KR101584501B1 - Apparatus for cooling coated strip - Google Patents

Abstract

A plated steel plate cooling apparatus for varying a flow rate of a cooling fluid in a width direction of a plated steel plate is disclosed. The plated steel plate cooling apparatus according to an embodiment of the present invention includes a cooling unit located on both sides of a plated steel plate and a supply unit for supplying a cooling fluid to the cooling unit, A chamber connected to the chamber and connected to the supply connection portion to receive a cooling fluid; and an air outlet for discharging a cooling fluid toward the surface of the coated steel plate connected to the chamber, wherein the chamber is made of a plated steel sheet And divided into three or more compartments by the partition in the width direction.

Description

[0001] APPARATUS FOR COOLING COATED STRIP [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plated steel plate cooling apparatus, and more particularly, to a plated steel plate cooling apparatus that varies a flow rate of a cooling fluid in a width direction of a plated steel plate.

Hereinafter, zinc plating will be described as an example of the plating method. It should be understood, however, that the technology underlying the present invention includes zinc plating.

Generally, the zinc-plated steel sheet is galvanized on the surface of the steel sheet produced by rolling to improve the corrosion resistance. After the zinc plating is performed, cooling is performed as a means for curing the zinc plated layer in order to prevent the zinc plated layer from being peeled off from the plate during a process of being transferred to a post-process or a process of performing a post-process.

If the cooling is performed slowly after performing the zinc plating, the quality of the plate material such as occurrence of an abnormal pattern or wrinkle in the galvanized layer may be deteriorated and the process of the entire manufacturing line may be delayed. To solve these problems, recently, a cooling device for rapid cooling after zinc plating has been developed. The cooling device includes a device using air and a device using cooling water.

Korean Patent Laid-Open No. 10-2009-0069729 discloses a cooling device for manufacturing a zinc-plated sheet material using a cooling fluid.

Korean Unexamined Patent Application Publication No. 10-2009-0069729 (published on 07.01.2009)

An embodiment of the present invention is intended to provide a plated steel plate cooling apparatus capable of reducing quality defects on the surface of a plated steel plate.

More specifically, the present invention is to provide a coated steel plate cooling apparatus which prevents surface defects that may be formed by spraying a high-pressure cooling fluid to an uncoagulated portion of a plating layer remaining in an edge portion.

Another object of the present invention is to provide a coated steel plate cooling apparatus for preventing surface defects in a boundary region that may occur due to different cooling capacities of a center portion and an edge portion.

Also, there is a need to provide a coated steel sheet cooling apparatus to be applied to various sizes of coated steel sheets.

According to an aspect of the present invention, there is provided a cooling unit comprising: a cooling unit located on both sides of a plated steel plate; And a cooling unit connected to the supply unit to receive a cooling fluid, a cooling fluid connected to the chamber and directed toward the surface of the coated steel plate, Wherein the chamber is divided into at least three compartments by partition walls in the width direction of the plated steel plate and includes a central chamber for receiving a cooling fluid for cooling the central portion of the plated steel plate, And a first and a second edge chambers for receiving cooling fluids for cooling the edge portions of the steel sheet, wherein the jet holes are provided in the respective divided chambers.

The jet port is formed in a slit shape that opens in the width direction of the plated steel plate and the flow rate of the cooling fluid ejected to the center portion of the plated steel plate and the flow rate of the cooling fluid ejected to the edge portion of the plated steel plate can be made different from each other A plated steel plate cooling apparatus can be provided which further includes a control section.

Wherein the jet port is in the form of a nozzle continuously provided in the width direction of the plated steel plate and the flow rate of the cooling fluid ejected to the center portion of the plated steel plate and the flow rate of the cooling fluid ejected to the edge portion of the plated steel plate are different from each other A plated steel plate cooling apparatus can be provided which further includes a control section that can be operated.

The jetting port connected to the first and second edge chambers is slit-shaped to be opened in the width direction of the plated steel plate, and the cooling fluid ejected from the central portion of the plated steel plate And a control unit capable of making the flow rate of the cooling fluid ejected to the edge of the plated steel sheet different from the flow rate of the cooling fluid ejected from the edge of the plated steel sheet.

