KR20200040467A - Apparatus for preventing oxidization of hot dip plated steel sheet - Google Patents

Abstract

The present invention relates to a device for preventing oxidation of a hot dip plated steel sheet which efficiently responds to changes of steel sheet widths and at the same time can manage concentration of oxygen in a sealing box low. The device comprises: a sealing box which surrounds a steel sheet passing through a plating bath, generates inert atmosphere with inert gas, and forms an entrance for passing the steel sheet; a variable shielding part which is installed to be adjacent to the entrance of the sealing box to adjust an opening area of the steel sheet entrance according to a width of the steel sheet; and a variable sealing part which is installed at the variable shielding part to at least partially seal the steel sheet entrance.

Description

Anti-oxidation device of hot-dip galvanized steel sheet {APPARATUS FOR PREVENTING OXIDIZATION OF HOT DIP PLATED STEEL SHEET}

The present invention relates to, for example, an apparatus for preventing oxidation of a hot-dip galvanized steel sheet that can prevent oxidative surface defects of a hot-dip galvanized steel sheet that is produced when a high corrosion-resistant plated steel sheet is produced in a continuous hot-dip galvanizing process.

Generally, zinc (Zn), aluminum (Al), lead (Pb), etc. are mixed individually or two or more of hot-dip galvanized steel sheets, or magnesium (Mg), titanium (Ti), nickel (Ni), etc. Refers to a plated steel sheet manufactured by a method of passing a steel sheet in a molten plating bath.

In the case of manufacturing a hot-dip galvanized steel sheet, an oxide film is formed on the surface of the plating layer by reacting with oxygen in the atmosphere at the time when the molten metal attached to the surface of the steel sheet solidifies. This oxide film causes various defects in the plating layer by making the solidification rate and solidification characteristics of the molten metal non-uniform. In particular, it causes surface defects such as flow patterns, whisker patterns, and rain marks, resulting in product uniformity, smoothness, and glossiness. Lowers.

Particularly, in the zinc-based plating bath in which strong oxidizing materials such as magnesium, titanium, and aluminum are added, the degree of formation of an oxide film becomes severe. Accordingly, when the surface is painted to improve the corrosion resistance and aesthetics of the steel sheet, it is difficult to secure a beautiful and excellent coating surface.

In order to solve this disadvantage, when controlling the plating adhesion amount of the steel sheet lifted from the plating bath, through the method of performing wiping using nitrogen gas instead of air wiping using conventional air in the state exposed to the atmosphere, the zinc A technique for manufacturing a hot-dip galvanized steel sheet with improved surface quality by reducing the oxidation reaction has been put into practical use.

For example, in Korean Registered Patent Publication No. 1419585, a sealing box is installed on a plating bath and nitrogen is introduced through a wiping nozzle inside the sealing box to maintain the atmosphere in the sealing box as a non-oxidizing atmosphere. An oxide film is not formed on the surface of the plating layer.

However, the conventional sealing box is provided with a conveying passage of the steel plate to enable the mailing, but has a problem in that it cannot efficiently respond to changes in the width of the steel sheet.

Accordingly, an object of the present invention is to provide an anti-oxidation device for a hot-dip galvanized steel sheet that can efficiently cope with a change in the width of the steel sheet and manage a low oxygen concentration inside the sealing box.

Anti-oxidation device according to an embodiment of the present invention, surrounds the steel sheet that has passed through the plating bath, forms an inert atmosphere with an inert gas, a sealing box formed with a doorway for mailing of the steel sheet; A variable shielding part installed adjacent to the doorway of the sealing box to adjust the open area of the doorway according to the width of the steel sheet; And a variable sealing part installed at the variable shielding part to seal the steel plate entrance at least partially.

As described above, according to the present invention, it is possible to efficiently respond to changes in the width of the steel sheet, and at the same time, it is possible to manage the oxygen concentration inside the sealing box low, thereby preventing oxidative surface defects of the hot-dip galvanized steel sheet, and thereby hot-dip galvanized steel sheet. It has the effect of improving the surface quality of.

1 is a view schematically showing a hot dip plating apparatus to which an antioxidant is applied according to an embodiment of the present invention.
Figure 2 is a plan view showing an antioxidant device according to an embodiment of the present invention.
3 and 4 are views showing an operating state of the antioxidant device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail through exemplary drawings. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

1 is a view schematically showing a hot dip plating apparatus to which an antioxidant is applied according to an embodiment of the present invention.

The hot-dip plating apparatus includes a plating bath 1 in which molten metal 2 is accommodated; A gas knife (3) for adjusting the plating thickness by spraying the wiping gas (4) on the steel sheet (S) drawn out from the plating tank; A frame 5 spaced from the gas knife and provided to surround the upper region where the steel sheet is transferred; And a sealing box 10 that surrounds the gas knife and the frame and isolates the bath surface of the plating bath from the surrounding atmosphere.

