JP4505432B2 - Steel plate shape correction method and shape correction device - Google Patents

Description

  The present invention relates to a shape correction method and a shape correction device for a steel sheet in a hot dipping line such as zinc.

  When manufacturing a hot-dip galvanized steel sheet, first, the steel sheet is run in a hot dip plating bath, and plating is attached to the front and back surfaces. Next, the steel plate with the plating adhered is moved out of the hot dipping bath, and while traveling, high pressure gas such as air is blown from the wiping nozzle toward the front and back surfaces, and the plating adhering to the steel plate is blown away. Adjust the amount of adhesion. Thereafter, a hot dip plated steel sheet is manufactured by subjecting the steel sheet to which the plating has been applied to an alloying treatment.

  In order to produce a hot-dip plated steel sheet with a uniform coating amount, it is necessary to keep the distance between the wiping nozzle and the front and back surfaces of the steel sheet as constant as possible. For this reason, generally, a support roll for pressing the steel plate in the thickness direction and flattening the shape of the steel plate is installed near the outlet side in the hot dipping bath. However, with this support roll alone, the shape of the steel sheet cannot be corrected sufficiently, and warpage with respect to the axis in the plate width direction (so-called C warpage, W warpage, etc.) occurs on the steel sheet that has exited from the hot dipping bath. End up.

  Conventionally, as shown in Patent Document 1, for example, a shape correction technique using a plurality of electromagnets has been used to correct such warpage.

  More specifically, FIG. 1 is a configuration diagram of the shape correction device 100 of Patent Document 1 showing an example of a case where the warpage of the steel sheet cannot be properly corrected. As shown in FIG. The shape correction apparatus 100 is so configured as to leave a hot-dip plating bath (not shown) and sandwich the steel plate I traveling in the transport direction X (the direction from the near side to the far side with respect to the paper surface of FIG. 1) in the plate thickness direction Z. Nine pairs of electromagnets 101 and 102 arranged opposite to each other are provided along the plate width direction Y at a predetermined interval. Each of the electromagnets 101 and 102 is provided with a sensor 110 at the center position in the plate width direction Y on the side facing the steel plate I. Each sensor 110 detects the steel plate I when the opposing steel plate I is in the detection range W in the plate width direction Y, and detects the detected steel plate I portion (hereinafter referred to as a detected portion) 120 in the plate thickness direction Z. It is comprised so that the position of can be measured.

  When each sensor 110 detects each detected part 120, the shape correcting apparatus 100 measures the position in the thickness direction Z of the detected part 120, and the measured position in the thickness direction Z of the detected part 120 is a predetermined target correction. The electromagnets 101 and 102 are set to be excited so as to be corrected toward the line M (center line M equidistant in the plate thickness direction Z from both the opposing electromagnets 101 and 102 in FIG. 1). That is, when the position of the detected portion 120 in the plate thickness direction Z is on the electromagnet 101 side when viewed from the target correction line M, the detected portion 120 is moved to the target correction line M side (that is, the electromagnet 102) using the electromagnet 102. When the position of the detected portion 120 in the plate thickness direction Z is on the electromagnet 102 side when viewed from the target correction line M, the detected portion 120 is moved to the target correction line M side using the electromagnet 101. In other words, magnetic attraction is performed on the electromagnet 101 side. However, as will be described later, even if a steel plate having a large warp (so-called C warp, W warp) is not appropriate and the plate width passes through the shape correcting device 100, sufficient correction cannot be performed. Therefore, conventionally, it has been required to carefully manage warpage in the pre-plating process.

  As described above, Patent Document 2 and Patent Document 3 disclose a shape correction technique for correcting a warp of a steel sheet having a large warp and not an appropriate plate width. Patent Document 2 describes correcting the warpage of a steel sheet using an electromagnet disposed downstream of the wiping nozzle. A plurality of electromagnets are arranged along the plate width direction so as to face the traveling steel plate together with the sensor. The plurality of electromagnets and sensors are arranged side by side in the plate width direction of the steel plate over a range larger than the maximum plate width of the steel plate to be passed based on the length information in the plate width direction of the steel plate acquired in advance. It is described that the electromagnet is turned on and the steel plate in the width direction is pulled to correct the warpage of the steel plate.

  In the technique disclosed in Patent Document 3, as in Patent Document 2, correction of the warpage of the steel sheet is performed using a plurality of electromagnets and sensors arranged downstream of the wiping nozzle. It is configured to be movable in the plate width direction. In addition, an X-ray measuring device capable of measuring the amount of plating attached to the front and back surfaces of the steel plate is provided downstream of the electromagnet and the sensor. Based on the adhesion amount of the plating measured with this X-ray measuring device, the position in the plate thickness direction of the steel plate is calculated over the plate width direction, the warp shape of the steel plate is obtained, and a plurality of electromagnets and sensors are attached to the plate. The warp of the steel sheet is corrected in a state where the steel sheet is moved along the width direction and each is disposed at a more effective position in the sheet width direction.

JP-A-5-246594 JP-A-7-256341 JP-A-8-199323

  However, in the shape correction technology of the steel sheet described in Patent Document 1, for example, the position and shape of the steel sheet to be corrected such that both ends of the steel sheet in the plate width direction are positioned between the sensors (and electromagnets) in the plate width direction. If the condition is bad, the warpage of the steel sheet such as C warp cannot be corrected appropriately.

  Specifically, both end portions 130 of the steel sheet I in the plate width direction Y are positioned between the sensors 110 in the plate width direction Y as shown in FIG. It is located on the electromagnet 102 side as seen. On the other hand, all the detected parts 120 detected by the sensors 110 and measuring the position in the thickness direction Z are on the electromagnet 101 side when viewed from the target correction line M. For this reason, in the situation shown in FIG. 1, when the shape correction method of Patent Document 1 is used, the output of the electromagnet 101 is small and the electromagnet 102 is shown as being indicated as ON (small output) in FIG. 1. Is set so as to increase, and the entire steel sheet I is magnetically attracted to the electromagnet 102 side. That is, the shape of the both ends 130 of the steel plate I protruding toward the electromagnet 102 cannot be corrected. For this reason, the plating adhesion amount of the steel sheet I becomes uneven at the extreme end portions 130 on both sides in the sheet width direction Y, and is alloyed in an alloying furnace (not shown) arranged downstream of the shape correcting device 100. In other words, parts that are not alloyed (so-called unalloyed parts) are formed. In addition, since the entire steel plate I is magnetically attracted to the electromagnet 102 side and moves in parallel, the protruding both end portions 130 may rub or collide with the electromagnet 102 or the sensor 110 as shown by the dotted lines in FIG. As a result, scratched surface defects may be generated at the ends of the steel sheet, or in the worst case, the electromagnet 102 or the sensor 110 may be damaged.

