JP2000282207A - Wiping device in hot dip metal coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the uniformity of hot dip metal coating weight by using both of a technique for correcting the warping with an electric magnet and a technique for straightening gas flow at the edge parts of a steel strip with buffle plates. SOLUTION: The electric magnets 36 are arranged on buffle plate shifting carrages 22 for shifting the buffle plates 20 which are arranged at both edge parts in the width direction of the steel strip 10 to straighten the gas flow at the edge parts and arranged in the width direction of the steel strip while following the edge parts of the steel strip 10, and traveling on a rail 24 so as to be faced to the front and the back surfaces of the steel strip 10. Further, range finders 32 for measuring a deviation (or called as a vibration) in the thickness direction of the steel strip 10, are arranged and a control unit 40 for controlling a current value flowing in the electric magnet 30 is provided so that the deviation between a distance signal from the range finder and a predecided target value becomes zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiping apparatus for hot-dip galvanizing, and more particularly to a wiping apparatus for hot-dip galvanizing, which is suitable for adjusting the amount of hot-dip galvanized coating.

[0002]

2. Description of the Related Art When a steel strip is continuously subjected to hot-dip metal plating such as zinc plating, the amount of coating is generally controlled by a gas wiping method. In the hot-dip metal plating line that performs this gas wiping method, as shown in FIG. 1, molten zinc is stored in a plating bath 8, and a sink roll 12 and a pair of support rolls 14 are contained in the molten zinc. It is rotatably provided, and a pair of wiping nozzles 16 is provided above the support roll 14. The wiping nozzle 16 sprays a wiping gas onto the steel strip 10 that has traveled in the plating bath 8 to scrape off the molten zinc attached to the steel strip 10,
The amount of adhesion (thickness) is controlled. Above the wiping nozzle 16, that is, on the downstream side in the running direction of the steel strip 10 with respect to the wiping nozzle 16, a pair of plating adhesion meters 18 are provided movably in the width direction of the steel strip 10.

In this gas wiping method, when the wiping gas is blown from the wiping nozzle 16 toward both the front and back surfaces of the steel strip 10 to adjust the amount of coating, the molten metal that has locally adhered excessively is removed. It is desirable to make it uniform in the width direction of the steel strip.

[0004] However, the steel strip, particularly the edge portion, is generally warped, and the amount of adhesion between the front surface and the back surface is different due to the influence of the warp, so that there is a problem that the amount of plating applied becomes uneven in the width direction of the steel strip.

In order to solve this problem, for example, Japanese Patent Application Laid-Open
In −302455, the width of the steel strip in the width direction is detected at a position close to the wiping gas spraying position, and the steel strip 10 is attracted by an electromagnet in a direction to cancel the warp in accordance with the amount of the warp. Attempts have been made to maintain the distance between the surface of the band 10 and the wiping nozzle 16 constant without contact, thereby eliminating the unevenness in the width direction of the plating adhesion amount.

On the other hand, at both edges of the steel strip, the turbulence of the gas flow caused by the collision of the wiping gases blown from the front and back nozzles has an adverse effect, the removal ability is reduced, and the excess plating metal remains attached. , A so-called edge overcoat phenomenon may occur.

In order to prevent the edge overcoat phenomenon, an attempt has been made to arrange a baffle plate as a dummy close to the edge of the steel strip and add a virtual steel strip, so to speak, to rectify the gas flow at the edge. This is particularly effective in making the amount of adhesion uniform at the edge.

[0008]

However, there is a technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-302455 for correcting unevenness in the width direction of molten zinc by correcting warpage of a steel strip with an electromagnet. However, the technology that eliminates the non-uniform amount of molten zinc adhering to the edge by the rectifying effect of the gas flow at the edge by the baffle plate has the problem that the baffle plate and the electromagnet interfere with each other and cannot be used at the same time. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to obtain a uniform coating amount in the width direction by using both the correction of warpage by an electromagnet and the rectification of gas flow by a baffle plate. As an issue.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a wiping apparatus for hot-dip metal plating, which is located on both sides in the thickness direction of a steel strip running continuously through a hot-dip metal plating bath, and is attached to the steel strip. A pair of wiping nozzles for controlling the amount of adhered molten metal, provided at both ends in the width direction of the steel strip,
A baffle plate for rectifying an end gas flow, a baffle plate moving truck for moving the baffle plate following an end of the steel strip, and a steel strip mounted on the moving truck. An electromagnet for controlling the distance to the wiping nozzle by suction, and a distance meter for detecting the distance to the steel strip, and flow to the electromagnet so that the measured value of the distance meter becomes equal to a target value. The object is achieved by providing a control device for controlling a current value.

