JP2019051534A - Abnormality detection method and abnormality detection device - Google Patents

Abstract

To provide a method which improves a detection ratio of folding on a tail end side while suppressing erroneous detection due to disturbance.SOLUTION: A method for detecting folding abnormality on a tail end side of a metal strip 1 in winding equipment for winding the metal strip 1 rolled by a finishing mill 6 around a mandrel 4 via a pinch roll 3. According to this method, load actual performance in the pinch roll 3, which holds the metal strip 1, is collected at a preset sampling period, non-periodic hunting of load fluctuation associated with folding occurrence is detected from collected plural load actual performance, and on the basis of said detection, presence or absence of folding occurrence on a tail end side of the metal strip 1 is determined. For example, non-periodic hunting of load fluctuation associated with folding occurrence is determined from such a load fluctuation difference that folding abnormality can be detected based on load actual performance, in such a manner that a sampling period is so made as to be 30 [ms] or less.SELECTED DRAWING: Figure 1

Description

  The present invention is an abnormality detecting whether or not folding occurs at the tail end side of a metal band that has become a coil in a winding device that winds a rolled metal band with a pinch roll and winds it around a mandrel to form a coil. It relates to detection technology. In particular, the present invention is a technique suitable for hot-rolled steel sheets and the like in a hot strip mill.

As a metal band abnormality detection method, there are techniques described in Patent Documents 1 to 3.
In Patent Document 1, a load or the like when a thin plate passes through a pair of rolls arranged in a thin plate line is detected, and depending on whether the detected value or the integrated value thereof exceeds a threshold value, the folding portion of the thin plate is detected. Detect the presence or absence.
Here, in patent document 1, the folding in the front-end | tip part in a thin plate is detected (refer paragraph 0002, paragraph 0009).
In Patent Document 2, a coil end face wound around a mandrel is imaged, and the captured image is subjected to image processing to acquire a spiral figure, and the two folded coils are detected from the acquired spiral figure.

In Patent Document 3, when a load on a pinch roll that guides a steel plate to a mandrel (coiler) and an oil column of a hydraulic cylinder are measured, and there is no oil column variation of the hydraulic cylinder and only a load variation is detected, an ear loss occurs. Is detected, and the occurrence of folding is detected when both oil column fluctuation and load fluctuation (load increase) of the hydraulic cylinder are detected.
Here, in patent document 3, it is aimed at the folding in the front-end | tip part and stationary part of a steel plate (refer paragraph 0019).

Japanese Patent Laid-Open No. 7-80547 JP-A-10-213550 JP 2005-262275 A

In Patent Documents 1 and 3, the presence or absence of folding is detected by a pinch roll based on the load absolute value in load fluctuation, its integrated value, oil column fluctuation, and load fluctuation (load absolute value).
However, when the pinch roll load absolute value exceeds the threshold, when detecting the folding in the pinch roll, depending on the sampling period of the load measurement value, it is not possible to detect the vicinity of the peak value when the folding occurs, There is a possibility that load fluctuation (absolute load value) for detecting abnormalities in folding cannot be detected.
Further, if it is simply determined whether or not the absolute value of the pinch roll load exceeds the threshold value, there is a possibility that it is erroneously detected that there is a fold due to a disturbance even though the fold does not occur.
In addition, the abnormality detection methods of Patent Documents 1 and 3 do not assume detection of a folded portion on the tail end side.
The present invention has been made paying attention to the above points, and an object thereof is to improve the detection rate of folding on the tail end side while suppressing erroneous detection due to disturbance.

In order to solve the problem, one aspect of the present invention is to provide a tail of the metal strip wound around the mandrel in a winding facility that winds the metal strip rolled by a finish rolling mill onto a mandrel via a pinch roll. An abnormality detection method for detecting a bending abnormality on an end side, wherein a load record at the pinch roll holding the metal band is sampled at a sampling period of 30 [ms] or less, and a plurality of sampled load records are obtained. From the detection of the non-periodic hunting of the load fluctuation accompanying the occurrence of folding, and determining the presence or absence of folding on the tail end side of the metal band based on the detection For example, the load fluctuation accompanying the occurrence of folding The non-periodic hunting is determined by setting the sampling cycle to 30 [ms] or less and detecting the folding abnormality based on the actual load with a detected load fluctuation difference.

  According to one embodiment of the present invention, it is possible to improve the detection rate of folding on the tail end side while suppressing erroneous detection due to disturbance.

It is a figure explaining the hot rolling line which concerns on embodiment based on this invention. It is a figure explaining the structure of an abnormality detection apparatus. It is a figure which shows the case where the peak of a load fluctuation | variation comes during the sampling at the time of a sampling period of 50 ms, and cannot be detected.

