Bath surface floating foreign matter removal device

Abstract

To provide a device for removing foreign matters floating on a bath surface, capable of smoothly moving foreign matters floating on a molten metal bath surface in the inside of a snout to a suction port to collect them and easily performing maintenance in the snout.SOLUTION: A device 11 for removing foreign matters floating on a bath surface includes: a suction port 12 provided in a vicinity of a molten zinc plating bath surface on one side of a steel sheet 1 and for sucking molten zinc; and a discharge port 13 provided in the vicinity of the molten zinc bath surface on the other side of the steel sheet 1 and for discharging the molten zinc. The discharge port 13 arranged in the central part in the snout thickness direction on the other side of the steel sheet 1 includes: first discharge ports 14 and 14 obliquely discharging the molten zinc to both wall surfaces 2a and 2b of a snout 2 facing both plate surfaces of the steel sheet 1; and second discharge ports 15 and 15 for discharging the molten zinc. The molten zinc discharged from the second discharge ports 15 and 15 flows in parallel to both wall surfaces 2a and 2b of the snout 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a bath surface floating foreign matter removal device for removing foreign matter floating on the surface of a molten metal bath inside a snout through which a metal plate is passed. [Background technology]

[0002] Metal-plated steel sheets used in automotive applications and other fields are manufactured by annealing a steel sheet (steel strip) by heating it in an annealing furnace under a reducing atmosphere, and then introducing it into a snout connected to the annealing furnace and continuously immersing it in a molten metal bath (molten metal plating bath) to plate it. The lower part of the snout is immersed in the molten metal bath, and the inside of the snout is kept in a reducing atmosphere by nitrogen gas, etc., to prevent oxidation of the steel surface. Metal vapor that evaporates from the molten metal bath surface condenses when it comes into contact with the cold wall surface, becoming metallic ash called ash, which eventually falls to the bath surface and floats there. Also, trace amounts of oxygen and moisture are contained in the input gas or are carried in from the steel sheet, and can react with the molten metal on the bath surface to form oxides, which can form a thin oxide film on the bath surface in the snout. Dross is also produced when Fe eluted from the steel sheet reacts with the molten metal or Al added to the molten metal bath. These foreign objects (metal ash, oxides / oxide films, and dross) float on the surface of the molten metal bath and adhere to the steel sheet surface. If they are caught in the plating surface during plating, they can cause plating defects.

[0003] Generally, two methods are known for removing floating foreign matter from the surface of a molten metal bath: the push-pull method and the pull-pull method. In the PUSH-PULL method, a discharge port is provided on one side of the steel plate and a suction port on the other side. The molten metal is discharged from the discharge port and sucked up through the suction port while also collecting and removing foreign matter floating on the bath surface. In the PULL-PULL method, suction ports are provided on both sides of the steel plate, and the molten metal is sucked in from both ports while foreign matter floating on the bath surface is collected and removed. However, with the push-pull method, foreign matter floating on the bath surface near the discharge port moves toward the steel sheet and is likely to adhere to the steel sheet surface, and the appearance of the steel sheet may develop asymmetric diagonal unevenness. In addition, with the pull-pull method, although it is easy to suck up foreign matter floating on the bath surface near the sides of the steel plate, as the steel plate is immersed in the molten metal bath, a flow of molten metal is formed toward the center of the plate width, making it difficult to suck up foreign matter floating on the bath surface in the center of the steel plate.

[0004] To solve these problems, various methods have been proposed for promoting the flow of molten metal and removing floating foreign matter from the bath surface. For example, the methods described in Patent Documents 1 to 3 are known as examples of a push-pull method for removing floating foreign matter on the bath surface. In the method described in Patent Document 1, molten metal is sprayed from a nozzle onto the front and back surfaces of the steel sheet in a direction opposite to the traveling direction of the steel sheet and toward the suction port. In the method described in Patent Document 2, a variable mechanism is provided for adjusting the height of the discharge port. In the method described in Patent Document 3, a straightening plate is provided at the suction port and / or discharge port to straighten the flow of molten metal in the width direction of the steel sheet. In the methods described in the above patent documents, these are used to enhance the effect of removing floating foreign matter on the bath surface. Also, one example of a method for removing floating foreign matter on the bath surface using the pull-pull method is known from Patent Document 4. In this method, guide plates are provided on the front and back surfaces of the steel sheet, and a discharge port is provided from the center of the guide plate to discharge molten metal toward the steel sheet, thereby enhancing the effect of removing floating foreign matter on the bath surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-59942 A [Patent Document 2] JP 2003-293107 A [Patent Document 3] International Publication No. 2017 / 110945 [Patent Document 4] JP 2008-231484 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order to remove floating foreign objects on the bath surface, molten metal is discharged from a nozzle (discharge port) toward the steel plate, and when the molten metal collides with the steel plate, it changes direction and is sucked into the suction port. If the molten metal is discharged directly onto the steel plate, the physical properties of the part of the steel plate that is hit will differ from those of other parts, which may result in uneven quality of the steel plate.

