JP2016156077A - Apparatus for manufacturing hot-dip galvanized steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus capable of manufacturing a hot-dip galvanized steel sheet having less surface defects, and having less restrictions on equipment arrangement.SOLUTION: An apparatus 100 for manufacturing a hot-dip galvanized steel sheet comprises a container 10 for storing molten zinc, a snout 14, a sink roll 16, a support roll 18 and a current plate 20. In the current plate 20, one surface 22 faces a steel sheet P1 between the snout and the sink roll above the sink roll and in a molten zinc bath 12, and the other surface 24 is positioned so as to face a steel sheet P2 after passing the sink roll. The current plate has a shape in which the shortest distance between the one surface 22 and the steel sheet P1 facing the one surface is gradually increased in the horizontal direction toward both end portions from a central portion of the one surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for producing a hot dip galvanized steel sheet.

  Hot dip galvanized steel sheets are widely used in fields such as building materials, automobiles, and home appliances. And in these uses, it is requested | required with respect to the hot dip galvanized steel plate that it is excellent in an external appearance irrespective of the presence or absence of coating. Here, not only in the case of no coating, but also the appearance after coating is strongly influenced by surface defects such as wrinkles and foreign matter adhesion, so it is important that the hot dip galvanized steel sheet has no surface defects.

  The hot dip galvanized steel sheet is generally manufactured using a manufacturing apparatus as shown in FIG. That is, the sink roll 16 and the support roll 18 are installed in the molten zinc bath 12, and the steel sheet P enters the molten zinc bath 12 through the snout 14, and the sheet passing direction is directed upward by the sink roll 16. After the change, it is guided to the support roll 18 and leaves the molten zinc bath 12.

  In such a hot-dip galvanized steel sheet production apparatus, iron is eluted from the steel sheet in the plating bath, and an intermetallic compound is formed with the plating components, which is called dross. Since this dross contains an iron component, in general, the density of the dross is larger than the density of the plating bath and settles in the plating bath. However, since it is an intermetallic compound with iron eluted from the steel sheet, the particle size of the dross is small, and the sedimentation rate due to the density difference is extremely slow, so that the dross tends to adhere to the steel sheet during sedimentation. It is known that surface defects occur when the dross adheres to the steel sheet. In particular, when the support roll 18 disposed on the sink roll 16 comes into contact with the steel plate, there are many cases where defects occur due to the dross. This is because the triangular zone 12B formed between the steel plate and the bath surface of the molten zinc bath becomes a closed space, and dross is not easily discharged outside the triangular zone.

  In order to suppress surface defects (hereinafter also referred to as “dross defects”) caused by the dross, Patent Document 1 describes a technique of installing a rectifying plate in the vicinity of a sink roll in a triangular zone. Moreover, in patent document 2, the technique which installs a baffle plate in the vicinity of the bath surface of a triangular zone is described.

JP 2000-119829 A JP 2013-224457 A

  However, in patent document 1, the baffle plate is arrange | positioned in the sink roll vicinity and the deep position of a plating bath, and there exists a problem in application to an actual machine from the restrictions on equipment arrangement | positioning. In addition, dross accumulates on the current plate arranged near the wedge-shaped area formed between the steel plate and the sink roll that penetrates into the molten zinc bath, and dross defects are caused by the fall of this deposit. May occur.

  Further, according to the study by the present inventors, the rectifying plate of Patent Document 2 rises from the wedge-shaped region formed between the steel sheet and the sink roll entering the molten zinc bath toward the molten zinc bath surface. The flow of molten zinc flowing to the outside of the triangle zone is weak in the direction of the width of the steel sheet, the dross is insufficiently discharged outside the triangle zone, and there is room for improvement from the viewpoint of suppressing surface defects It has been found.

  Then, in view of the said subject, this invention aims at providing the manufacturing apparatus with few restrictions on equipment arrangement | positioning which can manufacture the hot dip galvanized steel plate with few surface defects.