  On the other hand, in the shape correction technology of the steel sheet described in Patent Document 2, it is necessary to pull the steel sheet in the sheet width direction, and in order to correct the C warp, it is necessary to use a considerably strong electromagnet. Must be prepared. Therefore, in order to apply Patent Document 2, it is difficult to adjust the shape of the steel sheet unless the electromagnet is significantly replaced and the power source is modified. In Patent Document 2, only the electromagnet (and sensor) necessary for correction is turned on according to the length of the steel plate in the plate width direction, so both ends in the plate width direction of the steel plate are turned on in the plate width direction. When the conditions are poor with respect to the electromagnet (and sensor) (for example, when the end of the steel plate in the plate width direction is located outside the electromagnet turned on in the plate width direction, etc.) Appropriate correction according to the warpage of the steel sheet is not possible.

  Moreover, in the shape correction technology of the steel sheet described in Patent Document 3, the displacement meter and the electromagnet are moved to the extreme ends on both sides of the steel sheet using a shape correction device configured to move the electromagnet and the sensor in the plate width direction. Since the displacement meter and the electromagnet are installed at extremely short intervals, as described above, the extreme ends on both sides of the steel plate in the plate width direction are sensors (and electromagnets) in the plate width direction. Although it is possible to avoid a situation where they are positioned between each other, in order to make the electromagnet and the sensor movable, the equipment cost is high and the equipment configuration is likely to be complicated. Further, if the installed sensor cannot properly detect the detected portion near the end in the plate width direction of the steel plate, the same problem as in the case of Patent Document 2 described above may occur. Furthermore, if the displacement meter and the electromagnet are installed at extremely short intervals, the equipment cost will be excessive.

  The present invention has been made in view of the above problems, and even when it is difficult to correct with the conventional steel plate shape correction technology, the warpage of the steel plate is appropriately corrected to prevent the occurrence of non-alloyed portions. It is an object of the present invention to provide a shape correction method and a shape correction device for a steel plate that can be used.

  In order to solve the above-mentioned problems, according to the present invention, a plurality of electromagnets and sensors are arranged along the plate width direction so as to face a steel plate that runs away from a hot dipping bath, and the steel plate measured by the sensor is used. A method of correcting the shape of a steel sheet is provided, in which each detected portion is magnetically attracted in a predetermined correction direction by the electromagnet based on the warp in the thickness direction of each detected portion. In this method for correcting the shape of a steel plate, first, the position in the thickness direction of each detected portion is measured by the sensor that detects the steel plate, and the correction of each detected portion is performed based on the measured position in the thickness direction. Determine the direction. Next, the position in the thickness direction of the endmost portion in the sheet width direction of the steel sheet is obtained using a sensor different from the sensor, and the position of the endmost portion is determined based on the obtained position in the thickness direction of the endmost part. A correction direction for reference of the detected part closest to each is determined. Of the detected parts that have determined the correction direction, the detected part that is closest to each of the outermost ends in the sheet width direction of the steel sheet is determined based on the position in the measured thickness direction. When the correction direction is different from the reference correction direction, the electromagnet performs magnetic attraction in the reference correction direction.

  According to the present invention, it is possible to perform correction in consideration of the position in the plate thickness direction of the end portion in the plate width direction of the steel plate, and the end portion in the plate width direction of the steel plate is directly adjusted with a sensor and an electromagnet. Even when it is difficult to correct, the shape of the steel sheet can be corrected more appropriately than before.

  In the method for correcting the shape of the steel sheet, the position in the plate thickness direction of the detected portion closest to the plate is in a position where correction is not required, and the position in the plate thickness direction of the end portion in the plate width direction of the steel plate is corrected. If it is in the required position, magnetically attract the detected portion closest to the reference in the correction direction, and the position of the closest detected portion in the thickness direction is in a position that requires correction; and When the position in the plate thickness direction of the end portion in the plate width direction of the steel plate is at a position where correction is not required, the closest detected portion may not be magnetically attracted.

  In the method for correcting the shape of the steel plate, the positions in the plate thickness direction of both ends of the steel plate in the plate width direction may be obtained based on the amount of plating attached to the steel plate.

  In the method for correcting the shape of the steel sheet, the force for magnetically attracting the closest detected part in the correction direction for reference based on the measured position in the thickness direction of the endmost part in the sheet width direction of the steel sheet. It is also possible to determine the length.

  In the method for correcting the shape of the steel sheet, the magnitude of the force for magnetically attracting the detected portion closest to the reference in the correction direction for reference is from the center line that is equidistant from the opposing electromagnets in the plate thickness direction. It may be determined depending on the difference between the distance in the plate thickness direction to the extreme end in the plate width direction and the distance in the plate thickness direction from the center line to the closest detected portion.

  Further, according to the present invention, the shape correction device for the steel plate is provided in each of the electromagnets, a plurality of electromagnets arranged along the plate width direction so as to face the steel plate traveling out of the hot dipping bath. , A sensor capable of measuring the position in the plate thickness direction of each detected portion of the opposing steel plate, a plating adhesion measuring device for measuring the amount of plating adhesion adhering to the front and back surfaces of the steel plate, the electromagnet, the sensor, and the plating A controller connected to the adhesion amount measuring device and individually controlling the electromagnet and the sensor based on the plating adhesion amount measured by the plating adhesion amount measuring device; The control device determines the correction direction of each detected portion based on the measurement result of the sensor, and further, based on the measurement result of the plating adhesion measuring device, the extreme ends on both sides in the plate width direction of the steel plate The correction direction for reference of the detected part closest to each part is determined. Of the detected parts that have determined the correction direction, the detected part closest to each of the extreme ends on both sides of the steel sheet in the plate width direction is based on the position in the measured thickness direction. When the determined correction direction is different from the reference correction direction, the electromagnet is controlled so as to be magnetically attracted in the reference correction direction.