[0007] Therefore, the inventors of the present invention have reconsidered the flow of molten metal in order to solve these problems. First, in the push-pull method, floating foreign matter on the bath surface that has accumulated on the side of the steel sheet on the discharge port side must be guided across the steel sheet to the suction port. At this time, the floating foreign matter on the bath surface joins the flow that is drawn into the steel sheet (the steel sheet accompanying flow) before reaching the suction port, and adheres to the steel sheet, causing coating defects. On the other hand, with the pull-pull method, the suction effect of the suction port only reaches the area very close to the port, and the flow of the molten metal is mainly dominated by the flow accompanying the steel plate, which creates a flow toward the steel plate, making it difficult to adequately suck in foreign matter floating on the bath surface.

[0008] As described above, both the PUSH-PULL and PULL-PULL methods can cause problems with coating defects due to floating foreign matter on the bath surface caused by the accompanying flow of the steel sheet.However, the PUSH-PULL method has a faster flow speed of molten metal than the PULL-PULL method, which means that there are more control parameters for the accompanying flow of the steel sheet, making control more difficult, but it is possible to achieve stricter control, so the inventors have investigated a floating foreign matter removal device for the bath surface based on the PUSH-PULL method.

[0009] In order to promote the flow of the molten metal on the surface of the steel plate in the PUSH-PULL method, it is sufficient to make the molten metal flow from the discharge port located on the side of the steel plate toward the suction port located on the other side of the steel plate. In order to control the flow of the molten metal, for example, as described in Patent Document 1, a number of spray nozzles are provided in addition to the supply nozzle, and the molten metal is sprayed from these spray nozzles in the direction opposite to the traveling direction of the steel plate and toward the suction port onto the front and back surfaces of the steel plate. In this way, the fluidity of the molten metal is increased, but since a number of spray nozzles are arranged in the snout, maintenance of the device becomes difficult. In addition, as described in Patent Document 2, it is also possible to provide a variable mechanism for adjusting the height of the discharge port, but in this case, maintenance of the device is also difficult. Furthermore, as described in Patent Document 3, it is also possible to provide a straightening plate at the suction port and / or discharge port to straighten the flow of the molten metal in the width direction of the steel plate. In this case, if a straightening plate is simply provided in the PUSH-PULL method, it is possible that the straightening plate will become a resistance to the flow of the molten metal and the flow will become worse.

[0010] The present inventors have conducted extensive research into the flow of molten metal flowing from the discharge port to the suction port so as to prevent foreign matter floating on the surface of the molten metal bath from adhering to the steel sheet due to the flow of molten metal (discharge flux), and have arrived at the following findings. In order to prevent floating foreign matter on the bath surface from adhering to the steel sheet, the discharged molten metal should flow at a position as far away from the steel sheet as possible so as not to be caught in the flow accompanying the steel sheet, i.e., the flow rate of the discharged molten metal should pass near the wall surface of the snout. For this purpose, a discharge port is provided obliquely toward the wall surface of the snout so that the molten metal is discharged. At this time, it is necessary to discharge the molten metal toward the wall surface of the snout that faces the front and back surfaces of the steel plate so that the molten metal is not entrained on both the front and back surfaces of the steel plate. On the other hand, when the molten metal discharged from the discharge port hits the wall of the snout, it bounces back and heads toward the steel sheet. If foreign matter floating on the bath surface is entrained in this flow of molten metal, it will adhere to the steel sheet and cause coating defects. To avoid this, an auxiliary outlet can be provided to make the molten metal flow parallel to the snout wall. Specifically, another outlet can be provided behind the outlet that discharges the molten metal at an angle to the snout wall (opposite the suction port) to guide the molten metal flow toward the suction port.

