JP2004025211A - Method and device for controlling electromagnetic stirring apparatus for continuous casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method and its device with which the development of breakdown caused by abnormal vibration in an electromagnetic stirring apparatus for continuous casting, electromagnetically stirring non-solidified part in the inner part of a continuously cast material is reduced. <P>SOLUTION: Vibration data of at least one direction in the electromagnetic stirring apparatus for continuous casting are collected, and these collected vibration data are compared with the normal vibration data. In the case of judging this result as the abnormal, a current value and/or a frequency set to the electromagnetic stirring apparatus for continuous casting, are reduced by preset prescribed values. In the other case of judging this result as the normal, the treatment is continued as it is. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for preventing abnormal vibration of an electromagnetic stirring device for continuous casting in continuous casting and preventing occurrence of a failure due to the abnormal vibration.
[0002]
[Prior art]
First, an outline of the continuous casting line will be described with reference to FIG.
In the continuous casting line, molten steel 2 is cast from a ladle 3 through a tundish 4 into a mold 5, and a continuous cast material 1 whose interior is still in an unsolidified state is drawn from below the mold 5. At this time, the unsolidified molten steel 2 in the continuous cast material 1 is electromagnetically stirred by the electromagnetic stirrer 10 to improve the quality of the continuous cast material 1. Reference numeral 6 denotes a roll for pressing the continuous casting material. However, description of water cooling and the like is omitted here.
[0003]
An electromagnetic stirrer (also referred to as an EMS (Electro Magnetic Stirrer)) generates an electromagnetic force in an unsolidified portion inside a continuous cast material, and agitates the molten steel in the unsolidified portion with the stirring force to improve the properties of the continuous cast material. Device. Since the electromagnetic force is applied in this manner, vibrations are generated in the device itself due to the reaction force. Therefore, from the design stage of the electromagnetic stirrer, a design that assumes a certain degree of vibration has been made, and the device has been manufactured taking various measures against vibration.
[0004]
[Problems to be solved by the invention]
However, depending on operating conditions, such as fluctuations in the drawing speed of the continuous casting material and bulging conditions in the continuous casting line, such vibrations may be promoted, and vibrations more than expected at the time of design often occur.
Due to such abnormal vibrations, stress concentrates on weak parts such as joints and flanges of water-cooled copper pipes circulated inside the electromagnetic stirrer for cooling the coil, and various kinds of cracks and the like occur. Failures occurred frequently.
[0005]
An object of the present invention is to reduce the occurrence of a failure due to such abnormal vibration.
[0006]
[Means for Solving the Problems]
The present invention has solved the above-mentioned problems by a method and an apparatus for controlling an electromagnetic stirrer for continuous casting described in the following items.
(1) A method for controlling a continuous casting electromagnetic stirrer for electromagnetically stirring an unsolidified portion inside a continuous casting material, wherein vibration data in at least one direction of the continuous casting electromagnetic stirrer is collected, and the vibration data and By comparing the reference vibration data, if it is determined to be abnormal, the current value and / or frequency set in the electromagnetic agitator for continuous casting is reduced by a predetermined value set in advance. A method for controlling an electromagnetic stirrer for continuous casting, characterized in that a process is performed in which it is determined that the condition is not abnormal when the condition is not abnormal.
{Circle around (2)} After the set current value and / or frequency is reduced to a predetermined value, data on the set current value and / or frequency is further collected, and the collected data and the electromagnetic stirring for continuous casting are collected. Comparing the set current value and frequency data for each steel type within a range that does not impair the effect of the electromagnetic stirring of the apparatus, and when it is determined that the effect of the electromagnetic stirring is impaired, an alarm output is performed. 3. The method for controlling an electromagnetic stirring device for continuous casting according to item 1.
{Circle over (3)} The control method of the electromagnetic stirring apparatus for continuous casting according to <1> or <2>, wherein the vibration data is collected one by one in three-dimensional directions.
(4) A control device of an electromagnetic stirring device for continuous casting for electromagnetically stirring an unsolidified portion inside a continuous casting material, wherein at least one vibration sensor provided in the electromagnetic stirring device for continuous casting, and the vibration sensor By comparing the vibration data and the reference vibration data collected by the above, if it is determined to be abnormal, the current value and / or frequency set in the electromagnetic agitator for continuous casting is reduced by a predetermined value, On the other hand, there is provided a PLC for performing a process for keeping the vibration data as it is when it is determined that the vibration data is not abnormal.
