JP2007136530A - Method for detecting crease of metal strip, and metal strip manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal strip crease detecting method capable of detecting not only a crease generated over the total width of the metal strip but also a crease generated on a width end of the metal strip. <P>SOLUTION: When a steel strip S is wound by a winding device 4, a crease generated over the total width of the steel strip S and a crease generated on a width end of the steel strip S is detected based on the signal output of a pressure sensor 6 for detecting the pressure change in a pinch roll rolling-reduction cylinder 5, and the signal output of a Magnescale 7 for magnetically measuring the displacement of a piston rod of the pinch roll rolling-reduction cylinder 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for detecting breakage of a metal band and a method for manufacturing the metal band, for example, when winding a metal band such as a steel band in hot rolling.

  In the hot rolling line of a metal strip, the metal strip that has been rolled to a desired thickness by a finishing mill runs on a run-out table and is coiled by being wound by a winding device. At this time, when the tip of the metal band floats up from the runout table due to wind pressure, it is folded and overlapped, and is wound up as it is by a winding device, so that it is folded into two at the tip of the metal band (hereinafter referred to as “head fold”). May also occur). Also, after the tip of the metal band is wound around the winding device, the metal band after the tip snakes and comes into contact with the side guide that restrains the metal band. As a result of being taken up by the take-up device, two sheets of metal band may be folded (hereinafter also referred to as “aperture” for distinction).

Regarding the detection of such a two-piece metal band breakage, conventionally, a method of detecting a two-piece breakage by measuring a gap fluctuation of a pinch roll arranged just before the winding device has been adopted (for example, Patent Document 1).
JP 2003-285118 A

  However, in the method of detecting the folding of the metal strip from the gap fluctuation of the pinch roll, the fluctuation of the pinch roll gap occurs in the case of the double folding that occurs over the entire width of the metal band, such as the head folding at the tip of the metal band. However, in the case of a double fold occurring at the end of the width of the metal strip, it is difficult to detect because the gap fluctuation of the pinch roll is small. It is not permitted in terms of quality assurance that the metal strip that has been folded twice is delivered to the customer as it is.

  The present invention has been made paying attention to the above-mentioned problems, and its purpose is to detect not only double folding that occurs over the entire width of the metal band, but also double folding that occurs at the width end of the metal band. An object of the present invention is to provide a method for detecting a broken metal strip. In addition, another object of the present invention is to prevent the occurrence of double folding such as a squeeze when winding the metal band, or the metal band that has been double-folded such as a head fold to the customer as it is. An object of the present invention is to provide a method of manufacturing a metal strip that can be prevented from being delivered.

In order to solve the above-mentioned problem, the method for detecting the folding of a metal strip according to claim 1 of the present invention is such that when the metal strip is wound by the winding device, the metal strip is broken immediately before the winding device. It is detected from gap fluctuation and pressing force fluctuation of the arranged pinch rolls.
The metal strip manufacturing method according to claim 2 of the present invention is characterized in that the detection method according to claim 1 is used.

According to the method for detecting a double break of a metal strip according to claim 1 of the present invention, the double strip of the metal strip is detected from the fluctuation of the pinch roll gap and the fluctuation of the pressing force. Even when the fluctuation is small, it is possible to detect the folding of the two sheets, so it is possible to detect not only the folding of the two sheets that occurs over the entire width of the metal band but also the folding of the two sheets that occurs at the end of the width of the metal band.
According to the metal band manufacturing method of the present invention of the present invention, it is possible to detect not only two sheet folds that occur over the entire width of the metal band but also two sheet folds that occur at the width end of the metal band. Therefore, when winding the metal band, it prevents the occurrence of double folding like a squeeze, or prevents the metal band with double folding like a head fold from being delivered to the customer as it is. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment in which the present invention is applied to a steel strip hot rolling line. In FIG. 1, reference numeral 1 denotes a finish rolling mill, and a steel strip S rolled to a desired thickness by the finish rolling mill 1 is wound up by a winding device 4 through side guides 2 and pinch rolls 3 and 3. It is like that.

The side guide 2 is arranged in the middle of the run-out table between the finishing mill 1 and the pinch rolls 3 and 3, and the steel strip S that has passed through the finishing mill 1 is pinched while being meandered by the side guide 2. It is sent to rolls 3 and 3.
The pinch rolls 3 and 3 are disposed immediately before the winding device 4, and a pinch roll pressing force is applied to the steel strip S passing between the pinch rolls 3 and 3 by the pinch roll reduction cylinder 5. It has become.