  In the steel sheet shape correction device, the position in the plate thickness direction of the detected portion closest to the steel plate is a position where correction is not required, and the position in the plate thickness direction of the plate width direction of the steel plate is corrected. If it is in the required position, magnetically attract the detected portion closest to the reference in the correction direction, and the position of the closest detected portion in the thickness direction is in a position that requires correction; and When the position in the plate thickness direction of the end portion in the plate width direction of the steel plate is at a position where correction is not required, the closest detected portion may not be magnetically attracted.

  In the steel sheet shape correction device, the control device further determines the closest detected portion for reference based on the positions in the plate thickness direction of the end portions on both sides in the plate width direction of the measured steel plate. You may make it determine the magnitude | size of the force magnetically attracted in the correction direction.

  In the steel sheet shape correction device, the control device further determines the magnitude of the force for magnetically attracting the detected portion closest to the reference detection direction in the reference correction direction from the opposing electromagnets in the plate thickness direction. It is determined depending on the difference between the distance in the plate thickness direction from the center line to both ends in the plate width direction of the steel plate and the distance in the plate thickness direction from the center line to the closest detected portion. May be.

  According to the present invention, even when the extreme ends on both sides in the plate width direction of the steel plate cannot be directly corrected by the sensor and the electromagnet, the thickness in the plate thickness direction at the extreme ends on both sides in the plate width direction of the steel plate. By performing correction with reference to the position information, the warpage of the steel sheet can be corrected more appropriately than in the past. This prevents the amount of plating deposit from becoming uneven at the extreme ends on both sides in the plate width direction of the steel plate, thereby preventing the occurrence of unalloyed portions. In addition, when the extreme end of the steel plate in the plate width direction protrudes on either side of the plate thickness direction, it is possible to prevent the occurrence of dragging at the extreme end of the plate width direction, as well as electromagnets, etc. This prevents improper correction that could cause damage to the equipment. It is also possible to prevent the equipment configuration from becoming complicated and the equipment cost from increasing.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 2 is a configuration diagram of a hot dipping line 1 suitable for carrying out the shape correction method according to the embodiment of the present invention. As shown in FIG. 2, the hot dipping line 1 is configured such that the steel sheet I travels in the direction of the arrow and travels through the hot dipping bath 3 filled with hot dipping such as zinc in the hot dipping bath 2 and then exits. Has been. In the hot dipping bath 3, a sink roll 4 and a support roll 5 that guide the steel plate I are provided that are rotatably supported with the axial direction horizontal. The support rolls 5 are provided in pairs near the exit side in the hot dipping bath above the sink roll 4 and are configured to correct the shape of the steel sheet I by pressing the steel sheet I in the thickness direction Z. Yes.

  A pair of gas wiping nozzles for adjusting the amount of plating adhered to the steel sheet I by blowing air to the steel sheet I from both sides in the thickness direction Z near the exit side outside the hot dipping bath 3 above the support roll 5 10 and 11 are arranged facing each other. Above the gas wiping nozzles 10, 11, a shape correction device 20 for the steel plate I according to the embodiment of the present invention for correcting warpage (so-called C warpage, W warpage, etc.) of the steel plate I with respect to the axis in the plate width direction Y is provided. Is provided. The steel sheet I that has left the hot dipping bath 3 travels in the transport direction X (that is, upward in the vertical direction) and passes through the gas wiping nozzles 10 and 11 and the shape correction device 20. In the present embodiment, as shown in FIG. 2, the transport direction X, the plate width direction Y, and the plate thickness direction Z are all orthogonal to each other.

  The shape correction device 20 for the steel sheet I according to the embodiment of the present invention is disposed opposite to both sides of the sheet thickness direction Z of the steel sheet I that retreats from the gas wiping nozzles 10 and 11 and travels in the transport direction X. Each has an electromagnet group 22 and 23 for magnetic attraction. Above the electromagnet groups 22 and 23, plating adhesion amount measuring devices 24 and 25 are provided so as to face each other in the plate thickness direction Z of the traveling steel plate I. In the present embodiment, the amount of plating adhering to the front and back surfaces of the steel sheet I is measured by irradiating the front and back surfaces of the steel sheet I with X-rays and measuring the amount of fluorescent X-ray emitted from the deposited plating. The X-ray fluorescence apparatus that can do this is used as the plating adhesion amount measuring devices 24 and 25.

  The plating adhesion amount measuring devices 24 and 25 and the electromagnet groups 22 and 23 are connected to the control device 30. The control device 30 calculates the plate width of the steel plate I based on the empirical correlation data held in advance from the information on the measurement results of the coating amount of the front and back surfaces of the steel plate I input from the plating adhesion amount measuring devices 24 and 25. The position in the plate thickness direction Z of each detected portion along the direction Y is calculated, and the electromagnet groups 22 and 23 are controlled based on the calculated position in the plate thickness direction Z of each detected portion, and the steel plate I is shaped. It is configured to correct.

  FIG. 3 is a view taken along the line PP in FIG. As shown in FIG. 3, the electromagnet group 22 has nine electromagnets 40 to 48 arranged at predetermined intervals along the plate width direction Y, and the electromagnet group 23 is arranged at predetermined intervals along the plate width direction Y. It has nine electromagnets 50 to 58 arranged. The electromagnet 40 of the electromagnet group 22 and the electromagnet 50 of the electromagnet group 23 are arranged to face each other so as to sandwich the steel plate I traveling in the transport direction X in the plate thickness direction Z. Similarly, the remaining electromagnets 41 to 48 of the electromagnet group 22 and the remaining electromagnets 51 to 58 of the electromagnet group 23 are arranged to face each other in a one-to-one relationship. In the present embodiment, the electromagnet group 22 and the electromagnet group 23 are separated by a distance 2L in the thickness direction Z. As shown in FIG. 3, a center line indicating an intermediate position at an equal distance L in the plate thickness direction Z from the electromagnet group 22 and the electromagnet group 23 is defined as a target correction line M. In the present specification, for the purpose of simplifying the description, the target correction line M is described as being a center line. However, the steel plate I is formed at the portion of the wiping nozzle 10 so as to uniformize the coating amount. The target correction line M may be set so that a small amount of warpage is generated in the portions of the electromagnet groups 22 and 23.