[0011] The present invention has been made based on the above-mentioned findings, and aims to provide a bath surface floating foreign matter removal device that can smoothly move and collect bath surface floating foreign matter floating on the molten metal bath surface inside the snout to a suction port and also facilitates maintenance inside the snout. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides a bath surface floating foreign matter removal device for removing bath surface floating foreign matter floating on a molten metal bath surface inside a snout through which a metal plate is threaded, the device comprising: a suction port provided in the vicinity of a molten metal bath surface on one side of the metal plate for sucking in the molten metal; a discharge port provided in the vicinity of the molten metal bath surface on the other side surface of the metal plate and for discharging the molten metal; The discharge port is a first discharge port that is disposed in a center portion in a thickness direction of the snout on the other side surface side of the metal plate and that discharges molten metal obliquely toward both wall surfaces of the snout that face both plate surfaces of the metal plate; and a second outlet for discharging the molten metal. The molten metal discharged from the second discharge port flows parallel to both wall surfaces of the snout from the other side surface of the metal plate toward one side surface of the metal plate.

[0013] Here, for example, a steel plate is used as the metal plate, molten zinc is used as the molten metal, and a hot-dip galvanizing bath is used as the molten metal bath, but the present invention is not limited to these.

[0014] In the present invention, the first discharge port is positioned in the center of the snout thickness direction on the other side of the metal plate, and the molten metal is discharged at an angle relative to both wall surfaces of the snout. Therefore, the molten metal discharged from the first discharge port hits both wall surfaces of the snout at an angle, while the molten metal discharged from the second discharge port flows parallel to both wall surfaces of the snout from the other side of the metal plate toward one side. Therefore, the molten metal discharged from the first discharge port and hitting both wall surfaces of the snout at an angle is assisted by the flow of molten metal discharged from the second discharge port, which flows parallel to both wall surfaces of the snout, flows along both wall surfaces along the flow of molten metal, and is sucked through a suction port provided near the molten metal bath surface on one side of the metal plate. In this way, the foreign matter floating on the bath surface rides on the flows of both molten metals and moves smoothly toward the suction port without colliding with the metal plate, and is collected from the suction port. Therefore, the foreign matter floating on the molten metal bath surface can be smoothly moved to the suction port and collected. Furthermore, since only the first discharge port, the second discharge port and the suction port are provided inside the snout, the inside of the snout is not complicated and maintenance is also easy.

[0015] In the above-mentioned configuration of the present invention, when the metal plate side of the first discharge port is the front side, The second discharge port is disposed on a rear side opposite to the front side of the first discharge port, and discharges molten metal perpendicular to both wall surfaces of the snout, The molten metal may flow parallel to the walls.

[0016] With this configuration, the second discharge port is positioned on the rear side of the first discharge port and discharges molten metal perpendicular to both wall surfaces of the snout, so that the molten metal can be easily discharged toward both wall surfaces. Since the discharged molten metal flows parallel to both wall surfaces of the snout, the molten metal discharged from the first discharge port and hitting both wall surfaces is assisted by the flow of molten metal discharged from the second discharge port and can flow along both wall surfaces. Effect of the Invention

[0017] According to the present invention, foreign matter floating on the surface of the molten metal bath inside the snout can be smoothly moved to the suction port and collected, and maintenance inside the snout is also made easier. [Brief description of the drawings]

[0018] [Figure 1] 1 is a side cross-sectional view showing a schematic configuration of a continuous hot-dip galvanizing apparatus equipped with a bath surface floating foreign matter removal device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the snout of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a bath surface floating foreign matter removing device according to the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of a bath surface floating foreign matter removal device, in which FIG. 1 is a side cross-sectional view showing the schematic configuration of a continuous hot-dip galvanizing apparatus equipped with a bath surface floating foreign matter removal device 11, and FIG. 2 is a cross-sectional view showing the schematic configuration of a snout.