(5) After the PLC reduces the set current value and / or frequency to a predetermined value, the PLC further collects data on the set current value and / or frequency. By comparing the set current value and frequency data for each steel type in a range that does not impair the electromagnetic stirring effect of the continuous casting electromagnetic stirrer, when it is determined that the effect of the electromagnetic stirring is impaired, an alarm is output. The control device of the electromagnetic stirring device for continuous casting according to the above item (4), wherein
(6) The control device of the electromagnetic stirring device for continuous casting as described in (4) or (5) above, wherein the vibration sensors are arranged one by one in three-dimensional directions.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
First, an electromagnetic stirring device (EMS) 10 for continuous casting to which the present invention is applied will be described with reference to FIG.
The electromagnetic agitator 10 for continuous casting is a device in which a coil winding and an iron core 11 are built in a water-cooled casing 17 and electromagnetically agitates molten steel 2 in an unsolidified portion inside the continuous casting material 1.
[0008]
Here, the coil winding formed on the iron core is divided into, for example, two coils. Then, an alternating current of about 1000 A is applied to one coil and about 600 A is applied to the other coil, and the two coils are switched at about 2 Hz or about 1.5 Hz to efficiently perform electromagnetic stirring. I have.
The water-cooled casing 17 is provided with an iron core fixing frame 14 for fixing and holding the built-in iron core, thereby suppressing the vibration of the coil.
[0009]
The present invention is characterized in that at least one vibration sensor 15, preferably one vibration sensor 15 is attached to the iron core fixed frame 14 in a three-dimensional direction.
Here, since the vibration generated in the electromagnetic agitator 10 for continuous casting shows a complicated behavior due to various factors such as an operation state, the vibration sensor 15 is arranged in a three-dimensional direction, and the spatial vibration state is reduced. It is preferable to be able to capture. However, when the direction in which the abnormal vibration described later is generated or when the direction in which the vibration is generated can be specified, a single vibration sensor may be provided.
[0010]
The present invention is characterized in that abnormal vibration of the electromagnetic stirring device 10 for continuous casting is detected based on the signal of the vibration sensor 15 arranged in this way, and control is performed to eliminate the abnormal vibration.
Each sensor signal cable 16 of the vibration sensor 15 is connected to a PLC (Programmable Logic Controller) 20 so that the PLC 20 can continuously monitor the vibration state. Further, a storage device 21 and an alarm device 22 are connected to the PLC 20. These functions will be described later.
[0011]
Next, a control scheme for suppressing abnormal vibration in the present invention will be described based on the flowchart shown in FIG.
In the present invention, first, as preprocessing, data serving as a reference for performing control of abnormal vibration suppression is collected.
First, in a normal operation state, a signal of the vibration sensor 15 attached to the EMS 10 is continuously input to the PLC 20, and vibration data (acceleration, amplitude, frequency, etc.) normally generated in the EMS 10 is collected, and "reference vibration" The data is stored in the storage device 21 (110).
[0012]
At the same time, if necessary, data of the set current value and frequency of the EMS 10 within a range that does not impair the effect of the EMS 10 is collected for each steel type, and stored in the storage device 21 in the form of a table (120).
Next, the following processing is performed during the EMS vibration determination processing during online operation.
[0013]
First, EMS vibration data is measured (210).
Then, the PLC compares the measured data with the reference vibration data stored in the storage device, and determines whether or not the vibration is abnormal (220).
In the simplest case, for example, a method based on a threshold value determination for comparing the magnitude of the deviation of the measured data from the reference vibration data is effective.
[0014]
Here, when it is determined that the vibration is not abnormal, the process proceeds to the next loop and the EMS vibration data is measured again.
On the other hand, if it is determined that the vibration is abnormal, a process of reducing the current value and / or frequency set in the EMS by a predetermined value is performed (230). Note that the predetermined value to be reduced is appropriately determined based on the operation results so far.
[0015]
Next, data collection is performed on the set current value and / or frequency after the reduction, and a comparison process is performed with a table value stored in the storage device 21 to determine whether the effect of the EMS is impaired (240).