For example, in the continuous hot-dip galvanizing process, the steel sheet S is annealed in a heat treatment furnace (not shown) and then enters the plating bath 1 filled with molten metal 2 through a snout (Snout, 6). The direction is changed through the sink roll (7) in the plating bath and proceeds to the top.

Stabilizer roll (8) and collector roll (Corrector roll, 9) are located on the upper part of the sink roll (7), and these rolls are steel plates by tension while pushing the front and back surfaces of the steel plate (S). It plays a role of suppressing the halftone and vibration.

When immersed in the plating bath 1 and then exiting the plating bath, molten metal 2 is attached to the surface of the steel sheet S, and the plating thickness of the molten metal is sprayed by a gas knife 3 installed on the top of the plating bath. It can be controlled by the wiping gas (4).

Gas knife 3 is provided in a pair, it is possible to control the amount of plating on one side and the other side of the steel sheet (S).

The gas knife 3 may be connected to the frame 5 by a gas supply pipe (not shown), which surrounds the upper region of the gas knife to which the steel sheet S is transferred.

The wiping gas 4 may be supplied to the gas knife 3 through the frame 5 and the gas supply pipe. An inert gas such as nitrogen or argon may be used as the wiping gas.

2 is a plan view showing an antioxidant device according to an embodiment of the present invention, and FIGS. 3 and 4 are views showing an operating state of the antioxidant device according to an embodiment of the present invention.

As shown in these drawings, the anti-oxidation device according to an embodiment of the present invention surrounds the steel sheet S that has passed through the plating bath 1, forms an inert atmosphere with an inert gas, and is used for mailing of the steel sheet. Sealing box 10 is formed with a doorway 11; A variable shield 20 installed adjacent to the entrance of the sealing box to adjust the open area of the steel entrance according to the width of the steel plate; And a variable sealing part 30 installed at the variable shielding part to at least partially seal the steel plate entrance.

As described above, the sealing box 10 may enclose the gas knife 3 and the frame 5 and isolate the bath surface of the plating bath 1 from the surrounding atmosphere. In this sealing box, only the doorway 11 formed with the minimum area is left so that the steel plate S can pass vertically, and all other spaces are shielded. In addition, between the sealing box and the hot water surface of the plating bath is sealed by a sealing member (not shown).

By injecting an inert gas such as nitrogen or argon into the closed space formed by the sealing box 10, the residual oxygen concentration can be lowered to form an inert atmosphere, that is, an oxidized atmosphere. In addition, in order to maintain the non-oxidizing atmosphere of the sealed space in the sealing box, the gas knife 3 continuously sprays an inert gas such as nitrogen or argon as the wiping gas 4.

The entrance 11 of the sealing box 10 is formed to have a larger opening area than the cross-sectional area of the steel plate so as not to contact the steel plate in order to prevent scratches on the plated layer of the steel plate when the steel plate S passes through vertically.

The entrance 11 may be formed to extend over the entire width of the sealing box 10 (total length in a direction parallel to the width direction of the steel sheet) in order to cope with the change in the width of the steel sheet, in which case free space is secured. As it can be, it is possible to respond to all the widths of the steel sheet.

The shielding plate 21 of the variable shielding portion 20, which will be described later, is similarly adjusted so as not to be in contact with the steel plate S.

The variable shielding portions 20 are provided so as to be located outside the both ends of the steel plate S in the width direction. The variable shield portion, the shielding plate 21 is movably installed to shield the entrance 11 of the sealing box 10; A transfer part 22 connected to the shield plate; And a drive unit 23 connected to the transfer unit and driving the transfer unit.

In the anti-oxidation device according to an embodiment of the present invention, the shielding plate 21 may be formed in the form of a bellows that can be folded and unfolded, but is not necessarily limited thereto and may be formed as a flat plate. However, the bellows type shielding plate is preferable because it has the advantage of reducing the installation space of the facility.

When considering the size of the steel plate S actually manufactured, the size of the shielding plate 21 is preferably about 1000 mm as the maximum length (length in a direction parallel to the width direction of the steel plate). In addition, considering the distance between the steel plate and the gas knife 3 or the width of the entrance 11 of the sealing box 10 (length in a direction parallel to the thickness direction of the steel plate), the minimum width of the shielding plate (the thickness of the steel plate) The length in the direction parallel to the direction) is preferably approximately 300 mm.