  The electromagnets 40 to 48 of the electromagnet group 22 and the electromagnets 50 to 58 of the electromagnet group 23 detect the steel plate I in the center on the side facing the steel plate I, respectively. A sensor 70 capable of measuring positions in the thickness direction Z of 60 to 66. In the present embodiment, as the sensor 70, an eddy current displacement meter that measures the position of the steel sheet I (detected part) in the thickness direction Z based on the impedance change of the sensor coil due to the eddy current generated in the steel sheet I is used. ing.

  4 and 5 are enlarged views of the electromagnet 42 of the electromagnet group 22 and its sensor 70. FIG. FIG. 4 shows a case where the detected part 61 of the steel plate I can be detected by the sensor 70 of the electromagnet 42. As shown in FIG. 4, the sensor 70 of the electromagnet 42 is opposed when the opposing steel plate I exists over the entire detection range W from the center in the plate width direction Y of the sensor 70 to the distance W / 2 on both sides. It is possible to detect the detected portion 61 of the steel plate I to be measured and measure the position in the thickness direction Z thereof. On the other hand, as shown in FIG. 5, the outermost end 75 in the sheet width direction Y of the steel plate I exists in the detection range W, and the steel plate I facing the sensor 70 does not exist over the entire detection range W. In this case, the sensor 70 of the electromagnet 42 cannot detect the opposing steel plate I (detected portion 61). In the present embodiment, the detection range W of the sensor 70 of the electromagnet 42 is set to a value larger than the length H of the electromagnet 42 in the plate width direction Y.

  Although the sensor 70 of the electromagnet 42 has been described above, the same applies to the sensors 70 of the other electromagnets 40, 41, 43 to 48, and 50 to 58 of the electromagnet groups 22 and 23. Each sensor 70 can be individually set to start and stop by a control device 30 described later. In the present embodiment, the control device 30 to be described later acquires in advance information on the length in the plate width direction Y of the steel plate I traveling in the transport direction X, and based on this length information, among the plurality of sensors 70. Only the sensor 70 in which the steel plate I passes the detection range W (that is, faces the steel plate I) is activated in advance.

  As described above, the electromagnets 40 to 48 of the electromagnet group 22 and the electromagnets 50 to 58 of the electromagnet group 23 facing each other in a one-to-one manner have the same width when the sensor 70 included therein detects the steel plate I. The steel plate I is set to be magnetically attracted to one side of each pair of electromagnets facing each other at the position in the direction Y. In the present embodiment, as shown in FIG. 3, when the opposing steel plates I are detected by the sensors 70 included in the electromagnet pairs 42 and 52 in the same plate width direction Y, the electromagnet pairs 42 and 52 Among them, the output of the electromagnet 52 on the far side from the opposing steel plate I is set to be larger than the output of the electromagnet 42 on the closer side, and the detected steel plate I is magnetized toward the target correction line M. The suction is set to correct toward the target correction line M. When the electromagnet pairs 42 and 52 are equidistant from the opposing steel plates I (that is, on the target correction line M), the detected steel plates I do not need to be corrected, so the electromagnets 42 and 52 Are set to be equal.

  As described above, each sensor 70 is configured to input information on the position of each detected portion (60 to 66 in the case of FIG. 3) in the plate thickness direction Z to the control device 30. Yes. Further, the control device 30 receives information on the position in the plate thickness direction Z of each detected portion (60 to 66 in the case of FIG. 3) input from the sensors 70 of the electromagnet groups 22 and 23 and the plating adhesion described above. Based on the information on the measurement results of the adhesion amount of the plating on the front and back surfaces of the steel sheet I input from the quantity measuring devices 24, 25, the respective detected parts (60 to 66 in the case of FIG. 3) are detected 2 It is set to adjust the output level of two electromagnets (in the case of FIG. 3, 41 and 51, 42 and 52,..., 47 and 57). Each detected part (in the case of FIG. 3, 60 to 66) is parallel to the plate thickness direction Z on the side of the electromagnet (41, 47, 52 to 56 in the case of FIG. 3) having a larger output. Magnetic attraction. However, when the outputs of the electromagnets on both sides of each detected part are equal, the steel plate I is not magnetically attracted in any direction and is in a stationary state. In the present specification, directions in which each detected portion is magnetically attracted (directions indicated by solid arrows in FIG. 3) are referred to as “correction directions”.

  The shape correction apparatus 20 is configured as described above. Next, a shape correction method according to an embodiment performed using the shape correction apparatus 20 will be described with reference to FIGS. 2 and 3.

  First, the procedure for running the steel sheet I on the hot dipping line 1 will be described. As shown in FIG. 2, on the hot dipping line 1, the steel plate I is caused to travel in the direction of the arrow and enters the hot dipping bath 3 from the upper side to the lower side at a predetermined inclination angle. By causing the steel sheet I that has entered to run in the hot dipping bath 3, hot dipping is adhered to the front and back surfaces. The steel plate I traveling in the hot dipping bath 3 is withdrawn from the hot dipping bath 3 in the vertically upward conveying direction X through the sink roll 4 and the support roll 5. The retreated steel plate I is made to travel along the conveying direction X, and is advanced between the gas wiping nozzles 10 and 11 that are arranged to face each other. At this time, air is blown from the gas wiping nozzles 10 and 11 on both sides in the plate thickness direction Z of the traveling steel plate I, and the plating adhering to both surfaces of the steel plate I is blown off to adjust the amount of plating.

  The steel sheet I withdrawn from the gas wiping nozzles 10 and 11 is caused to travel along the transport direction X, and sequentially advances between the electromagnet groups 22 and 23 of the shape correction device 20 and the plating adhesion amount measuring devices 24 and 25, and further downstream. The alloying treatment is performed in an alloying furnace (not shown) arranged in (1).

  Next, an example of the procedure when the shape correction method according to the embodiment is performed on the steel sheet I traveling on the hot dipping line 1 as described above will be described with reference to FIGS. 6 and 7. FIG. 6 is a P-P arrow view of FIG. FIG. 7 is a flowchart showing the procedure of the method for correcting the shape of the steel sheet I according to the embodiment of the present invention.

