Gas wiping nozzle and method for manufacturing molten metal coated metal strip

Abstract

The present invention provides a gas wiping nozzle and a method for manufacturing a molten metal-plated metal strip, which can uniformly maintain a gap in the width direction of a slit along the length direction even in a high-temperature atmosphere when the slit is divided along the length direction of the slit. In a gas wiping nozzle (10), a first nozzle member (11) and a second nozzle member (12) are each divided into two or more nozzle members (11A) to (11C) and (12A) to (12C) along the length direction X of a slit (14). When the thickness of the slit (14) of the first nozzle member (11) in the width direction Z is set to T1 and the thickness of the slit (14) of the second nozzle member (12) in the width direction Z is set to T2, the length of the dividing surface (20) in the cross section of each of the first nozzle member (11) and the second nozzle member (12) is 1.5T1 or more for the first nozzle member (11) and 1.5T2 or more for the second nozzle member (12).

Description

Technical Field

[0001] The present invention relates to a gas wiping nozzle for blowing gas onto a metal strip pulled up from a molten metal bath to adjust the amount of molten metal attached to the surface of the metal strip, and a method for producing a molten metal-coated metal strip using the gas wiping nozzle. Background Art

[0002] Hot-dip galvanized steel sheets, which are a type of molten metal-plated steel sheets, are widely used in the fields of building materials, automobiles, and home appliances. In addition, in these applications, hot-dip galvanized steel sheets are required to have excellent appearance. Here, since the appearance after coating is strongly affected by surface defects such as uneven coating thickness, flaws, and foreign matter adhesion, it is important that the hot-dip galvanized steel sheets do not have surface defects.

[0003] In a continuous molten metal coating production line, generally, a steel strip as a metal strip obtained by annealing in a continuous annealing furnace in a reducing atmosphere passes through a furnace snout and is introduced into a molten metal bath in a coating tank. Then, the steel strip is lifted above the molten metal bath via a sinking roller and a support roller in the molten metal bath. Then, a wiping gas is sprayed onto the surface of the steel strip from gas wiping nozzles arranged on both sides of the steel strip to scrape off the excess molten metal attached to the surface of the steel strip and lifted, thereby adjusting the amount of molten metal attached (hereinafter also referred to as unit area weight). Here, in order to cope with a variety of steel strip widths and to cope with positional deviations in the width direction when the steel strip is lifted, the gas wiping nozzle is generally constructed in a manner wider than the width of the steel strip and extends to the outside of the width direction end of the steel strip.

[0004] In such a gas wiping method, wavy water marks (also called hot metal sagging) are often produced on the surface of the coating layer due to the slight vibration of the steel strip caused by the blowing of the wiping gas and the irregular flow of the coating layer. When the coating layer surface is used as the coating base surface in the application of external coating, the surface properties, especially the smoothness, of the coating film are impaired, and the coating cannot be used for the external coating treatment that should be suitable for excellent appearance, which has a great impact on the yield of the plated steel sheet.

[0005] In order to solve this problem, a method disclosed in Patent Document 1 is conventionally known, for example.

[0006] In the continuous molten metal coating method disclosed in Patent Document 1, a steel strip is continuously immersed in a molten metal coating bath, and a gas is sprayed from a gas wiping nozzle onto the steel strip just pulled out of the molten metal coating bath to control the coating deposition amount. Then, the temperature T of the wiping gas sprayed from the gas wiping nozzle is controlled according to the D / B value represented by the ratio of the distance D between the front end of the gas wiping nozzle and the steel strip to the gap B of the gas wiping nozzle.

[0007] In addition, in the conventional gas wiping method, the edge of the steel strip is overcooled compared to the center during wiping, causing the steel strip to warp and the coating adhesion in the width direction to become uneven. Sometimes, a lot of zinc is wasted in order to ensure the lower limit of the zinc coating adhesion.

[0008] In order to solve this problem, a method disclosed in Patent Document 2, for example, has been conventionally known.

[0009] In the wiping method in continuous hot-dip galvanizing disclosed in Patent Document 2, when wiping gas is ejected from a gas wiping nozzle in continuous hot-dip galvanizing to wipe off the molten zinc adhering to the surface and back of the plated steel strip, the temperature of the wiping gas is set to T G The wiping gas is heated so that the following formula (1) is satisfied between the temperature (°C) and the plate thickness D (mm) of the plated steel strip.

[0010] Wiping gas temperature T G (℃)≥-400D+400…(1)

[0011] In addition, as a conventional gas wiping nozzle, for example, a gas wiping nozzle disclosed in Patent Document 3 is also known.

[0012] The gas wiping nozzle shown in Patent Document 3 sprays gas to the steel strip lifted upward from the molten metal coating bath to adjust the film thickness of the molten metal film attached to the surface of the steel strip. In addition, the gas wiping nozzle includes: a first lip and a second lip that are arranged opposite to each other and form a nozzle chamber into which the gas is introduced; a slit formed between the ends of the first lip and the second lip on the steel strip side as an injection port for the gas injected from the nozzle chamber; and a fixing member that is arranged on the slit side of the nozzle chamber and fixes the first lip and the second lip. In addition, a plurality of first connecting holes that connect the slit side with the opposite side of the slit relative to the fixing member are arranged side by side along the width direction of the steel strip.

[0013] According to the gas wiping nozzle disclosed in Patent Document 3, even when the components constituting the gas wiping nozzle are reassembled to replace part or all of the components, the gap between the assembled slits (hereinafter also referred to as slit gap) can be suppressed.

[0014] Prior art literature

[0015] Patent Literature

[0016] Patent Document 1: Japanese Patent No. 6011740

[0017] Patent Document 2: Japanese Patent Application Laid-Open No. 8-176776

[0018] Patent Document 3: Japanese Patent Application Publication No. 2018-178159 Summary of the invention

[0019] Problems to be solved by the invention

[0020] However, the conventional continuous molten metal coating method disclosed in Patent Document 1, the wiping method in continuous hot-dip galvanizing disclosed in Patent Document 2, and the gas wiping nozzle disclosed in Patent Document 3 have the following problems.

[0021] That is, in the case of the continuous molten metal plating method shown in Patent Document 1 and the wiping method in the continuous hot-dip galvanizing shown in Patent Document 2, the wiping gas is heated, and the surrounding of the gas wiping nozzle becomes a high-temperature atmosphere, but the gas wiping nozzle itself is also heated along with the heating of the wiping gas. Here, in Patent Documents 1 and 2, there is no description of whether the gas wiping nozzle is made in the form of an integral body or divided along the length direction of the slit as the gas injection port provided at the end of the steel strip side of the gas wiping nozzle. When making the gas wiping nozzle, it is sometimes difficult to make it in the form of an integral body due to the material of the gas wiping nozzle, and the gas wiping nozzle has to be divided along the length direction of the slit. In this case, when the gas wiping nozzle is divided along the length direction of the slit, if the surrounding of the gas wiping nozzle becomes a high-temperature atmosphere, there is a problem that the gap in the width direction orthogonal to the length direction of the slit as the gas injection port becomes uneven due to the assembly method of the gas wiping nozzle, and the coating adhesion amount of the steel strip along the width direction of the steel strip becomes uneven.

[0022] In addition, in the case of the gas wiping nozzle shown in Patent Document 3, since the first lip and the second lip are fixed to the slit side in the nozzle chamber by a fixing member, it is possible to suppress the deviation of the assembled slit gap of each assembly when part or all of the components constituting the gas wiping nozzle are replaced.