Here, if it is determined that the effect is not impaired, the process directly proceeds to the next loop and shifts to the step of measuring EMS vibration data again.
[0016]
On the other hand, when it is determined that the effect of the EMS is impaired, an alarm process is appropriately performed (250). The alarm is issued by a buzzer sound, a warning light, a display on a display, or the like.
When an alarm is issued, processing such as reduction of the pouring speed of the line or reduction of the throughput is performed according to the judgment of the operator. At the same time, a check is made to see if a problem such as bulging has occurred. However, it is more preferable to construct an automation system that automates a series of these operator tasks and uses an alarm output as a trigger.
[0017]
【Example】
The control method of the electromagnetic stirring device for continuous casting of the present invention was applied to an electromagnetic stirring device for continuous casting attached to a continuous casting line of a slab for steelmaking. As a result, a failure such as a crack breakage of a water-cooled copper tube, which has conventionally occurred about 4 to 5 times a year, can be reduced to once a year or less.
[0018]
【The invention's effect】
According to the present invention, abnormal vibration of the electromagnetic stirring device for continuous casting can be effectively reduced, the occurrence of device failure can be reduced, and the reliability of the equipment can be improved.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a control flow of the present invention.
FIG. 2 is a schematic view of an electromagnetic stirring device for continuous casting to which the present invention is applied.
FIG. 3 is a schematic diagram of a continuous casting line.
[Explanation of symbols]
1 Continuous cast material 2 Molten steel 3 Ladle (ladle)
4 Tundish 5 Mold 6 Roll 10 Electromagnetic stirrer (EMS)
DESCRIPTION OF SYMBOLS 11 Coil winding and iron core 12 Cable connection port 13 Cooling water flange 14 Iron core fixed frame 15 Vibration sensor 16 Sensor signal cable 17 Water-cooled casing 20 PLC (Programmable Logic Controller)
21 storage device 22 alarm device

Claims (6)

A method of controlling an electromagnetic stirrer for continuous casting that electromagnetically stirs an unsolidified portion inside a continuous cast material,
Collecting vibration data in at least one direction of the electromagnetic agitator for continuous casting,
By comparing the vibration data with the reference vibration data, if it is determined to be abnormal, the current value and / or the frequency set in the continuous casting electromagnetic stirrer are reduced by a predetermined value. A method of controlling an electromagnetic stirrer for continuous casting, characterized by performing a process of keeping the vibration data as it is when it is determined that the vibration data is not abnormal. After reducing the set current value and / or frequency to a predetermined value, data collection is further performed on the set current value and / or frequency, and the collected data and the electromagnetic force of the electromagnetic agitator for continuous casting are collected. 2. The continuous output according to claim 1, wherein a comparison is made between the set current value and the frequency data for each steel type in a range that does not impair the stirring effect, and when it is determined that the effect of the electromagnetic stirring is impaired, an alarm output is performed. A method for controlling an electromagnetic stirring device for casting. 3. The method according to claim 1, wherein the vibration data is collected one by one in a three-dimensional direction. A control device of an electromagnetic stirring device for continuous casting that electromagnetically stirs an unsolidified portion inside a continuous casting material,
At least one vibration sensor provided in the electromagnetic agitator for continuous casting,
By comparing the vibration data collected by the vibration sensor with the reference vibration data, if it is determined that there is an abnormality, the current value and / or frequency set in the electromagnetic agitator for continuous casting is set to a predetermined value. A PLC that performs processing for reducing the vibration data and, when it is determined that the vibration data is not abnormal, leaving the vibration data unchanged;
A control device for an electromagnetic stirrer for continuous casting, comprising: The PLC is
After reducing the set current value and / or the frequency to the predetermined value, data collection for the set current value and / or frequency is further performed, and the collected data and the electromagnetic stirring device for the continuous casting are collected. Comparing the set current value and frequency data for each steel type within a range that does not impair the effect of electromagnetic stirring, and when it is determined that the effect of electromagnetic stirring is impaired, an alarm is output. Item 5. A control device for an electromagnetic stirring device for continuous casting according to item 4. The control device of the electromagnetic stirring device for continuous casting according to claim 4 or 5, wherein the vibration sensors are arranged one by one in a three-dimensional direction.

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