JP7512993B2 - Equipment damage prevention device and equipment damage prevention method for hot rolling mill - Google Patents

Description

This invention is a technology related to hot rolling operations.

As an example of conventional technology, there is the technology described in Patent Document 1. The method described in Patent Document 1 estimates the load torque from the generated torque and speed of the electric motor of a mill that is undergoing torque control. Then, when it is predicted that the estimated load torque will increase sharply and the speed will decrease sharply, the target current value given to the motor is reduced to prevent the generated torque from increasing beyond the allowable value. This protects the equipment on the electric motor side.

JP 2001-16884 A

The technology described in Patent Document 1 protects the motor because it controls with torque, but does not provide protection against high loads generated by the roughing stand (rolling mill). In addition, because the rolling load of the roughing stand is transmitted to the motor via the drive system, there is a risk that the drive system, such as the spindle, may be damaged under high loads. Even if rolling is possible at the stand in question, there is an issue that there is no way to prevent damage from the predicted high load of the next stand due to the increase in load caused by cooling during transport.

In addition, estimating the load on the rolling mill from the current value of the electric motor, etc., has the problem of poor responsiveness.

The present invention was made with the above points in mind, and aims to provide a more responsive system and prevent damage to hot rolling mill equipment.

According to the study of the inventors, in a continuous hot rolling operation, when a slab passes through a roughing mill, the load during rolling may increase due to an increase in deformation resistance caused by a decrease in the temperature of the slab on the conveying table. The inventors have found that this increase in load (high load) leads to destruction of the rolling mill equipment.
The temperature drop of the slab occurs, for example, due to waiting time between stands while the slab is being straightened out from its upward camber.
The present invention was made based on these findings.

That is, one aspect of the present invention is an equipment damage prevention device for a hot rolling mill, which is characterized by comprising a load cell that detects the rolling load of the rolling mill, and a control unit that outputs an emergency stop command to the equipment of the rolling mill when it is determined that the rolling load detected by the load cell exceeds a first threshold value set in advance.

The first threshold value may be set based on, for example, past performance or the load guaranteed by the manufacturer.

According to this aspect of the present invention, it is possible to more reliably avoid damage to rolling mill equipment caused by an increase in the deformation resistance of the slab due to a decrease in the slab temperature.

FIG. 1 is a diagram showing an example of an apparatus configuration according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of a control unit. FIG. 2 is a schematic diagram for explaining a process according to an embodiment of the present invention.

Next, an embodiment of the present invention will be described with reference to the drawings.
(composition)
1, the continuous hot rolling facility of this embodiment includes a row of rolling mills 1A to 1E (stands), and sequentially rolls the transported slabs into metal plates of a desired thickness. The slabs sent to the rolling mills 1A to 1E are heated in a heating furnace to a predetermined temperature.
The multiple rolling mills 1A to 1E may be a row of roughing mills, a row of finishing mills, or a row combining a row of roughing mills and a row of finishing mills.
In the following, a description will be given assuming a row of roughing mills.

<Load cells 2A to 2E>
The rolling mills 1A to 1E are respectively equipped with load cells 2A to 2E for detecting the rolling load.
Each of the load cells 2A to 2E outputs a detected load signal to the control unit 3.

<Control unit 3>
As shown in FIG. 2, the control unit 3 includes a high load determination unit 3A and an emergency stop unit 3B.

[High Load Determination Unit 3A]
The high load determination unit 3A first determines whether or not the rolling load detected by the load cells 2A to 2E provided in the rolling mills 1A to 1E that have started rolling or are currently rolling has exceeded a first threshold value that has been set in advance. If it is determined that the first threshold value has been exceeded, the high load determination unit 3A transitions to the emergency stop unit 3B.

On the other hand, if the rolling load detected by the load cells 2A to 2E is lower than the first threshold value, the load cell 2A to 2E judges whether the rolling load detected by the load cells 2A to 2E exceeds the second threshold value. If it is judged that the rolling load exceeds the second threshold value, the process proceeds to the emergency stop unit 3B.
Here, the determination as to whether the rolling load has exceeded the second threshold value may be performed when rolling is completed by the current rolling mill. In this case, the maximum value of the detected rolling load is updated based on the rolling loads continuously detected by the load cells 2A to 2E. Then, for each of the rolling mills 1A to 1E, it is determined whether the maximum value of the rolling load at the end of rolling has exceeded the second threshold value.