The apparatus may further include a supply connection unit connecting the chamber and the supply unit, wherein the control unit controls the supply connection unit to control a flow rate of the cooling fluid flowing into the chamber.

The cooling units on both sides may be provided with a plated steel plate cooling device capable of adjusting the distance between them.

The partition wall may be provided with a plated steel plate cooling device capable of being moved in the width direction of the plated steel plate.

The plating unit may further include a sensor capable of measuring a plating amount in the width direction of the plated steel plate, and the control unit may be provided with a plating steel plate cooling apparatus capable of controlling the supply connection portion according to the plating amount measured by the sensor.

The plated steel plate cooling apparatus may be provided in which the cooling fluid is cooling air.

And an outlet port connected to the central chamber may be provided in a range of 58.3% to 75% of the width of the plated steel plate.

The central chamber may be provided with a plated steel plate cooling apparatus having different widths in the conveying direction of the plated steel plates.

The partition defining the central chamber may include first and second partition walls having a step in the width direction of the plated steel plate and a partition wall connecting the first and second partition walls, A plated steel plate cooling apparatus for partitioning the chamber can be provided.

According to another aspect of the present invention, there is provided a method for cooling a plated steel sheet including a cooling unit located on both sides of a plated steel plate and a supply unit for supplying a cooling fluid to the cooling unit, A plated steel plate having a central portion along a width direction and first and second edge portions located at an outer periphery of the plated steel plate, the plated steel plate having a plating portion for discharging a cooling fluid at a higher flow rate than the first and second edge portions, A steel plate cooling method may be provided.

There is provided a plating steel plate cooling method for measuring the plating amount in the width direction of the plated steel sheet by a sensor and controlling the flow rate of the cooling fluid sprayed to the center portion and the first and second edge portions according to the measured plating amount .

The method of plating the steel sheet may be a hot-dip galvanizing method, and a method of cooling a coated steel sheet used when the coated amount of both surfaces of the coated steel sheet is 300 g / m ² or more.

The center portion may be provided with a coated steel plate cooling method in a range of 58.3% to 75% of the plated steel plate width.

Wherein the cooling unit comprises a central chamber corresponding to the division of the plated steel plate and first and second edge chambers, wherein the width of the plated steel plate is measured so that the center portion is at least 58.3% % Or less of the thickness of the chamber.

The plating steel plate cooling apparatus according to the embodiment of the present invention improves the quality of the plating surface by varying the flow rate of the cooling fluid sprayed on the edge portion of the plated steel sheet and the central portion where the solidification layer is formed, .

Further, by setting the width of the central chamber to be different, surface defects in the boundary region can be prevented.

In addition, it can be applied to various types of coated steel sheets.

In addition, it is possible to improve the cooling performance while reducing the surface defects by changing the shape of the air outlet of the center portion and the edge portion.

1 is a view showing a plating process according to an embodiment of the present invention.
2 is a partial cross-sectional view of a front view of a cooling device according to an embodiment of the present invention.
3 is a schematic view of the cross section AA in Fig.
4 is a view showing the plating state of the thin plating of the article.
5 is a view showing the plating state of the post-plating of the after-water.
6 is a graph showing the air flow rate in the width direction of the strip.
7 is a flowchart illustrating a cooling process according to an embodiment of the present invention.
8 is a view showing an air outlet according to an embodiment of the present invention.
9 is a view showing an ejection port according to another embodiment of the present invention.
FIG. 10 is a view showing an ejection port according to another embodiment of the present invention. FIG.
11 is a cross-sectional view showing a cooling apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments described below are provided by way of example so that those skilled in the art will be able to fully understand the spirit of the present invention. The present invention is not limited to the embodiments described below, but may be embodied in other forms. In order to clearly explain the present invention, parts not related to the description are omitted from the drawings, and the width, length, thickness, etc. of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

The plating steel plate cooling apparatus according to the embodiment of the present invention can be used in all the processes of plating the surface of the steel sheet, but for convenience of explanation, the cooling apparatus used in the continuous hot-dip galvanizing process will be described as an embodiment. In addition, the plating steel cooling apparatus according to the embodiment of the present invention can be used to fabricate an alloy-coated steel sheet having high corrosion resistance.