[0023] However, in the case of the gas wiping nozzle shown in Patent Document 3, the first lip and the second lip on the upper side are each manufactured as an integral body along the length direction of the slit as the gas injection port, and each of the first lip and the second lip is not manufactured separately along the length direction of the slit. Therefore, in the case of manufacturing each of the first lip and the second lip separately along the length direction of the slit, the same problem as the case of manufacturing the gas wiping nozzle separately along the length direction of the slit described above occurs.

[0024] Therefore, the present invention is completed to solve the above-mentioned existing problems, and its purpose is to provide a gas wiping nozzle and a method for manufacturing a molten metal-coated metal strip using the gas wiping nozzle. When the gas wiping nozzle is manufactured in a divided manner along the length direction of a slit serving as a gas injection port, even in a high-temperature atmosphere, the gap in the width direction orthogonal to the length direction of the slit can be uniformly maintained along the length direction of the slit, thereby making the coating adhesion amount of the steel strip along the width direction of the steel strip uniform.

[0025] Methods used to solve problems

[0026] In order to solve the above-mentioned problems, a gas wiping nozzle according to one embodiment of the present invention is a gas wiping nozzle that adjusts the amount of molten metal attached to the surface of the metal strip by blowing a wiping gas onto the metal strip lifted from a molten metal bath, wherein the gas wiping nozzle includes a first nozzle member and a second nozzle member, a slit serving as a gas injection port is formed between the first nozzle member and the second nozzle member at an end portion of the gas wiping nozzle on the metal strip side, the first nozzle member and the second nozzle member are each divided into two or more nozzle members in the longitudinal direction of the slit, and when the thickness of the first nozzle member in the width direction of the slit is set to T1 and the thickness of the second nozzle member in the width direction of the slit is set to T2, the length of the dividing surface of each of the first nozzle member and the second nozzle member in the cross section of each of the first nozzle member and the second nozzle member that is cut at least at one point in the depth direction orthogonal to the longitudinal direction of the slit along the longitudinal direction of the slit is 1.5T1 or more for the first nozzle member and 1.5T2 or more for the second nozzle member.

[0027] In addition, the essence of the method for manufacturing a molten metal-coated metal strip according to another embodiment of the present invention is to arrange a pair of the above-mentioned gas wiping nozzles on both sides of the metal strip lifted from the molten metal bath, spray wiping gas from the respective slits of the pair of gas wiping nozzles onto each side of the above-mentioned metal strip, adjust the amount of molten metal attached to the two sides of the above-mentioned metal strip, and continuously manufacture the molten metal-coated metal strip.

[0028] Effects of the Invention

[0029] According to the gas wiping nozzle and the method for manufacturing a molten metal-coated metal strip of the present invention, a gas wiping nozzle and a method for manufacturing a molten metal-coated metal strip using the gas wiping nozzle can be provided. When the gas wiping nozzle is manufactured in a divided manner along the length direction of a slit serving as a gas injection port, the gap in the width direction orthogonal to the length direction of the slit can be uniformly maintained along the length direction of the slit even in a high-temperature atmosphere, thereby making the amount of coating adhesion on the steel strip along the width direction of the steel strip uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram showing a schematic configuration of a continuous molten metal coating facility including a gas wiping nozzle according to an embodiment of the present invention.

[0031] Figure 2 It is shown in Figure 1 A perspective view showing a schematic structure of a gas wiping nozzle used in a continuous molten metal coating apparatus shown.

[0032] Figure 3 It is along Figure 2 Cross-sectional view along line AA.

[0033] Figure 4 It is along Figure 3 Cross-sectional view along line BB in FIG.

[0034] Figure 5 The gas wiping nozzle of the reference example is Figure 4 Same cross-section.

[0035] Figure 6 It is used to illustrate Figure 5 A cross-sectional view showing a case where a misalignment occurs between the dividing surfaces of the first nozzle member and the second nozzle member in the gas wiping nozzle of the reference example shown.

[0036] Figure 7 The gas wiping nozzle of the first modified example is Figure 4 Same cross-section.

[0037] Figure 8 The gas wiping nozzle of the second modified example is Figure 4 Same cross-section.

[0038] Fig. 9 The gas wiping nozzle of the third modified example is Figure 4 Same cross-section.

[0039] Fig.10 The gas wiping nozzle of the fourth modification is Figure 4 Same cross-section.

[0040] Fig.11 The gas wiping nozzle of the fifth modification is Figure 4 Same cross-section.

[0041] Fig.12 The gas wiping nozzle of the sixth modification is Figure 4 Same cross-section.

[0042] Fig.13 The gas wiping nozzle of the seventh modification example is Figure 4 Same cross-section.

[0043] Fig.14 The gas wiping nozzle of the eighth modification example is Figure 4 Same cross-section.

[0044] Fig.15 yes Fig.13 A schematic top view of a gas wiping nozzle according to a seventh variation is shown.

[0045] Fig.16 The gas wiping nozzle of the ninth modification example is Figure 4 Same cross-section.

[0046] Fig.17 Yes Fig.16 FIG. 1 is an enlarged view showing the groove portion of the first nozzle member, the groove portion of the second nozzle member, the spacer member, and the vicinity of the pin. DETAILED DESCRIPTION

[0047] The embodiments of the present invention are described below with reference to the drawings. The embodiments shown below illustrate devices and methods for implementing the technical concept of the present invention, and the technical concept of the present invention does not specify the material, shape, structure, arrangement, etc. of the components to the following embodiments.

[0048] In addition, the drawings are schematic, so it should be noted that the relationship and ratio of thickness and plane dimensions are different from the actual ones, and the drawings also include portions where the relationship and ratio of dimensions are different from each other.

[0049] exist Figure 1 Schematic diagram of a continuous molten metal coating facility including a gas wiping nozzle according to an embodiment of the present invention is shown in FIG.

[0050] Figure 1 The continuous molten metal coating equipment 1 shown is an equipment for immersing a steel strip S as a metal strip in a molten metal bath 4 composed of molten metal to continuously adhere molten metal to the surface of the steel strip S and to adjust the molten metal to a predetermined adhesion amount.

[0051] The continuous hot-dip metal coating equipment 1 includes a nose 2 , a coating tank 3 , a sink roll 5 , and a backup roll 6 .

[0052] The furnace nose 2 is a member having a rectangular cross section perpendicular to the running direction of the steel strip S and partitioning the space through which the steel strip S passes, and its upper end is connected to, for example, the outlet side of the continuous annealing furnace, and its lower end is immersed in the molten metal bath 4 stored in the coating tank 3. In the present embodiment, the steel strip S annealed in the continuous annealing furnace in a reducing atmosphere passes through the furnace nose 2 and is continuously introduced into the molten metal bath 4 in the coating tank 3. Then, the steel strip S is lifted from the molten metal bath 4 to the upper side thereof via the sinking roller 5 and the support roller 6 in the molten metal bath 4.

[0053] Then, wiping gas is sprayed from a pair of gas wiping nozzles 10 (slits 14 described later) to both sides of the steel strip S lifted from the molten metal bath 4, thereby adjusting the amount of molten metal attached to both sides of the steel strip S. The pair of gas wiping nozzles 10 are arranged on both sides of the steel strip S. Then, the steel strip S is cooled by a cooling device (not shown) and guided to the next step, and the molten metal-coated strip S is continuously manufactured.

