JPS60137512A - Method and device for detecting chattering of cold rolling mill - Google Patents

Abstract

PURPOSE:To detect accurately the chattering of a rolling mill by a noncontact system by converting the characteristic sounds of chattering into an electric signal and detecting the generation of chattering when the signal exceeds a set value. CONSTITUTION:The sounds generating as the resonant phenomenon of work rolls 12, backup rolls 14, and a mill housing 16, are collected by a microphone 20, and are converted into an electric signal. Only the characteristic frequency- components of chattering of the output of microphone 20 are passed through a band-pass filter 22. After integrating the outputs of filter 22 by a integrator 24 for a fixed time, it is inputted to a comparator 26 to compare the output voltage of integrator 24 with a set voltage, and a chattering generation signal is outputted when the output voltage of integrator 24 exceeds the set voltage. The chattering generation signal is inputted to a speaker 30 through an alarm-output circuit 28, to produce the alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for detecting chatter in cold rolling.

In general, in cold rolling mills, chattering occurs due to surface damage to the backup roll, excessive or insufficient lubricity of the rolling oil, fluctuations in the strip surface temperature of the strip, etc.
A -second resonance phenomenon called a mark may occur.

This chattering phenomenon is an important factor in operation, and when this chattering phenomenon occurs frequently, horizontal stripe-like thickness fluctuations occur on the board surface with a pitch of several squares to several tens of pitches, and in severe cases, , it is difficult to reach plate breakage.

Therefore, if chattering starts to occur,
It is necessary to take measures such as reducing the rolling speed within 2 seconds, and if this action is delayed, it will lead to plate breakage and quality deterioration, so detection of the chattering phenomenon is extremely important. .

Conventionally, as a device for detecting chattering, for example, a vibration detector is installed in the housing of a rolling mill or in the chock of a backup roll, as shown in Japanese Patent Publication No. 52-2708, and the output voltage exceeds a certain amplitude. It has been proposed to detect the occurrence of chattering when the frequency of occurrence exceeds a predetermined value by counting the frequency of occurrence of chattering.

However, the device proposed in Japanese Patent Publication No. 52-2708 does not detect only the frequency components specific to chattering, and therefore it is easy to erroneously detect the vibration # of the rolling mill drive system. Also, with this device, it is more effective to install a vibration detector in the chock of the backup roll than to install a vibration detector in the housing. There was a problem in that it was necessary to remove the container and reattach it, making the roll rearranging work complicated.

Defense A was made in order to solve the above-mentioned problems of the conventional method. A second object of the present invention is to provide a chattering detection device for a cold rolling mill in which the chattering detection method described above is adopted.

The present invention converts the sound peculiar to chattering generated during rolling of a material to be rolled in a cold rolling mill into electrical No. 18, and since the magnitude of the electrical signal exceeds a set value,
The first objective is achieved by detecting the occurrence of chattering.

The present invention also provides a method for detecting chatter in a cold rolling mill, comprising: a microphone disposed near the cold rolling mill for converting sound generated during rolling of a material to be rolled into electrical No. 13; Extracting means for extracting frequency components specific to chattering from the electrical signal output from the microphone;
The second object is achieved by including a comparator for outputting a chattering occurrence signal when the magnitude of the extraction signal output from the extraction means exceeds a set value.

In the present invention, this occurs during rolling of the material to be rolled. The sound peculiar to chattering is converted into an electrical signal, and when the magnitude of the electrical signal exceeds the set value, the occurrence of chattering is detected. It can be detected well.

In other words, according to the experience of the inventors with branch pieces, when chatter link occurs, it is so severe that it can be heard even if it is about 10 m away from the cold rolling mill (at a position 1 mm away from the cold rolling mill). Approximately 100 to 120 phon) A distinctive buzzing sound can be heard.

Therefore, due to the loudness peculiar to this chatter link,
If you leave it as is, it will disappear naturally, or
It can be determined whether serious problems such as plate breakage will occur if the speed is not reduced immediately.

However, in recent years, rolling operations have been centrally managed away from the rolling mill, making it impossible to hear this sound and often delaying treatment.

Therefore, the present invention is an IC that converts the sound peculiar to chattering into an electrical signal, and detects the occurrence of chattering according to the magnitude of the electrical signal.

The inventors have determined that the frequency of the sound unique to this chattering is
When examined using a 6-stand tandem mill, the frequency was approximately 220 Hz, as shown in Figure 1. In general, the chattering phenomenon is determined by the resiliency constants of the work roll, backup roll, and mill housing, so in the case of this mill, 180
It is determined that this is true based on frequency components around ~250Hz.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a chattering detection device for a six-stand tandem mill to which the present invention is applied will be described in detail with reference to the drawings.

A first embodiment of the present invention includes a work roll 12, a backup roll 14, and a mill housing 1, as shown in FIG.
A microphone 2 disposed near the six-stand tandem mill 10 including the six-stand tandem mill 10 for collecting the sound generated during rolling of the strip 18, which is the material to be rolled, and converting it into an electrical signal.
0 and a bandpass filter 22 that extracts and passes frequency components specific to chattering, for example, 180 to 2507, from the electrical signal output from the microphone 20, and integrates the extracted signal output from the bandpass filter 22 for a certain period of time. an integrator 24, a comparator 26 that outputs a chattering occurrence signal when the integrated signal output from the integrator 24 exceeds a set value, and a comparator 26 that amplifies the chattering occurrence signal output from the comparator 26 and outputs the chattering occurrence signal to a speaker. 30, etc., and an alarm output circuit 28 for outputting an alarm.

