JP2000219944A - Apparatus for producing steel sheet coated with hot-dip metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing apparatus of steel sheet coated with a hot-dip metal, in which the molten metal can surely be sealed by a simple apparatus constitution at a low cost regardless of the defective shape of the steel sheet, even at the initial stage of filling the molten metal. SOLUTION: In this producing apparatus of a hot-dip metal coated steel sheet, an opening hole part is arranged at a bottom part of a plating pot 3 for holding the molten metal 2 and a steel sheet 1 is inputted into the plating pot 3 from the lower part of the opening hole part to undergo the hot-dip metal coating. Shape correcting rolls 4 for correcting the shape of the steel sheet just before being inputted into the plating pot 3 at just below the opening hole part and a seal device 5 for molten metal arranged by fixing to roll supporting parts 6 of the shape correcting rolls 4 at the opening hole part are disposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a galvanized steel strip using an air pot.

[0002]

2. Description of the Related Art As one of new methods of hot-dip metal plating of steel strip, a method using an air pot has been proposed.
In this method, openings are provided for passing a steel strip above and below a plating pot filled with molten metal, and the steel strip is moved vertically upward from an opening at the bottom of the plating pot to pass through the plating pot, The molten metal adhered to the band is solidified and plated. At this time, as means for preventing the molten metal from leaking from the opening at the lower portion of the plating pot, for example, JP-A-08-337860 and JP-A-07-2588 are used.
As disclosed in Japanese Patent Laid-Open No. 11, a sealing method has been proposed in which an electromagnetic force is applied to a molten metal, and furthermore, a static gas pressure is used in combination with the electromagnetic force.

[0003]

However, the method using electromagnetic force is not only complicated and expensive, but also has a high running cost, and also causes the steel strip to be heated. There was a problem in plating quality. In addition, there are some which use static gas together with electromagnetic force, but the shape of steel strip is poor (C warp, flapping, ear extension, etc.)
In order to avoid contact between the steel strip and the sealing member due to, the opening is widened, and as a result, the distance between the steel strip and the
There is a problem that molten metal leaks.

The present invention has been made in view of the above circumstances, and has a simple device configuration at a low cost irrespective of a shape defect of a steel strip.
An object of the present invention is to provide an apparatus for manufacturing a hot-dip metal-plated steel strip which can reliably seal a molten metal even at an initial stage of filling a molten metal.

[0005]

In order to solve the above-mentioned problems, according to the present invention, the balance between the surface tension of the molten metal and the head pressure of the molten metal in the plating pot at the opening at the bottom of the plating pot filled with the molten metal. From the viewpoint of minimizing the differential pressure between the two at the time of collapse, the above-mentioned differential pressure is minimized by always maintaining the opening area at the bottom of the plating pot in the minimum necessary range.

As a means for keeping the area of the opening to the minimum necessary, a shape straightening roll for straightening the shape of the steel strip immediately before entering the plating pot is provided immediately below the opening, and a roll supporting portion for the shape straightening roll is provided. And a sealing device for sealing the molten metal in the plating pot. When the vertical distance between the seal end closest to the steel strip in the seal portion of the seal device and the axis of the shape correction roll is Y and the diameter of the shape correction roll is D, the seal device and the shape correction roll are D / They are arranged so as to satisfy the relationship of 8 <Y <D. When the sealing device and the shape correction roll are disposed so as to satisfy the relationship of Y <D, the effect of the shape defect of the steel strip at the seal portion is eliminated, and the effect of preventing the contact between the steel strip and the seal member is more excellent. . The smaller the vertical distance Y is, the better the above effect is. However, if the vertical distance Y is small, there is a possibility that the structure of the sealing device may be restricted or the operation may be hindered.

In addition, the shape correcting roll and the sealing device are integrally moved so that the horizontal distance X between the sealing end of the sealing device and the steel strip can be freely adjusted within the range of 0 mm <X <5 mm. A moving mechanism is attached to the shape correction roll.
In this way, even if the thickness of the steel strip changes, the entire roll shifts left and right accordingly,
The opening distance between the steel strip and the sealing device can always be kept constant. Further, it is possible to avoid making the opening larger than necessary in order to avoid contact with the sealing device due to the shape defect of the steel strip.

In order to prevent the molten metal from leaking from the opening, means for applying a static gas pressure is provided below the opening, and the static gas is applied by the means to provide a molten metal at the opening of the sealing device. The difference between the surface tension of the head and the head pressure of the molten metal in the plating pot. As a means for applying a static gas pressure, a static gas pressure box may be provided below the plating pot, and a static gas pressure greater than the pressure head in the plating pot may be applied to the static gas box. A gas nozzle may be disposed below the opening of the plating pot, and the nozzle may apply a static gas pressure larger than that of the pressure head in the plating pot. With such an apparatus configuration, the molten metal in the plating pot can be reliably sealed with a simple structure irrespective of the variation in the thickness of the steel strip and the defective shape and without using a magnetic force or the like.

