JPH0671618B2 - Steel strip rolling equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel strip rolling apparatus, and more particularly, to a temperature drop by heating a longitudinal end portion of a steel strip before the steel strip is finish-rolled. The present invention relates to a steel strip rolling apparatus capable of improving the inconvenience.

[Conventional technology]

Explaining conventional steel strip rolling, generally, in hot rolling, a heated slab having a thickness of about 120 to 130 mm is rolled by a rough rolling mill to a sheet bar having a thickness of about 15 to 60 mm, and Was further rolled to a desired product thickness by a finish rolling mill.

As shown in FIG. 7, the hot sheet bar 3 roughly rolled by the rough rolling machine 1 is transferred to the crop shear 4 by the transport table roller 5, and the tip portion of the sheet bar is cut. Then, a high-pressure injection type scaling device having a nozzle 8 for removing the surface scale of the sheet bar 3
The sheet bar 3 is transferred to 11, and the finish bar 2 is finish rolled by the finish rolling mill 2.

During the processing steps from the rough rolling to the finish rolling, part of the heat retained by the hot sheet bar 3 is dissipated into the atmosphere.
This amount of radiated heat increases as the distance from the heat radiating surface decreases, so there is a difference in the amount of heat radiated into the atmosphere between the widthwise end portion and the central portion of the hot sheet bar, and the temperature of the hot sheet bar is , The temperature at the widthwise end is lower than that at the widthwise central part. For this reason, there is a problem that a material defect occurs at the end portion in the width direction and the quality of the finish-rolled product deteriorates.

Therefore, in order to solve such a problem, an edge heater 10 consisting of a pair of upper and lower induction heating coils 10A for compensating for the temperature drop at both ends in the width direction of the seat bar is installed, and the edge part of the hot seat bar is locally arranged. There is a conventional example in which the temperature rises rapidly (for example, “Iron and Steel”, 1986, No. 2, 177 to 178).
page).

However, heat dissipation from the seat bar occurs not only in the widthwise end portion but also in the longitudinal end portion (front end / rear end), which causes a material defect in the longitudinal end portion. There is a problem that roll scratches occur when rolled by finishing rolls.

Therefore, the present applicant has proposed to heat not only the widthwise end portion but also the longitudinal end portion of the sheet bar between the rough rolling and the finish rolling (JP-A-2-321011).

In this conventional example, the induction heating coil 10A can be moved to the central portion in the width direction of the seat bar to enable heating of the end portion in the longitudinal direction of the seat bar.

[Problems to be Solved by the Invention]

In the conventional example, when heating the rear end portion of the seat bar in the longitudinal direction, the rear end portion of the seat bar must be heated while finish rolling the front portion. However, after the sheet bar is incorporated into the finishing mill, the sheet bar conveying speed is controlled by the finishing mill, and therefore the sheet bar conveying speed is sufficiently reduced during heating of the rear end portion so as to be suitable for heating. I can't. In order to sufficiently heat the rear end portion of the seat bar in such a situation, a large and expensive heating device having an extremely high heating capacity is required, resulting in an increase in cost and a required space. vice versa,
A conventional apparatus that heats the edges, which are the end portions in the width direction of the seat bar, has a problem that the amount of heat rise at the rear end portion is insufficient, and the problems such as material deterioration as described above cannot be solved.

Further, when the present inventor examined the temperature distribution at the longitudinal end and the widthwise end of the steel strip, it was found that the temperature drop at the longitudinal end was larger as shown in FIG. This is because the temperature drop region is extended by rolling. When the sheet bar conveyance speed is controlled by the finishing mill in heating such an expanded temperature range, a heating device with a conventional capacity can sufficiently heat the rear end portion in the longitudinal direction of the sheet bar. It will not be possible. Therefore, a device having an extremely high heating capacity is required.