The conveying unit 22 may be selectively implemented as a linear motion guide. The transfer part is installed adjacent to the entrance 11 of the sealing box 10 and extends in the width direction of the sealing box (parallel to the width direction of the steel plate), and forward and reverse through the driving force of the driving unit 23 connected to one side. A bolt shaft 24 rotating in the direction; And a moving block 25 which is connected to the shield plate 21 and is screwed with the bolt shaft to be reciprocated along the bolt shaft.

The driving unit 23 may be a driving motor capable of forward and reverse rotation. Thus, when the bolt shaft 24 is rotated by the rotational driving of the driving unit, the moving block 25 and the shield plate 21 are linearly reciprocated by the action of the nut 26 screwed to the bolt shaft.

The moving block 25 may be fixedly connected to at least one end of the shield plate 21. The nut portion 26 may be integrally formed with the moving block in the form of a through hole, or may be firmly attached to the moving block after being made separately.

The shield plate 21 may be located above or below the bolt shaft 24. Optionally, when the shielding plate is in the form of bellows, as illustrated in the drawings, the insertion hole 27 may be formed in the shielding plate so that the bolt shaft can penetrate. The insertion hole may have a larger diameter than the diameter of the bolt shaft or may be formed in an oval shape.

In addition, the variable shield portion 20 may include at least one guide rail (not shown) installed to extend parallel to the bolt shaft 24. In this case, a guide hole (not shown) is formed in the moving block 25, and the guide hole is fitted to the guide rail, so that the moving block and the shield plate 21 can be smoothly moved.

On the other hand, as shown in FIG. 2, when the two transfer parts 22 connected to the shield plate 21 are arranged one by one on both sides of the entrance 11 of the sealing box 10, the transfer part 22 and the drive part 23 ) Between the power transmission unit 40 may be interposed.

The power transmission unit 40 may include a side gear box 41, a connecting shaft 42, and a central gear box 43 when a driving motor is employed as the driving unit 23.

Two side gear boxes 41 are disposed, and may be installed on a separate support portion 12 outside the sealing box 10 together with the driving portion 23. This side gear box is connected to the transfer section 22, more specifically the bolt shaft 24.

In addition, the central gear box 43 is connected to the rotating shaft of the driving unit 23.

Each of the two connecting shafts 42 may have one end connected to the side gear box 41 and the other end connected to the central gear box 43. For example, a first gear such as a bevel gear, a worm gear, or the like is formed at both ends of the connecting shaft, and accordingly, each end of the bolt shaft 24 of each transfer unit 22 and the end of the rotation shaft of the driving unit 23 are beveled. A second gear such as a gear or a worm wheel may be formed.

Therefore, one driving unit 23, that is, two driving units 22 respectively arranged on both sides of the entrance 11 of the sealing box 10 by the driving motor can be operated by interlocking at the same time.

Here, the configuration, connection relationship, and operation relationship of the transfer unit 22, the drive unit 23, and the power transmission unit 40 are not limited to the above-described examples.

For example, the transfer plate 22 and the drive unit 23 that provide a driving force for the reciprocating movement of the shield plate 21 or the moving block 25 connected to the shield plate may be any, such as a fluid pressure cylinder with an operating rod or the like. The actuator may be applied.

In addition, a configuration in which a plurality of driving units 23 are connected to the plurality of transfer units 22 without a power transmission unit may be used.

In addition, when a single drive unit 23 without a power transmission unit is connected to the transfer unit 22 provided on one side of the shield plate 21, a guide rail is disposed on the other side of the shield plate to guide the moving block 25. You may.

The variable sealing part 30 is fixed to the end of the shielding plate 21 or the moving block 25, extends parallel to the width direction of the shielding plate, and a nozzle on which a slit 32 for gas injection is formed on one side ( 31).

The other side of the nozzle 31 may be connected to a supply pipe 33 for supplying a high pressure inert gas such as nitrogen or argon to prevent oxidation of the plating layer of the steel sheet S. Since the position of the shielding plate 21 or its length is variable according to the width of the steel sheet, it is preferable to use a flexible tube made of a material such as a corrugated pipe or a fiber, rubber, resin, etc. in order to cope with this.

As a result, the nozzle 31 and the supply pipe 33 move together when the shielding plate 21 or the moving block 25 moves in response to a change in the width of the steel sheet, so that its position can be changed.

The slit jet sprayed from the nozzle 31 is sprayed in the width direction of the steel plate S, and at least forms an aerodynamic sealing diaphragm between the shield plate 21 and the front end of the steel plate in the width direction.

As described above, the shielding plate 21 of the variable shielding portion 20 needs to be adjusted so that it is spaced at a predetermined distance so as not to contact the front end of the steel sheet S in order to avoid interference with the front end of the steel sheet S There is. However, in order to prevent the formation of an oxide film on the surface of the steel plate and the plating layer at the tip of the steel plate, sealing of this gap is also required.

