, a hot rolling facility according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 (a),
(B), (c) is a schematic block diagram of a strip hot-rolling equipment equipped with a medium-thickness, thin-slab continuous casting device, showing a third embodiment of the present invention.

FIG. 6A shows a medium-thickness slab continuous casting apparatus 131A capable of producing a slab having a thickness of, for example, about 90 mm.
On the downstream side of the pass line, roughing mills R ₁ and R ₂ are arranged via a shear 132 for cutting the slab to a predetermined length and a heating furnace 102 for heating and keeping the cut slab. The slab is turned into a steel strip 14 having a thickness of about 30 mm by one-pass rough rolling using rolling mills R ₁ and R ₂ , and a coil box 133 is formed.
Once. Thereafter, the steel strip 14 unwound from the coil box 133 is finish-rolled in five stages by a finishing mill F comprising a plurality of stands (five stands in the figure) and a four-high rolling mill, for example, a strip having a thickness of 1.2 mm. Made into steel 14,
It is wound on a winder 8 through a cooling device 7.

[0040] Then, proximally out of the final stand rolling mill F ₅ of the finishing mill F, with a soft reduction rolls 12 as in the first embodiment a pair of upper and lower ceramics (including ceramics sprayed) A light rolling mill 13 is arranged.

In FIG. 6B, a rough rolling mill R ₁ is provided downstream of a pass line of a continuous thin slab casting apparatus 131 B capable of producing a slab having a thickness of 60 mm via a shear 132 and a heating furnace 102. , R ₂ and these rolling mills R ₁ , R ₂
The steel strip 14 has a thickness of about 30 mm by one-pass rough rolling, and is once wound around a coiler and kept in a heat retaining furnace 134.
Thereafter, the strip 14 unwound from the coiler is finish-rolled in six stages by a finishing mill F comprising a plurality of stands (six stands in the figure) and a four-high rolling mill.
It is made into a 2 mm steel strip 14, passed through a cooling device 7, and taken up by a winder 8.

[0042] Then, proximally out of the work roll 7 in the final stand rolling mill F ₆ of the finishing mill F, soft reduction rolls as in the first embodiment a pair of upper and lower ceramics (including ceramics sprayed) Rolling mill 1 equipped with 12
3 are arranged.

In FIG. 6 (c), a plurality of stands (in the figure) are arranged downstream of the pass line of a continuous thin slab casting apparatus 131C capable of producing a slab having a thickness of 50 mm via a shear 132 and a heating furnace 102. In this example, a finishing mill F composed of a four-high rolling mill of 7 stands) is directly connected, and the slab coming out of the heating furnace 102 is finish-rolled in seven stages by the finishing mill F to form a steel strip 14 having a thickness of 1.2 mm, for example. Then, it is wound on a winder 8 through a cooling device 7.

[0044] Then, proximally out of the work roll 7 in the final stand rolling mill F ₇ of the finishing mill F, soft reduction rolls as in the first embodiment a pair of upper and lower ceramics (including ceramics sprayed) Rolling mill 1 equipped with 12
3 are arranged.

Also in these facilities, in the rolling step, when the rear end of the strip 14 passes through the work roll of the rolling mill just before the final stand in the finishing mill F,
Since the steel strip 14 is sandwiched between the work roll 11 and the pair of light reduction rolls 12 of the final stand rolling mill, the restraining effect prevents meandering and avoids the occurrence of narrowing.

Next, a hot rolling facility according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 (a),
(B), (c) is a schematic block diagram of a thick plate hot rolling equipment, showing a fourth embodiment of the present invention.

As shown in the figure, a rough rolling mill R is disposed downstream of a pass line of a heating furnace 202 for heating a slab 201 having a predetermined thickness. 4A is reciprocally passed through a reversible rolling mill 203 a plurality of times to finish-roll to a predetermined thickness (for example, 6 mm or more). The finish-rolled thick plate 4A is sent to a hot leveler (not shown), and is cooled on a cooling floor after hot straightening. Then, on the rear surface (downstream of the pass line P) of the work roll 229 of the reversible rolling mill 203, a light rolling mill 13 provided with a pair of upper and lower ceramic (including ceramic sprayed) light rolling rolls 12 is arranged.