The continuous galvanizing line (CGL) is composed of several unit processes, but its core process is a process in which hot zinc is plated in a plating bath and the plating is cured by passing through a cooling device can see.

1 is a view showing a plating process according to an embodiment of the present invention.

The steel sheet S heat-treated in the annealing furnace (not shown) flows into the zinc molten bath of the plating bath 5 through the Snout 1 and then flows out of the plating bath 5, The molten zinc is attached. The hot dip galvanized steel sheet P is redirected by the sink roll 2 in the plating bath 5 and is guided by the guide roll 3 and moved vertically.

The plating layer C (see the enlarged view of FIG. 3) coated on the surface of the steel sheet S passing through the plating bath 5 is adjusted to an appropriate thickness by a gas or the like injected at a high speed from the air knife 4, Is cooled while passing through the apparatus (10) and solidified, and then the direction is changed by the upper roll (9) to move to the next process. The cooling apparatus 10 includes a cooling unit 100 and the cooling unit 100 may be provided with two successive ones 100-1 and 100-2 along the conveying direction of the coated steel sheet P. [ The length and the number of the cooling units 100 may be appropriately changed depending on the thickness or the width of the steel plate, the thickness of the plating layer, and the like.

Although not shown, an embodiment of the present invention may be provided with an induction heating apparatus (not shown) or a cracking pad (not shown) selectively between the air knife 4 and the cooling apparatus 10. When the steel sheet P on which the plating layer is formed passes through the induction heating or cracking zone, the alloying element such as Al diffuses between the steel sheet and the plating layer to perform galvannealing.

Next, a cooling device 10 according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a partial cross-sectional view of a front view of a cooling device 10 according to an embodiment of the present invention, and FIG. 3 is a schematic view of a cross-section taken along line A-A of FIG.

The cooling apparatus 10 includes a pair of cooling units 100 located on both sides of a coated steel sheet P and a supply unit 101 for supplying a cooling fluid to the cooling unit 100. The cooling unit 100 includes a case 110, a supply connection portion 120 connected to the supply unit 101, a chamber 130 provided inside the case 110 to receive a cooling fluid, And a jet port 150 connected to the plated steel sheet P for jetting the cooling fluid toward the surface of the coated steel sheet P. The supply unit 101 also includes a cooling line 161 connected to the supply connection portion 120 and a blower 160 for supplying a cooling fluid to the cooling line 161. Hereinafter, cooling air is used as an example of the cooling fluid. As other cooling fluid, HN gas or cooling water can be used.

Since the cooling unit 100 is provided symmetrically on both sides of the coated steel sheet P, the cooling unit 100 on either side will be described below. Further, the description thereof may be applied to the cooling unit on the other side as it is.

The case 110 may be provided so that a set of cooling units 100 are integrally formed. However, FIG. 3 shows a case 110 separated from both sides of the coated steel sheet P. This is to allow the cooling fluid sprayed on the coated steel sheet P to flow along the surface of the coated steel sheet P and be easily discharged to the outside of the cooling unit 100. [

An inlet hole 111 through which cooling air flows is formed on one side of the case 110 and an inlet hole 111 is connected to the supply connection portion 120. In addition, a chamber 130 in which the cooling air introduced through the supply connection portion 120 is accommodated is provided in the case 110. [ In addition, a jet port 150 is formed on the surface of the case 110 facing the plated steel sheet P. The chamber 130 may be used as an intermediate zone for discharging the cooling air introduced from the supply connection portion 120 through the plurality of air outlets 150.

FIG. 2 shows a slit 150 formed in the width direction of the coated steel strip P as an example of the spout 150. The slit 150 can form a narrow gap to speed up the flow rate of the cooling air blown out. The slit 150 may be provided to cover the entire width of the coated steel sheet P. Further, the slits 150 may be provided in plural along the conveying direction of the coated steel strip P. The size, width and number of gaps of slits 150 and gaps between adjacent slits can be increased or decreased as needed.