Next, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, a hot-rolled steel sheet will be described as an example of the metal strip. However, the metal strip targeted by the present invention is not limited to the hot-rolled steel sheet.
(Constitution)
In the hot rolling line, a slab heated in a heating furnace (not shown) is supplied to a hot rolling mill. Subsequently, the slab is rolled into a metal strip by a hot finish rolling mill. In addition, a metal strip is conveyed by the table roller not shown arrange | positioned along the pass line of a hot rolling line.
As shown in FIG. 1, the metal strip 1 after finish rolling is cooled while being conveyed by the run-out table 2, then sent to the mandrel 4 through the pinch roll 3, and wound around the mandrel 4. It becomes a coil. In FIG. 1, the code | symbol 6 shows a finishing mill.
The pinch roll 3 is rotationally driven by the pinch roll motor 5 and the gap adjusting device 20 adjusts the gap (pinch gap) between the upper pinch roll and the lower pinch roll constituting the pinch roll 3. Further, the motor current (armature current) of the motor 5 is detected and supplied to the control device 7.

The control device 7 controls the pinch roll motor 5 so that the tip of the metal band 1 passes through the pinch roll 3 so that the peripheral speed is higher than the conveying speed of the metal band 1. Further, when the control device 7 determines that the leading end of the metal strip 1 has been wound around the mandrel 4 by several turns, the motor for the pinch roll is adjusted so that the peripheral speed of the pinch roll 3 is equal to the conveying speed of the metal strip 1. 5 is speed controlled. Wrapping several turns means that tension can be applied from the mandrel 4 to the metal strip 1.
Further, the control device 7 does not perform the speed control by the motor 5 until the tail end portion of the metal strip 1 passes through the designated stand 6b of the finish rolling mill 6 or is minimum for idling. The motor 5 is controlled so that a torque corresponding to the required mechanical friction (mechanical loss) is output in a compensatory manner. It is assumed that the tip of the metal band 1 is wound around the mandrel 4. Here, the designated stand 6b is a stand set in advance from the stands between the first stand and the final stand 6a.

  And if the control apparatus 7 determines with the tail end part of the metal strip 1 having passed through the designated stand 6b of the finishing mill 6 (the last stand 6a was turned off) and starting the tail end pinch roll control, the set target tension The control of the pinch roll 3 for controlling the take-up tension is started so as to be a value. For example, the control device 7 controls the motor 5 for the pinch roll 3 so that the peripheral speed is slower than the conveying speed of the metal band 1 by a set lag rate, and the pinch gap at the pinch roll 3 is set to the set gap amount. adjust. As a result, the tail end side of the metal band 1 is wound around the mandrel while being pinched by the pinch roll 3 and given a predetermined tension.

Moreover, this embodiment is provided with the abnormality detection apparatus 10 for detecting the folding abnormality on the tail end side of the metal band 1 that occurs in the pinch roll 3.
The abnormality detection device 10 includes a load detection unit 11 and an abnormality detection unit main body 12. As shown in FIG. 2, the abnormality detection unit main body 12 includes a load record acquisition unit 12A and a folding determination unit 12B.
The load detection unit 11 detects the load by measuring the actual load of the pinch roll 3 that sandwiches the metal band 1. The detection of the load result is, for example, a pressing force by the upper and lower pinch rolls 3.
The pressing force is detected from, for example, the actual current value of the motor 5 for the load cell or the pinch roll 3.

The load record acquisition unit 12A acquires load information from the load detection unit 11 at a preset sampling cycle.
In the present embodiment, the preset sampling period is in the range of 15 [ms] to 30 [ms], and is set to 25 [ms], for example.
The folding determination unit 12B detects the non-periodic hunting of the load fluctuation corresponding to the occurrence of folding from the load information acquired by the load record acquisition unit 12A, and based on the detection, the tail end side of the metal strip 1 It is determined whether or not there is a fold.

In this embodiment, as a detection of non-periodic hunting of load fluctuation corresponding to the occurrence of folding, a preset sampling period is specified in a range of 15 [ms] to 30 [ms], for example, 25 [ms]. Further, the load fluctuation difference (sampling value difference) of the actual load is obtained, and the presence or absence of the occurrence of folding on the tail end side of the metal strip 1 is determined from the obtained load fluctuation difference. For example, when the load fluctuation difference, which is the difference between two load results, exceeds a preset threshold value, it is detected that the metal band 1 is folded on the tail end side.
As the threshold value to be set, for example, a value capable of detecting a load fluctuation difference when the folding on the tail end side of the metal band 1 actually occurs (a value having a safety allowance by a predetermined value) is set.

  This threshold value varies depending on the plate thickness of the metal strip 1 after finish rolling, but the inventors have investigated that the metal strip 1 has a plate thickness of 1.80 mm or less and the plate thickness is over 1.8 mm to 5 mm. In the metal strip 1 of 0.000 mm or less, the load fluctuation difference when the folding on the tail end side of the metal strip 1 actually occurred was almost the same value. On the other hand, the load fluctuation difference when the folding on the tail end side of the metal strip 1 with a plate thickness exceeding 5.00 mm occurs is on the tail end side of the metal strip 1 with a plate thickness of 5.00 mm or less. It was larger than the load fluctuation difference when folding occurred.

Therefore, the threshold value is preferably set to a different value when the thickness after rolling is 5.00 mm or less and when the thickness after rolling exceeds 5.00 mm.
However, since folding is likely to occur in the metal strip 1 having a thickness of 3.2 mm or less after rolling, the metal strip 1 having such a thickness may be targeted.
Here, when the sampling period is set to around 25 [ms], the difference between the target load record P (t) and its previous value P (t−1) may be used as the load fluctuation difference.