Also in this equipment, in the rolling process,
The thick plate 4A is sandwiched between the work roll 229 of the reversible rolling mill 203 and the light rolling roll 12 on the rear surface thereof, and meandering can be prevented by its restraining effect. In addition, there is a thick plate hot rolling facility without the rough rolling mill R, and the same operation and effect can be obtained in this case by configuring in the same manner as in the above embodiment.

[0049]

According to the hot rolling equipment of the present invention, the exit side of a rolling roll of a final stand rolling mill of a finishing rolling mill in which a plurality of rolling mills are arranged in a row, or a steel strip is reciprocated a plurality of times. Since the output side of the rolling rolls of the reversible finishing rolling mill that finish-rolls to a predetermined thickness, a light reduction rolling mill having a pair of light reduction rolls for lightly reducing the steel strip by driving the reduction driving means is arranged. When the rear end of the strip passes through the rolling roll of the rolling mill in front of the final stand, the strip can be sandwiched between the rolling roll of the final stand rolling mill and the light rolling roll to prevent meandering. In particular, when rolling a thin steel strip, it is possible to prevent the occurrence of narrowing. Therefore, defects such as flaws, cracks, and breaks in the steel strip do not occur on the rolling rolls of the rolling mill, and it is possible to reduce the number of times of changing the rolling roll assembly per hour, thereby reducing downtime of the apparatus. Can be. In addition, since bending and the like due to narrowing of the steel strip do not occur, it is possible to use a high-speed roll for the rolling roll of the final stand rolling mill, further reducing the downtime of the apparatus due to a reduction in the number of times of reassembly per hour. Can be.

Further, a load detecting means for detecting the load of the light reduction roll when the steel strip is lightly reduced is provided, and the reduction driving means is adapted to keep the load of the light reduction roll constant based on the detection information of the load detection means. Control means for controlling the driving of the light reduction roll to control the reduction force of the light reduction roll, the reduction force of the light reduction roll is controlled based on the detection information of the load detection means so that the load becomes constant, It does not affect the steel thickness.

As a result, it is possible to prevent meandering of the steel strip without affecting the sheet thickness and to prevent the narrowing of the rear end of the thin steel strip in particular.

In the hot rolling method of the present invention, the strip is lightly reduced by a constant load by a pair of light reduction rolls on the downstream side of the rolling roll of the finishing mill. When the end has passed through the rolling roll of the rolling mill in front of the final stand, the steel strip can be pinched between the rolling roll of the final stand rolling mill and the light rolling roll to prevent meandering. When rolling a thin strip of steel, it is possible to prevent the occurrence of narrowing and does not affect the thickness of the strip of steel. As a result, it is possible to prevent meandering of the rear end portion of the steel strip without affecting the thickness of the steel strip, and particularly to prevent narrowing of the rear end portion of the thin steel strip.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a hot rolling facility according to a first embodiment of the present invention.

FIG. 2 is a side view of a finishing mill in which a plurality of rolling mills are arranged in a row.

FIG. 3 is a side sectional view of a final stand of the finishing mill.

FIG. 4 is a view taken along the line IV-IV in FIG. 3;

FIG. 5 is a side view of a finishing mill in a hot rolling facility according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a strip steel hot rolling facility provided with a medium and thin slab continuous casting apparatus, showing a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a thick plate hot rolling facility showing a fourth embodiment of the present invention.

[Explanation of symbols]

2 Slab 3 Guide roll 4 Pinch roll 5 Plate cutting device 6 Heating furnace 8 Winding machine 11 Rolling roll 12 Light rolling roll 13 Light rolling mill 14 Strip steel 15 Housing 16 Work roll chock 17 Backup roll 18 Backup roll chock 19 Rolling cylinder 20 Light Reduction Roll Chock 21 Light Reduction Cylinder 22 Load Cell 23 Controller 24 Servo Valve 25 Load Cell 31 Reversible Finishing Rolling Machine 32 Work Roll 33 Backup Roll 34 Rolling Mill 35 Front Coiler Furness Pinch Roll 36 Rear Coiler Furness Pinch Roll 37 Front Coiling Furnace 38 after the gate 39 guide 41 surface coiler furnace 42 gate 43 guides R _1, R _2, R ₃ rough rolling mill F finishing mill

Continuation of front page (72) Inventor Shuji Uba 4-6-22 Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Works (56) References JP-A-1-197001 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B21B 1/00-1/46 B21B 27/00 B21B 37/00-37/78 B21C 47/00-49/00

Claims (7)