The chamber 130 may be divided into three or more parts in the width direction of the coated steel sheet P by the partition 140. The partition wall 140 may be formed in the casing 110, And may be divided into segments 130-1, 130-2, and 130-3. Basically, the chamber 130 includes a central chamber 130-1 positioned at the center and first and second edge chambers 130-2 and 130-3 located at both sides of the central chamber 130-1. . The number of chambers 130 can be increased or decreased as needed. The center chamber 130-1 can be divided in the width direction of the coated steel sheet P and the first and second edge chambers 130-2 and 130-3 can also be divided in the width direction of the coated steel sheet P So that four or more chambers may be provided as a whole.

2 and 3 show an integrated slit 150 capable of covering the entire width of the coated steel sheet P and show that the slit 150 is divided into three zones by two partition walls 140 . Alternatively, however, separate slits 150 are provided in each chamber 130 section. Further, a plurality of slits 150 are continuously provided in one chamber 130.

The supply connection portion 120 is provided with a valve 121 and the flow amount of the cooling air flowing through the cooling line 161 can be adjusted by adjusting the opening amount of the valve 121. [ As an example of adjusting the opening amount of the valve 121, a damper may be used. The supply connection unit 120 may be provided in each of the divided chambers 130. The supply connection unit 120-1 and the edge chambers 130-2 and 130-3, which are connected to the central chamber 130-1, The supply connection portions 120-2 and 120-3 connected to the valves 121-1, 121-2, and 121-3 may have different opening amounts. Thus, even though the air flows from one cooling line 161 to each supply connection 120, the valve 121 can be adjusted to vary the flow rate of the cooling air flowing through each supply connection 120 . 3 shows one blower 160 and the same flow rate of cooling air reaches the valve 121 of each supply connection 120 along the cooling line 161. In this example, However, the amount of opening of each of the valves 121-1, 121-2, and 121-3 may be varied, and accordingly, the amount of opening of the chambers 130-1 through 120-3 through the respective supply connections 120-1, 120-2, 1, 130-2, and 130-3 may vary.

The flow rate of the cooling air flowing into the central chamber 130-1 may be larger than the flow rate of the cooling air flowing into the edge chambers 130-2 and 130-3. That is, the amount of opening of the valve 121-1 for introducing the cooling air into the central chamber 130-1 is increased and the amount of the cooling air flowing into the edge chambers 130-2 and 130-3 , 121-3 may be made smaller or zero. Accordingly, the flow rate of the cooling air discharged through the slit 150 connected to the central chamber 130-1 is controlled by the flow rate of the cooling air discharged through the slit 150 connected to the edge chambers 130-2 and 130-3 The cooling efficiency of the central portion of the coated steel sheet P is improved. This is to reduce the surface defects of the edge portion to produce a product having excellent surface properties. This will be described in detail below.

3, a supply unit 101 for supplying cooling air to the cooling unit 100 includes a blower 160 for supplying cooling air, a blower 160 for blowing air from the blower 160 to the supply connection 101, And a coolant line 161 connected to the coolant line 120 to form a coolant flow path. Further, although not shown in the drawing, a heat exchanger (not shown) for cooling the cooling air supplied into the cooling unit 100 may be provided. The centrifugal fan rotates by driving the electric motor and the air sucked by the centrifugal fan rotates while passing through the heat exchanger to cool the cooling line 161 And then flows into the supply connection unit 120.

An electric motor that provides power for rotating the centrifugal fan of the blower 160 may employ an inverter. Therefore, the supply amount of the cooling air can be controlled in accordance with the thickness, the width, or the advancing speed of the plated steel sheet P.

Next, the necessity of changing the cooling air flow rate at the center portion and the edge portion of the plated steel sheet P will be described with reference to FIG. 4 and FIG. Fig. 4 is a diagram showing the plating state of the thin plating of the article, Fig. 5 is a chart showing the plating state of the post-plating of the after-water, and Fig. 6 is a graph showing the air flow rate with respect to the width direction of the strip.