[0054] Here, if Figure 2 As shown in FIG. 1 , a pair of gas wiping nozzles 10 disposed on both sides of the steel strip S each include a nozzle manifold 15, a first nozzle member 11 disposed on the upper side connected to the nozzle manifold 15, and a second nozzle member 12 disposed on the lower side. The first nozzle member 11 and the second nozzle member 12 are disposed opposite to each other, and a slit 14 as a gas injection port is formed between the inclined ends (ends) 11c and 12c on the steel strip S side of each of the first nozzle member 11 and the second nozzle member 12 in a manner extending slenderly in the longitudinal direction X. Moreover, each gas wiping nozzle 10 is disposed on each side of the steel strip S in such a manner that the longitudinal direction X of the slit 14 is along the plate width direction of the steel strip S, the width direction Z orthogonal to the longitudinal direction X of the slit 14 is along the plate length direction (conveying direction) of the steel strip S, and the depth direction Y orthogonal to the longitudinal direction X of the slit 14 is along the plate thickness direction of the steel strip S. The width direction Z of the slit is the same direction as the up-down direction of the gas wiping nozzle 10. Furthermore, the wiping gas is sprayed from the slit 14 of one gas wiping nozzle 10 to one surface of the steel strip S. In addition, the wiping gas is sprayed from the slit 14 of the other gas wiping nozzle 10 to the other surface of the steel strip S. As a result, the excess molten metal is scraped off on both surfaces of the steel strip S, and the amount of coating (molten metal) is adjusted and uniformed in the plate width direction and plate length direction of the steel strip S. In order to cope with various plate widths of the steel strip S and to cope with positional deviation in the width direction when the steel strip S is lifted, etc., each gas wiping nozzle 10 is configured so that the length of the slit 14 is longer than the plate width of the steel strip S and extends to the outside of the end of the steel strip S in the width direction.

[0055] Here, the nozzle manifold 15 of each gas wiping nozzle 10 is formed in a substantially rectangular shape extending in the length direction X, the depth direction Y, and the width direction Z, and is made of metal such as chrome-molybdenum steel. In addition, at the base end (rear end) of the nozzle manifold 15, a gas supply path 16 is formed that is connected to the gas supply pipe 17 and connects the gas supply pipe 17 to the hollow portion 13 described later.

[0056] In addition, the first nozzle member 11 disposed on the upper side will be described in detail later. Figure 2As shown in FIG. 1 , the slit 14 is divided into two or more (three in this embodiment) nozzle members 11A, 11B, and 11C by two or more dividing surfaces 20 along the length direction X of the slit 14. Figure 2 to Figure 4 As shown in the figure, each nozzle member 11A, 11B, 11C includes a flat plate portion 11a extending with a predetermined thickness T1 in the length direction X and the depth direction (front-rear direction) Y, a flange portion 11b protruding upward from the rear end of the flat plate portion 11a, and the above-mentioned inclined end portion 11c extending obliquely downward from the front end of the flat plate portion 11a. A hollow portion forming space 13a is formed on the lower side of the flat plate portion 11a of each nozzle member 11A, 11B, 11C to form a hollow portion described later.

[0057] In addition, the second nozzle member 12 disposed on the lower side is also Figure 2 As shown in FIG. 1 , the slit 14 is divided into two or more (three in this embodiment) nozzle components 12A, 12B, and 12C by two or more dividing surfaces 20 along the length direction X of the slit 14. Figure 2 to Figure 4 As shown in the figure, each nozzle member 12A, 12B, 12C includes a flat plate portion 12a extending with a predetermined thickness T2 in the length direction X and the depth direction (front-rear direction) Y, a flange portion 12b protruding downward from the rear end of the flat plate portion 12a, and the above-mentioned inclined end portion 12c extending obliquely upward from the front end of the flat plate portion 12a. On the upper side of the flat plate portion 12a of each nozzle member 12A, 12B, 12C, a hollow portion forming space 13b is formed to form a hollow portion described later.

[0058] Furthermore, the first nozzle member 11 and the second nozzle member 12 are fixed by a gasket member 30 described later so as to be matched with each other in the upper and lower parts, and the rear end surface 11ba of the flange portion 11b of the first nozzle member 11 and the rear end surface 12ba of the flange portion 12b of the second nozzle member 12 are respectively connected to the front surface of the nozzle manifold 15. Thus, the hollow portion 13 is formed by the hollow portion forming space 13a formed in the first nozzle member 11 and the hollow portion forming space 13b formed in the second nozzle member 12.

[0059] Furthermore, the lower surface of the inclined end 11c of the first nozzle member 11 on the steel strip S side and the upper surface of the inclined end 12c of the second nozzle member 12 on the steel strip S side form opposing planes, and the slit 14 as the gas injection port described above is formed between these planes. As described above, the slit 14 extends elongated in the longitudinal direction X, and the length in the longitudinal direction X is L1 (refer to Figure 2 ), the width in the width direction Z perpendicular to the length direction X, i.e. the gap is L3 (refer to Figure 3 ), the depth in the depth direction Y perpendicular to the length direction X is L2 (refer to Figure 3). The size of the slit 14 is not particularly limited, and the length L1 of the slit 14 can be set with a margin according to the width of the steel strip S, and can be set to, for example, about 1500 mm to about 2500 mm. In addition, the gap L3 of the slit 14 can be set to, for example, about 0.5 mm to about 3.0 mm. In addition, the depth L2 of the slit 14 can be set to, for example, about 5 mm to about 30 mm.

[0060] Here, the slit 14 communicates with the hollow portion 13 in the depth direction Y. The hollow portion 13 functions as a pressure equalizing portion, and the wiping gas introduced into the hollow portion 13 from the gas supply pipe 17 through the gas supply path 16 is sprayed at a uniform pressure over the entire range of the slit 14 in the length direction X.

[0061] In addition, if Figure 2 to Figure 4 As shown, each gas wiping nozzle 10 includes a pair of spacer members 30 for adjusting a gap L3 in a width direction Z that is orthogonal to a longitudinal direction X of the slit 14 .

[0062] These spacer members 30 also have the function of fixing the first nozzle member 11 and the second nozzle member 12. In order to fix the first nozzle member 11 and the second nozzle member 12 by using these spacer members 30, the first nozzle member 11 and the second nozzle member 12, specifically, the nozzle members 11A, 11C and the nozzle members 12A, 12C are each as shown in FIG. Figure 4 The illustrated embodiment has grooves 28 and 29 into which these spacer members 30 are inserted.

[0063] In addition, the first nozzle member 11, the second nozzle member 12 and each gasket member 30 use a ceramic material, a carbon material, a carbon fiber reinforced carbon composite material or a ceramic matrix composite material that has low wettability to molten metals such as molten zinc, is difficult to plastically deform and has a low linear expansion coefficient. Specifically, as ceramic materials, aluminum oxide, silicon aluminum oxide nitrogen ceramics (SiAlON), silicon nitride, zirconium oxide, barium titanate, hydroxyapatite, silicon carbide (SiC), fluorite, etc. can be listed, and as carbon materials, graphite can be listed, but it is not limited to these. In addition, graphite will oxidize and volatilize in a highly oxidizing atmosphere, so it is preferred to apply silicon dioxide or the like on the surface.

[0064] It should be noted that since Invar and tungsten have low linear expansion coefficients but undergo plastic deformation, they are not suitable as the material for the first nozzle component 11, the second nozzle component 12 and each gasket component 30, especially as the material for each gasket component 30.

[0065] Here, as ceramic materials, carbon materials, carbon fiber reinforced carbon composite materials or ceramic matrix composite materials, preferably the bending strength is 600MPa or more, more preferably 800MPa or more. Therefore, as ceramic materials, preferably zirconium oxide, silicon nitride, silicon aluminum oxynitride ceramics, etc. are used. If these materials are used, plastic deformation is difficult, and as long as the fracture strength is below, substantial deformation can be suppressed.