The high load determination unit 3A is executed for each of the rolling mills 1A to 1E that have started rolling or are currently rolling. That is, the high load determination unit 3A is executed continuously at each predetermined sampling time from the time when the slab starts to be bitten until the slab is removed in each of the rolling mills 1A to 1E.
Here, the rolling load at which the rolling mills 1A to 1E break varies from one rolling mill to another, and therefore the first threshold value and the second threshold value vary from one rolling mill to another.

The first threshold value is selected, for example, as follows, and stored in the storage unit for each of the rolling mills 1A to 1E.
That is, for each of the rolling mills 1A to 1E, the rolling load when the target rolling mill 1A to 1E equipment is damaged by a high load is obtained from the past rolling results, and the value obtained by subtracting a safety allowance from the obtained rolling load is set as the first threshold value. Alternatively, the value obtained by subtracting a safety allowance from the rolling load guaranteed by the manufacturer of the rolling mills 1A to 1E is set as the first threshold value.

The second threshold value is selected, for example, as follows, and stored in the storage unit for each of the rolling mills 1A to 1E.
That is, the rolling load when the rolling mill 1A-1E equipment is damaged by high load in the next stand of the target rolling mill 1A-1E is obtained from the past rolling results in the next stand, and the second threshold value is determined by subtracting from the obtained rolling load a safety allowance corresponding to the increase in deformation resistance due to the drop in slab temperature between the target rolling mill 1A-1E and the next stand. Alternatively, the second threshold value is determined by subtracting from the manufacturer-guaranteed rolling load of the next stand a safety allowance corresponding to the increase in deformation resistance due to the drop in slab temperature between the target rolling mill 1A-1E and the next stand.

However, if the second threshold value is greater than the first threshold value, there is no need to make a judgment using the second threshold value. For example, each rolling mill may have second threshold value information (e.g., zero or a negative value), and based on that information, the second threshold value judgment may not be made, or the second threshold value may be set to a value greater than the first threshold value.

Alternatively, if the second threshold value obtained is greater than the first threshold value, the second threshold value may be obtained from the rolling load at the time of the high load failure in the next stand of the next stand of the target rolling mills 1A to 1E.
Of course, there is no second threshold for the rearmost stand.

[Emergency stop unit 3B]
When the emergency stop unit 3B determines, based on the judgment of the high load judgment unit 3A, that the rolling load of the current rolling mills 1A to 1E has exceeded a first threshold value, it outputs an emergency stop command to the equipment of the current rolling mills 1A to 1E that has exceeded the first threshold value.
Furthermore, the emergency stop unit 3B outputs a rolling stop command to the rolling equipment of the next stand when it is determined that the rolling load of the current rolling mill 1A-1E has exceeded the second threshold value based on the determination by the high load determination unit 3A. This rolling stop command is output, for example, during rolling by the current rolling mill 1A-1E or after rolling by the current rolling mill 1A-1E is completed.

The rolling mills 1A to 1E to which the emergency stop command has been input carry out processing to stop rolling, for example by stopping the drive motor and increasing the roll gap.
Similarly, the rolling equipment of the next stand to which the rolling stop command has been input also performs processing to stop rolling, for example, by stopping the drive motor and increasing the roll gap.

(Action etc.)
In this embodiment, when it is determined that the rolling load exceeds the first threshold value during rolling of the slab 10, the rolling mill 1(n) is brought to an emergency stop during rolling as shown in FIG. 3 (see the rolling mill on the left side in FIG. 3).
This makes it possible to prevent damage to the electric motor and mechanical system (spindle, etc.) of the rolling mill 1(n) during rolling.
At this time, the rolling load during rolling is detected by the load cells 2A to 2E, so that the response is also high.

Also, if it is determined that the rolling load is lower than the first threshold value but exceeds the second threshold value while the slab 10 is being rolled in the rolling mill 1(n), the next stand 1(n+1) is stopped.
As a result, although the current rolling at rolling mill 1(n) continues, rolling at the next stand 1(n+1) is stopped to prevent damage to the equipment at the next stand 1(n+1).