  According to the study by the present inventors, a current plate is disposed in the vicinity of the molten zinc bath surface in the triangular zone, and by devising the shape of the current plate, the gap between the steel plate and the sink roll entering the bath is determined. The flow component in the plate width direction of the steel sheet can be added to the flow of the molten zinc flow that rises toward the bath surface from the wedge-shaped region formed on the surface, thereby effectively reducing the dross outside the triangular zone. I found that it can be discharged.

This invention is completed by said knowledge, The summary structure is as follows.
(1) a container for containing molten zinc and forming a molten zinc bath;
A snout that is positioned so as to be immersed in the molten zinc bath, and defines a space through which a steel plate continuously supplied into the molten zinc bath passes;
A sink roll located in the molten zinc bath, wound around the steel sheet that has entered the molten zinc bath, and the steel sheet is directed toward the molten zinc bath surface with the traveling direction of the steel sheet upward,
A support roll located above the sink roll and in the molten zinc bath, in contact with the steel plate facing upward from the sink roll, and leading the steel plate out of the molten zinc bath;
A rectifying plate positioned above the sink roll and in the molten zinc bath so that one side faces the steel plate between the snout and the sink roll and the other side faces the steel plate after passing through the sink roll. And having
The rectifying plate has a shape in which the shortest distance between the one surface and a steel plate facing the one surface gradually increases from the central portion of the one surface toward both ends in the horizontal direction. manufacturing device.

  (2) The shape of the one surface in a cross section perpendicular to the line connecting the points where the shortest distance between the one surface and the steel plate facing the one surface is the shortest at each vertical position on the one surface is on the snout side. The apparatus for producing a hot dip galvanized steel sheet according to the above (1), which has a convex bent shape or a curved shape.

(3) When the shape of the one surface is a bent shape, the bending angle θ1 of the one surface in a cross section perpendicular to the line is 5 degrees or more and 45 degrees or less,
The apparatus for producing a hot-dip galvanized steel sheet according to (2) above, wherein, when the shape of one side is a curved shape, a radius of curvature R of the one side in a cross section perpendicular to the line is 707 mm or more and 5737 mm or less.

  (4) The apparatus for producing a hot dip galvanized steel sheet according to the above (2) or (3), wherein an angle θ2 on the opposite side to the snout, which the line forms with the hot dip zinc bath surface, is 45 degrees or more and 100 degrees or less. .

  (5) The upper end of the one side is located on the snout side with respect to the radial center of the sink roll, and the horizontal distance D1 between the upper end of the one side and the radial center of the sink roll is 200 mm or more and 600 mm or less. The apparatus for producing a hot-dip galvanized steel sheet according to any one of (1) to (4) above.

  (6) The apparatus for producing a hot dip galvanized steel sheet according to any one of (1) to (5), wherein a distance D2 between the upper end of the current plate and the hot dip galvanized bath surface is 0 mm or greater and 100 mm or less.

  (7) The apparatus for producing a hot dip galvanized steel sheet according to any one of (1) to (6), wherein a shortest distance D3 between the lower end of the current plate and the sink roll is 50 mm or more and 300 mm or less.

  The apparatus for producing a hot-dip galvanized steel sheet according to the present invention can produce a hot-dip galvanized steel sheet with few surface defects, although there are few restrictions on the arrangement of equipment.

It is a figure which shows the manufacturing apparatus 100 of the hot dip galvanized steel plate by one Embodiment of this invention, (A) is a top view, (B) is a front view. It is a figure which shows the baffle plate 20 shown in FIG. 1, (A) is a top view, (B) is a front view, (C) is the figure seen from I direction of (B), (D) is a figure of (B). It is the figure seen from the II direction. It is a schematic diagram explaining the position of the baffle plate 20 in the manufacturing apparatus 100 of a hot dip galvanized steel plate. It is a figure which shows the other baffle plate 30 applicable to this invention, (A) is a top view, (B) is a front view, (C) is the figure seen from I direction of (B), (D) is It is the figure seen from the II direction of (B). It is a figure which shows the manufacturing apparatus of the conventional hot dip galvanized steel plate, (A) is a top view, (B) is a front view. It is a figure which shows the manufacturing apparatus of the other conventional hot dip galvanized steel plate, (A) is a top view, (B) is a front view.