In the present invention, the baffle plate for rectifying the gas flow at the end of the steel strip is sucked onto a baffle plate moving cart for moving following the end of the steel strip by wiping by sucking the steel strip. An electromagnet for controlling the distance to the nozzle, and a distance meter for detecting the distance to the steel strip, so that the measured value of the distance meter is equal to the target value,
Since the current value passed through the electromagnet is controlled, the end position of the wiping nozzle can be controlled without contacting the steel strip, and correction can be performed even for local warpage of the end, and the width can be reduced. This makes it possible to control the amount of adhesion evenly in the direction.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows the overall configuration of a hot-dip galvanizing apparatus in which an embodiment of the wiping apparatus according to the present invention is arranged, FIG. 3 is a side view showing the wiping apparatus part of FIG. 2, and FIG. The figure is shown in FIG.

In the present embodiment, baffle plates 20 provided at both ends in the width direction of the steel strip 10 for rectifying the gas flow at the end are provided so as to follow the end of the steel strip 10. An electromagnet 30 is provided on a baffle plate moving trolley 22 running on a rail 24 for moving in the direction opposite to the front and back of the steel strip 10. Further, a distance meter 32 for measuring displacement (also referred to as vibration) of the steel strip 10 in the thickness direction is provided, and the distance signal from the distance meter 32 is supplied to the electromagnet 30 so that the deviation between the target signal and a predetermined target value is reduced to zero. A control device 40 for controlling a current value is provided.

As described above, by providing the electromagnet 30 for attracting the steel strip 10 integrally with the baffle plate 20, the electromagnet 30 does not interfere with the baffle plate 20.
The warpage of the end portion of the steel strip can be reliably corrected, and the uniform control of the amount of deposition on the front and back and in the width direction becomes possible. Steel strips 10 with different widths
Also, since the electromagnet 30 moves with the movement of the baffle plate 20, the magnetic force can always be applied to an appropriate position at the end of the steel strip.

In the above-described embodiment, the present invention is applied to hot-dip galvanizing. However, the application of the present invention is not limited to the hot-dip galvanizing. Clearly applicable.

[0017]

According to the present invention, since the end position of the steel strip end of the wiping nozzle can be controlled without making contact with the steel strip, it is possible to correct even the local warpage of the end of the steel strip, By using the correction of the warpage by the electromagnet and the rectification of the gas flow by the baffle plate, it is possible to uniformly control the amount of plating applied in the width direction.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of a hot-dip galvanizing apparatus using a gas wiping method.

FIG. 2 is a front view showing the entire configuration of a hot dip galvanizing apparatus to which an embodiment of the present invention is applied.

FIG. 3 is a side view showing the wiping device of the embodiment.

FIG. 4 is a horizontal sectional view of the same.

[Explanation of symbols]

 Reference Signs List 8 hot-dip galvanizing bath 10 steel strip 16 wiping nozzle 20 baffle plate 22 baffle plate moving trolley 24 rail 30 electromagnet 32 distance meter 40 control device

Claims (1)

[Claims] A pair of wiping nozzles located on both sides in the thickness direction of a steel strip running continuously through a hot-dip metal plating bath to control the amount of molten metal attached to the steel strip; A baffle plate provided at both ends in the width direction of the band for rectifying an end gas flow, a baffle plate moving truck for moving the baffle plate following an end of the steel strip, An electromagnet mounted on the movable trolley for sucking the steel strip to control the distance to the wiping nozzle, a distance meter for detecting the distance to the steel strip, and the measured value of the distance meter being a target. A controller for controlling a value of a current flowing through the electromagnet so as to be equal to a value of the electromagnet.