JP2011042821A - Gas-wiping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-wiping device which can measure an amount of the warpage of a steel sheet even while straightening the warpage of the steel sheet in a noncontact state by using an electromagnetic force. <P>SOLUTION: In a gas-wiping device that sprays a gas from a wiping nozzle 5 toward the steel sheet 2 to wipe out an extra molten metal, which has been raised from a molten plating bath 1 after a continuous steel sheet 2 has been immersed into the molten plating bath 1, the direction of the steel sheet 2 has been converted upward by a sink roll 3 arranged in the molten plating bath 1, and rolls 4a and 4b in the bath have been brought into contact with the steel sheet 2 from both sides, this gas-wiping device has a vibration-damping device 8 arranged on the top part of the wiping nozzle 5, which straightens the warpage of the steel sheet 2 in the noncontact state by the electromagnetic force, and one or more distance sensors 9 which can measure the positions at least of three portions of the steel sheet 2 arranged at a position at which an elastic deformation of the steel sheet 2 decays due to the vibration-damping device 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas wiping apparatus. Specifically, the roll in the bath and the vibration control device are used in combination to surely correct the plate warp.

As a method for plating molten metal on a continuous steel plate, a method using a gas wiping apparatus is generally used.
For example, as shown in FIG. 2 (a), this method uses a sink roll 3 disposed in the molten metal 1 while continuously infiltrating the steel plate 2 into the molten metal (hot dip plating bath) 1. Is turned upward, and the bath rolls (support rolls) 4a and 4b are brought into contact with the steel plate 2 from both sides, and then the steel plate 2 is pulled up from the molten metal 1 and directed toward both sides of the steel plate 2 to the wiping nozzle 5. The air is blown almost horizontally to wipe away excess molten metal. Further, the steel plate 2 pulled up vertically is horizontally changed by the top roll 6, and then the plating adhesion amount on both surfaces is measured by the plating adhesion amount sensor 7.

Here, as shown in FIG. 3, when the sink roll 3 comes into contact with the steel plate 2, L warpage occurs due to cylindrical plastic bending in which the outer peripheral portion is stretched and stretched and the inner peripheral portion is compressed and contracted. The L warp is constrained by the tension, and the C warp (plastic warp) which is warp deformation in the plate width direction occurs.
Therefore, as shown in FIG. 2 (a), a vibration damping device 8 is provided above the wiping nozzle 5, and an electromagnetic force is applied to the steel plate 2, thereby suppressing vibration of the steel plate 2 and C of the steel plate 2. The warping is corrected without contact (see Patent Documents 1 and 2). The vibration damping device 8 may also be called a non-contact type plate position adjusting device. The vibration damping device 8 incorporates a plate warpage sensor that measures the position of the steel plate 2.

As shown by a solid line in FIG. 2B, when the vibration damping device 8 is turned on, the steel plate 2 is elastically deformed and the warpage at the position of the vibration damping device 8 becomes substantially zero. Since the elastic deformation effect decreases as the distance from the wiping nozzle 5 is increased, the plate warp remains at the position of the wiping nozzle 5.
In order to reduce this, as shown in FIG. 4, it is necessary to correct the plastic warp by adjusting the position (pushing amount δ) of the rolls 4a and 4b in the bath, but there is no means for measuring the plate warp amount. For this reason, the amount of plating adhesion in the width direction is uneven, and visual adjustment is required.

  In order to use the bath rolls 4a and 4b as described in Patent Document 2, as shown by a broken line in FIG. 2 (b), the vibration damping device 8 is once turned off and the vibration damping device 8 is temporarily turned off. The plate warpage is measured by the plate position sensor built in the plate and the position of the rolls 4a and 4b in the bath is adjusted. During this time, the function of the vibration damping device 8 is OFF, Becomes uneven.