  A hot-dip galvanized steel sheet manufacturing apparatus 100 (hereinafter also simply referred to as “manufacturing apparatus”) according to an embodiment of the present invention will be described with reference to FIGS. With reference to FIG. 1, the manufacturing apparatus 100 includes a container 10, a snout 14, a sink roll 16, a support roll 18, and a current plate 20.

  The container 10 is for containing molten zinc and forming a molten zinc bath 12. The snout 14 is the last part of the continuous annealing furnace for annealing the steel sheet P, and is positioned so that the end portion 14A is immersed in the molten zinc bath 12, and is continuously supplied into the molten zinc bath 12. The space that passes through. The sink roll 16 is located in the molten zinc bath 12 and is wound with a steel plate P1 that has entered the molten zinc bath, and the steel plate P1 is directed toward the molten zinc bath surface with the traveling direction of the steel plate P1 upward. The support roll 18 is positioned above the sink roll 16 and in the molten zinc bath 12, is in contact with the steel plate P <b> 2 that extends upward from the sink roll 16, and guides the steel plate P <b> 2 to the outside of the molten zinc bath 12. In this embodiment, there are two support rolls, but the number is not particularly limited, and may be one.

  In this embodiment, the current plate 20 having a specific shape is placed above the sink roll 16 and in the molten zinc bath 12, with one side 22 facing the steel plate P1 between the snout and the sink roll, and the other side 24 being the sink. It is important to arrange so as to face the steel plate P2 after passing through the roll. Hereinafter, the technical significance will be described while comparing with the conventional example.

  FIG. 5 shows a conventional hot-dip galvanized steel plate manufacturing apparatus in which a current plate is not installed. Along with the movement of the steel plate P1, a flow of molten zinc is generated in the vicinity of the steel plate P1 from the end portion 14A of the snout toward the sink roll 16. The flow reaches a wedge-shaped region 12 </ b> C formed between the steel plate P <b> 1 entering the molten zinc bath and the sink roll 16. And the flow of the molten zinc which raises toward the bath surface 12A from the said wedge-shaped area | region 12C arises, and this flow is directing to the support roll 18. As shown in FIG. Therefore, when the support roll 18 comes into contact with the steel plate P2 after passing through the sink roll, there is a high possibility that a dross is involved and a surface defect is generated due to this.

  Next, FIG. 6 shows a conventional hot-dip galvanized steel plate manufacturing apparatus in which a flat current plate 30 is installed. This baffle plate 30 is located above the sink roll 16 and in the molten zinc bath 12, so that one side faces the steel plate P1 between the snout and the sink roll, and the other side faces the steel plate P2 after passing through the sink roll. Is located. Therefore, the flow of molten zinc rising from the wedge-shaped region 12C toward the bath surface 12A is pushed back toward the snout 14 by the flat plate type rectifying plate 30 installed in the vicinity of the bath surface in the triangular zone 12B. However, the force which pushes out along the board width direction of a steel plate outside the triangular zone 3 is weak, and dross circulates in the triangular zone 12B. Therefore, the effect of suppressing dross defects is insufficient.

  On the other hand, in this embodiment, with reference to FIG.1 and FIG.2, the baffle plate 20 bent in the V shape is installed in the snout 14 side. With reference to FIG. 2, the shape of the baffle plate 20 and the detail of an installation place are demonstrated.

  As shown in FIGS. 2 (A) and 2 (B), the rectifying plate 20 is located above the sink roll 16 and in the molten zinc bath 12, with one side 22 facing the steel plate P1 between the snout and the sink roll. The other surface 24 is positioned so as to face the steel plate P2 after passing through the sink roll, that is, in the triangular zone 12B.