It is described that the cooling device 10 according to the embodiment of the present invention can be used in a continuous hot dip galvanizing process and can be used for manufacturing a high corrosion resistant alloy plated steel sheet. In order to improve the corrosion resistance, a high corrosion resistant alloy-plated steel sheet is generally subjected to post-plating. In particular, when the amount of plating on both sides is 300 g / m < ² > or more, when a conventional cooling apparatus is used, a plating mark in the form of a comb-like pattern is formed on the surface of the edge portion of the coated steel sheet,

1, the plated steel sheet P to which the molten zinc 6 in the non-solidified state is adhered in the plating bath 5 passes through the air knife 4 and the amount of plating is controlled and the surface layer is solidified. During the solidification, the molten zinc (C) on the surface of the coated steel sheet P is subjected to a tangential force in both edge directions due to the momentum generated as the coated steel sheet P proceeds, The molten zinc C partially moves from the central portion to the edge portion, so that the amount of molten zinc in the edge portion becomes larger than the amount of molten zinc in the central portion. This is shown in Figs. 4 and 5.

The temperature of the plating bath 5 is usually about 440 degrees, and the solidifying point of the high corrosion resistant alloy plating is usually about 330 to 380 degrees. Therefore, a temperature difference of from about 60 degrees to about 110 degrees is obtained. In order to improve the quality of the product, the high corrosion-resistant alloy plating should be solidified through a quenching process. However, overcoating occurs at the edge portion of the coated steel sheet P to cause the presence of the molten zinc (C) in the non-solidified state. When high-pressure air is injected into the molten zinc in the non-solidified state, a mark due to air pressure is generated on the surface, and comb-like defects are caused after solidification.

Accordingly, it is possible to prevent defects in the surface layer by spraying high-pressure cooling air to the central portion where the molten zinc solidifies and spraying low-pressure cooling air or spraying cooling air to the edge portion where molten zinc is present in the non- have. At this time, even if high-pressure cooling air is not directly sprayed to the edge portion, tangential force acts in both edge directions due to the momentum generated as the coated steel sheet P advances, so that the high- (P) to cool the edge portion.

Next, the relationship between the degree of plating and the degree of formation of the non-solidified layer will be described. In the case of a plating process after which coating weight is increased (in the case of two-sided coating weight less than 300g / m ²⁾ there are the even and increases the thickness of the coating layer (C-2) as shown in FIG. 5 increases the conduction coefficient cooling rate is reduced accordingly And the time to remain in the non-solidified layer is increased. For example, the conduction coefficient, which was 0.68 W / mK · 10 ⁷ , the thickness of the plated layer (C-1 in FIG. 4) being 7 μm, was 2.37 W / mK · 10 ⁷ .

Further, even in the case of the thickness of the same plating layer, the degree of formation of the non-solidified layer may vary depending on the thickness of the steel sheet. That is, when the thickness of the steel sheet becomes thick (S-2 in FIG. 5), the latent heat inside increases, and the formation time of the non-solidified layer becomes longer due to the latent heat. However, in general, since the thin plating (C-1) is used in the ware (S-1 in FIG. 4) and the back plating (C-2) It is also acceptable to set the standard for use.

Next, the criteria for distinguishing the center portion and the edge portion in the width direction of the plated steel sheet P will be described. Hereinafter, a commonly used plated steel sheet (P) having a width of 1200 mm will be used as a reference. The range in which surface defects occur may vary depending on the type of plating metal, the thickness of the plating layer, or the thickness of the steel sheet, but surface defects usually occur within the range of 50 mm to 150 mm at one edge portion. That is, when the width of 600 mm from the center of the steel sheet is taken as a reference, surface defects occur in a width range of about 8.3% to 25%.

Therefore, when the maximum range of 150 mm is used as a reference, a surface defective layer of 300 mm may occur in both edge portions, and the length of the central portion from which high-pressure cooling air is ejected should not exceed 900 mm at maximum. Further, when the width of the central portion is not sufficient, the flow rate of the cooling air may not be sufficient. Therefore, it has been found through experiments that the size of the center portion should not be smaller than at least 700 mm to satisfy the flow rate of sufficient cooling air. That is, it is preferable that the center portion is in a range of 700 mm or more and 900 mm or less when referring to a 1200 mm-thick plated steel plate (P), and it is preferable that the center portion is provided in a ratio of 58.3% to 75% of the width of the plated steel plate (P).