  When the shape correction method for the steel plate I is started (step 0), the control device 30 acquires the length in the plate width direction Y of the steel plate I traveling on the hot dipping line 1 from a host control device (not shown). The control device 30 activates only the sensor 70 facing the steel plate I among all the sensors 70 of the shape correction device 20 based on the acquired information on the length in the plate width direction Y of the steel plate I. Control is performed so that the non-opposing sensors 70 are stopped. As shown in FIG. 6, in the present embodiment, among the sensors 70 of the electromagnet groups 22 and 23, the electromagnets 41 to 47 and 51 to 57 facing the steel plate I are shown as shaded in FIG. 6. Only the provided sensors 70 are activated by the control device 30, and the sensors 70 provided on the electromagnets 40, 48, 50, 58 at both ends not facing the steel plate I are not activated (OFF shown in FIG. 6). In FIG. 6, ON (small output) and ON (large output) displayed in the electromagnets 41 to 47 and 51 to 57 indicate that the electromagnets 41 to 47 and 51 to 57 are activated. It is shown together with information on the size of each output. As for each sensor 70, the shaded one indicates the ON state, and the one not shaded indicates the OFF state.

  The gas wiping nozzles 10 and 11 are withdrawn, and the steel plate I traveling between the electromagnet groups 22 and 23 of the shape correction device 20 is detected by the sensors 70 of the activated electromagnets 41 to 47 and 51 to 57 (step 1). ), The positions in the plate thickness direction Z of the respective detected portions 60 to 66 facing each other are measured (step 2). For example, as shown in FIG. 6, in the case of the sensor 70 provided on the electromagnet 42, the distance in the plate thickness direction Z between the sensor 70 and the detected portion 61 facing the sensor 70 is measured as J. Information on the measured positions of the detected portions 60 to 66 in the thickness direction Z is input from the sensors 70 to the control device 30.

  The control device 30 determines the correction direction α of each of the detected portions 60 to 66 of the steel sheet I based on the input position of the detected portions 60 to 66 in the plate thickness direction Z (step 3). In the present embodiment, the correction direction α of each of the detected parts 60 to 66 is set so that the position in the plate thickness direction Z of each of the detected parts 60 to 66 is close to the target correction line M and is parallel to the plate thickness direction Z. Determine as direction. In the case of FIG. 6, since the positions of the detected parts 60 to 66 in the plate thickness direction Z are all located on the electromagnet group 22 side with respect to the target correction line M, the detected parts 60 to 66 are included. 6 is determined as a direction from the electromagnet group 22 toward the target correction line M and parallel to the plate thickness direction Z, as indicated by the dotted and solid arrows in FIG. In the above description, the case where the positions of the detected parts 60 to 66 in the thickness direction Z are not on the target correction line M and the detected parts 60 to 66 need to be corrected has been described. When the positions of the portions 60 to 66 in the thickness direction Z are on the target correction line M, it is not necessary to correct the detected portions 60 to 66, so the correction direction α is a steel plate as an exceptional option. It is determined that “no direction” that does not correct I in any direction.

  The electromagnet groups 22 and 23 of the shape correction device 20 are withdrawn, and the front and back surfaces of the steel sheet I traveling between the plating adhesion measuring devices 24 and 25 are irradiated with X-rays from the plating adhesion measuring devices 24 and 25, respectively. The amount of plating adhered to the front and back surfaces of the steel sheet I is measured (step 4). Information of the measurement result of the measured adhesion amount of the steel sheet I is input from the plating adhesion amount measuring devices 24 and 25 to the control device 30.

  The control device 30 calculates the positions in the plate thickness direction Z of the extreme end portions 75 and 76 on both sides of the plate width direction Y of the steel plate I based on the input information of the measurement result of the coating amount of the steel plate I. (Step 5). In the present embodiment, the controller 30 empirically correlates data (or approximate expression) regarding the amount of plating attached to the steel plate I and the amount of warpage of the steel plate I (that is, the position in the thickness direction Z of the steel plate I). ) In advance and referring to this correlation data (or calculating based on the approximate expression), based on the input information of the measurement result of the coating amount of the steel sheet I, the sheet width direction Y of the steel sheet I The positions in the plate thickness direction Z of the extreme end portions 75 and 76 on both sides are calculated.

  Next, the control device 30 is based on the calculated positions in the plate thickness direction Z of the extreme end portions 75 and 76 on both sides of the plate width direction Y of the steel plate I in the same manner as the procedure for determining the correction direction α in step 3 above. The correction direction β for reference of the extreme end portions 75 and 76 on both sides of the steel plate I in the plate width direction Y is determined (step 6). In the case of FIG. 6, the positions in the plate width direction Z of the extreme ends 75 and 76 on both sides in the plate width direction Y of the steel plate I are both positioned on the electromagnet group 23 side with respect to the target correction line M. Therefore, the reference correction directions β of the extreme ends 75 and 76 on both sides in the sheet width direction Y of the steel plate I are all directed from the electromagnet group 23 toward the target correction line M as indicated by the dotted arrows in FIG. And a direction parallel to the plate thickness direction Z. In the above description, the positions of the end portions 75 and 76 on both sides of the steel sheet I in the plate width direction Y are not on the target correction line M, and the end portions 75 and 76 need to be corrected. However, when the positions of the extreme end portions 75 and 76 in the thickness direction Z are on the target correction line M, the correction direction β is an exception because it is not necessary to correct the extreme end portions 75 and 76. As a typical option, it is determined that “the direction is not present” in which the steel sheet I is not corrected in any direction.

  Next, the control device 30 corrects the final correction directions of the detected portions 61 to 65 other than the detected portions 60 and 66 closest to the extreme ends 75 and 76 on both sides in the plate width direction Y of the steel plate I. Each direction is determined (step 7). On the other hand, for the detected portions 60 and 66 closest to the extreme end portions 75 and 76 on both sides in the plate width direction Y of the steel plate I, the correction directions α of the detected portions 60 and 66 are set on the both sides closest to each other. Compared with the correction direction β for reference of the extreme end portions 75 and 76. If each correction direction α of the detected parts 60 and 66 is the same as the corresponding correction direction β for reference, the final correction direction is set to the correction direction α. If each correction direction α is different from the corresponding reference correction direction β, the final correction direction is set to the correction direction β (step 8).

