JP2005015837A - Hot dip metal coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot dip metal coating apparatus realizing more speeding up. <P>SOLUTION: A blade type wiping apparatus 20 is arranged on the part at which a steel strip 1 comes out from the upper face of molten zinc 2 in a plating tank 10. The blade type wiping apparatus includes a pair of blades 22 supported by a blade support apparatus 21. In each blade 22, the downstream side is formed from a thin, almost wedge-shaped sheet, in the edge parts on the upstream and downstream sides, each cross-section is rounded so as to be a circular-arc shape, and it is tilted so that the edge part on the downstream side is made close to the steel strip 1 than the edge part on the upstream side. The molten zinc flows along the inside of each blade, and the lift of a large quantity of molten zinc by the steel strip is prevented, so that a load on a gas type wiping apparatus 30 arranged in the upper direction of the blade type wiping apparatus is reduced, splashes are less prone to occur, and speeding-up is made possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molten metal plating apparatus.
[0002]
[Prior art]
A molten metal plating apparatus for producing a galvanized steel sheet or the like is known. In this method, a metal strip to be plated is passed through a plating tank storing molten metal. Currently, such a molten metal plating apparatus often uses a gas type wiper apparatus that blows gas so that excess molten metal does not adhere to the metal strip exiting the plating tank (for example, Japanese Patent Laid-Open No. Hei 3-219061). Issue gazette).
[0003]
And to improve productivity, the speed of the metal strip has been increased. Increasing the speed of the metal strip increases the amount of molten metal lifted from the plating bath. Therefore, the nozzle of the gas wiper device has been brought close to the metal strip to be plated to cope with the increase in speed. However, if the nozzle is brought too close, the return flow rate of the molten metal flowing in the direction opposite to the traveling direction of the metal strip increases, and the molten metal scatters from the liquid surface, generating so-called splash, which is caused after the wiper device. It adheres to the metal strip on the flow side, or falls as a foreign substance (oxide called top dross) into the plating tank, and adheres to the metal strip, leading to a reduction in product quality. As a result, it is impossible to increase the speed of the metal strip to a certain value (approximately 150 m / min) or more, and the improvement in productivity is at a standstill.
[0004]
[Patent Document 1]
JP-A-3-219061
[Problems to be solved by the invention]
An object of this invention is to provide the molten metal plating apparatus which can respond to higher speed in view of the said problem.
[0006]
[Means for Solving the Problems]
According to the invention of claim 1, a molten metal plating apparatus for plating the surface of the metal strip by passing the metal strip through the molten metal stored in the plating tank,
A first stage wiping device for reducing the thickness of the molten metal deposited on the metal strip where the metal strip exits the molten metal;
A second-stage wiping device for further reducing the film thickness of the metal adhering to the metal strip on the downstream side in the movement direction of the metal strip from the first-stage wiping device;
A molten metal plating apparatus is provided.
[0007]
In the molten metal plating apparatus constructed as described above, the film thickness of the molten metal adhering to the metal strip is reduced by the first stage wiping device when the metal strip comes out of the molten metal, and the metal strip moves more than the first stage wiping apparatus. The film thickness of the metal adhering to the metal strip is further reduced by the second stage wiping device downstream in the direction. In the second stage wiping device, since the film thickness is reduced in the first stage in advance, even when the distance between the nozzle and the metal strip is reduced during high-speed feeding, the return flow rate of the molten metal is small and splash is unlikely to occur. .
[0008]
In the invention of claim 2, in the invention of claim 1, the first-stage wiping device is inclined with respect to the metal strip so that the downstream side is thinner than the upstream side and the downstream side is closer to the metal strip than the upstream side. The blade-type wiping device has a pair of blades arranged, and the second-stage wiping device is a gas-type wiping device that blows gas from a gas outlet to a metal strip. By making the first-stage wiping into a blade type, the return flow from the second-stage wiping device travels along the outer surface of the blade (the surface not facing the metal strip) and returns to the plating tank. There is no accumulation of liquid at the tip exit side.
[0009]
In the invention of claim 3, in the invention of claim 2, the downstream end of the blade has a roundness of 30 mm or less in diameter. The smaller the diameter is, the less liquid is accumulated at the blade tip, and the first-stage wiping performance is improved.