The width of the cooling unit 100 may be as large as about 1900 mm. This is because it is necessary to produce a plated steel sheet P having various widths. At this time, it is desirable that the width direction range of the jet port 150 connected to the central chamber 130-1 is 700 mm to 900 mm, so that the connection between the first and second edge chambers 130-2 and 130-3 The width direction range of the jet port 150 can be set between 500 mm and 600 mm.

The chamber 130 is partitioned by the partition wall 140 positioned perpendicularly to the coated steel sheet P as shown in FIG. 3, and the discharge port 150 is divided into the discharge port 150, The above numerical values may be applied to the width of the chamber 130 as it is. In other words, the width direction range of the central chamber 130-1 is 700 mm to 900 mm, and the width direction range of the first and second edge chambers 130-2 and 130-3 is 500 mm to 600 mm desirable.

The width of the center chamber 130-1 according to an embodiment of the present invention may be varied depending on the conveying direction of the coated steel sheet P. Referring to FIG. 2, one of the barrier ribs 140 includes first and second barrier ribs 141 and 142 having stepped portions, and a diaphragm barrier rib 143 that connects the first and second barrier ribs and is inclined . In addition, the partition 140 is provided symmetrically with respect to the centerline to define the central chamber 130-1. Although the diaphragm 143 is inclined in the drawing, the diaphragm 143 includes a curved surface.

In this case, the width of the first central chamber partitioned by the first partition wall 141 may be 900 mm, and the width of the second central chamber partitioned by the second partition wall 142 may be 700 mm. Alternatively, the width of the first central chamber defined by the first partition wall 141 may be 75% of the width of the coated steel sheet P, and the width of the second central chamber defined by the second partition wall 142 may be plated It can be 58.3% of the width of the steel plate (P). As described above, it is sufficient that the width of the central portion satisfies a range of from 58.3% to 75% of the width of the steel sheet P (P).

Although the width of the central chamber 130-1 has been described above, the width of the slit 150, which is connected to the central chamber 130-1 independently of the width of the central chamber 130-1, May vary.

The reason why the width of the central chamber 130-1 or the width of the jet port 150 connected to the central chamber 130-1 is set differently according to the conveyance direction of the plated steel sheet P will be described. The cooling air is discharged at different flow rates at the central portion and the edge portion as described above. If the central portion and the edge portion are uniformly divided in the conveying direction of the coated steel sheet P, a boundary line may be formed on the surface of the coated steel sheet P due to the difference in cooling ability between the center portion and the edge portion.

However, when the width of the center chamber 130-1 is varied in the longitudinal direction of the coated steel sheet P as in the cooling unit 100 according to the embodiment of the present invention, the interface between the center portion and the edge portion is not constant. Therefore, the formation of the boundary line due to the difference in cooling ability can be prevented. More specifically, in the case where the width of the first central chamber is 900 mm and the width of the second central chamber is 700 mm, an intermediate zone of 100 mm on one side is described based on the center of the coated steel sheet P. As shown in FIG. 2, while the steel plate P advances from bottom to top, the second central chamber of the first cooling unit 100-1 -> the first central chamber -> the cooling which is injected from the second central chamber The central portion of the coated steel sheet P is cooled by the air, and the same process is repeated in the second cooling unit 100-2. Therefore, since the interface between the center portion and the edge portion is not constant, the formation of the boundary due to the difference in cooling ability can be prevented.

Next, a cooling method of the coated steel sheet P according to the embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 is a flowchart showing a cooling process according to an embodiment of the present invention, and FIG. 8 is a view showing an ejection opening 150 according to an embodiment of the present invention.

1, the cooling apparatus 10 according to the embodiment of the present invention may include a sensor 7 capable of measuring the amount of plating of the coated steel sheet P. The sensor 7 is provided in the width direction of the coated steel sheet P and can measure the amount of the coated steel sheet P according to the width direction of the coated steel sheet P (S100).