[0066] In addition, when zinc adheres to the first nozzle member 11 and the second nozzle member 12 and blocks the slit 14 during actual machine operation, the amount of zinc adhesion locally increases at this location, causing linear defects on the steel strip S in the same direction as the traveling direction of the steel strip S. Therefore, the zinc attached to the first nozzle member 11 and the second nozzle member 12 is removed using a special fixture. At this time, if the hardness of the nozzle surface is low, cracks and defects may occur. In order to avoid such cracks and defects, the Vickers hardness of the ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material is preferably 800Hv or more, more preferably 1000Hv or more. For the same reason, the fracture toughness of the ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material is preferably 5MPa·m 1 / 2 above.

[0067] In addition, when using high-temperature gas as the wiping gas, cracks may occur if the thermal shock resistance of the nozzle material is below the temperature of the high-temperature gas. The thermal shock resistance of the ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material is preferably above the temperature used as the wiping gas, preferably a material with a thermal shock resistance of 430°C or above, and more preferably a material with a thermal shock resistance of 600°C or above.

[0068] In addition, from the viewpoint of suppressing deformation of the nozzle due to heat, the linear expansion coefficient of the first nozzle member 11 (nozzle members 11A, 11B, 11C) and the second nozzle member 12 (nozzle members 12A, 12B, 12C) is preferably 1 / 2 or less, more preferably 1 / 3 or less, of the linear expansion coefficient of the nozzle manifold 15 fixed to these first nozzle members 11 and second nozzle members 12. As the material of the nozzle manifold 15, for example, stainless steel is used, and its linear expansion coefficient is about 10×10 -6 / K~approx.18×10 -6 / K.

[0069] When manufacturing the first nozzle member 11 and the second nozzle member 12, if ceramic is selected as a material that is not easily plastically deformed, it is generally difficult to manufacture a nozzle width of more than 1500 mm in an integrated form due to restrictions such as the size of a furnace for sintering the ceramic.

[0070] In addition, when manufacturing the first nozzle component 11 and the second nozzle component 12, even if carbon material is selected as a material that is not easily plastically deformed, it is generally difficult to manufacture a nozzle width of more than 1500 mm in the form of an integrated body due to reasons such as the size restrictions of the mold used in forming.

[0071] Furthermore, when manufacturing the first nozzle member 11 and the second nozzle member 12, even when carbon fiber reinforced carbon composite materials and ceramic-based composite materials are selected, it is generally difficult to manufacture a nozzle width of more than 1500 mm in an integrated form due to the limitations of the furnace for forming.

[0072] Therefore, when ceramic materials, carbon materials, carbon fiber reinforced carbon composite materials or ceramic-based composite materials are selected to manufacture the first nozzle component 11 and the second nozzle component 12, as described above, the first nozzle component 11 is divided into two or more (three in the present embodiment) nozzle components 11A, 11B, 11C by two or more dividing surfaces 20 along the length direction X of the slit 14, and the second nozzle component 12 is divided into two or more (three in the present embodiment) nozzle components 12A, 12B, 12C by two or more dividing surfaces 20 along the length direction X of the slit 14.

[0073] Furthermore, in this embodiment, if Figure 4 As shown, the length (D1+D2+D3) of the dividing surface 20 of the first nozzle member 11 and the second nozzle member 12 in their respective cross sections, which are cut off at least at one point in the depth direction Y orthogonal to the length direction X of the slit 14 along the length direction X of the slit 14, is greater than 1.5T1 for the first nozzle member 11 and greater than 1.5T2 for the second nozzle member 12, when the thickness of the slit 14 in the width direction Z of the first nozzle member 11 is set to T1 and the thickness of the slit 14 in the width direction Z of the second nozzle member 12 is set to T2.

[0074] It should be noted that, when the thickness of the slit 14 of the first nozzle member 11 in the width direction Z is T1 and the thickness of the slit 14 of the second nozzle member 12 in the width direction Z is T2, T1 and T2 may be the same thickness or different thicknesses.

[0075] The reason why the length of the dividing surface 20 is set to be 1.5T1 or 1.5T2 or more will be described below.

[0076] When the first nozzle member 11 and the second nozzle member 12 are divided into two or more nozzle members 11A, 11B, 11C; 12A, 12B, 12C by two or more dividing surfaces 20 along the length direction X of the slit 14, the following method is considered: Figure 5 As shown, the shape of the dividing surface 20 is a straight line parallel to the nozzle thickness direction (width direction Z of the slit 14), and its length is the same as the thickness of the slit 14 in the width direction Z of the first nozzle component 11 and the second nozzle component 12, and an adhesive is applied to the dividing surface 20 to combine them.

[0077] However, in this method, the nozzle members 11B and 12B at the center of the longitudinal direction X of the slit 14 that are not fixed by the pair of spacer members 30 in the upper and lower directions are not fixed in the width direction ( Figure 1 The force in the Z direction is weak, such as Figure 6 As shown in FIG. 1 , the split surface 20 is offset 31 in the direction of the gap expansion of the slit 14 due to thermal deformation when the high-temperature gas is ejected. In addition, the split surface 20 is offset 31 due to nozzle cleaning to remove zinc blocking the slit 14 and the influence of the internal pressure of the gas. Due to this offset 31, as shown in FIG. Figure 6 As shown in FIG. 1 , the shape of the hollow portion 13 changes, and the shape of the gap of the slit 14 changes in the nozzle width direction. If the shape of the gap of the slit 14 is different, the amount of gas ejected in the longitudinal direction X of the slit 14 is different, and the wiping ability in the longitudinal direction X of the slit 14 is different. As a result, the coating adhesion amount of the steel strip S along the width direction of the steel strip S cannot be made uniform. In addition, as Figure 6 As shown in FIG. 1 , if the gap of the slit 14 is enlarged, the probability of zinc splashed by the wiping gas invading the slit 14 increases. As a result, linear unevenness in the amount of zinc deposited (linear marks) is likely to occur, which is caused by clogging of the slit 14.

[0078] In order to solve this problem, it is necessary to prevent the nozzle members 11B and 12B in the center of the slit 14 in the longitudinal direction X from deforming in the width direction Z of the slit 14, that is, to strengthen the fastening force of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C. Figure 4 As shown, with respect to the length (D1+D2+D3) of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 in each cross section of the first nozzle member 11 and the second nozzle member 12 cut at least at one point in the depth direction Y along the length direction X of the slit 14, when the thickness of the slit 14 of the first nozzle member 11 in the width direction Z (the thickness of the flat plate portion 11a) is set to T1 and the thickness of the slit 14 of the second nozzle member 12 in the width direction Z (the thickness of the flat plate portion 12a) is set to T2, the length is 1.5T1 or more for the first nozzle member 11 and is 1.5T2 or more for the second nozzle member 12.

[0079] Here, in Figure 4In the embodiment, the shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is a shape having a step 20b. That is, each dividing surface 20 of the first nozzle member 11 includes a first straight portion 20a extending linearly downward from the upper surface of the first nozzle member 11 (flat portion 11a), a step 20b extending linearly outward from the lower end of the first straight portion 20a in the longitudinal direction X of the slit 14, and a second straight portion 20c extending linearly downward from the front end of the step 20b toward the lower surface of the first nozzle member 11 (flat portion 11a). In addition, each dividing surface 20 of the second nozzle member 12 includes a first straight line portion 20a extending straightly upward from the lower surface of the second nozzle member 12 (flat plate portion 12a), a step difference 20b extending straightly outward from the upper end of the first straight line portion 20a in the longitudinal direction X of the slit 14, and a second straight line portion 20c extending straightly upward from the front end of the step difference 20b toward the upper surface of the second nozzle member 12 (flat plate portion 12a).