As described above, in this embodiment, it is possible to more reliably avoid equipment damage to the rolling mill caused by an increase in the deformation resistance of the slab due to a drop in slab temperature. That is, in this embodiment, equipment damage to the drive system caused by a high load on the stand side, which could not be expressed by the torque load of the electric motor alone, is protected based on the stand load. Also, when a highly loaded material is rolled, if the load of the next stand exceeds the allowable value based on the stand load of the current stand, rolling in the next stand is stopped after the current rolling to prevent damage. As a result, the effect of preventing equipment damage to the rolling mill can be obtained.

If the rolling mill is stopped due to high load, the temperature of the heating furnace may be increased to reduce the rolling load for subsequent strips.

(others)
The present disclosure may also have the following configuration.
(1) A device for preventing equipment damage in a hot rolling mill, comprising:
A load cell for detecting the rolling load of the rolling machine;
a control unit that outputs an emergency stop command to the rolling mill equipment when it is determined that the rolling load detected by the load cell exceeds a first threshold value set in advance;
Equipped with.
(2) A device for preventing damage to hot continuous rolling equipment consisting of a row of multiple rolling mills, comprising:
A load cell is provided for each rolling mill to detect the rolling load of the target rolling mill;
a control unit that, when detecting a rolling mill whose rolling load exceeds a second threshold value set individually for each rolling mill based on the rolling load detected by the load cell, outputs a rolling stop command to a rolling mill located downstream in the conveying direction from the detected rolling mill;
Equipped with.
(3) when the control unit determines that the rolling load of the rolling mill has exceeded a preset first threshold value based on the detection value of the load cell, the control unit outputs an emergency stop command to the rolling mill equipment that has exceeded the first threshold value;
The second threshold is lower than the first threshold.
(4) A method for preventing equipment damage in a hot rolling mill, comprising the steps of:
A load cell is provided to detect the rolling load of the rolling machine.
When it is determined that the rolling load of the rolling mill exceeds a preset first threshold value based on the detection value of the load cell, the rolling mill is stopped in an emergency.
(5) A method for preventing equipment damage in a continuous hot rolling facility consisting of a row of a plurality of rolling mills, comprising the steps of:
A load cell is provided for each rolling mill to detect the rolling load of the rolling mill,
When a rolling mill whose rolling load exceeds a second threshold value set individually for each rolling mill is detected based on the rolling load detected by the load cell, the rolling mill located downstream in the conveying direction from the detected rolling mill is stopped.
(6) when it is determined based on the detection value of the load cell that the rolling load of the rolling mill has exceeded a preset first threshold, the rolling mill that has exceeded the first threshold is stopped in an emergency;
The second threshold is lower than the first threshold.

1A to 1E Rolling mills 2A to 2E Load cell 3 Control unit 3A High load determination unit 3B Emergency stop unit 10 Slab

Claims (4)

A device for preventing damage to hot continuous rolling equipment consisting of a row of multiple rolling mills, comprising:
A load cell is provided for each rolling mill to detect the rolling load of the target rolling mill;
a control unit that, when detecting a rolling mill whose rolling load exceeds a second threshold value set individually for each rolling mill based on the rolling load detected by the load cell, outputs a rolling stop command to a rolling mill located downstream in the conveying direction from the detected rolling mill;
An equipment damage prevention device for a hot rolling mill, comprising: When the control unit determines that the rolling load of the rolling mill has exceeded a preset first threshold value based on the detection value of the load cell, the control unit outputs an emergency stop command to the rolling mill equipment that has exceeded the first threshold value,
The second threshold is lower than the first threshold.
2. A device for preventing damage to hot rolling mill equipment according to claim 1 . A method for preventing equipment damage in a continuous hot rolling facility consisting of a row of multiple rolling mills, comprising the steps of:
A load cell is provided for each rolling mill to detect the rolling load of the rolling mill,
When a rolling mill whose rolling load exceeds a second threshold value individually set for each rolling mill is detected based on the rolling load detected by the load cell, the rolling mill located downstream in the conveying direction from the detected rolling mill is stopped.
A method for preventing damage to hot rolling mill equipment, comprising: When it is determined based on the detection value of the load cell that the rolling load of the rolling mill has exceeded a preset first threshold, the rolling mill that has exceeded the first threshold is stopped in an emergency;
The second threshold is lower than the first threshold.
4. A method for preventing damage to hot rolling mill equipment according to claim 3 .

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