Therefore, in order to solve such a problem, the present invention provides a steel strip rolling apparatus capable of sufficiently heating the end portion in the longitudinal direction of a steel strip before finish rolling even if a heating apparatus having a normal or small heating capacity is used. The purpose is to

[Means to solve the problem]

In order to achieve such an object, the present invention provides a rolling apparatus for a steel strip, which includes a rough rolling machine that roughly hot-rolls a steel strip and a finish rolling machine that finish-rolls the roughly rolled steel strip. In the above, a heating device for heating an end portion in the longitudinal direction of the steel strip is provided before the final stage of the rough rolling mill.

[Action]

By placing a heating device that heats the longitudinal end of the steel strip before the final stage (final stand) of the rough rolling mill, it is possible to heat the rear end of the steel strip before it is installed in the finish rolling mill. Therefore, the transport speed of the steel strip is not limited by the finish rolling mill. Therefore, when heating the rear end portion of the steel strip in the longitudinal direction, the transport speed of the steel strip can be sufficiently reduced to be suitable for heating, and heating that does not have a high heating capacity like the conventional edge heater can be performed. The device can be used as it is for heating the rear end of the steel strip in the longitudinal direction.

Moreover, since the heating device for the longitudinal ends of the steel strip is arranged in front of the final stage of the rough rolling mill, it is possible to minimize the expansion of the temperature drop region at the longitudinal ends to be stretched by rolling.

〔Example〕

 Next, examples of the present invention will be described.

FIG. 1 is a configuration diagram showing an embodiment of a rolling apparatus according to the present invention.

FIG. 1 shows a steel strip rolling apparatus that finish-rolls a sheet bar 3 roughly rolled by a rough rolling mill 1 by a finish rolling mill 2.

The rough rolling mill 1 is a 3/4 continuous hot strip mill having four rough mills, and only R3 mill and R4 mill are shown.

Instead of the edge heater 10 shown in FIG. 7, an induction heating device 6 for heating the longitudinal end portion and the side end portion of the seat bar 3 is provided.

The induction heating device 6 is provided on the R4 mill entry side table, which is before the final stage of the rough rolling mill. That is, it is provided between the R3 mill and the R4 mill.

As shown in FIGS. 2 and 4, the induction heating device 6 is composed of a pair of upper and lower induction heating coils 6A and 6B which are arranged to face each other with the seat bar 3 interposed therebetween. Two induction heating coils are provided in parallel with the width direction of the seat bar 3 as shown in FIG. 3 which is a plan view. These induction heating coils can individually control the output, and can adjust the movement position of the seat bar 3 in the width direction.

As shown in the side view of FIG. 4, the induction heating device 6 used in this embodiment includes a pair of upper and lower induction heating coils 6A and 6B, and the upper induction heating coil 6A is fixed to the tip of the upper support arm 31A. Has been done. The lower induction heating coil 6B is fixed to the tip of the lower support arm 31B. The induction heating coils 6A and 6B are arranged so as to sandwich the seat bar 3 from above and below.

The pair of upper and lower support arms 31A and 31B are rotatably fixed to the left side end of the support base 38 of the carriage 32. An opening / closing hydraulic cylinder 35 is fixed to the right end of the upper support arm 31, and an opening / closing hydraulic cylinder 36 is similarly fixed to the right end of the lower support arm 31B. 33 is a rail formed at right angles to the rolling line, and 34 is a wheel for moving the truck 32 along the rail. In addition, 36 is a bearing stand of the conveying roller.

The support arms 31A, 31B of the induction heating device shown in FIG. 3 have induction heating coils 6A, 6B provided at the tip end thereof in the seat bar 3.
It has a sufficient length to be moved to the central part. In the induction heating device, the wheels 34 are driven to rotate by a driving device provided in the carriage 32, so that the rails 33 can be moved forward and backward at a right angle in the conveying direction of the seat bar 3. That is, when the induction heating coils 30A and 30B are moved to the widthwise central portion of the seat bar 3, by traveling on the rail 33 toward the seat bar,
It is possible to move these induction heating coils toward the widthwise central portion of the seat bar. In addition, seat bar 3
Since the induction heating coil may be damaged if there is a warp in the open / close cylinder 35
And 36 are driven to allow the support arms 31A, 31 to rotate about the support shaft 39.