JP-A-2004-273315 (Japanese Patent Application No. 2002-187519) JP 2008-280587 (Japanese Patent Application No. 2007-126212)

Problem 1: When correcting the warpage of the steel plate 2 by using the rolls 4a and 4b in the bath and the vibration control device 8 together, the elastic deformation of the plate by the vibration control device 8 causes the vibration at the plate warpage sensor position. The plate plastic deformation is canceled out, and the amount of plastic deformation of the plate is unknown. There is a method of measuring the warp of the plate from the attractive force of the electromagnet without using the plate warp sensor (Patent Document 1), but the prediction calculation is complicated and the accuracy is low.

Problem 2: If there is insufficient adjustment of the rolls 4a and 4b in the bath for correcting plastic deformation of the steel plate 2, an excessive load is applied to the vibration damping device 8, so it is desired to reduce it.
Problem 3: I want to measure sheet plastic deformation with high accuracy even when the steel sheet 2 meanders.

  The gas wiping apparatus according to claim 1 of the present invention for solving the above-described problem is to cause the steel sheet to turn upward with a sink roll disposed in the hot dipping bath while allowing a continuous steel sheet to enter the hot dipping bath. In the gas wiping apparatus for wiping excess molten metal by blowing a gas from a wiping nozzle to the steel plate pulled up from the hot dipping bath after contacting the steel roll from both sides with respect to the steel plate, A vibration damping device that corrects the warpage in a non-contact manner by electromagnetic force is installed on the steel plate at the top of the wiping nozzle, and the steel plate is placed at a position where the effect of elastic deformation of the steel plate by the vibration damping device is attenuated. One or more distance sensors (hereinafter referred to as plate warpage sensors) capable of measuring at least three positions in the plate width direction are provided.

  A gas wiping apparatus according to a second aspect of the present invention for solving the above-mentioned problem is that, in the first aspect, the amount of warpage of the steel sheet is calculated based on information from the sensor so that the warpage becomes substantially zero. In addition, the position of the roll in the bath is controlled.

  The gas wiping device according to a third aspect of the present invention for solving the above-mentioned problems is the gas wiping device according to the first or second aspect, wherein the sensor comprises two sensors for detecting plate positions at both ends of the steel plate, and a plate center of the steel plate. And a single sensor for detecting the plate position of the part.

  A gas wiping apparatus according to a fourth aspect of the present invention for solving the above-mentioned problems is characterized in that, in the first, second or third aspect, at least one of the sensors is movable in the plate width direction.

  In the present invention, since the plate warpage sensor is installed at a position where the effect of elastic deformation by the vibration damping device is attenuated, the roll in the bath is set so that the C warpage amount of the steel sheet becomes substantially zero even when the vibration damping device is ON. Can be adjusted appropriately, and this reduces the load on the vibration damping device. If the position of the center part of a steel plate and the both ends of a steel plate is measured with a plate warp sensor, the amount of C warp of the steel plate can be measured by approximating the shape of the plate warp with a quadratic curve. If the plate warp sensor can move in the width direction, the amount of plastic deformation in the plate width direction of the steel plate can be reliably measured even when the steel plate meanders or the plate width of the steel plate changes. .

FIG. 1A is a schematic view of a gas wiping apparatus according to a first embodiment of the present invention, and FIG. 1B is a positional diagram of C warpage in the gas wiping apparatus according to the first embodiment of the present invention. It is a graph which shows a change. FIG. 2A is a schematic diagram of a gas wiping apparatus according to the background art, and FIG. 2B is a graph showing a positional change of C warpage in the gas wiping apparatus according to the background art. It is explanatory drawing which shows the cylindrical plastic bending by a sink roll. It is explanatory drawing which shows the relationship between arrangement | positioning of the roll in bath, and C curvature correction characteristic. 5A is a layout view of the plate warpage sensor in the gas wiping apparatus according to the first embodiment of the present invention as viewed from above, and FIG. 5B is a layout view of the plate warpage sensor as viewed from the front. FIG. 5C is a layout view of the plate warpage sensor as viewed from the side.