[0020] In this continuous hot-dip galvanizing apparatus, the tip (lower end in Figure 1) of a hot-dip galvanizing bath snout (hereinafter referred to as the snout) 2, which surrounds the strip-shaped steel sheet 1 being transported, is inserted into the hot-dip galvanizing bath 3 in the hot-dip galvanizing bath 10, and the steel sheet 1 is transported directly into the hot-dip galvanizing bath 3 through the snout 2. In addition, the tip of the snout 2 becomes shorter in the thickness direction of the steel plate 1 toward the tip. In other words, at the tip of the snout 2, the distance between the wall surfaces facing both plate surfaces (front and back surfaces) of the steel plate 1 becomes shorter. The steel sheet 1 brought into the hot-dip galvanizing bath 3 goes around a sink roll 4 disposed deep inside the hot-dip galvanizing bath 10, and is then pulled up to the outside of the hot-dip galvanizing bath 10, so that the steel sheet 1 is continuously zinc-plated as it moves through the hot-dip galvanizing bath 10.

[0021] The steel sheet 1 is degreased and cleaned, then annealed to a predetermined temperature in a continuous annealing furnace (not shown) mainly using hydrogen and nitrogen, and then cooled to a predetermined temperature, and is immersed in a molten zinc plating bath 3 in a molten zinc plating bath 10 through the snout 2 to be hot-dip galvanized. Note that a turndown roll 5 is provided above the sink roll 4 and at the top inside the snout 2, for continuously transporting the steel sheet 1 in cooperation with the sink roll 4. The snout 2 is provided at its base end and tip end with inlet holes 6a, 6a for introducing N2 gas into the snout, and at its tip end with inlet hole 6b for introducing AX gas into the snout. The snout 2 is provided with a snout ejector 7 having an exhaust hole 7a for exhausting the atmospheric gas in the snout to the outside of the system, and a heater 8 for heating the snout 2. Reference numeral 9 denotes a thermometer for measuring the temperature of the steel sheet 1 introduced into the snout 2.

[0022] Such a continuous hot-dip galvanizing apparatus is equipped with a bath surface floating foreign matter removal device 11. As shown in Fig. 2, this bath surface floating foreign matter removal device 11 has a suction port 12 provided near the hot-dip galvanizing bath surface 3a (see Fig. 1) on one side (the right side in Fig. 2) of the steel sheet 1 for sucking in molten zinc, and a discharge port 13 provided near the hot-dip galvanizing bath surface 3a on the other side (the left side in Fig. 2) of the steel sheet 1 for discharging molten zinc.

[0023] The discharge port 13 includes a first discharge port 14, 14 and a second discharge port 15, 15. The first discharge port 14, 14 is disposed at the center of the snout thickness direction (the vertical thickness direction in FIG. 2) on the other side surface side (the left side surface side in FIG. 2) of the steel plate 1. The first discharge ports 14, 14 are disposed symmetrically with respect to the center of the snout thickness direction, and the upper first discharge port 14 discharges molten zinc obliquely to the upper wall surface 2a of the snout 2 facing the upper surface of both plate surfaces (upper surface (front surface) and lower surface (rear surface)) of the steel plate 1. That is, the upper first discharge port 14 is provided at the tip of an upper nozzle 21 provided in the discharge pump 20, and the nozzle 21 is inclined with respect to the upper wall surface 2a so that the tip faces obliquely upward in FIG. 2. The lower first discharge port 14 is configured to discharge molten zinc obliquely toward a lower wall surface 2b of the snout 2 facing the lower surface of both plate surfaces (upper surface (front surface) and lower surface (back surface)) of the steel plate 1. That is, the lower first discharge port 14 is provided at the tip of a lower nozzle 21 provided in the discharge pump 20, and the nozzle 21 is inclined with respect to the lower wall surface 2b so that the tip faces obliquely downward in FIG. 2.

[0024] The molten metal discharged from the second discharge port 15, 15 flows parallel to both wall surfaces 2a, 2b of the snout 2 from the other side surface of the steel plate 1 to one side surface. For example, in this embodiment, if the steel plate 1 side of the first discharge port 14, 14 is the front side, the second discharge port 15, 15 is arranged on the back side opposite to the front side of the first discharge port 14, 14, and the molten zinc is discharged perpendicularly to both wall surfaces 2a, 2b of the snout 2, and the molten zinc is changed in direction at a right angle by hitting both wall surfaces 2a, 2b, and then flows parallel to both wall surfaces 2a, 2b. Two nozzles 22, 22 are connected to the discharge pump 20, one nozzle 22 is arranged facing upward, and the other nozzle 22 is arranged facing downward. The second discharge ports 15, 15 are provided at the tips of these nozzles 22, 22.