Although the sampling period may be smaller than 15 [ms], the time interval for taking the load fluctuation difference is 15 to 30 [ms] for detecting non-periodic hunting of the load fluctuation accompanying the occurrence of folding. Preferably, 23 to 28 [ms] is more preferable.
Therefore, when the sampling cycle is 5 [ms], for example, the load fluctuation difference between the target load record P (t) and the load record P (t-5), that is, the load record 25 [ms] before. use.

Here, if the sampling cycle is set to 5 [ms], and the load fluctuation difference between the target load record P (t) and the previous load record P (t−1) is used, the sampling cycle is too short. There is a possibility that the hunting of the periodicity of load fluctuation due to disturbance from the above will be erroneously detected.
Thus, the load fluctuation difference and the threshold value for detecting the non-periodic hunting of the load fluctuation accompanying the occurrence of the folding are, for example, the load when the folding on the tail end side of the metal strip 1 actually occurs. A load fluctuation difference and a threshold value that can detect non-periodic hunting of the load fluctuation accompanying the occurrence of folding may be set based on the actual change state.

  Here, the inventors set the sampling period to 50 [ms], and there is a folding error when the load fluctuation (load absolute value) exceeds the set threshold (for example, 10 tons) continuously for 50 [msec]. As a result, there was a case where the folding of the tail end portion was not detected. When the reason was examined, when the load performance of the pinch roll 3 at the time of folding of the pinch roll 3 was evaluated, for example, it changed only at 30 [msec] or less, and when the sampling period was 50 [ms], As shown in FIG. 3, it has been found that the load fluctuation at the time of folding at the tail end may not be detected. For example, when the sampling cycle is 50 [ms] and the peak of load fluctuation at the time of folding is located at the middle of the sampling time, only the initial part of the rise is detected. Even if it sees, the rise is small (refer FIG. 3).

On the other hand, when the sampling cycle is set to 25 [ms] and the load fluctuation (absolute load value) continuously exceeds the set threshold value for 25 [msec], it is determined that there is a folding abnormality. It has increased. From the investigation results, it was found that the threshold value was exceeded due to disturbance of the pinch roll 3.
The disturbance of the pinch roll 3 is, for example, periodic hunting due to vibration from a bearing that supports the pinch roll 3. Here, it was also confirmed that the periodic hunting due to the vibration from the bearing may exceed the set threshold value.

In view of the above, as described above, when the sampling period is set to 25 [ms] and the load fluctuation difference exceeds a set threshold (for example, 2 tom), the folding abnormality is set. It was confirmed that there was no undetected fold and no false detection due to disturbance.
As described above, in the present embodiment, it can be seen that the presence or absence of folding in the pinch roll 3 when the tail end portion of the metal strip 1 is wound around the mandrel can be detected with high accuracy.

DESCRIPTION OF SYMBOLS 1 Metal strip 3 Pinch roll 4 Mandrel 5 Motor 6 Finishing mill 7 Control apparatus 10 Abnormality detection apparatus 11 Load detection part 12 Abnormality detection part main body 12A Load performance acquisition part 12B Inclusion determination part P (t) Load performance

Claims (4)

An anomaly detection method for detecting an abnormal folding on the tail end side of the metal band wound around the mandrel in a winding facility for winding the metal band rolled by a finish rolling mill onto a mandrel via a pinch roll Because
The actual load with the pinch roll that sandwiches the metal band is sampled at a sampling period of 30 [ms] or less,
A feature is to detect non-periodic hunting of load fluctuation accompanying the occurrence of folding from a plurality of collected load results, and to determine the presence or absence of folding on the tail end side of the metal strip based on the detection. Anomaly detection method. An anomaly detection method for detecting an abnormal folding on the tail end side of the metal band wound around the mandrel in a winding facility for winding the metal band rolled by a finish rolling mill onto a mandrel via a pinch roll Because
The actual load with the pinch roll that sandwiches the metal band is sampled at a sampling period of 30 [ms] or less,
An abnormality detection method characterized by determining the presence or absence of folding on the tail end side of the metal strip based on the load fluctuation difference of the collected load results.   3. The abnormality detection according to claim 2, wherein when the difference in load variation due to the collected load results exceeds a preset threshold value, it is determined that folding occurs on the tail end side of the metal strip. Method. Provided in a winding facility for winding a metal strip rolled by a finish rolling mill onto a mandrel via a pinch roll, and detects an abnormal folding on the tail end side of the metal strip wound around the mandrel An anomaly detection device,
A load detection unit that detects a load on the pinch roll that sandwiches the metal band;
A load record acquisition unit for collecting load information detected by the load detection unit at a preset sampling period;
Based on the load information acquired by the load record acquisition unit, a folding determination unit that determines whether or not folding occurs on the tail end side of the metal strip, and
Set the sampling period to a value in the range of 30 [ms] or less,
The abnormality detection device characterized in that the folding determination unit determines whether or not folding has occurred based on a load fluctuation difference of actual load.

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