  Both the one surface 22 and the other surface 24 have a shape bent in a V shape on the snout 14 side. More specifically, the single side 22 is connected to the line where the shortest distance between the single side 22 and the steel plate P1 facing the single side at the respective vertical positions is the shortest. FIG. 2 (A), (B), (D ) In L). The shape of the one surface 22 in the cross section perpendicular to the line L (that is, the shape of the one surface 22 in FIG. 2C) is a bent shape that protrudes toward the snout side. In FIG. 2, both ends (upper and lower ends of one side) of the line L are indicated by reference numerals 22A and 22D, both horizontal ends of the upper end of one side are indicated by reference numerals 22B and 22C, and both horizontal ends of the lower end of one side are indicated by reference numerals. 22E and 22F.

  In the present embodiment, as indicated by the dashed arrows in FIG. 1A, the molten zinc flow rising from the wedge-shaped region 12C toward the bath surface 12A is installed in the vicinity of the bath surface in the triangular zone 12B. The V-shaped rectifying plate 20 is swept out of the triangular zone 12B along the plate width direction of the steel plate. Therefore, dross is quickly discharged out of the triangular zone 12B. As a result, dross defects can be effectively suppressed.

  Next, with reference to FIG.2 and FIG.3, the suitable shape and installation place of the baffle plate 20 are demonstrated. Referring to FIG. 2C, the bending angle θ1 of one surface 22 in the cross section perpendicular to the line L is preferably not less than 5 degrees and not more than 45 degrees. Here, “one side bend angle” means the bend angle of one side when the one side (broken line in FIG. 2C) when the current plate is a flat plate is used as a reference (0 degree). . In addition, the broken line in FIG.2 (C) corresponds with the board width direction of a steel plate. In the present embodiment, since the cross-sectional shape of the single side 22 does not change along the line L, the angle formed by the line connecting the upper ends 22B and 22A of the single side and the plate width direction of the steel plate is the bending angle θ1, The angle between the line connecting the lower ends 22E and 22D on one side and the sheet width direction of the steel sheet is equal. When the bending angle θ <b> 1 is less than 5 degrees, the force of the rectifying plate 20 to push the dross out of the triangular zone 12 </ b> B along the plate width direction of the steel plate is weak, and the effects of the present invention may not be sufficiently obtained. . When the bending angle θ1 exceeds 45 degrees, the flow of the dross directly toward the support roll 18 becomes larger than the flow of the rectifying plate 20 quickly discharging the dross out of the triangular zone 12, and There is a possibility that the effect cannot be obtained sufficiently.

  The rectifying plate 20 has a symmetrical shape with respect to the line L, and the other bending angle (the angle formed by the line connecting the upper ends 22C and 22A on one side and the sheet width direction of the steel plate) is also the bending angle. It is preferably the same as θ1. Thereby, the flow of the molten zinc of the triangular zone 12B can be directed in the plate width direction of the steel plate symmetrically.

  In addition, since the flow of molten zinc depends on the shape of the single side | surface 22, the shape of another surface is not specifically limited. However, as in the present embodiment, the shape of the cross section perpendicular to the line L of the other surface 24 is also preferably a bent shape convex toward the snout side from the viewpoint of ease of manufacture.

  Next, referring to FIG. 3, it is preferable that the angle θ2 on the side opposite to the snout 14 that the line L forms with the molten zinc bath surface 12A is 45 degrees or more and 100 degrees or less. When θ2 is less than 45 degrees or too large, more than 100 degrees, the wedge-shaped region 12C formed between the steel plate P1 and the sink roll 16 entering the molten zinc bath is directed toward the bath surface 12A. This is because the rising flow of molten zinc does not hit the rectifying plate 20 so much and may be directed directly to the support roll 18.