[0080] Moreover, the length obtained by adding the length D1 of the first straight portion 20a of each dividing surface 20, the length D2 of the step 20b, and the length D3 of the second straight portion 20c ((D1+D2+D3)) is greater than 1.5T1 for the first nozzle component 11 and greater than 1.5T2 for the second nozzle component 12.

[0081] Here, when the length (D1+D2+D3) of each dividing surface 20 is less than 1.5T1 or 1.5T2, the shape of the dividing surface 20 is close to Figure 5 In the case shown, the nozzle members 11B and 12B in the center portion of the slit 14 in the longitudinal direction X are easily moved in the width direction Z of the slit 14, and it is difficult to exert the effect of processing into the shape having the step 20 b.

[0082] On the other hand, when the length (D1+D2+D3) of each split surface 20 is greater than 5T1 or 5T2, the effect of improving the fastening force of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C is saturated, and further, if the length of each split surface 20 is too long, cracks may be generated. Therefore, it is preferred that the upper limit of the length of the split surface 20 of the first nozzle member 11 is 5T1, and the upper limit of the length of the split surface 20 of the second nozzle member 12 is 5T2.

[0083] It should be noted that in order to make the length of each dividing surface 20 greater than 1.5T1 or 1.5T2, Figure 7As in the gas wiping nozzle 10 of the first modified example shown in the figure, the shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is a tapered shape inclined relative to the width direction Z (vertical direction) of the slit 14. In this case, the dividing surface 20 is inclined so that the length E1 of each dividing surface 20 is 1.5T1 or more for the first nozzle member 11 and 1.5T2 or more for the second nozzle member 12. On the other hand, even in this case, the upper limit of the length E1 of each dividing surface 20 is preferably 5T1 or 5T2.

[0084] Here, in Figure 4 and Figure 7 In the case shown, the gap of the slit 14 generally tends to expand due to the internal pressure of the gas and the influence of heat, and therefore the nozzle division is designed with the idea of ​​suppressing the expansion of the gap of the slit 14.

[0085] On the other hand, the narrowing of the gap of the slit 14 may become a problem. In this case, by making the shape of the dividing surface 20 as Figure 8 or Fig. 9 The shape shown can prevent the gap of the slit 14 from being reduced.

[0086] exist Figure 8 FIG. 2 shows a cross section of a gas wiping nozzle according to a second modified example. The shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is similar to that of FIG. Figure 4 The shapes of the dividing surfaces 20 shown are symmetrical. That is, each dividing surface 20 of the first nozzle member 11 includes a first straight portion 20a extending linearly downward from the upper surface of the first nozzle member 11 (flat portion 11a), a step 20b extending linearly inward from the lower end of the first straight portion 20a in the longitudinal direction X of the slit 14, and a second straight portion 20c extending linearly downward from the front end of the step 20b toward the lower surface of the first nozzle member 11 (flat portion 11a). In addition, although Figure 8 Although there is no symbol recorded in the figure, each dividing surface 20 of the second nozzle member 12 also includes a first straight line portion 20a extending straightly upward from the lower surface of the second nozzle member 12 (flat plate portion 11a), a step difference 20b extending straightly inward from the upper end of the first straight line portion 20a in the length direction X of the slit 14, and a second straight line portion 20c extending straightly upward from the front end of the step difference 20b toward the upper surface of the second nozzle member 12 (flat plate portion 12a).

[0087] Moreover, the length obtained by adding the length D1 of the first straight portion 20a of each dividing surface 20, the length D2 of the step 20b, and the length D3 of the second straight portion 20c ((D1+D2+D3)) is greater than 1.5T1 for the first nozzle component 11 and greater than 1.5T2 for the second nozzle component 12.

[0088] In addition, Fig. 9 FIG. 2 shows a cross section of a gas wiping nozzle according to a third modified example. The shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is similar to that shown in FIG. Figure 7 The shapes of the dividing surfaces 20 of the first nozzle member 11 and the second nozzle member 12 in the gas wiping nozzle 10 of the first modified example shown are symmetrical.

[0089] In addition, when the first nozzle member 11 and the second nozzle member 12 are each divided into two or more parts along the longitudinal direction X of the slit 14 by two or more dividing surfaces 20, Figure 4 The situation shown (split into 3) is different, and can be Fig.10 As in the fourth modified example shown in FIG. 1 , the gas wiping nozzle is divided into four nozzle members 11A, 11B, 11C, and 11D; and 12A, 12B, 12C, and 12D.

[0090] In order to make the length of each dividing surface 20 greater than 1.5T1 or 1.5T2, Fig.10 As in the gas wiping nozzle of the fourth modified example shown, the shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is a fitting surface shape in which the concave surface 20d and the convex surface 20e of the adjacent nozzle members 11A, 11B; 11B, 11C; 11C, 11D; 12A, 12B; 12B, 12C; 12C, 12D after the division are fitted. Taking the adjacent nozzle members 11A and 11B after the division as an example, the shape of the dividing surface 20 is a key-shaped shape in which the concave surface 20d formed on the nozzle member 11A and the convex surface 20e formed on the nozzle member 11B are fitted.

[0091] exist Fig.10In the gas wiping nozzle 10 of the fourth modified example shown, the lengths of the respective dividing surfaces 20 are the same length, and the length of the dividing surface 20 formed on the first nozzle member 11 will be described. The length of the dividing surface 20 is the sum of the length F1 of the first straight-line portion extending linearly downward from the upper surface of the first nozzle member 11 (flat plate portion 11a), the length F2 of the second straight-line portion extending linearly outward from the lower end of the first straight-line portion in the longitudinal direction X of the slit 14, the length F3 of the third straight-line portion extending linearly downward from the front end of the second straight-line portion, the length F4 of the fourth straight-line portion extending linearly inward from the lower end of the third straight-line portion in the longitudinal direction X of the slit 14, and the length F5 of the fifth straight-line portion extending linearly downward from the front end of the fourth straight-line portion toward the lower surface of the first nozzle member 11 (flat plate portion 11a).

[0092] In this way, by making the shape of the dividing surface 20 of each of the first nozzle component 11 and the second nozzle component 12 a mating surface shape, the fastening force of each nozzle component 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D can be made stronger, and even if an external force that causes the gap of the slit 14 to expand or shrink acts on the dividing surface 20, the expansion or shrinkage of the gap can be appropriately avoided.

[0093] It should be noted that, in order to make the shape of each division surface 20 a fitting surface shape, it may be made into a U-shape.

[0094] In order to make the length of each dividing surface 20 greater than 1.5T1 or 1.5T2, Fig.11 As in the gas wiping nozzle of the fifth modified example shown, the shape of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is made so that the adjacent nozzle members 11A, 11B; 11B, 11C; 11C, 11D; 12A, 12B; 12B, 12C; 12C, 12D after division fit together.