The information of the sensor 7 is input to the control unit 8 and the control unit 8 analyzes the information of the sensor 7 and supplies the analyzed information to the central chamber 130-1 and the edge chambers 130-2 and 130-3 The flow rate of the cooling air is calculated (S200). According to the calculated information, the control unit 8 can control the current input to the blower 160 and control the amount of opening of the valve 121 of each supply connection unit 120 (S300).

8, the flow rate of the cooling air discharged to the slit 150-1 through the central chamber 130-1 is large, while the flow rate of the cooling air discharged through the slit 150-1 through the edge chamber 130-2, 150-2, and 150-3) is small. Particularly, it has been found through experimentation that as the flow rate of the cooling air discharged through the edge chambers 130-2 and 130-3 to the slits 150-2 and 150-3 becomes smaller, defects on the surface of the plating layer become smaller. Therefore, the amount of opening of the valves 121-2 and 121-3 of the supply connection portions 120-2 and 120-3 connected to the edge chambers 130-2 and 130-3 is set to 0, May be preferred. Even in this case, since the high-pressure cooling air is injected at a large flow rate in the central portion, it may suffice that the cooling air diffused along the surface cools the edge portion.

FIG. 9 is a view showing an air outlet 151 according to another embodiment of the present invention, and FIG. 10 is a view showing an air outlet 152 according to another embodiment of the present invention.

8, the air outlet 150 of the cooling unit 100 according to the embodiment of the present invention is in the form of a slit. However, as shown in FIG. 9, the cooling unit 100 according to another embodiment of the present invention 102 is in the form of a nozzle. The nozzles 151 include nozzles 151-1 connected to the central chamber 130-1 and nozzles 151-2 and 151-3 connected to the edge chambers 130-2 and 130-3 And can be disposed in the width direction of the coated steel sheet P. Further, it can be arranged with a plurality of rows in the conveying direction of the plated steel sheet P.

8, the control unit 8 controls the supply connection unit 120 to discharge a large amount of cooling air from the nozzle 151-1 connected to the central chamber 130-1, A small amount of cooling air can be discharged from the nozzles 151-2 and 151-3 connected to the edge chambers 130-2 and 130-3. The nozzle 151 is advantageous in that it can be injected at a high pressure as compared with the slit-shaped jet port 150. On the contrary, the jet port 150 of the slit shape has an advantage that it can jet at a more uniform flow rate in the width direction as compared with the nozzle 151.

10, the jet port 152-1 connected to the central chamber 130-1 is provided in the form of a nozzle as the jet port 152 of the cooling device 103 according to another embodiment of the present invention And the ejection outlets 152-2 and 152-3 connected to the edge chambers 130-2 and 130-3 may be provided in a slit shape. Since the central portion of the coated steel sheet P is solidified, surface defects do not occur even when cooling air is injected at high pressure through the nozzle 152-1. In addition, since the cooling air injected at a high pressure is advantageous for diffusion, the edge portion can be cooled more quickly.

Since the edge portion of the coated steel sheet P includes an uncoagulated state, high-pressure cooling air concentrated at one point may cause surface defects. Therefore, the air outlets 152-2 and 152-3, which are connected to the edge chambers 130-2 and 130-3, are provided in the form of slits so that the cooling air discharged through the slits 152-2 and 152-3, So that surface defects of the coated steel sheet P can be minimized.

11 is a cross-sectional view showing a cooling apparatus according to another embodiment of the present invention.

The cooling apparatus 10-1 according to another embodiment of the present invention can be applied to the coated steel sheet P having various thicknesses or various widths. The cooling unit 104 may include a case guide member 112 coupled with the case 110 positioned on both sides of the coated steel sheet P. [ The case 110 may be movably coupled to the case guide member 112. The case 110 is slidable in the thickness direction while being fixed in the width direction of the plated steel sheet P by the case guide member 112. Therefore, the present invention can be applied to a plated steel sheet P having various thicknesses.

The thickness information previously known or known by the sensor 7 is inputted to the control unit 8 and the control unit 8 moves the case 110 up and down according to the thickness of the coated steel sheet P, .

The partition wall 140 partitioning the central chamber 130-1 and the edge chambers 130-2 and 130-3 can be coupled with the case 110 so as to be movable in the width direction of the coated steel sheet P . Therefore, the present invention can be applied to a plated steel sheet P having various widths.