  The pinch roll pressure reduction cylinder 5 is operated by pressure oil supplied from a pressure oil supply source (not shown) such as a hydraulic motor via a pressure oil supply line. A pressure sensor 6 for detecting a pressure change in the pinch roll pressure reduction cylinder 5 is provided, and a magnet scale 7 for magnetically measuring the piston rod displacement amount (oil column deviation) of the pinch roll pressure reduction cylinder 5 is provided. Yes.

  A control signal is supplied from the control device 8 to the finishing mill 1, the winding device 4 and the pinch roll reduction cylinder 5. The control device 8 includes a calculation unit 81 that calculates the fluctuation of the pressing force of the pinch rolls 3 and 3 with respect to the steel strip S and the fluctuation of the gap between the pinch rolls 3 and 3. And the signal output of the magnescale 7 is supplied.

  Further, the control device 8 has a comparison unit 82 for comparing the calculation result of the calculation unit 81 with a predetermined set value. In this comparison unit 82, the pinch rolls 3 and 3 obtained by the calculation unit 81 are connected. The first threshold value set to a value (1.6 mm) lower than the plate thickness (eg, 2.0 mm) of the steel strip S by, for example, 20%, and 0.1 times the plate thickness of the steel strip S, for example. Is compared with a second threshold value corresponding to (see FIG. 2), and the fluctuation amount of the pressing force of the pinch rolls 3 and 3 obtained by the calculation unit 81 is more than 50 times the normal pinch roll pressing force (for example, 10 kN). For example, a third threshold value (see FIG. 2) set to a value that is 20% lower (400 kN) and a fourth threshold value corresponding to a value (40 kN) that is, for example, 20% lower than five times the normal pinch roll pressing force (see FIG. 2). 2)).

  FIG. 2 is a diagram showing the experimental results when the sheet strip S having a thickness of 2.0 mm is used and when it does not occur. In FIG. An example of the case where no occurred. In the figure, ● represents an example of the case where the steel strip S is folded twice. It is determined that the second threshold value in FIG. 2 and the region on the right side of the second threshold value and the fourth threshold value or more have at least two folds called a restriction at the width end of the steel strip S. The first threshold value and the region on the right side of the first threshold value or the third threshold value or higher region are regions where it is determined that a head break has occurred at the tip of the steel strip S.

Hereinafter, a method for determining occurrence of folding of two sheets will be specifically described.
The control device 8 determines the occurrence of folding of two sheets based on the comparison result of the comparison unit 82, and the finish rolling mill 1, the winding device 4, and the pinch roll reduction cylinder based on the determination result of the determination unit 83. In the determination unit 83, the gap fluctuation between the pinch rolls 3 and 3 obtained by the calculation unit 81 has reached the second threshold value, and the calculation unit 81. When the fluctuation of the pressing force of the pinch rolls 3, 3 obtained in step 4 reaches the fourth threshold value, at least the width end of the steel strip S (for example, a region corresponding to 1/10 of the full width) is referred to as a restriction. It is determined that the two sheets are broken. According to the determination method described above, at least means that there is a possibility that two-fold folding called “head folding” described below has occurred.

  For example, when a two-fold fold called a head fold occurs in the steel strip S having a thickness of 2.0 mm, the gap between the pinch rolls 3 and 3 disposed immediately before the winding device 4 is a normal set value (for example, 2 .0 mm) and fluctuate about twice. At this time, the control device 8 takes in the signals output from the pressure sensor 9 and the magnescale 7 at intervals of, for example, 5 msec, and the pinch roll 3 for the steel strip S from the pressure change in the pinch roll reduction cylinder 5 detected by the pressure sensor 9. , 3 is calculated, and the calculation unit 81 calculates the gap fluctuation between the pinch rolls 3 and 3 from the piston rod displacement of the pinch roll reduction cylinder 5 measured by the magnescale 7. At some point, the comparison result is compared with the third threshold value and the fourth threshold value set in advance by the comparison unit 82. Here, when the amount of gap fluctuation between the pinch rolls 3 and 3 obtained by the calculation unit 81 has reached a third threshold value (for example, 1.6 mm), the determination unit 83 of the control device 8 starts with the steel strip S. It can be determined that two-fold folding called folding has occurred.

  Alternatively, in such a configuration, for example, when a two-fold fold called a head fold occurs in a steel strip S having a thickness of 2.0 mm, the pressing force of the pinch rolls 3 and 3 against the steel strip S is a normal set value ( For example, the fluctuation of the pressing force of the pinch rolls 3 and 3 obtained by the calculation unit 81 reaches the third threshold value (for example, 400 kN) as described above. It may be determined that a fold has occurred. Otherwise, it is determined that an aperture has occurred.