Accordingly, the sealing diaphragm by the slit jet ejected from the nozzle 31 creates an oxidized atmosphere in the shielding area to prevent external flow from penetrating into the shielding area or vice versa. It plays a role.

Hereinafter, the operation of the antioxidant device according to an embodiment of the present invention will be briefly described.

The steel sheet S to which the molten metal 2 is attached through the plating bath 1 is wiped by the wiping gas 4 ejected through the gas knife 3 to adjust the plating adhesion amount. The ejected wiping gas forms an inert atmosphere in the sealing box 10 so that an oxide film is not formed on the surface of the plating layer.

Depending on the width of the steel sheet (S) passing through, the driving unit 23 is operated to move the shielding plate 21, and the entrances 11 of the sealing box 10 are within the limits that both ends of the steel plate do not contact the shielding plate. ) Adjust the position of the shielding plate 21 to block as much as possible.

Accordingly, the opening area of the entrance 11 of the sealing box 10 can be adjusted.

In particular, when the shielding plate 21 is in the form of a bellows that can be folded and unfolded, when the width of the steel plate S is narrow, the shielding plate proceeds toward the tip of the steel plate by driving of the driving unit 23 and the conveying unit 22. , If the width of the steel sheet is wide, the shielding plate is adjusted in the opposite direction, and its position is adjusted to a predetermined distance according to the tip of the steel sheet.

In addition, the slit jet injected from the nozzle 31 of the variable sealing portion 30 is sprayed in the width direction of the steel plate S, and at least forms an aerodynamic sealing diaphragm between the shield plate 21 and the front end of the steel plate in the width direction. Thus, it prevents the external flow from penetrating into the shielding area or, conversely, the internal flow of the shielding area from flowing out.

Therefore, according to the anti-oxidation apparatus of the present invention, it is possible to efficiently respond to changes in the width of the steel sheet and at the same time to manage the oxygen concentration in the sealing box low, thereby preventing the oxidative surface defects of the hot-dip galvanized steel sheet. It is to obtain the effect of improving the surface quality of the hot-dip galvanized steel sheet.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain them, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

10: sealing box 11: entrance
20: variable shield 21: shielding plate
22: transfer unit 23: drive unit
30: variable sealing portion 31: nozzle
32: supply piping 40: power transmission

Claims (11)

A sealing box surrounding the steel sheet that has passed through the plating bath, forming an inert atmosphere with an inert gas, and having an entrance and exit for mailing of the steel sheet;
A variable shielding part installed adjacent to the doorway of the sealing box to adjust the open area of the doorway according to the width of the steel sheet; And
A variable sealing portion installed at the variable shielding portion to at least partially seal the steel plate entrance.
Antioxidation device comprising a.
According to claim 1,
Anti-oxidation device, characterized in that the entrance is formed to extend over the entire width of the sealing box.
According to claim 2,
The variable shield,
A shield plate movably installed to shield the entrance of the sealing box;
A transfer part connected to the shield plate; And
Drive unit connected to the transfer unit to drive the transfer unit
Anti-oxidation device comprising a.
According to claim 3,
Anti-oxidation device, characterized in that the shield plate is formed in the form of bellows that can be folded and unfolded.
According to claim 3,
The transfer unit,
A bolt shaft extending adjacent to the entrance of the sealing box and extending in the width direction of the sealing box and rotating through a driving force of the driving unit connected to one side; And
A moving block connected to the shield plate and provided with a nut part that is screwed with the bolt shaft to reciprocate along the bolt shaft.
Anti-oxidation device comprising a.
The method of claim 5,
The variable shield portion, the anti-oxidation device further comprises at least one guide rail installed to extend parallel to the bolt shaft.
According to claim 3,
When the two transfer parts connected to the shield plate are disposed adjacent to the entrance of the sealing box, an oxidation preventing device characterized in that a power transmission part is interposed between the transfer part and the drive part.
The method of claim 7,
The power transmission unit,
Two side gear boxes respectively connected to the transfer part;
A central gear box connected to the rotating shaft of the driving unit; And
Two connecting shafts, one end of which is connected to the side gearbox and the other end of which is connected to the central gearbox
Anti-oxidation device comprising a.
The method of claim 8,
The connecting shaft has first gears at both ends,
Anti-oxidation device, characterized in that the second gear is formed at the end of the rotary shaft of the end of the transfer unit and the driving unit.
The method of claim 5,
The variable sealing portion, fixed to the end of the shielding plate or the moving block, extends parallel to the width direction of the shielding plate, has an oxidation preventing device characterized in that it has a nozzle formed with a slit for gas injection to one side .
The method of claim 10,
Anti-oxidation device, characterized in that the other side of the nozzle, a supply pipe for supplying an inert gas is connected.

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