  In the present invention, a plate warpage sensor is provided above the vibration damping device at a position where the effect of elastic deformation by the vibration damping device is attenuated, and the position of the roll in the bath is adjusted so that the plate warpage at that position becomes substantially zero. To implement. This makes it possible to correct plastic warp by adjusting the position of the roll in the bath while the vibration damping device is always ON, and it is possible to perform plating with the plate being flat and free of vibration. This stabilization makes it possible to bring the position of the wiping nozzle closer to the steel plate, so that the wiping ability (ability to squeeze excess zinc thin) is improved, the line speed can be increased, and the production capacity is increased. Moreover, by making the plastic warpage substantially zero, the load on the vibration damping device (electromagnet) is reduced, energy saving is achieved, and further downsizing is possible.

Hereinafter, the present invention will be described in detail based on examples.
FIG. 1 shows a gas wiping apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1 (a), the steel plate 2 is continuously infiltrated into the molten metal (hot dip plating bath) 1, and the steel plate 2 is turned upward by the sink roll 3 disposed in the molten metal 1. After the rolls 4a and 4b in the bath are brought into contact with the steel plate 2 from both sides, the steel plate 2 is pulled up from the molten metal 1, and air is blown horizontally from the wiping nozzle 5 toward both surfaces of the steel plate 2 to melt excessively. Wipe away metal. Further, the steel plate 2 pulled up vertically is horizontally changed by the top roll 6, and then the plating adhesion amount on both surfaces is measured by the plating adhesion amount sensor 7.

As shown in FIG. 3, when the sink roll 3 comes into contact with the steel plate 2, L warpage occurs due to cylindrical plastic bending, and thereafter, the L warpage is constrained by tension, and C warpage that is warpage deformation in the plate width direction occurs. appear.
If the C warpage of the steel plate 2 remains, the distance between the wiping nozzle 5 and the steel plate 2 is not constant, and the amount of plating adhesion is not constant.

Therefore, the C warpage of the steel plate 2 generated by the sink roll 3 is corrected by using the rolls 4a and 4b in the bath and the vibration damping device 8 in combination.
That is, the steel plate 3 turned upward by the sink roll 3 is subjected to bending stress when contacting the rolls 4 a and 4 b in the bath from both sides in the molten metal 1.
Here, the rolls 4a and 4b in the bath are in a regular arrangement in this embodiment, as shown in FIG.
In the normal arrangement of the rolls 4a and 4b in the bath, the roll 4a in the bath located on the opposite side of the sink roll 3 with the steel plate 2 in between is placed in the lower position, as in the background art shown in FIG. It is arrange | positioning and it is arrange | positioning the roll 4b in a bath located in the same side of the sink roll 3 in an upper position.

On the other hand, the reverse arrangement of the in-bath rolls 4a and 4b means that the in-bath roll 4a located on the opposite side of the sink roll 3 with the steel plate 2 interposed therebetween is arranged in the upper position and is located on the same side of the sink roll 3. It is to arrange | position the roll 4b in a bath in a lower position.
Whether the rolls 4a and 4b in the bath are arranged in the normal direction or in the reverse arrangement, the plastic bending process is not changed when the steel plate 2 passes through.

However, as shown in FIG. 4, the C warpage correction characteristics with respect to the pushing amount δ of the roll in the bath are different.
As shown in the lower left column in FIG. 4, the C warpage correction characteristic with respect to the pushing amount δ in the normal arrangement takes a minimum value after decreasing as the pushing amount δ increases, and then rises.

  On the other hand, the C warpage correction characteristic with respect to the pushing amount δ in the reverse arrangement is a curve that decreases as the pushing amount δ increases as shown in the lower right column in FIG. Therefore, there is an advantage that the optimum point of the pushing amount δ is one and control becomes easy.

