JP3458499B2 - Detection and treatment method of joint breakage in hot strip mill - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hot endless rolling in which rolled materials are joined and continuously rolled, and more particularly to a method for detecting and treating a joint break in a hot strip mill.

[0002]

2. Description of the Related Art Conventionally, there is known a technique of joining sheet bars with a hot strip mill and rolling them. In equipment for performing such rolling, a shear for cutting (running device) for cutting between sheets is again arranged in front of the finish-rolling mill take-up winder to cut the joined sheet bars again into independent hot coils. Has been done.

The cutting target point of this strip shear (cutting device) is ideally the sheet bar joining point itself, but normally the joining point tracking accuracy depends on the advanced rate prediction accuracy, and the advanced rate is the roll skin. Since the rate changes depending on the condition, the advance rate must include some errors. Therefore, as a result, the occurrence of some tracking error cannot be suppressed, and the cutting point is slightly deviated from the joining point.

[0004]

However, the joining point sometimes breaks in the finishing mill or between the finishing mill and the winder, and if the breaking point is overlooked and the cutting control is performed as planned, as described above. In addition, since the cutting point by the strip shear deviates slightly from the joining point, a short cutting plate is formed between the cutting point by the strip shear and the broken joining point, which hinders the subsequent material from advancing and winding on the winder. There is a problem that causes a big trouble of.

[0005] In the bonding roll, also have increased rolling speed more sheet passing speed limit, the row material through plate inhibited after after fracture, it is causing you easily generate further accident .

The present invention, wherein those solve such conventional problems, automatically detects junctions break, hot to the accident caused by the subsequent by Ri fracture the appropriate measures can prevent An object of the present invention is to provide a method for detecting and treating a joint breakage in a strip mill.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a hot endless rolling method in which rolled materials are joined and continuously rolled, when the joining point is between the final stage of the finish rolling mill and the cutting device. By monitoring the change in the state of the winding device that winds the material, and when detecting an abnormal value that represents the breakage of the joint, by changing the control of one or more of the finish rolling mill, the winding device, or the cutting device, It has achieved its purpose.

The present invention also relates to the state change of the winding device,
By monitoring the mandrel speed or the pinch roll speed or the pinch roll current, the above-mentioned object was achieved in the same manner.

Further, according to the present invention, depending on the state of the winding device for winding the rolled material when the speed of the finish rolling mill is slightly reduced immediately after the joining point passes through the final stage of the finish rolling mill, By monitoring the condition, the above-mentioned object is achieved as well.

[0010]

[Operation] Usually, a strip is placed between the finish rolling machine and the winding machine.
While the strip-shaped rolled material is present, the winder mandrel performs torque control in order to appropriately maintain the tension applied to the strip- shaped rolled material . The above control state is stably maintained when there is no break, that is, a break point of the plate on the exit side of the finish rolling mill. However, if the rolled material has a break, the finish rolling machine cannot pull the rolled material , so that the winding speed of the plate increases due to the mandrel tension of the winding machine.

According to the present invention, since the more the winding machine fracture will not be able to maintain control state until it detects a rupture because the state is changed, and to take action against the junction breaking, Accidents can be prevented.

As a coping method, for example, a trailing rolled material (hereinafter simply referred to as a trailing material) is obtained by lowering the finishing rolling mill speed to be equal to or lower than a strip running limit speed determined according to the plate thickness.
Of the pre- rolled material (below
Lower, simply referred to as the preceding material) and spread distance of the breaking portion of the following material, it is considered to facilitate the switching of coiler.

It is also conceivable, for example, to change the control of the winding machine to suppress an excessive increase in the winding speed of the tail end of the preceding material.

It is also conceivable to change the control of the strip shear, for example. That is, the control of the strip shear is set to the cutting target point at the joining point or the vicinity thereof, and tracking and cutting are performed.
By stopping this, the generation of short end plates is suppressed.

[0015] According to the invention, by monitoring the pinch rolls varying current in accordance with the speed increase of the mandrel due to fracture, to detect the rupture, by taking action as described above, fracture Can quickly take accident prevention measures.