  Next, referring to FIG. 3, the upper end 22A of one side is located on the snout 14 side with respect to the radial center 16A of the sink roll, and the horizontal distance between the upper end 22A of this single side and the radial center 16A of the sink roll D1 is preferably 200 mm or more and 600 mm or less. If the distance D1 is too small (less than 200 mm) or too large (more than 600 mm), the flow of molten zinc rising from the wedge-shaped region 12C toward the bath surface 12A does not hit the rectifying plate 20 and directly contacts the support roll 18. This is because there is a possibility of heading.

  Next, referring to FIG. 3, the distance D2 between the upper end 20A of the current plate and the molten zinc bath surface 12A is preferably 0 mm or more and 100 mm or less. As the distance D2 is smaller, the flow of molten zinc rising from the wedge-shaped region 12C toward the bath surface 12A can be pushed along the plate width direction of the steel plate by the current plate 20 outside the triangular zone 12B. Because. When the distance D2 exceeds 100 mm, the dross tends to face the support roll 18 through the rectifying plate 20.

  Next, referring to FIG. 3, it is preferable that the shortest distance D3 between the lower end 20B of the current plate and the sink roll 16 is 50 mm or more and 300 mm or less. If the distance D3 is too small as less than 50 mm, the current plate 20 may come into contact with the sink roll 16, and if the distance D3 is too large as more than 300 mm, it rises from the wedge-shaped region 12C toward the bath surface 12A. This is because there is a possibility that the flow of molten zinc does not hit the current plate 20 so much and goes directly to the support roll 18.

  In a general hot-dip galvanized steel sheet manufacturing apparatus, the width of the sink roll is 2000 to 2300 mm, the diameter is 600 to 1000 mm, and the depth position from the bath surface at the center in the width direction is 900 to 1000 mm. These dimensions can be taken. Further, the horizontal distance between the end portion of the snout (position closest to the sink roll) and the width direction center 16A of the sink roll can be set to 600 to 1000 mm.

  The shape of the current plate used in the present invention is not limited to a V-shaped bent shape like the current plate 20 described above. That is, the rectifying plate used in the present invention may have a shape in which the shortest distance between one surface and the steel plate facing the one surface gradually increases from the central portion of the one surface toward both ends in the horizontal direction. If it is such a shape, similarly to what was shown with the broken-line arrow in FIG. 1 (A), the molten zinc flow of the sheet width direction of a steel plate will be produced in the triangular zone 12B, and dross will be outside the triangular zone 12B. It can be discharged quickly. As a result, dross defects can be effectively suppressed.

  Moreover, the baffle plate used for this invention should just have the part of the above shapes in at least one part of a perpendicular direction. Since it can be generally grasped by the operating conditions etc. which part of the rectifying plate the flow of the molten zinc rising from the wedge-shaped region 12C toward the bath surface 12A hits, the part may be formed in the above-mentioned shape. However, as in the present embodiment, the above shape is preferable at all positions in the vertical direction because it can flexibly cope with changes in operating conditions and the like.

  Another rectifying plate 30 applicable to the present invention is shown in FIG. The rectifying plate 30 is also above the sink roll 16 and in the molten zinc bath 12, with one side 32 facing the steel plate P1 between the snout and the sink roll, and the other side 34 facing the steel plate P2 after passing through the sink roll. That is, it is located in the triangular zone 12B.

  Both the one side 32 and the other side 34 have a U-shaped shape on the snout 14 side. More strictly describing the single side 32, lines connecting the points where the shortest distance from the steel plate P1 facing the single side at each vertical position on the single side 32 is the shortest are shown in FIGS. 4 (A), 4 (B), (D). ) In L). And the shape of the single side | surface 32 in the cross section perpendicular | vertical to this line L (namely, the shape of the single side | surface 32 in FIG.4 (C)) is a curved shape convex to a snout side. In FIG. 4, both ends (upper and lower ends of one side) of the line L are indicated by reference numerals 32A and 32D, both horizontal ends of the upper end of one side are indicated by reference numerals 32B and 32C, and both horizontal ends of the lower end of one side are indicated by reference numerals. 32E and 32F. In the present embodiment, the cross-sectional shape of the single side 32 does not change along the line L.