Further, in order to reduce the C warpage of the steel plate 2 remaining after the plastic warp correction by the rolls 4a and 4b in the bath, as shown in FIG. 1A, a vibration damping device 8 is provided above the wiping nozzle 5, and the steel plate 2 By applying an electromagnetic force to the steel plate, the vibration of the steel plate 2 is suppressed and the C warpage of the steel plate 2 is corrected without contact.
The vibration damping device 8 is not particularly limited as long as it has a structure for damping the steel plate 2 and adjusting the warpage of the steel plate 2 by electromagnetic force. For example, JP-A-2003-105515, JP-A-2003-113659. And those disclosed in JP-A No. 2003-113460 can be used.

The closer the distance between the wiping nozzle 5 and the vibration damping device 8 is, the greater the effect of elastic bending is. Therefore, it is preferable that the distance between the vibration damping device 8 and the wiping nozzle 5 is smaller.
The current value for the electromagnet of the vibration damping device 8 is obtained by the controller 10 shown in FIG. 5 and is adjusted by the plate warp adjusting mechanism 20 using electromagnetic force.

Furthermore, in the present invention, above the vibration damping device 8, at a position where the effect of the elastic deformation by the vibration damping device 8 is attenuated, that is, a position where the elastic deformation is sufficiently small, for example, about 0. The plate warpage sensor 9 is installed at a position of 5 m.
Since the plate warpage sensor 9 is installed at a position where the effect of elastic deformation by the vibration damping device 8 is attenuated, the plate warpage sensor 9 detects the C warpage of the plate to be corrected by the roll in the bath even when the vibration damping device 8 is ON. Can do.

As described in the background art section above, conventionally, the vibration damping device had to be turned off while measuring the plastic warpage of the plate and correcting the warpage. As shown in FIG. 1B, it is possible to correct the plastic warp of the plate with the vibration damping device 8 turned on. Moreover, the complicated and low-precision prediction calculation performed in Patent Document 2 is not necessary.
The plate warpage sensor 9 is not particularly limited as long as it is one or more distance sensors capable of measuring at least three positions of the steel plate 2, but an example thereof is shown in FIG.

As shown in FIG. 5, two two-dimensional laser type position sensors 9a and 9c for detecting the plate position and the plate edge at both ends of the steel plate 2, and one laser type for detecting the plate position at the center of the plate of the steel plate 2. The position sensor 9b is used.
In this way, by measuring a total of three points of the plate position (two points) at both ends of the steel plate 2 and the plate position (one point) at the center of the plate, it is possible to accurately obtain the amount of C warpage of the steel plate 2. It becomes.

  In addition, one laser type position sensor 9b that detects the plate position at the center of the plate of the steel plate 2 is fixed to the center, while two two-dimensional laser type position sensors that detect the plate position and the plate edge at both ends of the steel plate 2. If 9a and 9c can be moved in the plate width direction, the amount of C warpage of the steel plate 2 can be obtained reliably by flexibly responding to the meandering of the steel plate 2 or changing the plate width of the steel plate 2. Is possible. The laser position sensor 9b may be movable in the plate width direction.

<How to determine the amount of roll push in the bath δ>
The roll push-in amount δ in the bath is obtained by a method of Examples 1 to 3 below by creating a characteristic curve between the plate warp and the roll position for each representative plate thickness by experiment or numerical analysis. Different characteristic curves are used for the normal arrangement and the reverse arrangement. The warpage of the plate is approximately proportional to the square of the curvature of the plate surface × the plate width.

Example 1: Adjustment method by a fixed step This method is a method of moving in a direction in which the warpage is reduced by a preset amount of movement at every measurement period of the plate warp.
That is, the movement of the roll is controlled to be pushed in at regular intervals for each control cycle, and this is repeated to control the roll position. In the reverse arrangement of FIG. 4, “the direction in which the warp decreases” is the direction in which the roll is pushed if the warp is + (plus), and the direction in which the roll is pulled if the warp is − (minus). .