Further, according to the present invention, if the speed of the mill is slightly reduced immediately after the joining point passes through the final stand of the finishing mill, the speed on the winder side synchronizes with this if there is no break in the rolled material. It decreases Te, but the decrease in the winder speed when there is a break in the strip for not occur, which can be detected by even rupture. This therefore by taking action as described above, it is possible to correct for preventing accidents against fracture.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing rolling equipment to which an embodiment of the present invention is applied.

In FIG. 1, 2 is a finish rolling mill, 4 is a strip (rolling material), 6 is a table on which the strip 4 runs, 8 is a strip shear (cutting device) for cutting the strip 4, and 10 is a pinch. Roll, 12 is a mandrel (winding device) for winding the strip 4, 14 is a coil wound around the mandrel 12, and 16 is a motor for driving the mandrel 12. 18 is a motor 16 for detecting the speed of the mandrel 12. Speed sensor,
20 is a motor for driving a pinch roll, 22 is a motor 2
A pulse generator (PLG) that detects the rotation speed of the pinch roll 10 through 0, and 24 is a motor that drives the strip shear 8.

Further, 26 is a speed control device for controlling the speed of the finish rolling mill 2, 28 is a cutting control device for controlling the strip shear 8 through the motor 24, and 30 is a computer (CPU) for controlling these devices. is there.

First, the first embodiment will be described.

The strip 4 that has passed through the finish rolling mill 2 is conveyed on a table 6 and wound around a mandrel 12 via a pinch roll 10 to form a coil 14.

After the joining point passes through the finish rolling mill 2, the joining point is tracked by the pulse generator 22 attached to the lower pinch roll 10 and cut by the strip shear 8.

During this period, the finish rolling mill 2 performs constant speed control, the mandrel 12 controls tension, and the pinch roll 10 controls fine tension.

When the strip 4 breaks at the joining point, the back tension from the finish rolling mill 2 does not act and the speed of the mandrel 12 increases. Further, as a result of the fine tension control, the pinch roll speed also rises.

This state will be described with reference to the drawings.

FIG. 2 is a graph showing changes in the preceding material speed and the motor current after the joining point has passed through the finishing mill.

When the joining point breaks and exits the finish rolling mill 2, the tension between the finish rolling mill 2 and the mandrel 12 is lost, so that the winding speed of the preceding material increases as shown in FIG. When the preceding material speed increases to a certain degree, Table 6
And a back tension due to the roller of the table 6 acts, which reduces the rate of speed increase as indicated by point A in FIG.

Further, as the preceding material progresses, a gradual increase in speed continues due to a decrease in back tension accompanying a decrease in the remaining amount of the preceding material on the table 6.

FIG. 2 shows an example of the pinch roll speed control. As the preceding material speed increases, the pinch roll speed increases, and the pinch roll speed control system suppresses this speed increase. Therefore, the pinch roll current changes faster than the preceding speed change.

Here, when the deviation between the preceding material speed and the finish rolling speed exceeds a certain threshold value, or when the pinch roll current exceeds a certain threshold value, it is regarded as a junction breakage.

In the case of the pinch roll zero current control (fine tension control), the change in pinch roll current is extremely small, and the pinch roll speed reference rises as the preceding material velocity rises. Therefore, it is difficult to make a determination based on the change in pinch roll current, and the determination is made based on the change in pinch roll speed or winding speed (mandrel speed).

A speed sensor 18 attached to the mandrel motor 16 or the motor 2 of the pinch roll 10 detects the increase in the mandrel speed or the pinch roll speed.
It is detected by the pulse generator 22 of 0. These controls are performed by the CPU 30.

Further, upon detecting this, the CPU 30 outputs a deceleration command to the speed control device 28 of the finish rolling mill and outputs a cutting stop command to the cutting control device 26 which controls the motor 24 of the strip shear 8.

Here, an example in which the fine tension of the pinch roll 10 is controlled has been described, but the present invention is not limited to this. For example, the pinch roll 10 may be controlled at a constant speed. In this case, the current of the pinch roll 10 match the speed increase of the mandrel 12 due to the fracture can be varied. Therefore, it becomes possible to detect fracture by monitoring the pinch rolls current.

Next, the second embodiment will be described.

The device configuration to which the second embodiment is applied is also shown in FIG. 1 similarly to the first embodiment, and the basic control of each part is the same as that of the first embodiment. However, in the second embodiment, the speed control of the finish rolling mill 2 is not always constant.