[0095] exist Fig.11 In the gas wiping nozzle 10 of the fifth modified example shown in FIG. Figure 4 The gas wiping nozzle 10 shown is similarly a length (D1+D2+D3) obtained by adding the length D1 of the first straight portion 20a, the length D2 of the step difference 20b, and the length D3 of the second straight portion 20c, which is greater than 1.5T1 for the first nozzle component 11 and greater than 1.5T2 for the second nozzle component 12. Fig.11 The gas wiping nozzle 10 of the fifth modified example shown is an example in which the nozzle is divided into four parts, but in the case of dividing the nozzle into five parts, the nozzle can be made into a nozzle having a plurality of parts. Fig.12 The structure of the gas wiping nozzle 10 of the sixth modified example shown.

[0096] In addition, in order to improve the fastening force of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C, it is possible to Fig.13 The gas wiping nozzle of the seventh modification shown or Fig.14 As in the gas wiping nozzle of the eighth modified example shown in FIG. 1 , the pin 32 is used to connect the divided nozzle members 11A, 11B, 11B, and 11C of the first nozzle member 11 and the divided nozzle members 12A, 12B, 12B, and 12C of the second nozzle member 12. Thus, the fastening force between the divided nozzle members 11A, 11B; 11B, 11C; 12A, 12B; 12B, and 12C can be further improved.

[0097] Here, the cross-sectional shape of the pin 32 may be rectangular or circular. Fig.13 In the gas wiping nozzle of the seventh modification shown, when the pin 32 is inserted into the step 20b of the dividing surface 20 along the width direction Z of the slit 14, the width of the pin 32 in the slit length direction X must be smaller than the length D2 of the step 20b.

[0098] In addition, Fig.14 In the gas wiping nozzle of the eighth variant shown, when the pin 32 is inserted into the tapered dividing surface 20 along the width direction Z of the slit 14, the width of the pin 32 in the slit length direction X must be smaller than the width between the front end and the rear end of the tapered dividing surface 20.

[0099] In addition, Fig.13 The gas wiping nozzle and Fig.14 In the gas wiping nozzle of the eighth modified example shown in FIG. Fig.15 As shown, when the pins 32 are inserted, the pins 32 can be inserted in any number and at any position in the slit length direction X and the slit depth direction Y.

[0100] Next, refer to Figure 1 to Figure 4 A method of fixing the first nozzle member 11 and the second nozzle member 12 will be described.

[0101] First, the first nozzle member 11 and the second nozzle member 12 are assembled. Before the first nozzle member 11 and the second nozzle member 12 are assembled, the groove 28 is formed by groove processing the nozzle members 11A and 11C of the first nozzle member 11 from the rear end surface 11ba, and the groove 29 is formed by groove processing the nozzle members 12A and 12C of the second nozzle member 12 from the rear end surface 12ba.

[0102] When assembling the first nozzle member 11, the adjacent nozzle members 11A and 11B are aligned at the dividing surface 20, and a ceramic adhesive is applied to fix the adjacent nozzle members 11A and 11B. Also, the adjacent nozzle members 11B and 11C are aligned at the dividing surface 20, and a ceramic adhesive is applied to fix the adjacent nozzle members 11B and 11C. Thus, the assembly of the first nozzle member 11 is completed.

[0103] In addition, when assembling the second nozzle member 12, the adjacent nozzle members 12A and 12B are aligned at the dividing surface 20, and a ceramic adhesive is applied to fix the adjacent nozzle members 12A and 12B. In addition, the adjacent nozzle members 12B and 12C are aligned at the dividing surface 20, and a ceramic adhesive is applied to fix the adjacent nozzle members 12B and 12C. Thus, the assembly of the second nozzle member 12 is completed. It should be noted that as the adhesive used in the assembly of the first nozzle member 11 and the second nozzle member 12, an adhesive with zirconium oxide and silicon dioxide as the main component, an adhesive with aluminum oxide as the main component, an adhesive with silicon dioxide as the main component, etc. can be listed, but it is not limited to this.

[0104] Then, the assembled first nozzle member 11 is arranged on the upper side, the assembled second nozzle member 12 is arranged on the lower side, and the spacer member 30 is respectively embedded in the groove 28 of the first nozzle member 11 and the groove 29 of the second nozzle member 12 from the rear end surfaces 11ba and 12ba of the first nozzle member 11 and the second nozzle member 12 in a direction parallel to the direction in which the grooves 28 and 29 extend. At this time, the same adhesive material as described above is applied to the groove 28 of the first nozzle member 11 and the groove 29 of the second nozzle member 12, respectively.

[0105] Thereby, the first nozzle member 11 and the second nozzle member 12 are fixed.

[0106] Then, the fixed rear end surface 11 ba of the first nozzle member 11 and the rear end surface 12 ba of the second nozzle member 12 are connected to the front end surface of the nozzle manifold 15 by fixing members such as screws (not shown).

[0107] When the gas wiping nozzle 10 of the present embodiment is placed in a high temperature atmosphere and high temperature gas is ejected from the slit 14, the dividing surface 20 is offset in the direction in which the gap L3 of the slit 14 is enlarged due to thermal deformation at this time. Figure 4As shown, the length (D1+D2+D3) of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 in the cross section of each of the first nozzle member 11 and the second nozzle member 12 cut along the longitudinal direction X of the slit 14 is 1.5T1 or more for the first nozzle member 11 and 1.5T2 or more for the second nozzle member 12, when the thickness of the slit 14 in the width direction Z (thickness of the flat plate portion 11a) of the first nozzle member 11 is set to T1 and the thickness of the slit 14 in the width direction Z (thickness of the flat plate portion 12a) of the second nozzle member 12 is set to T2. Therefore, the deformation of the nozzle members 11B and 12B in the central part of the slit 14 in the longitudinal direction X to the width direction Z of the slit 14 is prevented, that is, the fastening force of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C is strengthened. As a result, the gap L3 of the slit 14 does not deviate in the direction of expansion of the dividing surface 20 due to thermal deformation, and the gap L3 in the width direction Z orthogonal to the length direction X of the slit 14 can be uniformly maintained along the length direction X of the slit 14. As a result, the amount of gas ejected in the length direction X of the slit 14 becomes uniform, and there is no difference in wiping ability in the length direction X of the slit 14, and the amount of coating adhesion of the steel strip S along the width direction of the steel strip S can be made uniform.

[0108] In addition, according to the gas wiping nozzle 10 of the present embodiment, the upper limit of the length (D1+D2+D3) of the split surface 20 of the first nozzle member 11 is 5T1, and the upper limit of the length (D1+D2+D3) of the split surface 20 of the second nozzle member 12 is 5T2. Thus, cracks in the nozzle members 11A, 11B, 11C; 12A, 12B, 12C constituting the first nozzle member 11 and the second nozzle member 12 can be prevented.

[0109] In addition, Figure 2 In the embodiment, if the length of the dividing surface 20 can be ensured to be 1.5T1 or 1.5T2 or more at least in one place in the depth direction Y of each of the first nozzle member 11 and the second nozzle member 12, the gap of the slit 14 can be kept constant. However, under such conditions, cracks may occur in the first nozzle member 11 (nozzle members 11A, 11B, 11C) and the second nozzle member 12 (nozzle members 12A, 12B, 12C). In order to suppress the cracks, the region in the depth direction Y where the length of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 is 1.5T1 or more for the first nozzle member 11 and 1.5T2 or more for the second nozzle member 12 is preferably the total length L in the depth direction of each of the first nozzle member 11 and the second nozzle member 12 (refer to Figure 3 ), and more preferably, an area equal to the total length L.

[0110] In addition, in the gas wiping nozzle 10 of the present embodiment, the first nozzle member 11, the second nozzle member 12 and the spacer member 30 are all made of ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material, and therefore, the linear expansion coefficient is small and there is no difference in the linear expansion coefficient between each other. Therefore, even in a high temperature atmosphere, the gap L3 in the width direction orthogonal to the longitudinal direction X of the slit 14 as the gas injection port can be uniformly maintained along the longitudinal direction X of the slit.