In the invention of claim 4, in the invention of claim 2, the angle of inclination of the blade with respect to the metal strip is adjustable.
In the invention of claim 5, in the invention of claim 2, the distance between the blade and the metal strip is made variable.
In the invention of claim 6, in the invention of claim 2, the position of the blade with respect to the molten metal surface is made variable.
According to a seventh aspect of the present invention, in the second aspect of the present invention, a device for heating the blade is provided. Thereby, the fluidity of the molten metal is maintained.
In the invention of claim 8, in the invention of claim 2, the distance between the blade of the blade-type wiping device and the gas outlet of the gas-type wiping device is made variable. By appropriately adjusting this distance, it is possible to promote the liquid flow that flows outside the first-stage blade-type wiper using the gas flow of the second-stage gas-type wiping device.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a molten metal plating apparatus of the present invention will be described with reference to the accompanying drawings, taking as an example the case of galvanizing a steel plate.
FIG. 1 is a diagram showing a configuration of a molten metal plating apparatus 100 according to the present invention. Reference numeral 10 indicates a plating tank, which is formed of a heat resistant material. Inside the plating tank 10, molten zinc 2 obtained by melting zinc, which is a plating metal, is stored.
[0011]
Reference numeral 1 indicates a steel strip to be plated (hereinafter referred to as a steel strip), and the steel strip 1 is fed into the plating layer 10 obliquely by a feed roller (not shown), After being passed through the sink roll 11 disposed on the upper side, the sheet is pulled up substantially vertically by a winding roller (not shown).
[0012]
A blade type wiping device 20 is disposed where the steel strip 1 exits from the upper surface of the molten zinc 2. The blade-type wiping device 20 has a pair of blades 22 supported by a blade support device 21 arranged in the rear side direction of the steel strip 1 in the drawing. The blade 22 is formed of a substantially wedge-shaped plate material that is thick on the upstream side and thin on the downstream side, and the upstream end portion and the downstream end portion are each rounded so that the cross-section has an arcuate shape, and at least the downstream end portion The diameter of the arc is 30 mm or less.
The blade 22 is inclined with respect to the steel strip 1 so that the downstream end is closer to the steel strip 1 than the upstream end.
[0013]
One end of the blade 22 is fixed to the other end of the shaft 23 attached to the drive device 24 in the blade support device 21, and the tilt angle with respect to the steel strip 1 can be changed by the drive device 24. Further, the drive device 24 itself is attached to the position adjusting mechanism 25, and the entire blade 22 can be moved in the vertical direction and the horizontal direction. In addition, if a link mechanism is utilized, the drive device 24 can also be arrange | positioned outside a plating tank.
[0014]
A gas wiping device 30 is disposed above the blade wiping device 20. The gas type wiping device 30 is formed by attaching a nozzle member 31 having a gas ejection port 32 to a nozzle support member 33 arranged in the rear side direction of the steel strip 1 in the drawing. The nozzle support member 33 includes a position adjustment mechanism 34, and can adjust the vertical and horizontal positions and the tilt angle of the nozzle 31. The gas ejected from the gas ejection port 32 is air, nitrogen gas, or the like, and is supplied from the gas supply device 35.
[0015]
Hereinafter, the operation of the molten metal plating apparatus 100 configured as described above will be described.
As the steel strip 1 leaves the molten zinc 2, the molten zinc 2 is dragged to the steel strip 1. At this time, since the blade 22 of the blade type wiping device 20 is disposed, a large amount of molten zinc 2 is prevented from being dragged by the inner surface of the blade 22, and the steel strip immediately after leaving the plating tank 10. The film thickness of the molten zinc 2 adhering to 1 becomes small. Moreover, the blade 22 has a smaller diameter of the arc of the wiping portion than that of the roller type, there is no liquid pool due to the return flow from the second stage gas wiping device 30, and the film thickness on the outlet side is stable.
[0016]
In this embodiment, since the blade type wiping device 20 has a position adjusting mechanism, the vertical position and the horizontal position of the blade 22 can be adjusted to optimum positions. Further, an electric resistance wire 26 is embedded in the blade 22, and an electric current is supplied to the electric resistance wire 26 from an external power source 27 through the nozzle support member 33 so that the blade 22 can be heated. Accordingly, the temperature of the molten metal that touches the blade 22 is prevented from lowering and the fluidity is prevented from being lowered, trouble is prevented, and the quality is stabilized.