  In addition, when each correction direction α of the detected units 60 and 66 is determined as “no direction” as described above and the reference correction direction β is determined other than “no direction”, the detected unit As a final correction direction 60, 66, a reference correction direction β is set (that is, correction by magnetic attraction is performed). On the other hand, when each correction direction α of the detected parts 60 and 66 is determined to be other than “no direction” and the reference correction direction β is determined to be “no direction”, the detected part 60 66, the same “no direction” as the reference correction direction β is set (that is, correction by magnetic attraction is not performed). Here, if “no direction” is regarded as one of the directions, when each correction direction α of the detected portions 60 and 66 is different from the reference correction direction β, the final detection of the detected portions 60 and 66 is performed. It is also possible to apply the procedure of setting the reference correction direction β in the correction direction as it is.

  In the case of FIG. 6, the correction direction α of the detected part 60 is opposite to the reference correction direction β of the endmost part 75 in the sheet width direction Y of the steel plate I, and the direction is different. The final correction direction is set to the reference correction direction β at the end 75. Similarly, since the correction direction α of the detected portion 66 is opposite to the reference correction direction β of the outermost portion 76 in the plate width direction Y of the steel plate I, and the direction is different, the final correction direction of the steel plate 66 is , The correction direction β for reference at the end 76 is set.

  Next, the control device 30 magnetically magnetizes the detected portions 60 to 66 in the final correction direction set as described above, among the magnets 40 to 48 and 50 to 58 included in the opposing electromagnet groups 22 and 23, respectively. Each of the electromagnets 41, 47, 52 to 56 that can be attracted is excited, and each detected portion 60 to 66 is magnetically attracted in the final correction direction as indicated by the solid line arrows in FIG. 6 (step 9). In the present embodiment, the strength of the attraction force when magnetically attracting the detected parts 60 to 66 using the electromagnets 41, 47, 52 to 56 is determined from the target correction line M to the detected parts 60 to 66. It is set to become stronger as the distance to the position in the plate thickness direction Z increases. Further, when the final correction direction of the detected part 60 (66) is set to the correction direction β instead of the correction direction α in step 8, the suction when the detected part 60 (66) is magnetically attracted. The strength of the force is determined from the distance A (B) in the thickness direction Z from the target correction line M to both ends 75 (76) of the steel sheet I, and from the target correction line M to the detected portion 60 (66), respectively. It is set to depend on a value Aa (Bb) obtained by subtracting the distance a (b) in the plate thickness direction Z.

  According to the above procedure, the steel sheet I is magnetically attracted in the final correction direction by some or all of the electromagnets 40 to 48 and 50 to 58 of the electromagnet groups 22 and 23 of the shape correction device 20, and before the correction shown by the solid line. The position is corrected to a corrected position Q indicated by a dotted line from the position O. Thereby, the procedure of the shape correction method according to the embodiment of the present invention is completed (step 10).

  According to the above embodiment, when the detected portions 60 and 66 closest to the extreme end portions 75 and 76 on both sides in the sheet width direction Y of the steel plate I are corrected, the detected portions 60 and 66 are corrected. The final direction of the detected parts 60 and 66 is made to match the direction α with the reference correction direction β determined from the information of the position in the plate thickness direction Z of the extreme end portions 75 and 76 on both sides of the steel plate I. By determining the correct correction direction, the sensor 70 near the extreme end portions 75, 76 on both sides has a large degree of warpage in the vicinity of the extreme end portions 75, 76 on both sides in the plate width direction Y of the steel plate I. Due to various factors such as failure, when the curvature of the extreme ends 75 and 76 on both sides in the sheet width direction Y of the steel sheet I cannot be detected properly, the equipment configuration becomes complicated and the equipment costs increase. Without making it possible, the shape of the steel sheet I can be appropriately corrected. Further, when the extreme ends 75 and 76 on both sides of the steel sheet I in the width direction Y are out of the detection range W of each sensor 70 and proper correction is difficult with the conventional shape correction technique. The shape of the steel plate I can be corrected appropriately. Further, the endmost portions 75 and 76 on both sides in the plate width direction Y of the steel plate I are abraded or collide with the electromagnets 40 to 48, 50 to 58 or the sensor 70 of the shape correcting device 20 to form the shape correcting device 20. It can be prevented from being damaged.

  The operation of the shape correction method according to the embodiment of the present invention described above will be described with some specific examples. FIGS. 8-12 is explanatory drawing at the time of applying the shape correction method of this invention when the shape of the end part 75 side of the sheet width direction Y of the steel plate I is various curvature shape. 8-12, the shape of the steel plate I before correction is shown by a solid line, and the shape of the steel plate I after correction by magnetic attraction by an electromagnet is shown by a dotted line.

  In the case of the shape before correction of the steel plate I shown in FIG. 8, as in the case shown in FIG. 6, the outermost end 75 in the plate width direction Y of the steel plate I is on one side of the target correction line M (− The detected part 60 closest to the outermost end 75 is arranged on the other side (+ side) of the target correction line M. That is, the correction direction α (the direction from the + side to the − side) of the detected portion 60 is the upward reference correction direction β (from the − side to the + side) based on the position in the thickness direction Z of the outermost end 75. Therefore, as described above, the final correction direction of the detected portion 60 is set to the reference correction direction β as indicated by the upward solid arrow in FIG. The correction direction of the detected portion 61 is a direction from the + side to the − side, and the steel plate I has a shape shown by a dotted line in FIG. 8 after correction.

  In the case of the shape before correction of the steel plate I shown in FIG. 9, the outermost end portion 75 in the plate width direction Y of the steel plate I is disposed on one side (− side) of the target correction line M, and the detected portion 60 Is arranged on the target correction line M. That is, since the correction direction α of the detected part 60 is “no direction” and is different from the reference correction direction β (direction from the − side to the + side), the final correction method of the detected part 60 is: As shown by the upward solid arrow in FIG. 9, the reference correction direction β is set. Since the detected portion 61 is also on the target correction line M, the correction direction is “no direction”, and the steel plate I has the shape shown by the dotted line in FIG. 9 after correction.