[0025] In this embodiment, the nozzles 22, 22 are arranged perpendicular to both wall surfaces 2a, 2b of the snout 2. However, in the present invention, since the molten metal (molten zinc) discharged from the second discharge port only needs to flow parallel to both wall surfaces 2a, 2b of the snout 2, a nozzle having a second discharge port may be arranged parallel to both wall surfaces 2a, 2b.

[0026] As described above, the suction port 12 for sucking molten zinc is provided near the hot-dip galvanizing bath surface on one side of the steel sheet 1 (the right side in FIG. 2). This suction port 12 is disposed near the lower wall surface 2b of the snout 2. The suction port 12 is provided in a suction pump. The suction port 12 may be disposed in the center of the snout thickness direction, but in this embodiment, the snout 2 is obliquely inserted into the hot-dip galvanizing bath surface 3a (see FIG. 1). Therefore, in the case of a discharge port that distributes molten zinc in two, such as the first discharge ports 14, 14, the molten zinc is not distributed in the same manner, and is discharged from the first discharge ports 14, 14 strongly on one side (the upper wall surface 2a side) and weakly on the other side (the lower wall surface 2b side). In order to eliminate this difference in strength, the suction port 12 is located closer to the lower wall surface 2b, and the side wall surface 2c of the snout 2 is used to weaken the flow on the upper wall surface 2a side, so that the flow is sucked in by the suction port 12.

[0027] In such a bath surface floating foreign matter removal device 11, the first discharge outlets 14, 14 are positioned in the center of the snout thickness direction on the other side side (left side side) of the steel plate 1, and molten zinc is discharged diagonally relative to both wall surfaces 2a, 2b of the snout 2.Therefore, the molten zinc discharged from the first discharge outlets 14, 14 hits both wall surfaces 2a, 2b of the snout 2 diagonally, while the molten zinc discharged from the second discharge outlets 15, 15 flows parallel to both wall surfaces 2a, 2b of the snout 2 from the other side side (left side side in Figure 2) of the steel plate 1 toward one side side (right side side in Figure 2). Therefore, the molten zinc discharged from the first discharge ports 14, 14 and hitting both wall surfaces 2a, 2b of the snout 2 at an angle is discharged from the second discharge ports 15, 15, assisted by the flow of molten zinc flowing parallel to both wall surfaces 2a, 2b of the snout 2, flows along both wall surfaces 2a, 2b along the flow of molten zinc, and is sucked from the suction port 12 provided in the vicinity of the hot-dip galvanizing bath surface on one side surface (right side surface) of the steel sheet 1. For this reason, a region S is generated between the both wall surfaces 2a, 2b and the steel sheet 1, where the molten metal discharged from the first discharge ports 14, 14 and the second discharge ports 15, 15 does not collide with the steel sheet 1. Therefore, the foreign matter floating on the bath surface rides on the flows of both molten zinc and moves smoothly toward the suction port 12 without colliding with the steel sheet 1, and is collected from the suction port 12. Therefore, the foreign matter floating on the hot-dip galvanizing bath surface 3a can be smoothly moved to the suction port 12 and collected. Furthermore, since only the first discharge ports 14, 14, the second discharge ports 15, 15 and the suction port 12 are provided inside the snout, the inside of the snout is not complicated and maintenance is also easy.

[0028] In addition, the second discharge ports 15,15 are positioned on the back side of the first discharge ports 14,14 and discharge molten zinc perpendicular to both wall surfaces 2a,2b of the snout 2, so that the molten zinc can be easily discharged toward both wall surfaces 2a,2b.Since the discharged molten zinc flows parallel to both wall surfaces 2a,2b of the snout 2, the molten zinc discharged from the first discharge ports 14,14 and hitting both wall surfaces 2a,2b is assisted by the flow of molten zinc discharged from the second discharge ports 15,15 and can flow along both wall surfaces 2a,2b. In addition, since the second discharge ports 15, 15 are arranged on the rear side of the first discharge ports 14, 14, foreign matter floating on the bath surface on the rear side can be removed to perform rear cleaning, and the removed foreign matter floating on the bath surface rides along with the flow of molten zinc described above and moves smoothly toward the suction port 12 without colliding with the steel sheet 1, and is recovered from the suction port 12.