[0017]
The steel strip 1 then reaches the gas wiping device 30, and the film thickness of the molten zinc 2 adhering to the surface is reduced by the gas supplied from the gas outlet 32 of the nozzle member 31. At that time, the returned downward flow of the molten zinc is returned to the plating tank 10 through the outside of the blade 22 of the blade type wiping device 20.
Here, as described above, since a large amount of molten zinc is not adhered to the surface of the steel strip 1 by the blade 22 of the blade type wiping device 20, the return flow rate in the gas type wiping device 30 is small, and the gas ejection port 32. Even if the steel strip 1 is made extremely close to the steel strip 1, splash is unlikely to occur, and the speed of the steel strip 1 can be increased.
[0018]
As described above, the return flow from the second-stage gas wiping affects the performance of the first-stage blade type wiping. In this embodiment, the blade-type wiping device 20 includes the position adjusting mechanism 25. Therefore, the vertical position and the horizontal direction position of the blade 22 can be adjusted to optimum positions, and the gas type wiping device 30 is also provided with a position adjusting mechanism 34, and the horizontal position of the gas outlet 32, that is, steel. Since the vertical position can be adjusted in addition to the adjustment of the distance to the strip 1, the distance between the blade 22 of the blade type wiping device 20 and the gas outlet 32 of the gas type wiping device 30 can be adjusted to an optimum value.
[0019]
【The invention's effect】
The invention described in each claim is a molten metal plating apparatus for plating the surface of the metal strip by passing the metal strip through the molten metal stored in the plating tank, where the metal strip is removed from the molten metal. A first stage wiping device for reducing the film thickness of the molten metal adhering to the metal, and a second stage for further reducing the film thickness of the metal adhering to the metal strip downstream of the first stage wiping device in the moving direction of the metal strip. A step wiping device.
Therefore, when the metal strip comes out of the molten metal, the film thickness of the molten metal adhering to the metal strip is reduced by the first-stage wiping device, and the second-stage wiping device is located downstream of the first-stage wiping device in the moving direction of the metal strip. As a result, the film thickness of the metal adhering to the metal strip is further reduced, the load on the second-stage wiping device is small, and splash is unlikely to occur, so it is possible to cope with high speed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a molten metal plating apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Steel strip 2 ... Molten zinc 10 ... Plating tank 11 ... Sink roller 20 ... Blade type wiping device 21 ... Blade support device 22 ... Blade 23 ... Shaft 24 ... Drive device 25 ... Position adjustment mechanism 30 ... Gas type wiping device 31 ... Nozzle member 32 ... gas jet 33 ... nozzle support member 34 ... position adjusting mechanism 35 ... gas supply device

Claims (8)

A molten metal plating apparatus for plating a surface of a metal strip by passing the metal strip through a molten metal stored in a plating tank,
A first stage wiping device for reducing the thickness of the molten metal deposited on the metal strip where the metal strip exits the molten metal;
A second-stage wiping device for further reducing the film thickness of the metal adhering to the metal strip on the downstream side in the movement direction of the metal strip from the first-stage wiping device;
A molten metal plating apparatus comprising: The first-stage wiping device is a blade-type wiping device having a pair of blades arranged to be inclined with respect to the metal strip so that the downstream side is thinner than the upstream side and the downstream side is closer to the metal strip than the upstream side ,
2. The molten metal plating apparatus according to claim 1, wherein the second stage wiping apparatus is a gas type wiping apparatus that blows gas from a gas outlet to a metal strip. The molten metal plating apparatus according to claim 2, wherein the downstream end of the blade has a roundness of 30 mm or less in diameter. The molten metal plating apparatus according to claim 2, wherein an angle of inclination of the blade with respect to the metal strip is adjustable. The molten metal plating apparatus according to claim 2, wherein the distance between the blade and the metal strip is variable. The molten metal plating apparatus according to claim 2, wherein the position of the blade with respect to the molten metal surface is variable. The molten metal plating apparatus according to claim 2, further comprising an apparatus for heating the blade. The molten metal plating apparatus according to claim 2, wherein a distance between a blade of the blade type wiping apparatus and a gas outlet of the gas type wiping apparatus is made variable.

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