[0009]

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

FIG. 1 is a view showing an apparatus for manufacturing a hot-dip metal-plated steel strip according to an embodiment of the present invention. In FIG. 1, 1 is a steel strip, 3 is a plating pot (aerial pot) filled with molten metal 2, 4 is a shape correction roll, 6 is a roll support portion of the shape correction roll 4, and 7 is a horizontal support of the roll support portion 6. Reference numeral 5 denotes a molten metal sealing device, and reference numeral 8 denotes a static gas box disposed below the plating pot 3. The sealing device 5 is provided so that a slide portion 9 between the static gas pressure box 8 and the plating pot 3 can be moved in the horizontal direction. The sealing device 5 includes a shape correcting roll 4.
The shape correcting roll 4 and the sealing device 5 are integrally moved in the horizontal direction by the slide mechanism 7. Static gas pressure box 8
Is provided so as to apply a gas static pressure larger than the pressure head in the plating pot 3, and the molten metal 2 and gas applied to the gas static pressure box 8 do not leak to the slide surface of the slide portion 9. As shown, a gas seal (not shown) is provided.

In this apparatus, the leak of the molten metal 2 from the opening 13 is prevented by applying a static gas pressure higher than the pressure head of the molten metal in the plating pot 3 to the gas static pressure box 8. When the sheet thickness of the steel strip 1 changes, the shape correcting roll 4 moves in the horizontal direction by the slide mechanism 7 according to the change in the sheet thickness, and at the same time, the sealing device 5 also moves in the horizontal direction integrally. Therefore, the distance X between the sealing device 5 and the steel strip 1 in the opening 13 is kept constant regardless of the thickness of the steel strip 1. Distance X between sealing device 5 and steel strip 1
Is preferably a minimum distance that does not make contact with the steel strip 1 within the range of 0 mm <X <5 mm. In this device, the slide mechanism 7, the shape correction roll 4, and the sealing device 5 are set to 2 mm.
Have been adjusted.

FIG. 2 is a view showing an apparatus in which a gas nozzle is provided below the opening of the plating pot 3 as means for applying a static gas pressure. In FIG. 2, 10 is a gas nozzle, 1
1 is a gas supply device, and 12 is an oxidation prevention chamber. A gas static pressure higher than the pressure head in the plating pot is applied to the gas nozzle 10 using the gas supply device 11. In this device, the gas nozzle 10 also serves as a sealing device. The gas nozzle 10 is fixedly attached to the roll support portion 6 of the shape correction roll 4, and is disposed so as to be able to move horizontally in a slide portion between the plating pot 3 and the oxidation prevention chamber 12. The slide mechanism 7 allows the shape correction roll 4 and the gas nozzle 10 to move integrally in the horizontal direction. When the thickness of the steel strip 1 changes, the shape correcting roll 4 moves in the horizontal direction by the slide mechanism 7 in accordance with the change in the thickness, and at the same time, the gas nozzle 10 integrally moves in the horizontal direction. Therefore, the same effect as that of the apparatus of FIG. 1 can be obtained in this apparatus.

[0013]

According to the apparatus for manufacturing a hot-dip metal-plated steel strip of the present invention, stable plating can be performed without leaking molten metal by applying a slight static gas pressure regardless of the thickness and shape of the steel strip. Can be applied.

Further, as compared with the case where electromagnetic force is used for the sealing device, a simple and inexpensive device is required, and there is no problem in plating quality due to heating of the steel strip.

[Brief description of the drawings]

FIG. 1 is a view showing an apparatus for manufacturing a hot-dip metal-plated steel strip according to an embodiment of the present invention.

FIG. 2 is a view showing a device for producing a hot-dip metal-plated steel strip according to an embodiment of the present invention, the device having a gas nozzle as a means for applying static gas pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel strip 2 Molten metal 3 Plating pot (air pot) 4 Shape correction roll 5 Seal device 6 Roll support part 7 Slide mechanism 8 Gas static pressure box 9 Slide part 10 Gas nozzle 11 Gas supply device 12 Oxidation prevention chamber 13 Opening

Claims (6)

[Claims] 1. An apparatus for manufacturing a molten metal plated steel strip, wherein an opening is provided in a bottom portion of a plating pot for holding a molten metal, and a steel strip is inserted into the plating pot from below the opening to perform molten metal plating. A shape straightening roll for straightening the steel strip shape immediately before entering the plating pot immediately below the opening, and a molten metal sealing device provided in the opening fixed to a roll support portion of the shape straightening roll were provided. An apparatus for manufacturing a hot-dip galvanized steel strip. 2. The horizontal distance between the seal end closest to the steel strip and the steel strip in the seal portion of the sealing device is X, the vertical distance between the axis of the shape correction roll and the seal end is Y, and the shape correction roll is Y. 2. The apparatus for manufacturing a hot-dip metal-plated steel strip according to claim 1, wherein when the diameter is D, the sealing device and the shape correcting roll are arranged so as to satisfy the following relationship. D / 8 <Y <D and 0 mm <X <5 mm 3. A horizontal movement in which the shape correcting roll and the sealing device are integrally moved, and the horizontal distance X between the sealing end of the sealing device and the steel strip can be adjusted within a range of 0 mm <X <5 mm. 3. The apparatus according to claim 1, wherein the mechanism is attached to the shape correcting roll. 4. The apparatus according to claim 1, further comprising means for applying a static gas pressure below the opening. 5. The static gas pressure applying means according to claim 4, wherein a static gas pressure box for applying a static gas pressure greater than a pressure head in the plating pot is provided below the plating pot. Manufacturing equipment for hot-dip galvanized steel strip. 6. A gas nozzle for applying a gas static pressure greater than a pressure head in a plating pot is provided below the opening of the plating pot as means for applying a static gas pressure. An apparatus for producing a hot-dip metal-plated steel strip according to the above.