[0029] (Experimental Example) Next, an experimental example will be described. (Preliminary experiment) An aquarium was used to represent the inside of a snout, and an acrylic plate representing a metal plate was placed inside the aquarium, with the shape of the outlet changed in various ways to investigate the movement of foreign objects (plastic) floating on the surface of the aquarium. Here, the outlet was placed on one side of the acrylic plate in the shape shown in Table 1, and water was supplied from a pump and discharged into the aquarium. Meanwhile, the same suction port was used in all the cases, and it was placed on the other side of the acrylic plate so that the top of the suction port was partially exposed above the surface of the bath, and the water sucked in by the pump was discharged outside the aquarium. Table 1 shows the observation results regarding the state of the discharge port and the movement of foreign matter.

[0030] [Table 1]

[0031] As shown in Table 1, when the outlet was located in the center of the snout thickness direction, had a first outlet with a nozzle that discharged molten metal at an angle to both wall surfaces of the snout, and had a second outlet located behind the first outlet (Example 4), the foreign matter reached the suction port without colliding with the acrylic plate and was discharged outside the tank, and did not remain behind the outlet. Therefore, with an outlet like this, it is believed that the foreign matter can be properly removed without colliding with the plate even in an actual machine.

[0032] (Applied to actual machine) Based on the results of the above preliminary experiment, the outlet of a snout installed in a manufacturing line for hot-dip galvanizing steel strips was modified. Specifically, the conventional outlet (Table 1, Example 1; box outlet type) was modified to include an outlet (Table 1, Example 4) that ejects molten zinc obliquely from the nozzle onto both wall surfaces of the snout (first outlet), and ejects molten zinc vertically from the center of the back surface (second outlet).

[0033] Furthermore, in the production line, the snout is positioned at a certain incline, and the steel strip diagonally enters the molten zinc bath, where its direction of travel is changed by a roller (sink roll) placed in the bath, and it is pulled up. When the above-mentioned discharge port is used (Example 4 in Table 1) because the snout is positioned at an incline, the molten zinc discharged by the pump from the discharge port has a slight difference in discharge pressure between the two nozzles, and this results in a difference in the flow speed of the molten metal on the front and back surfaces of the steel plate. To alleviate this, the suction port is positioned offset to the side with the weaker discharge pressure (the underside of the snout).

[0034] Table 2 shows the number of plating defects (pockmarks) caused by floating foreign matter (so-called scum; Al2O3) on the zinc plating bath surface and the percentage of yield loss caused by snouts before and after the revamp. Note that of the values ​​shown in Table 2, the values ​​before the revamp are the average values ​​for the nine months before the revamp, and the values ​​after the revamp are the average values ​​for the four months after the revamp.

[0035] [Table 2]

[0036] As shown in Table 2, after the modification, the plating defects were significantly reduced compared to before the modification, and the yield loss rate caused by these plating defects was also reduced by about 2%. [Explanation of symbols]

[0037] 1 Steel plate (metal plate) 2. Snout 2a, 2b Both walls of the snout 3a Hot-dip galvanizing bath surface (molten metal bath surface) 12 Suction port 13 Outlet 14 1st discharge port 15 2nd outlet

Claims

1. A bath surface floating foreign matter removal device for removing bath surface floating foreign matter floating on a molten metal bath surface inside a snout through which a metal plate is passed, comprising: a suction port provided in the vicinity of a molten metal bath surface on one side of the metal plate for sucking in the molten metal; a discharge port provided in the vicinity of the molten metal bath surface on the other side surface of the metal plate and for discharging the molten metal; The discharge port is a first discharge port that is disposed at a center in a thickness direction of the snout on the other side surface side of the metal plate and that discharges molten metal obliquely toward both wall surfaces of the snout that face both plate surfaces of the metal plate; a second outlet port for discharging the molten metal; The molten metal discharged from the second discharge port flows parallel to both wall surfaces of the snout from the other side surface side to one side surface side of the metal plate, The molten metal discharged from the first discharge port and hitting both wall surfaces of the snout at an angle is discharged from the second discharge port, and is assisted by a flow of molten metal flowing parallel to both wall surfaces of the snout, so as to flow along both wall surfaces.

2. When the metal plate side of the first discharge port is defined as a front side, The second discharge port is disposed on a rear side opposite to a front side of the first discharge port, and discharges molten metal perpendicular to both wall surfaces of the snout, 2. The apparatus for removing floating foreign matter on a bath surface according to claim 1, wherein the molten metal flows parallel to both of said wall surfaces.

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