The operation of the second embodiment will be described below.

As soon as the strip joining point passes through the final stand of the finishing rolling mill 2, the CPU 30 immediately issues a deceleration command to the speed control device 28 of the finishing rolling mill 2. At this time, add C
The PU 30 monitors the output of the speed sensor 18 installed on the mandrel 12 or the pulse generator 22 installed on the pinch roll 10, and determines whether or not the winding speed changes in synchronization with the finish rolling mill 2.

Even in this case, the behavior of the speed of the preceding material is the same as that in the case where the speed of the finish rolling mill 2 is not reduced if there is a break. As the finishing mill speed is decreasing,
Since the deviation between the preceding material and the finish rolling mill speed becomes large as shown in, the detection can be performed faster.

Further, when the pinch roll speed control is being performed, a deceleration command is output to the pinch roll 10 and a pinch roll deceleration current flows once as shown in FIG. Maintain the value of.

[0042] Thus, when a predetermined change in the winding speed does not occur, as there is a fracture, and outputs a further deceleration command immediately to the finishing mill speed controller 28, the motor 24 of the strip shear 8 Cutting control device 2 to control
A disconnection stop command is output to 6.

Further, the preceding material gradually increases in speed when left unattended, and stable winding end processing of the tail end becomes difficult. Therefore, the pinch roll 10 is switched to speed control, and the table speed is lower than the speed of the preceding material. Slow down,
Perform processing such as lowering the mandrel tension to an appropriate value.

[0044] Incidentally, when the zero current control of the pinch rolls 10 are performed slightly waving speed from the speed control in synchronism with the mill speed basically finish, even if rupture, finishing mill speed change The speed on the winder side may also change following the above. In order to prevent this, it is better to change the control in advance before the joining point leaves the finishing mill.

The best control is simple current control. However, in the case of zero current control by speed control with speed limitation, it is possible to achieve a sufficiently early purpose by simply changing the speed limitation.

[0046]

As described above, according to the present invention,
Automatically detect the junction breaking, and to take the accident prevention action automatically, has the effect that it is possible to prevent an accident due to the fracture.

[0047] Furthermore, the mandrel speed or pinch roll speed or the pinch rolls current, when to detect the rupture can perform reliable fracture detection.

[0048] Also, slightly the speed of the mill finish immediately after the joining point has passed through the finishing mill final stage lowered, when adapted to monitor the state change of the winding apparatus, certainly at an earlier response it is possible to detect the rupture can take appropriate measures to prevent accidents.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing rolling equipment to which the method of this embodiment is applied.

FIG. 2 is a diagram showing a state of a preceding material speed and a motor current after a breaking point has passed through a finishing mill.

FIG. 3 is a diagram showing a state of a preceding material speed and a motor current when the rolling mill speed is reduced after the breaking point has passed through the finish rolling mill.

[Explanation of symbols]

2 ... Finishing mill 4 ... strip 6 ... table 8 ... strip shear 10 ... Pinch roll 12 ... Mandrel 18 ... Speed sensor 22 ... Pulse generator (PLG) 26 ... Cutting control device 28 ... Speed control device 30 ... Computer (CPU)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshisada Takechi Inventor 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (72) Inoue Soichiro Onda 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Co., Ltd. Chiba Steel Works (56) References: Actual Development Sho 55-66013 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21B 37/00-37/78 B21B 33 / 00 B21C 51/00

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. A hot-endless rolling method in which rolled materials are joined and continuously rolled, and a winding device for winding the rolled material when the joining point is between the final stage of the finish rolling mill and the cutting device. When a state change is monitored and an abnormal value indicating a joint break is detected, one or more controls of the finish rolling machine, the winding device or the cutting device are changed, and the joint break in the hot strip mill is characterized. Detection and treatment method. 2. The method for detecting and treating a junction breakage in a hot strip mill according to claim 1, wherein a change in the state of the winding device is monitored by a mandrel speed, a pinch roll speed or a pinch roll current. 3. The winding device for winding rolled material according to claim 1, when the speed of the finish rolling mill is slightly reduced immediately after the joining point passes through the final stage of the finish rolling mill, A method for detecting and treating a joint breakage in a hot strip mill, which is characterized by monitoring the condition of the joint.