  This rectifying plate 30 also causes a molten zinc flow in the plate width direction of the steel sheet to be generated in the triangular zone 12B in the same manner as indicated by the broken line arrow in FIG. 1A, and the dross is quickly brought out of the triangular zone 12B. Can be discharged. As a result, dross defects can be effectively suppressed.

  In the rectifying plate 30, with reference to FIG. 3C, the curvature radius R of the one surface 32 in a cross section perpendicular to the line L is preferably 707 mm or more and 5737 mm or less. If the radius of curvature R exceeds 5737 mm, the force that the rectifying plate 30 pushes the dross out of the triangular zone 12B along the plate width direction of the steel plate is weak, and the effects of the present invention may not be sufficiently obtained. In addition, when the radius of curvature R is less than 707 mm, the flow of the dross directly toward the support roll 18 is larger than the flow of the rectifying plate 30 quickly discharging the dross out of the triangular zone 12. May not be enough.

  Suitable θ2, D1, D2, and D3 are the same as described above.

  The material of the current plate is not particularly limited as long as it has corrosion resistance and heat resistance against molten zinc. For example, SUS316L is preferable from the viewpoint of durability. A steel plate protected by Cr plating or the like can also be used.

  The hot dip galvanized steel sheet manufactured by the manufacturing apparatus of the present invention includes both a plated steel sheet (GI) that is not subjected to an alloying treatment after the hot dip galvanizing process and a plated steel sheet (GA) that is subjected to an alloying process.

  1 using the rectifying plate of FIG. 2, the manufacturing device using the rectifying plate of FIG. 4, the manufacturing device of FIG. 5, or the manufacturing device of FIG. A steel plate having a tensile strength of 450 MPa or less was passed through the hot dip galvanizing bath at a plate speed of 2.5 m / s to produce a hot dip galvanized steel plate.

  The width of the sink roll was 2200 mm, the diameter was 800 mm, and the depth position from the bath surface at the center in the width direction was 1000 mm. The horizontal distance between the end portion of the snout (the position closest to the sink roll) and the center of the sink roll in the width direction was set to 800 mm.

  In No. 1, the manufacturing apparatus shown in FIG. 5 without using a current plate was used. In No. 2, the manufacturing apparatus shown in FIG. 6 provided with a flat plate rectifying plate was used. In Nos. 3 to 26, the manufacturing apparatus shown in FIG. 1 using a bent current plate as shown in FIG. 2 was used. At that time, the bending angle θ1, the angle θ2, and the distances D1, D2, and D3 were as shown in Table 1. In Nos. 27 to 50, a manufacturing apparatus using a curved flow straightening plate as shown in FIG. 4 was used. At that time, the radius of curvature R, the angle θ2, the distances D1, D2, and D3 were set as shown in Table 1.

About the hot dip galvanized steel sheet manufactured in each test example, the surface defect was evaluated according to the following criteria. The results are shown in Table 1.
A: No adhesion of dross of 100 μm or more within the steel sheet surface length of 300 mm. No dross adhesion less than 100μm.
○: No adhesion of dross of 100 μm or more within the steel sheet surface length of 300 mm. 1 to 5 dross deposits less than 100 μm.
(Triangle | delta): There is no dross adhesion of 100 micrometers or more within the steel plate surface length 300mm. 6 to 10 dross deposits less than 100 μm.
X: One or more dross deposits of 100 μm or more within a steel sheet surface length of 30 mm.

  The apparatus for producing a hot-dip galvanized steel sheet according to the present invention can produce a hot-dip galvanized steel sheet with few surface defects, although there are few restrictions on the arrangement of equipment.