Then, a similar induction heating coil is arranged on the left side of the induction heating device 6 in FIG. 4, and two sets of a pair of upper and lower induction heating coils are installed in the width direction of the seat bar as shown in FIG.

Next, FIG. 5 shows a block diagram of the embodiment shown in FIG. This FIG. 5 shows a system for heating the seat bar 3. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

A high frequency power supply 27 is connected to each of the induction heating coils 6A and 6B. The drive device 22 is connected to the wheels 34. The drive device 22 and the high frequency power supply 27 are connected to the controller 21, respectively.

This controller 21, drive device 22, high-frequency power supply 27 is a dolly 32.
It is installed inside. On the upstream side of the induction heating coils 6A and 6B, a hot metal detector (HMD) 25 that detects the passage of the end of the seat bar 3 by the presence or absence of infrared rays and a temperature sensor 26 that detects the temperature of the seat bar are provided. these
The HMD 25 and the temperature sensor 26 are connected to the controller 21.

Further, one of the transport rollers 5 is connected to a measuring ring 23 including a pulse generator that measures the moving amount of the sheet bar 3 and generates a pulse signal according to the moving amount. Is the controller 21
It is connected to the.

The controller 21 is composed of, for example, a microcomputer, and can connect a temperature setting circuit (not shown) to an interface (not shown) to set a temperature value to be raised by the induction heating device 6.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 3 is a plan view showing the moving state of the induction heating coil, and FIG. 6 is a graph showing the control state of the coil position.

After the leading end of the sheet bar 3 passes through the rough rolling roll R3 and before the transition to the final rough rolling roll R4, the leading end of the sheet bar 3 is the HMD25.
When the HMD 25 reaches the position, the HMD 25 detects the infrared rays emitted from the seat bar, and outputs a signal of the theoretical value “1” indicating that the tip of the seat bar 3 has reached the controller 21.
Output to.

Next, the temperature sensor 26 starts temperature detection, detects the temperature of the tip portion of the hot seat bar 3, and outputs the detected signal to the controller 21. An infrared thermometer, for example, can be used as the temperature sensor.

When the controller 21 detects the tip portion of the seat bar 3 by the signal from the HMD 25, the distance between the induction heating coils 6A and 6B is set such that the warp of the tip portion of the sheet bar 3 does not damage the pair of upper and lower induction heating coils. Adjust.

The controller 21 can detect the movement amount of the seat bar 3 by a signal from the measuring roll 23. That is, the controller 21 is a measuring roll.
The movement amount of the seat bar 3 can be calculated by counting the number of pulses generated from the 23 pulse generators. Therefore, by storing the distance from the HMD25 to the induction heating coil in the storage device of the controller 21 in advance, it is possible to predict the time (T ₁ ) when the tip of the seat bar reaches the induction heating coil. it can.

In FIG. 6, T ₁ corresponds to FIG. 3 (1), which is the time when the sheet bar 3 is conveyed and its tip reaches the heating region of the induction heating coil. At the same time, the controller 21 outputs a control signal to the high frequency power supply 27 to bring the output of the induction heating coil to the H level.

Further, the sheet bar 3 is conveyed, and the induction heating coil 6 is moved from the center portion in the width direction of the sheet bar to the edge portion at T _{2 in} FIG. FIG. 3 (2) shows this state. As shown in FIG. 3 (2), when the induction heating coil moves to the edge portion of the sheet bar, the tip portion of the sheet bar is heated along with this movement. The induction heating coil generates an induced current in the seat bar 3 to heat the seat bar. The capacity of the dielectric heating coil can be made smaller as the expected warp amount (allowable amount) of the tip portion of the seat bar 3 is smaller, but when the allowable value of the warp amount is increased, It is necessary to use an induction heating coil having a corresponding capacity.