(57) [Claims] 1. A light reduction rolling mill for lightly reducing a strip by driving a reduction driving means on an output side of a finishing mill, and a load for detecting a load of the light reduction roll when the strip is reduced. Control means for controlling the driving of the screw-down driving means to adjust the rolling force of the light-rolling roll so that the load of the light-rolling roll becomes constant based on the detection information of the load-detecting means. A hot rolling facility comprising: 2. A heating device for heating a slab cast by a casting device is provided, and a rough rolling machine for rough rolling the slab heated by the heating device into a steel strip is disposed downstream of the heating device. A rolling mill having a plurality of stands is arranged in a row, and a finish rolling mill for finishing rolling the strip that has been rough-rolled to a predetermined thickness is disposed downstream of the rough rolling mill, and the finish-rolled rolling is performed. A down coiler for winding the steel strip in a coil shape is arranged downstream of the finishing mill, and the rolling-down driving means is driven to the exit side of the rolling roll of the final stand rolling mill among the rolling mills of the finishing mill. A light reduction rolling mill having a pair of light reduction rolls for lightly reducing the steel strip is disposed, and the load detection means includes a load detection means for detecting a load of the light reduction roll when the steel strip is reduced. Based on the detection information A hot rolling facility comprising control means for controlling the driving of the screw-down driving means so as to keep the load of the screw-down roll constant, thereby adjusting the screw-down force of the light pressure-roller. 3. A heating device for heating a slab cast by a casting device is provided, and a rough rolling machine for rough rolling the slab heated by the heating device into a steel strip is disposed downstream of the heating device. Then, a reversible finishing rolling mill for finishing rolling to a predetermined thickness by reciprocating the rough-rolled steel strip a plurality of times is disposed downstream of the rough rolling mill, and the finished-rolled steel strip is coiled. A down coiler for winding in a shape is arranged downstream of the reversible finishing mill, and the strip steel is lightened by a pair of light rolling rolls by driving a reduction driving means downstream of a rolling roll of the reversible finishing mill. A light reduction rolling mill to be reduced is provided, and a load detection means for detecting a load of the light reduction roll when the strip is reduced is provided, and a load of the light reduction roll is determined based on detection information of the load detection means. The rolling down to be constant A hot rolling facility comprising control means for controlling the driving of the driving means to adjust the rolling force of the light rolling roll. 4. A reversible finish rolling mill for reciprocating a slab heated in a heating furnace a plurality of times to finish-roll a slab to a thick plate having a predetermined thickness, and downstream of a rolling roll of the reversible finish rolling mill. A light reduction rolling mill for lightly reducing the strip by a pair of light reduction rolls by driving the reduction drive means is disposed on the side, and a load detecting means for detecting a load of the light reduction roll when the strip is reduced is provided. And control means for controlling the driving of the screw-down driving means so as to keep the load of the light reduction roll constant based on the detection information of the load detection means, and adjusting the reduction force of the light reduction roll. Hot rolling equipment. 5. A shear for cutting a slab having a thickness of 100 mm or less produced by a medium or thin slab continuous casting apparatus into a predetermined length, a heating furnace for heating the cut slab, and a multi-stand rolling mill. A finish rolling mill that finish-rolls the heated slab into a strip having a predetermined thickness, a down coiler that winds the finish-rolled strip into a coil, and the reversible finishing mill. A light reduction rolling mill that is disposed downstream of the rolling roll and is configured to lightly reduce the strip by a pair of light reduction rolls driven by a reduction driving unit, and detects a load of the light reduction roll when the strip is reduced. Control means for controlling the driving of the screw-down driving means so as to keep the load of the light reduction roll constant based on the detection information of the load detection means, and adjusting the reduction force of the light reduction roll. And Hot rolling equipment. 6. The control device according to claim 1, wherein a target load of the light reduction roll is stored in the control means, and the target load and an actual load detected by the load detection means are stored in the control means. A hot rolling facility having a function of controlling the driving of the screw-down driving means so as to adjust the rolling force of the light reduction roll so that the actual load becomes the target load in comparison. . 7. A hot rolling method in which a slab heated by a heating device is finish-rolled to a rolled material having a predetermined thickness by a finish rolling machine, wherein a pair of light pressure reductions is performed on a downstream side of a rolling roll of the finish rolling machine. A hot rolling method, wherein the rolled material is slightly reduced by a constant load by a roll.