DESCRIPTION OF SYMBOLS 100 Manufacturing apparatus of hot-dip galvanized steel sheet 10 Container 12 Hot-dip zinc bath 12A Hot-dip zinc bath surface 12B Triangular zone 12C Wedge-shaped area 14 Snout 14A End of snout 16 Sink roll 16A Radial center of sink roll 18 Support roll 20 Current plate 20A Upper end of current plate 20B Lower end of current plate 22 Single side of current plate 22A, 22B, 22C Upper end of single surface 22D, 22E, 22F Lower end of single surface 24 Other surface of current plate 30 Current plate 30A Upper end of current plate 30B Lower end of current plate 32 One side of the rectifying plate 32A, 32B, 32C Upper end of one side 32D, 32E, 32F Lower end of one side 34 Other side of the rectifying plate P Steel plate continuously supplied into the molten zinc bath P1 Steel plate between the snout and the sink roll P2 Steel plate after passing through the sink roll L Each vertical position on one side Line connecting points where the shortest distance between one side and the opposite steel plate is the shortest θ1 Bending angle on one side R Radius of curvature on one side θ2 Angle that is opposite to snout, where line L is the molten zinc bath surface D1 Upper end of one side Horizontal distance from the radial center of the sink roll D2 Distance between the upper end of the current plate and the molten zinc bath surface D3 Shortest distance between the lower end of the current plate and the sink roll

Claims (7)

A container for containing molten zinc and forming a molten zinc bath;
A snout that is positioned so as to be immersed in the molten zinc bath, and defines a space through which a steel plate continuously supplied into the molten zinc bath passes;
A sink roll located in the molten zinc bath, wound around the steel sheet that has entered the molten zinc bath, and the steel sheet is directed toward the molten zinc bath surface with the traveling direction of the steel sheet upward,
A support roll located above the sink roll and in the molten zinc bath, in contact with the steel plate facing upward from the sink roll, and leading the steel plate out of the molten zinc bath;
A rectifying plate positioned above the sink roll and in the molten zinc bath so that one side faces the steel plate between the snout and the sink roll and the other side faces the steel plate after passing through the sink roll. And having
The rectifying plate has a shape in which the shortest distance between the one surface and a steel plate facing the one surface gradually increases from the central portion of the one surface toward both ends in the horizontal direction. manufacturing device.   The rectifying plate is bent so that the shape of the one surface in a cross section perpendicular to the line connecting the points where the shortest distance from the steel plate facing the one surface is the shortest at each vertical position is convex toward the snout side. The apparatus for producing a hot dip galvanized steel sheet according to claim 1, wherein the apparatus is a shape or a curved shape. When the shape of the one surface is a bent shape, the bending angle θ1 of the one surface in a cross section perpendicular to the line is 5 degrees or more and 45 degrees or less,
The apparatus for producing a hot dip galvanized steel sheet according to claim 2, wherein, when the shape of the one surface is a curved shape, a radius of curvature R of the one surface in a cross section perpendicular to the line is 707 mm or more and 5737 mm or less.   The apparatus for producing a hot-dip galvanized steel sheet according to claim 2 or 3, wherein an angle θ2 opposite to the snout, which is formed by the line and the hot-dip zinc bath surface, is not less than 45 degrees and not more than 100 degrees.   The upper end of the one surface is located on the snout side with respect to the radial center of the sink roll, and a horizontal distance D1 between the upper end of the one surface and the radial center of the sink roll is 200 mm or more and 600 mm or less. The manufacturing apparatus of the hot dip galvanized steel plate as described in any one of -4.   The apparatus for producing a hot-dip galvanized steel sheet according to any one of claims 1 to 5, wherein a distance D2 between the upper end of the current plate and the hot-dip zinc bath surface is 0 mm or greater and 100 mm or less.   The apparatus for producing a hot-dip galvanized steel sheet according to any one of claims 1 to 6, wherein a shortest distance D3 between the lower end of the current plate and the sink roll is 50 mm or more and 300 mm or less.

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