[0111] Here, if the nozzle manifold 15 is also made of ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material, it will be more effective in uniformly maintaining the gap L3 of the slit 14. However, since it is difficult to make a ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material that can withstand high-pressure wiping gas (at least 60 kPa), the nozzle manifold 15 is not made of ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material.

[0112] In addition, in the case of the gas wiping nozzle shown in Patent Document 3, since the first lip and the second lip are fixed to the slit side in the nozzle chamber by a fixing member, it is possible to suppress the deviation of the slit gap after assembly when part or all of the components constituting the gas wiping nozzle are replaced.

[0113] However, since the fixing components for fixing the upper and lower nozzle components in the gas wiping nozzle shown in Patent Document 3 and the bolts used to fix the fixing components are made of metal, there is the following problem: the fixing components, bolts, etc. will stretch in a high-temperature atmosphere, thereby changing the slit gap and failing to maintain the slit gap uniformly along the length direction of the slit.

[0114] In contrast, in the gas wiping nozzle 10 of the present embodiment, not only the first nozzle member 11 and the second nozzle member 12 are made of a ceramic material, a carbon material, a carbon fiber reinforced carbon composite material, or a ceramic matrix composite material, but also the spacer member 30 is made of a ceramic material, a carbon material, a carbon fiber reinforced carbon composite material, or a ceramic matrix composite material, and the spacer member 30 also has a function of fixing the first nozzle member 11 and the second nozzle member 12. Therefore, there is no member for fixing the first nozzle member 11 and the second nozzle member 12 that acts in a manner of expanding the gap L3 of the slit 14 in a high temperature atmosphere. The spacer member 30 is a material that is difficult to plastically deform, and therefore, even in a high temperature atmosphere, the gap L3 of the slit 14 as the gas injection port can be uniformly maintained along the longitudinal direction X of the slit 14.

[0115] In addition, the gasket member 30 is not provided with the function of fixing the first nozzle member 11 and the second nozzle member 12, and the first nozzle member 11 and the second nozzle member 12 of the ceramic material are fixed by metal bolts. In this case, it is necessary to open bolt holes in the first nozzle member 11 and the second nozzle member 12 of the ceramic material, and screw the metal bolts into the bolt holes. In this case, due to the torque and thermal expansion when the metal bolts are screwed in, the first nozzle member 11 and the second nozzle member 12 of the ceramic material may be damaged.

[0116] In contrast, in the gas wiping nozzle 10 of the present embodiment, not only the first nozzle member 11 and the second nozzle member 12 are made of a ceramic material, a carbon material, a carbon fiber reinforced carbon composite material, or a ceramic matrix composite material, but also the gasket member 30 is made of a ceramic material, a carbon material, a carbon fiber reinforced carbon composite material, or a ceramic matrix composite material, and the gasket member 30 also has a function of fixing the first nozzle member 11 and the second nozzle member 12. Therefore, the first nozzle member 11 and the second nozzle member 12 will not be damaged due to torque or thermal expansion when the metal bolt is screwed in.

[0117] Next, refer to Fig.16 and Fig.17 A gas wiping nozzle according to a ninth modified example will be described.

[0118] Fig.16 and Fig.17 The gas wiping nozzle 10 shown is Figure 4 The basic structure of the gas wiping nozzle 10 shown is the same as that of the present invention, but the pin 33 is used to connect the groove 28 of the first nozzle member 11 and the spacer member 30, and the pin 33 is used to connect the groove 29 of the second nozzle member 12 and the spacer member 30. Figure 4 The gas wiping nozzle 10 shown is different.

[0119] Fig.16 and Fig.17 The groove 28 of the first nozzle member 11 and the groove 29 of the second nozzle member 12 are each rectangular in cross section. Figure 3 ) extends forward. In addition, the groove portion 29 of the second nozzle member 12 extends from the rear end surface 12ba (refer to Figure 3 ) extends forward. In addition, the corner 28a in the groove 28 and the corner 29a in the groove 29 can be formed in an arc shape. Thereby, the concentration of stress can be prevented, and the damage of the gasket member 30 can be prevented.

[0120] In addition, the spacer member 30 is in the shape of a rectangular parallelepiped, and its cross-sectional shape is a shape that is inserted into the groove portion 28 of the first nozzle member 11 and the groove portion 29 of the second nozzle member 12. Fig.17 As shown, the width C1 of the spacer member 30 corresponding to the width of the grooves 28 and 29 is about 5 mm to about 20 mm, and the height C2 of the spacer member 30 is about 5 mm to about 40 mm.

[0121] Furthermore, when the first nozzle member 11 and the second nozzle member 12 are fixed, the gasket member 30 is inserted into each of the groove 28 of the first nozzle member 11 and the groove 29 of the second nozzle member 12. In addition, two or more pins 33 are used to connect the groove 28 of the first nozzle member 11 and the gasket member 30, and the groove 29 of the second nozzle member 12 and the gasket member 30. In this way, in the seventh modified example, the gasket member 30 can be inserted before the first nozzle member 11 and the second nozzle member 12 are combined, so that the gasket member 30 can be assembled even without inserting the gasket member 30 from the rear end surfaces 11ba and 12ba of the first nozzle member 11 and the second nozzle member 12 into the grooves 28 and 29. Therefore, the gasket member 30 can be provided at multiple locations in the depth direction Y of the first nozzle member 11 and the second nozzle member 12, thereby maintaining the gap L3 of the slit 14 with higher accuracy.

[0122] Here, the pin 33 is as shown in the present embodiment. Fig.16 As shown, four pins 33 are used, namely, two pins for connecting the groove 28 of the first nozzle member 11 and the spacer member 30 and two pins for connecting the groove 29 of the second nozzle member 12 and the spacer member 30. When two or more spacer members 30 are provided in the depth direction Y of the first nozzle member 11 and the second nozzle member 12, the number of pins used may be increased according to the number of spacer members 30.

[0123] Furthermore, when the groove portion 28 of the first nozzle member 11 and the spacer member 30 are connected, as shown in FIG. Fig.16 and Fig.17 As shown in FIG. 1 , after the spacer member 30 is inserted into the grooves 28 and 29, the pin 33 is inserted into the spacer member 30 from the side of the first nozzle member 11 to a predetermined depth C3. Similarly, when the groove 29 of the second nozzle member 12 is connected to the spacer member 30, as shown in FIG. Fig.16 and Fig.17 As shown, after the spacer member 30 is fitted into the grooves 28 and 29 , the pin 33 is inserted into the spacer member 30 from the side surface of the second nozzle member 12 to a predetermined depth C3 .

[0124] It should be noted that, in the present embodiment, each pin 33 is formed as a cylinder, and its diameter C4 is set to Φ about 1 mm to about 10 mm, and the insertion depth C3 of the pin 33 is set to about 1 mm to about 15 mm. Among them, it is set that the insertion depth C3 of the pin 33 is less than the width C1 of the gasket member 30, and the diameter C4 of the pin 33 is less than the height C2 of the gasket member 30. As the material of each pin 33, ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material is also preferred. In addition, the bending strength of each pin 33 is preferably greater than 600 MPa, and more preferably greater than 800 MPa. Therefore, as a ceramic material, zirconium oxide, silicon nitride, silicon aluminum oxynitride ceramics, etc. are preferably used.