  In the case of the shape before correction of the steel plate I shown in FIG. 10, the outermost end portion 75 of the steel plate I in the plate width direction Y and the detected portion 60 closest to the outermost end portion 75 are in the target correction line M. Arranged on the same side (-side). That is, since the correction direction α of the detected part 60 and the reference correction direction β based on the endmost part 75 are the same (direction from the − side to the + side), the final correction direction of the detected part 60 is , The correction direction α is set as indicated by the upward solid arrow in FIG. Since the detected portion 61 is on the target correction line M, the correction direction is “no direction”, and the steel plate I has a shape shown by a dotted line in FIG. 10 after correction. Since this shape after correction is the same as the shape before correction shown in FIG. 9, the correction described above with reference to FIG. 9 is performed thereafter.

  In the case of the shape before correction of the steel plate I shown in FIG. 11, the shape is the same as the shape after correction in FIGS. That is, FIG. 11 shows the correction performed on the steel sheet I after the correction of FIGS. 8 and 9 is performed. The most end portion 75 in the plate width direction Y of the steel plate I before correction shown in FIG. 811 is arranged on the target correction line M. In addition, the detected portion 60 that is closest to the outermost end 75 is disposed on one side (+ side) of the target correction line M. Therefore, since the correction direction α (the direction from the + side toward the − side) of the detected unit 60 is different from the reference correction direction β of “no direction”, the final correction direction of the detected unit 60 is Set to “No Direction”. Since the correction direction of the detected portion 61 is also “no direction”, the detected portions 60 and 61 are not corrected and the shape of the steel sheet I is maintained as it is.

  In the case of the shape before correction of the steel plate I shown in FIG. 12, the shape is the same as the shape of the steel plate I shown in FIG. The most end portion 75 in the sheet width direction Y of the steel plate I shown in FIG. 12 and the detected portion 60 closest to the most end portion 75 are arranged on the same side (+ side) of the target correction line M. That is, since the correction direction α of the detected part 60 is the same as the reference correction direction β based on the endmost part 75 (the direction from the + side to the − side), the final correction direction of the detected part 60 Is set in the correction direction α as shown by the downward solid arrow in FIG. The correction direction of the detected portion 61 is “no direction”, and the steel plate I has a shape shown by a dotted line in FIG. 11 after correction. Since this shape after correction is the same as the shape before correction shown in FIG. 9, the correction described above with reference to FIG. 9 is performed thereafter.

  As described above, the method of correcting the shape of the steel sheet according to the embodiment of the present invention has been described with reference to FIGS. 8 to 12 in the case where the outermost end 75 in the sheet width direction Y of the steel sheet I has various warp shapes. When correcting the shape of I, the correction corresponding to the shape of the steel plate I is periodically repeated, and there is a possibility that vibrations may occur. Therefore, in order to prevent such a situation, the shape correction of the steel plate I is performed. It is necessary to appropriately set the time constant and control constant related to the control of the above. These time constants and control constants need to be set appropriately prior to operation and adjusted appropriately during operation.

  In the above-described embodiment, the case where the warpage of the extreme end portions 75 and 76 on both sides of the steel plate I in the plate width direction Y cannot be properly detected has been described, but the extreme end portions on both sides of the steel plate I in the plate width direction Y are described. Even in the case where the warpage of 75 and 76 can be detected appropriately, the shape correction method according to the embodiment of the present invention can appropriately correct the shape of the steel sheet I as in the conventionally known shape correction method. .

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  In the above-described embodiment, the gas wiping nozzles 10 and 11, the electromagnet groups 22 and 23 of the shape correcting device 20, and the plating adhesion amount measuring devices 24 and 25 are arranged on the hot dipping line 1 along the conveying direction X of the steel plate I. However, the hot dipping line 1 may have other arrangement configurations.

  In the above-described embodiment, the case where the electromagnet groups 22 and 23 are each composed of nine electromagnets 40 to 48 and 50 to 58 has been described. However, the number of electromagnets constituting the electromagnet groups 22 and 23 is other than nine. There may be.

  In the above-described embodiment, the case where the eddy current sensor is used as the sensor 70 for measuring the position of the detected portions 60 to 66 in the plate thickness direction Z has been described, but other sensors may be used.

  In the embodiment described above, the sensor 70 is provided at the center position in the plate width direction Y on the side facing the steel plate I of each of the electromagnets 40 to 48 and 50 to 58 of both the electromagnet group 22 and the electromagnet group 23. However, the sensor 70 may be provided at other positions. Further, the sensor 70 may be provided only in any one of the electromagnets 40 to 48 of the electromagnet group 22 or the electromagnets 50 to 58 of the electromagnet group 23.

  In the above-described embodiment, the case where a fluorescent X-ray apparatus is used as the plating adhesion amount measuring devices 24 and 25 has been described. However, other plating adhesions such as a measuring device for measuring the plating adhesion amount using β rays or γ rays. A quantity measuring device may be used.

  The present invention is particularly useful for a hot dipping line for producing hot dipped steel sheets, for example.