The controller 21 calculates the difference between the temperature of the seat bar 3 measured by the temperature sensor 26 and the target temperature (preliminarily set in the controller by a setting device), so that the difference becomes zero.
Further, the output of the heating coil can be controlled based on the thickness and material of the seat bar.

At time T ₃ in FIG. 6, the movement of the induction heating coil to the edge portion of the seat bar ends (FIG. 3 (3)). When the sheet bar is conveyed thereafter, the induction heating coil continues to heat the edge of the sheet bar 3 and subsequently the edge of the sheet bar 3.

Next, when the sheet bar 3 is further conveyed, the sheet bar 3
It is necessary to heat the rear end of the. At this time, it is necessary to detect the rear end portion of the seat bar 3. This is because the length of the seat bar is preset in the controller 21, and the movement amount of the seat bar 3 is determined by the majoring roll 23. Since it is constantly monitored, the rear end of the seat bar can be easily detected.

As shown in FIG. 3 (4), when the rear end of the seat bar approaches the induction heating coil, the coil is moved toward the center of the seat bar. This corresponds to the time of Figure 6 T _4. As shown in the graph of FIG. 6, the coil moves toward the center of the sheet bar, and immediately before T ₄ when the rear end of the sheet bar arrives at the heating area of the induction heating coil, the conveyance speed of the sheet bar increases. I try to stop very slowly.
In this case, since the sheet bar 3 is located between the R3 mill and the R4 mill, the conveyance speed of the sheet bar can be extremely low or stopped without being limited by the R3 mill and the R4 mill.

When the sheet bar is further conveyed, the state shown in FIG. 3 (5) is reached. In this state, the induction heating coil moves to the central portion of the seat bar, so that the moving region of the induction heating coil, that is, the rear end portion is heated. This state corresponds to T ₅ in FIG.

After passing the rear end portion of the sheet bar at T ₅ in FIG. 6 (corresponding to FIG. 3 (6)), the conveyance speed of the sheet bar is increased to the reference speed in the unheated state and becomes equal to the reference speed. T ₆
At that time, the output of the induction heating coil is reduced to the initial L level.

Thereafter, as the next sheet bar comes to the heating area, the sheet bars continuously conveyed can be heated by repeating the steps (1) to (6) in FIG.

In this example, the heating device for the sheet bar was installed before the final stage of the rough rolling mill, that is, between R3 and R4. Therefore, the process in which the rear end of the seat bar is heated (Fig. 3 (4))
In (6)), since the conveying speed of the sheet bar can be sufficiently reduced without being affected by the rolling speed (T _{4 to} T _{5 in} FIG. 6), the heating of the rear end portion is efficiently performed. be able to. Especially between the R3 stand and the R4 stand,
There is a margin in cycle time (for example, in the finish rolling, the margin time until the next rolling is compared with the rolling time of 1 minute.
It has only 10 seconds, but rough rolling has a margin of 40 seconds for rolling time of 30 seconds), and when heating the rear end of the sheet bar, the seat bar is stopped or extremely low speed (main Since heating can be performed while conveying at an extremely low speed in the embodiment), the heating efficiency of the rear end portion is improved. Therefore, a large-sized and large-output heating device is not required, and a small-sized and small-output heating device is sufficient.

Moreover, since the heating device is arranged in front of the R4 stand of the rough rolling mill, it is possible to heat the longitudinal end portion of the sheet bar in a state where the thickness of the sheet bar is close to the thickness on the entry side of finish rolling. Therefore, since the expansion of the temperature drop region can be suppressed to the minimum, there is no special inconvenience.