In addition, if the determination part 83 determines with the steel strip S having two-piece folds, such as a head fold and a squeeze, it sends an alarm generation signal to an alarm generation part (not shown).
Alternatively, as another example of the determination method, FIG. 3 shows a variation in the pressing force of the pinch rolls 3 and 3 and the pinch rolls 3 and 3 when the sheet strip S has a thickness of 2.0 mm. The relationship with the gap fluctuation is shown. As is clear from the figure, when the double fold (head fold) occurs over the entire width of the steel strip S, the gap fluctuation of the pinch rolls 3 and 3 becomes 2.0 mm, and the pressing force fluctuation of the pinch rolls 3 and 3 Is 500 kN. On the other hand, when two sheets are folded (drawn) at the width end of the steel strip S, the gap fluctuation of the pinch rolls 3 and 3 is 0.2 mm, and the pressing force fluctuation of the pinch rolls 3 and 3 is 50 kN.

Using this, first, if both the gap fluctuation and the pressing force fluctuation are higher than the level at which it can be determined that the head breakage has occurred, it is determined that the head breakage has occurred. If one or both of them are at or above a level at which it can be determined that an aperture has occurred, it may be determined that an aperture has occurred.
Therefore, when the steel strip S is taken up by the take-up device 4, the gap fluctuation and pressing force fluctuation of the pinch rolls 3, 3 arranged immediately before the take-up apparatus 4 are monitored, and the pinch rolls 3, 3 are pushed. By issuing an alarm or the like when the force fluctuation or the gap fluctuation between the pinch rolls 3 and 3 reaches a preset threshold value, for example, it is emitted at the longitudinal intermediate portion excluding the tip of the steel strip S. If there is, it may be performed by an operator's manual intervention operation or automatically. By temporarily widening the gap between the pinch rolls 3 and 3, the quality of the steel strip S caused by the folding of the two sheets is prevented. Can do. Because the two-folded portion generated at the width end is stretched and flattened by the tension acting between the finishing mill 1 and the winding device 4 and the force received from the steel strip wound further upward. is there.

  In the case of a broken head, it is difficult to flatten the head, so that the alarm is issued is temporarily stored in a storage medium (not shown) as information linked to the steel strip S (coil) from which the alarm is issued. In addition, by cutting off the broken part in the next passage process, such as pickling line and skin pass line (add these steps if the next passage process is not scheduled), When delivered, measures can be taken to ensure quality.

  Further, when the steel strip S is taken up by the take-up device 4, the pressing force fluctuation of the pinch rolls 3, 3 arranged immediately before the take-up device 4 is obtained from the pressure change in the pinch roll lowering cylinder 5, and the pinch By obtaining the gap fluctuation between the rolls 3 and 3 from the displacement of the piston rod of the pinch roll reduction cylinder 5, even if the gap fluctuation between the pinch rolls 3 and 3 is small, it is possible to detect the folding of the two sheets. It is possible to detect not only the two-sheet folding that occurs over the entire length but also the two-sheet folding that occurs at the width end of the steel strip S.

  In the above-described embodiment, the case where the present invention is applied to a hot rolling line of a steel strip is illustrated, but the present invention is not limited to this, for example, cold rolling a metal strip such as a steel strip. It can also be applied to. Further, although the magnet scale 7 is exemplified as a means for measuring the piston rod displacement amount of the pinch roll reduction cylinder 5, the piston rod displacement amount of the pinch roll reduction cylinder 5 is measured by using something other than the magnet scale. May be.

It is a figure which shows one Embodiment at the time of applying the two-piece folding detection method of the metal strip which concerns on this invention to the hot rolling line of a steel strip. It is a figure which shows the experimental result in the case where it does not generate | occur | produce with the case where 2 sheet bending generate | occur | produces using the steel strip whose plate | board thickness is 2.0 mm. It is a figure which shows the relationship between the pressing force fluctuation | variation of the pinch roll at the time of a 2-sheet fold occurring in a steel strip, and the gap fluctuation | variation between pinch rolls.

Explanation of symbols

DESCRIPTION OF SYMBOLS S Steel strip 1 Finishing mill 2 Side guide 3 Pinch roll 4 Winding device 5 Pinch roll reduction cylinder 6 Pressure sensor 7 Magnescale 8 Control device 81 Calculation part 82 Comparison part 83 Determination part

Claims (2)

  When winding a metal band with a winding device, the folding of the metal band is detected from gap fluctuation and pressing force fluctuation of a pinch roll arranged immediately before the winding apparatus. Detection method.   A method for producing a metal strip, wherein the detection method according to claim 1 is used.

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