It is a block diagram of the conventionally well-known shape correction apparatus 100 which shows an example when the curvature of a steel plate cannot be corrected appropriately. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the hot dipping line 1 suitable for implementing the shape correction method which concerns on embodiment of this invention. It is a PP arrow line view of FIG. It is an enlarged view of the electromagnet 42 of the electromagnet group 22 and its sensor 70 when the sensor 70 of the electromagnet 42 can detect the to-be-detected part 61 of the steel plate I which opposes. It is an enlarged view of the electromagnet 42 of the electromagnet group 22 and its sensor 70 when the sensor 70 of the electromagnet 42 cannot detect the to-be-detected part 61 of the steel plate I which opposes. It is a PP arrow line view of Drawing 2 showing the shape correction procedure of steel plate I. It is a flowchart which shows the procedure of the shape correction method of the steel plate I which concerns on embodiment of this invention. It is explanatory drawing which shows an example at the time of applying the shape correction method of the steel plate which concerns on embodiment of this invention with respect to the steel plate I of various shapes. It is explanatory drawing which shows an example at the time of applying the shape correction method of the steel plate which concerns on embodiment of this invention with respect to the steel plate I of various shapes. It is explanatory drawing which shows an example at the time of applying the shape correction method of the steel plate which concerns on embodiment of this invention with respect to the steel plate I of various shapes. It is explanatory drawing which shows an example at the time of applying the shape correction method of the steel plate which concerns on embodiment of this invention with respect to the steel plate I of various shapes. It is explanatory drawing which shows an example at the time of applying the shape correction method of the steel plate which concerns on embodiment of this invention with respect to the steel plate I of various shapes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot dipping line 2 Hot dipping bath 3 Hot dipping bath 4 Sink roll 5 Support roll 10,11 Gas wiping nozzle 20,100 Shape correction device 22,23 Electromagnet group 24,25 Plating adhesion amount measuring device 30 Control device 40-48, 50 to 58, 101, 102 Electromagnet 60 to 68, 120 Detected part 70, 110 Sensor 75, 76, 130 Both ends in the plate width direction of the steel plate A, B Position in the plate thickness direction of both ends in the plate width direction of the steel plate a, b Thickness position of the detected portion closest to both ends of the steel plate in the plate width direction H Length of the electromagnet in the plate width direction I Steel plate J Distance in the plate thickness direction between the sensor and the detected portion (an example) )
L Distance between electromagnet group 22 (23) and center line M M Center line (target correction line)
W Detection range (distance)
X Conveyance direction Y Plate width direction Z Plate thickness direction α Correction direction of the detected part β Correction direction for reference at both ends of the plate width direction of the detected part +, − Both sides of the target correction line

Claims (9)

A plurality of electromagnets and sensors facing the steel plate traveling out of the hot dipping bath are disposed along the plate width direction, based on the warpage in the plate thickness direction of each detected portion of the steel plate measured by the sensor, A method of correcting the shape of a steel sheet, wherein each detected portion is magnetically attracted in a predetermined correction direction by an electromagnet,
First, the position of each detected portion is measured by the sensor that detects the steel plate, and the correction direction of each detected portion is determined based on the measured position of the thickness direction,
On the other hand, the position in the plate thickness direction of the plate width direction of the steel plate is obtained using a sensor different from the sensor, and each of the extreme end portions is determined based on the obtained position of the extreme end portion in the plate thickness direction. Determining a correction direction for reference of the detected part closest to
Next, among the detected parts for which the correction direction has been determined, the detected part closest to each of the outermost ends in the sheet width direction of the steel sheet is determined based on the position in the measured thickness direction. A method of correcting the shape of a steel sheet, wherein the electromagnet is magnetically attracted in the reference correction direction when the corrected correction direction is different from the reference correction direction. When the position in the plate thickness direction of the detected portion closest to the plate is in a position that does not require correction, and the position in the plate thickness direction of the plate width direction of the steel plate is in a position that requires correction Is magnetically attracting the closest detected part in the reference correction direction,
When the position in the plate thickness direction of the detected portion closest to the plate is in a position that requires correction, and the position in the plate thickness direction of the end portion in the plate width direction of the steel plate is in a position that does not require correction 2. The method of correcting a shape of a steel sheet according to claim 1, wherein the detected part that is closest is not magnetically attracted. The shape correction method for a steel sheet according to claim 1 or 2, wherein a position in the plate thickness direction of an end portion in the plate width direction of the steel plate is obtained based on an adhesion amount of the plating attached to the steel plate. Based on the measured position in the plate thickness direction of the endmost portion in the plate width direction of the steel plate, the magnitude of the force that magnetically attracts the closest detected portion in the reference correction direction is determined. The method for correcting the shape of a steel sheet according to any one of claims 1 to 3. The magnitude of the force that magnetically attracts the closest detected portion in the reference correction direction is from the center line that is equidistant from the opposing electromagnets in the plate thickness direction to the extreme end in the plate width direction of the steel plate. 5. The shape correction of a steel sheet according to claim 4, wherein the correction is made depending on a difference between a distance in the thickness direction of the sheet and a distance in the thickness direction from the center line to the closest detected portion. Method. A plurality of electromagnets arranged along the plate width direction so as to face the steel plate traveling out of the hot dipping bath;
A sensor provided in each of the electromagnets and capable of measuring the position in the plate thickness direction of each detected portion of the opposing steel plate;
A plating adhesion measuring device for measuring the amount of plating adhered to the front and back surfaces of the steel sheet;
A control device connected to the electromagnet, the sensor, and the plating adhesion amount measuring device, and individually controlling the electromagnet and the sensor based on the plating adhesion amount measured by the plating adhesion amount measuring device;
The control device determines the correction direction of each detected portion based on the measurement result of the sensor, and further, based on the measurement result of the plating adhesion measuring device, the extreme ends on both sides in the plate width direction of the steel plate The correction direction for reference of the detected part closest to each part is determined, and among the detected parts for which the correction direction has been determined, the target closest to each of the extreme end parts on both sides in the plate width direction of the steel sheet. The detection unit controls the electromagnet so as to be magnetically attracted in the reference correction direction when the correction direction determined based on the measured position in the plate thickness direction is different from the reference correction direction. A steel sheet shape straightening device. When the position in the plate thickness direction of the detected portion closest to the plate is in a position that does not require correction, and the position in the plate thickness direction of the plate width direction of the steel plate is in a position that requires correction Is magnetically attracting the closest detected part in the reference correction direction,
When the position in the plate thickness direction of the detected portion closest to the plate is in a position that requires correction, and the position in the plate thickness direction of the end portion in the plate width direction of the steel plate is in a position that does not require correction 7. The steel sheet shape correction device according to claim 6, wherein the detected portion that is closest is not magnetically attracted. The control device further includes a force for magnetically attracting the closest detected part in the reference correction direction based on the positions in the plate thickness direction of the extreme ends on both sides in the plate width direction of the measured steel plate. The shape correction device for a steel sheet according to claim 6 or 7, wherein the size is determined. The control device is further configured to set the magnitude of the force for magnetically attracting the closest detected portion in the reference correction direction from a center line that is equidistant from the opposing electromagnets in the plate thickness direction. The thickness is determined depending on a difference between a distance in the thickness direction to the extreme end in the width direction and a distance in the thickness direction from the center line to the closest detected portion. The shape correction apparatus of the steel plate in any one of -8.

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