In this embodiment, the heating device 6 is arranged in front of the R4 stand,
Although the longitudinal end and edge of the seat bar were heated by this heating device, the same induction heating device 6'as described in the present embodiment was further added, and the longitudinal heating of the seat bar was performed by this additional heating device. You may make it heat a front-end | tip part and an edge part in a direction. In this case, the heating of the leading end portion in the longitudinal direction can be performed at the same time as the heating of the trailing end portion in the longitudinal direction when the conveyance speed of the sheet bar is stopped or sufficiently reduced, so that the heating of the leading end portion is not affected by the rolling speed. can do. In this case, the induction heating device 6 is dedicated to heating the rear end portion of the seat bar. When the rear end portion moves to the area of the front end heating device 6 ', as shown in FIG. 3, the induction heating coil of the front end heating device is moved to reheat the rear end portion of the seat bar. May be.

The heating of the edge portion may be performed by an edge heater installed on the entrance side of the finish rolling mill as in the conventional case.

In the above embodiment, a pinch roller for correcting the warp of the tip portion of the sheet bar 3 can be provided on the upstream side of the induction heating coil. The warp of the tip of the sheet bar 3 is corrected and flattened by the pinch roller so that the gap between the sheet bar 3 passing through the distance between the upper induction heating coil and the lower induction heating coil in the induction heating device 6 becomes smaller. Can be set to. Therefore, it is possible to significantly reduce the capacity of these heating coils and reduce the equipment cost. Further, it is not necessary to make the heating coil movable so as to move vertically toward the seat bar 3.

In this embodiment, the number of induction heating devices installed is not limited to that of this embodiment, and the number of installed induction heating devices can be further increased.

Further, although the infrared sensor detects the arrival of the front end of the seat bar, the present invention is not limited to this, and other optical sensors can be used.

Further, in the present embodiment, the longitudinal rear end of the seat bar is detected based on the distance tracking method by the microcomputer, but it is also possible to detect the rear end of the seat bar using another optical sensor. it can.

Furthermore, although the induction heating is described in this embodiment,
The present invention is not limited to this, and the same purpose can be achieved by using other heating means.

In addition, the output of the induction heating coil is set to H level and L level 2
Although set in stages, the induction heating coil output can be controlled in stages based on the difference between the target temperature at which the seat bar should be heated and the actual temperature.

〔The invention's effect〕

As described above, according to the rolling apparatus for a steel strip according to the present invention, the heating device for heating the longitudinal end portion of the steel strip is provided before the final stage of the rough rolling mill. It is possible to provide a steel strip rolling device capable of sufficiently heating the longitudinal end portion of the steel strip before finish rolling even by using a heating device having a small heating capacity.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of an embodiment of the rolling apparatus according to the present invention, FIG. 2 is a side view showing the installation state of induction heating coils in the embodiment of FIG. 1, and FIG. 3 is induction heating. FIG. 4 is a plan view showing the moving state of the coil, FIG. 4 is a side view showing the configuration of the induction heating device, FIG. 5 is a block configuration diagram for induction heating, and FIG. 6 is a graph showing the control state of the induction heating coil position. , FIG. 7 is a side view showing the structure of a conventional rolling apparatus, and FIG.
The figure is a graph showing the relationship between the distance from the end of the hot sheet bar and the temperature drop amount. In the figure, 1 is a rough rolling mill, 2 is a finish rolling mill, 3 is a sheet bar, 5 is a conveying roller, 6 is an induction heating device, and 6A and 6B are induction heating coils.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-141457 (JP, A) JP-A-47-33942 (JP, A) Practical application Sho-57-82408 (JP, U)

Claims (1)

[Claims] 1. A rolling apparatus for rolling a steel strip, comprising: a rough rolling mill that hot-rolls a steel strip hot; and a finish rolling mill that finish-rolls a rough-rolled steel strip. A rolling device for steel strips, characterized in that a heating device for heating the end portion is provided before the final stage of the rough rolling mill.