The width information previously known or known by the sensor 7 is inputted to the control unit 8 and the control unit 8 moves the partition wall 140 to the left and right according to the width of the coated steel plate P, The surface defect of the plating layer can be minimized.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. . Accordingly, the true scope of the invention should be determined only by the appended claims.

1: Snout, 2: Sync roll,
3: guide roll, 4: air knife,
5: plating bath, 6: molten zinc,
7: sensor, 8: control unit,
9: upper roll, 10: plated steel plate cooling device,
100: cooling unit, 110: case,
111: inlet hole, 112: case guide member,
120: supply connection portion, 121: valve,
130: chamber, 140: partition wall,
141: first partition, 142: second partition,
143: Coupling septum, 150: Slit,
160: blower, 161: cooling line.

Claims (15)

A cooling unit located on one side of the plated steel plate;
And a supply unit for supplying a cooling fluid to the cooling unit,
Wherein the cooling unit includes a chamber connected to the supply unit to receive a cooling fluid, and a discharge port connected to the chamber and discharging a cooling fluid toward a surface of the plated steel plate,
Wherein the chamber is divided into three or more sections by partition walls in the width direction of the plated steel plate, the central chamber accommodating a cooling fluid for cooling the central portion of the plated steel plate, and a cooling chamber for cooling the edge portion of the plated steel plate And a first and a second edge chamber for receiving a cooling fluid for the first and second edge chambers,
Wherein the partition dividing the chamber includes first and second partition walls having steps in the width direction of the plated steel plate and a partition wall connecting the first and second partition walls,
And the jet port is provided in each of the divided chambers. The method according to claim 1,
Wherein the jet port is in the form of a slit opening in the width direction of the plated steel sheet,
Further comprising a control unit capable of making the flow rate of the cooling fluid ejected to the center portion of the plated steel sheet different from the flow rate of the cooling fluid ejected to the edge portion of the plated steel sheet. The method according to claim 1,
Wherein the jet port is in the shape of a nozzle provided continuously in the width direction of the plated steel sheet,
Further comprising a control unit capable of making the flow rate of the cooling fluid ejected to the center portion of the plated steel sheet different from the flow rate of the cooling fluid ejected to the edge portion of the plated steel sheet. The method according to claim 1,
The jet port connected to the central chamber is in the shape of a nozzle,
The jet port connected to the first and second edge chambers is in the form of a slit opening in the width direction of the plated steel plate,
Further comprising a control unit capable of making the flow rate of the cooling fluid ejected to the center portion of the plated steel sheet different from the flow rate of the cooling fluid ejected to the edge portion of the plated steel sheet. 5. The method according to any one of claims 2 to 4,
Further comprising a supply connection portion connecting the chamber and the supply unit,
Wherein the control unit controls the supply connection unit to control the flow rate of the cooling fluid flowing into the chamber. The method according to claim 1,
Wherein the cooling unit is located on both sides of the plated steel sheet,
Wherein the cooling units on both sides can adjust the distance between each other. The method according to claim 1,
Wherein the partition wall is movable in the width direction of the plated steel plate. 6. The method of claim 5,
Further comprising a sensor capable of measuring a plating amount in the width direction of the plated steel sheet,
Wherein the controller controls the supply connection portion according to a plating amount measured by the sensor. The method according to claim 1,
Wherein the central chamber has different widths in the conveying direction of the plated steel sheet. 10. The method of claim 9,
Wherein the partition dividing the chamber includes a pair of partition walls symmetrically positioned in the width direction of the plated steel plate. delete The method according to claim 1,
A sensor for measuring a plating amount in the width direction of the plated steel plate;
And a control unit for controlling a flow rate of the cooling fluid ejected to the center portion and the first and second edge portions in accordance with the amount of plating measured by the sensor. 13. The method of claim 12,
Wherein the control unit is used when the plating amount of both surfaces of the plated steel sheet measured by the sensor is 300 g / m ² or more. The method according to claim 1,
Wherein the central chamber is provided in a range of 58.3% to 75% of the width of the plated steel plate. delete

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