Example 2: Method 1 using characteristic curve gradient
In this method, the gradient of the characteristic curve is obtained from the previous roll movement amount and the previous plate warpage change amount, and the current movement amount is obtained according to the following equation.
(Target value−Current warpage amount) / (Slope of previous characteristic curve) × Relaxation coefficient “Last time” is the previous time viewed from the current time, and refers to the timing once in the control cycle. The “target value” may not be 0 because the purpose is to control the distribution of plating adhesion. The relaxation coefficient is a parameter for adjusting control responsiveness (convergence stability), and is usually set to 1 or less. It is not a constant value because it is affected by usage conditions.

Example 3: Method 2 using characteristic curve gradient
This method is a method of setting a fixed value instead of obtaining a characteristic curve for every measurement period of the warp.

  As described above, in the present invention, a plate warpage sensor is disposed at a position where the effect of the amount of elastic deformation by the vibration damping device is attenuated, and the roll in the bath is based on the position information of the steel plate measured by the plate warpage sensor. Adjust the push-in amount. For this reason, since the pushing amount of the roll in the bath can be optimized even when the vibration damping device is on, the vibration damping device can always be operated in the on state.

  In the prior art described in the background art section, when the vibration damping device is turned on, the C warpage is reduced by the attractive force of the electromagnet, so the amount of C warpage caused by the plastic deformation of the plate cannot be measured correctly. The push-in position of the roll in the bath cannot be optimized. For this reason, a load more than necessary is applied to the magnet, or the warpage control range of the magnet is exceeded. In order to avoid this, in the conventional method, the C warp caused by the plastic deformation of the plate is measured with the vibration damping device turned OFF (electromagnetic attraction force 0) once, and the push amount of the roll in the bath is measured. Although the vibration damping device is turned on after the state is made appropriate, plate warping and plate vibration cannot be suppressed when the vibration damping device is turned off. However, according to the present invention, such a problem can be solved.

  INDUSTRIAL APPLICABILITY The present invention can be widely used industrially as a gas wiping device. In particular, when a roll in a bath and a vibration damping device are used in combination, the amount of plastic deformation (plastic warpage) of a steel sheet not including elastic deformation is measured. Therefore, it is possible to reliably correct the board warpage.

DESCRIPTION OF SYMBOLS 1 Molten metal 2 Steel plate 3 Sink roll 4a, 4b Roll in bath 5 Wiping nozzle 6 Top roll 7 Plating adhesion sensor 8 Damping device 9 Plate warpage sensor 10 Controller 20 Plate warpage adjustment mechanism 30 by electromagnetic force Position adjustment of roll in bath mechanism

Claims (4)

  While intruding a continuous steel plate in the hot dipping bath, the steel plate is turned upward with a sink roll disposed in the hot dipping bath, and after the roll in the bath is brought into contact with the steel plate from both sides, In a gas wiping apparatus for wiping off excess molten metal by blowing gas from a wiping nozzle to the steel plate pulled up from the hot dipping bath, the steel plate is non-contacted by electromagnetic force on the steel plate. One or more distances at which at least three positions of the steel plate can be measured in the plate width direction at a position where an effect of elastic deformation of the steel plate by the vibration damping device is attenuated by installing a vibration damping device that corrects the warp. A gas wiping apparatus comprising a sensor.   2. The gas wiping according to claim 1, wherein the amount of warpage of the steel sheet is calculated based on information from the sensor, and the position of the roll in the bath is controlled so that the warpage becomes substantially zero. apparatus.   3. The sensor according to claim 1, wherein the sensor includes two sensors that detect a plate position at both ends of the steel plate and one sensor that detects a plate position at a center portion of the steel plate. Gas wiping device.   4. The gas wiping device according to claim 1, wherein at least one of the sensors is movable in a plate width direction.

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