JPH0740021A - Method and instrument for monitoring abnormality of pinch roll in continuous casting equipment - Google Patents

Abstract

PURPOSE:To prevent a cast slab from being scrap with an appropriate countermeasure after detecting an abnormality by monitoring a load current in a driving motors for the whole pinch rolls, and analyzing the pattern of the current change, thereby detecting the abnormality such as wearing of bearing in the whole pinch rolls, wearing of the rolls. CONSTITUTION:The abnormality such as the wearing of the bearings in the hole pinch rolls of rolling reduction rolls 10 and driving rolls 11, the abnormality of excentricity and rolling reduction of the rolls, is detected by monitoring the load current in the driving motors 14 for the whole pinch rolls and analyzing the pattern of the current change. The driving motors 14 are provided in the whole pinch rolls, and sequencer 25 having the function for diagnosing the abnormal pattern by calculating the load current from the individual motor and a display device 18 for displaying the abnormal pattern as the picture are provided. By this method, the abnormality of the pinch roll can be detected before the producing cast steel 8 is affected with a fatal quality defect and the appropriate countermeasure can be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting abnormality of a pinch roll of continuous casting equipment.

[0002]

2. Description of the Related Art In a continuous casting facility, as shown in FIG. 4, molten steel 1 is poured from a ladle 2 into a tundish 3, cooled through a mold 4 through a guide roll 5 and a pinch roll 6. -The cast steel 8 is manufactured by drawing and shearing to a predetermined length with the shearing machine 7.

FIG. 2 shows the structure of the pinch roll. The reduction roll 10 is made of cast steel 8 by a hydraulic lifting cylinder 9.
Is pushed down against. The drive roll 11 is a drive motor 14
Is driven by the speed reducer 13. A speed detector 15 is connected to a shaft of the drive motor 14 on the side opposite to the load by a coupling 16. Reduction roll 10 and drive roll 1
1 is supported by a bearing 12 and rotates.

To ensure the shape and quality of cast steel, all pinch rolls must be pressed down against the cast steel at a constant pressure and withdrawn at a constant speed. However, if bearing wear, roll wear, roll eccentricity, or abnormal rolling reduction occurs on any of the pinch rolls, the rolling will be uneven with respect to the cast steel, and solidified inclusions will form in the cast steel. The produced cast steel is scrap due to poor quality.

[0005]

As a method for monitoring the abnormality of the pinch rolls, conventionally, as shown in FIG. 3, a speed detector 15 is attached to three driving rolls 11 of all the pinch rolls, and a reference roll is used. A method has been adopted in which when the speed difference from other rolls exceeds the limit, the speed deviation detection 17 in the sequencer 25 detects an abnormality. However, this method cannot detect that the reference roll is abnormal,
Abnormal detection of pinch rolls was impossible because rolls without detectors could not be detected, and speed differences were not produced because of speed control even if there was a difference in reduction between rolls.

Further, Japanese Patent Laid-Open No. 56-84162 discloses that the pinch roll speed control is performed by the motor field current control although it is not a pinch roll abnormality monitoring device. This controls the speed of the pinch roll by controlling the motor current of the pinch roll, but cannot detect the abnormality of the pinch roll.

An object of the present invention is to continuously and accurately detect wear of bearings of pinch rolls, wear of rolls, roll eccentricity, and abnormal rolling reduction in continuous casting equipment, and quality generated by abnormal rolling reduction applied to cast steel. It is to prevent defects.

[0008]

SUMMARY OF THE INVENTION A pinch roll abnormality monitoring method of the present invention is directed to continuously arranging a plurality of pinch rolls, pressing the pinch rolls and rotating the pinch rolls to continuously draw out a slab and cast steel. In the continuous casting equipment that manufactures, the pinch roll bearing wear, roll wear, roll eccentricity, and abnormal rolling reduction are monitored continuously for the current change pattern by continuously monitoring the load current of the drive motor of all pinch rolls. A pinch roll abnormality monitoring method in a continuous casting facility, which is characterized by detecting by analyzing, the pinch roll abnormality monitoring device of the present invention continuously arranges a plurality of pinch rolls and applies a reduction to the pinch rolls. In continuous casting equipment that produces cast steel by continuously pulling out slabs by rotating by rotating the motor, drive motors are installed on all pinch rolls, A sequencer having a function of diagnosing the abnormality of patterns of load current calculations, a pinch roll abnormality monitoring apparatus in continuous casting equipment, characterized in that a display device for displaying an abnormality of the pattern as an image.

[0009]

1 and 10 show the construction of the pinch roll abnormality monitoring apparatus of the present invention.

The load current of the driving motor 14 for the pinch roll is influenced by the vibration of the mold, and is ± ± in a cycle of 1.0 Hz.
Since there is a large variation of 50%, the abnormality cannot be detected as it is. Therefore, in the load current averaging time calculation 19, the load current integration 20, and the average load current calculation 21, the total load current of the pinch roll drive motor 14 is 10
Waveform shaping is continuously performed by averaging every cycle of one rotation. That is, in the load current averaging time calculation 19 in the sequencer 25, the time Y during which the roll makes one-tenth rotation is used as the load current averaging time, and the roll diameter D is calculated from the roll diameter D in accordance with Equation 1.