The operation of the first actual flow example will be explained below.

In the mill 10, chattering noise generated as a resonance phenomenon between the work roll 12, the backup roll 14, and the mill housing 16 is collected by the microphone 20 and transmitted to C.
converted into an electrical signal. The output of the microphone 20 is
The signal is input to a bandpass filter 22, where only frequency components characteristic of chattering, for example 180 to 250 Hz, are passed. , the output of the Hann I-pass filter 22 is integrated for a certain period of time by an integrator 24 and then input to a comparator 26. The comparator 26 compares the output voltage of the integrator 24 with a set voltage, and outputs a chattering occurrence signal when the integrated voltage of the integrator 24 output exceeds the set voltage. This chattering occurrence signal is transmitted to the alarm output circuit 28.
is inputted to the speaker 30 via the speaker 30, and an alarm is generated.

This first embodiment is installed in a 6-stand tandem mill,
According to the operating guidelines for the mill, the number of plate breaks due to chattering has been reduced to 1/3 compared to before installing the first embodiment.
was able to decrease to

In this first embodiment, the present invention can be implemented using a circuit configuration similar to that of the comparative fishing wheel IIi.

Next, a second embodiment of a chattering detection device for a six-stand tandem mill, in which the present invention is adopted, will be explained in detail.

As shown in FIG. 3, this second embodiment includes a microphone 20 similar to that of the first embodiment, and a frequency analyzer 32 for frequency-analyzing the electrical signal 13 output from the microphone 20.
and a band-pass filter 34 for extracting a frequency component peculiar to chattering, for example, 180 to 250 Hz, from the output of the frequency analyzer 32, and a band-pass filter 34 whose magnitude of the extracted signal output from the band-pass filter 34 is equal to or higher than a set value. When it became.

It is comprised of a comparator 26 similar to that of the first embodiment and l131 for outputting a chattering occurrence signal, and an alarm output circuit 28 and a speaker 30 similar to those of the first embodiment.

Many types of frequency analyzers 32 have been put into practical use, but in this embodiment, one that performs frequency analysis in real time using a fast Fourier transform method can be used.

The operation of the second embodiment will be explained below.

As in the f11 embodiment, the chattering sound collected by the microphone 20 is input to the frequency analyzer 32, where frequency analysis is performed. The output of the frequency analyzer 32 is input to a headband filter 34, which extracts frequency components related to chattering from the microphone 20 output.
For example, 180 to 25011z are extracted. The output of the band-pass filter 34 is input to a comparator 26, where it is compared with a set voltage in the same manner as in the first embodiment, and a chattering generation signal is output when the voltage exceeds the set voltage. Ru. The other points are the same as those of the first embodiment, so the explanation will be omitted.

In each of the above embodiments, an extraction means for extracting frequency components peculiar to chattering from the electrical signal output from the microphone 20 is provided, so that frequency components peculiar to chattering can be easily extracted. It can be extracted reliably. Note that the method of converting the sound peculiar to chattering into an electric signal is not limited to this, but for example, the extraction means may be implemented by giving the microphone 20 itself a characteristic that collects only the sound peculiar to chattering. It is also possible to omit it.

Furthermore, in all of the above embodiments, an alarm is output from the speaker 30 in accordance with the output of the comparator 26, but the method of issuing an alarm in response to a chattering occurrence signal is not limited to this. For example, it is possible to divide the alarm into several alarm levels and generate different alarms depending on the alarm levels. It is also possible to automatically decelerate the mill 10 in response to the chattering occurrence signal.

As explained above, according to the present invention, the occurrence of chattering in a cold rolling mill can be accurately detected without contact.
can be done. Therefore, plate breakage and quality deterioration due to the chattering phenomenon can be prevented. Further, it has excellent effects such as eliminating the need for complicated O-ru rearrangement work.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a sound waveform peculiar to chattering, which is intended to explain the detailed explanation of the present invention, and Fig. 2 is a chattering detection device for a 6-stand tandem mill in which the present invention is adopted. -f block diagram showing the configuration of the first embodiment of
Similarly, FIG. 3 is a block diagram showing the configuration of the second embodiment. 10...6-stand tandem mill, 18...Strip (material to be rolled), 20...Nicrophon, 22.34...Band pass filter, 24...Integrator, 26...Comparator , 32... frequency analyzer. Agent Takaya Ron (and 1 other person)

Claims (2)

[Claims] (1) In a cold rolling mill, the sound peculiar to chattering that occurs during rolling of a material to be rolled is converted into an electrical signal, and when the magnitude of the electrical signal exceeds a set value, chattering occurs. A method for detecting chattering in a cold rolling mill characterized by detecting. (2) A microphone installed in the vicinity of the cold rolling mill for converting the sound generated during rolling of the rolled material into electricity (FFI), and an electric signal output from the microphone. , an extraction means for extracting a frequency component peculiar to chattering, and a comparator for outputting a chattering occurrence signal when the magnitude of the extraction signal of the pressure of the jtJ output means exceeds a setting m. A chattering detection device for a cold rolling mill.