[0011]

[Equation 1] Y: One-tenth rotation time of the roll (second) D: Roll diameter (mm) π: Circular ratio S: Roll rotation speed (m / min)

In the load current integration 20, the total load current of the drive motor 14 of the drive roll 11 is 100 ms for each roll.
Sampling is performed in a cycle, and the sampling frequency and load current value are integrated. In the average load current calculation 21, at the load current averaging time Y second cycle calculated in the load current averaging time calculation 19, the pinch roll is 1 / 10th from the sampling number and the load current value integrated in the load current integration 20. The average load current value during the rotating time is calculated, and the waveform is shaped.

Next, the waveform-shaped full load current of the drive motor 14 is determined to be an abnormal roll by the bearing / roll wear diagnosis 22, the roll eccentricity diagnosis 23, and the reduction abnormality diagnosis 24 in the sequencer 25 according to the change pattern of the load current. Detects the cause of abnormality constantly / continuously.

In the bearing / roll wear diagnosis 22, as shown in FIG. 5, from the load currents of all the formed pinch rolls,
For example, it is detected that the actual load current is lower than the reference load current 26 based on the thickness and width of the cast steel 8 and the reduction and casting speed, and the wear of the bearing or roll is detected.

In the roll eccentricity diagnosis 23, as shown in FIG. 6, from the load currents of all the formed pinch rolls, for example, a change in the repeatability of the load current that matches the rotation cycle of the roll 11 is detected, and the roll 11 is detected. Detects eccentricity.

In the reduction abnormality diagnosis 24, it is detected from the load currents of all the formed pinch rolls that the load current does not change even if the reduction applied to the roll 10, for example, is changed as shown in FIG. Is abnormal.

FIG. 9 shows an example in which wear of the bearing is detected due to a decrease in load current.

The display device 18 displays an abnormal alarm indicating the abnormal roll detected by the bearing / roll wear diagnosis 22, the roll eccentricity diagnosis 23, and the reduction abnormality diagnosis 24 and the cause of the abnormality. The operator looks at the abnormal alarm display on the display device 18 and takes necessary measures.

[0019]

According to the present invention, it is possible to continuously monitor the abnormality of all pinch rolls. Further, by continuously managing the tendency, abnormality of the pinch roll can be detected before giving a definite quality defect to the cast steel to be manufactured, and appropriate measures can be taken. Therefore, it is possible to prevent the slab from becoming scrap due to the abnormality of the pinch roll.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a pinch roll abnormality monitoring device of the present invention.

FIG. 2 is a diagram showing the structure of pinch rolls.

FIG. 3 is a diagram showing an example of a conventional pinch roll abnormality monitoring device.

FIG. 4 is a diagram showing a continuous casting facility.

FIG. 5 is a diagram showing an example of a decrease in load current.

FIG. 6 is a diagram showing an example of a load current that periodically changes.

FIG. 7 is a diagram showing an example in which the load current does not change even when a reduction is applied to the pinch roll.

FIG. 8 is a diagram showing an example of waveform shaping of the original load current.

FIG. 9 is a diagram showing an example of detecting wear of a bearing due to a decrease in load current.

FIG. 10 is a diagram showing an example of the device of the present invention.

[Explanation of symbols]

 1 Molten Steel 2 Ladle 3 Tundish 4 Mold 5 Guide Roll 6 Pinch Roll 7 Shearing Machine 8 Cast Steel 9 Elevating Cylinder 10 Reduction Roller 11 Drive Roll 12 Bearing 13 Reducer 14 Drive Motor 15 Speed Detector 16 Coupling 17 Speed Deviation Detection 18 Display Device 19 Load current averaging time calculation 20 Load current integration 21 Average load current calculation 22 Bearing / roll wear diagnosis 23 Roll eccentricity diagnosis 24 Rolling down abnormality diagnosis 25 Sequencer 26 Reference load current

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Abe 1 Kimitsu, Kimitsu City, Chiba Nippon Steel Corporation Kimitsu Works

Claims (2)

[Claims] 1. In a continuous casting facility for continuously arranging a plurality of pinch rolls, rolling down the pinch rolls and rotating the pinch rolls to continuously draw out slabs to produce cast steel, a bearing for all pinch rolls is used. Continuous casting equipment characterized by detecting wear, roll wear, roll eccentricity, and abnormal rolling by detecting the load current of the drive motor of all pinch rolls continuously and analyzing the pattern of current change. Pinch roll abnormality monitoring method in. 2. In a continuous casting facility for continuously arranging a plurality of pinch rolls, drawing the slabs continuously by applying a reduction to the pinch rolls and rotating the pinch rolls to produce cast steel, a driving motor for all pinch rolls And a sequencer having a function of diagnosing an abnormal pattern by calculating a load current from each electric motor, and a display device for displaying the abnormal pattern as an image. Roll abnormality monitoring device.