[0125] Moreover, in Fig.16 and Fig.17 When the gas wiping nozzle 10 shown is placed in a high temperature atmosphere, for example, when the wiping gas is heated and the gas wiping nozzle 10 itself is also heated along with the heating of the wiping gas, the metal nozzle manifold 15 (see Figure 1 and Figure 2 ) tends to extend in the vertical direction, i.e., the width direction Z of the slit 14, due to thermal expansion. As a result, the first nozzle member 11 and the second nozzle member 12 are also pulled by them and tend to separate up and down. However, since the first nozzle member 11 and the second nozzle member 12 are connected to the gasket member 30 by the pin 33, and the gasket member 30 is a material that is difficult to plastically deform, the first nozzle member 11 and the second nozzle member 12 will not separate up and down. Since the first nozzle member 11 and the second nozzle member 12 will not separate up and down, the gap L3 of the slit 14 formed between the inclined ends 11c and 12c on the steel strip S side of the first nozzle member 11 and the second nozzle member 12 is maintained.

[0126] Next, in the production of the steel strip S, it is preferable to control the temperature of the wiping gas so that the temperature T (° C.) of the wiping gas immediately after being ejected from the slit 14 of the gas wiping nozzle 10 is equal to the melting point T (° C.) of the molten metal. M (℃) satisfies the relationship T M -150≤T≤T M +250. When the temperature T (°C) of the wiping gas is controlled within this range, the cooling and solidification of the molten metal can be suppressed, so that the viscosity is less likely to be uneven, and the generation of water marks can be suppressed. On the other hand, when the temperature T (°C) of the wiping gas is lower than T M If the temperature is too low, such as -150°C, the fluidity of the molten metal will not be affected, so it is not effective in suppressing the formation of water marks. M At +250°C, alloying is promoted and the appearance of the steel sheet deteriorates.

[0127] The method for increasing the temperature of the wiping gas supplied to the gas wiping nozzle 10 is not particularly limited, and examples thereof include a method of heating and supplying the wiping gas by heating with a heat exchanger and a method of mixing the combustion exhaust gas of an annealing furnace with air.

[0128] In addition, as a molten metal-plated metal strip manufactured by applying the gas wiping nozzle and the method for manufacturing a molten metal-plated metal strip of the present embodiment, a hot-dip galvanized steel strip can be cited. The hot-dip galvanized steel strip also includes any one of a plated steel sheet (GI) that is not subjected to alloying treatment after hot-dip galvanizing treatment and a plated steel sheet (GA) that is subjected to alloying treatment. However, the molten metal-plated metal strip manufactured by applying the gas wiping nozzle and the method for manufacturing a molten metal-plated metal strip of the present embodiment is not limited to this, and includes all molten metal-plated steel strips containing other molten metals such as aluminum and tin other than zinc.

[0129] As mentioned above, although embodiment of this invention was described, this invention is not limited to this, Various changes and improvements are possible.

[0130] For example, although the number of divisions of each of the first nozzle member 11 and the second nozzle member 12 is described as three and four in the above description, it may be two or five or more.

[0131] In addition, regarding the length of the dividing surface 20 of each of the first nozzle member 11 and the second nozzle member 12 in each cross section of the first nozzle member 11 and the second nozzle member 12 cut along the length direction X of the slit 14, when the thickness of the slit 14 in the width direction Z of the first nozzle member 11 is set to T1 and the thickness of the slit 14 in the width direction Z of the second nozzle member 12 is set to T2, the length of the dividing surface 20 is 1.5T1 or more for the first nozzle member 11 and 1.5T2 or more for the second nozzle member 12, and the shape of each dividing surface 20 is not limited to Figure 4 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 and Fig.12 Shape shown.

[0132] In addition, the thickness of the flat plate portion 11 a of the first nozzle member 11 and the thickness of the flat plate portion 12 a of the second nozzle member 12 are set to be constant, but they do not need to be constant.

[0133] In addition, although the upper limit of the length of the dividing surface 20 of the first nozzle member 11 is set to 5T1 and the upper limit of the length of the dividing surface 20 of the second nozzle member 12 is set to 5T2, each may be larger than 5T1 or 5T2.

[0134] In addition, although the first nozzle component 11, the second nozzle component 12 and the gasket component 30 are all set to be ceramic materials, carbon materials, carbon fiber reinforced carbon composite materials or ceramic-based composite materials, the first nozzle component 11, the second nozzle component 12 and the gasket component 30 may each not be a ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic-based composite material.

[0135] In addition, although the first nozzle member 11, the second nozzle member 12 and the gasket member are all set to ceramic materials, carbon materials, carbon fiber reinforced carbon composite materials or ceramic matrix composite materials, the concept is that the first nozzle member 11, the second nozzle member 12 and the gasket member may not all be set to the same material. Among them, it is preferred that the first nozzle member 11, the second nozzle member 12 and the gasket member are all made of the same material. In this way, the difference in linear expansion coefficient between the first nozzle member 11, the second nozzle member 12 and the gasket member can be reliably eliminated.

[0136] In addition, the spacer member is not limited to the mode of providing two as independent members in the longitudinal direction X of the slit 14. For example, as long as a part of the spacer member is embedded in the groove of the first nozzle member 11 and the groove of the second nozzle member 12, the spacer member may be provided with a connecting portion that connects the portions embedded in the grooves of the respective nozzle members to each other and be an integrated member.

[0137] In addition, when the pin 33 is used to connect the groove 28 of the first nozzle member 11 and the gasket member 30, and the groove 29 of the second nozzle member 12 and the gasket member 30, the cross-sectional shape of the grooves 28 and 29 is not limited to a rectangle, and may be a dovetail groove shape, a T-slot shape, or other shapes. In addition, the cross-sectional shape of the gasket member 30 may be changed corresponding to the cross-sectional shape of the grooves 28 and 29. In addition, the shape of the pin 33 does not need to be a cylinder, and may be a rectangular parallelepiped or other shapes.

[0138] Example

[0139] use Figure 1The continuous molten metal coating equipment 1 of the basic structure shown makes a steel strip S with a plate thickness of 1.0 mm and a plate width of 1200 mm enter a molten zinc bath at a plate passing speed of 2.0 m / s to produce a hot-dip galvanized steel strip. Regarding the dimensions of the slit 14 of the gas wiping nozzle 10, the length L1 is 1800 mm, the depth L2 is 20 mm, and the width (gap) L3 is 1.2 mm. The value obtained by dividing the length of the dividing surface 20 of the nozzle components 11A~11C, 12A~12C by the nozzle thickness T is shown in Table 1 over the entire length in the depth direction Y. In addition, the experiment was carried out under the conditions that the hot-dip galvanizing bath temperature was 460°C and the gas temperature T at the front end of the wiping nozzle was 500°C. The wiping gas uses a gas adjusted by mixing the exhaust gas of the burner with air. In addition, the melting point T of the hot-dip galvanizing bath M It is 420℃.

[0140] Hereinafter, the gas wiping nozzles of Inventive Examples 1 to 14 and Comparative Examples 1 to 5 will be described.

[0141] It should be noted that the sialon ceramics described in the following inventive examples 1 to 14 and comparative examples 1 to 5 have a bending strength of 980 MPa, a Vickers hardness of 1620 HV, and a fracture toughness of 6 MPa·m 1 / 2 , heat shock resistance is 650℃, linear expansion coefficient is 3.2×10 -6 / K. The yield stress of chromium-molybdenum steel is 400MPa, the Vickers hardness is 300HV, and the fracture toughness is 236MPa·m 1 / 2 , the linear expansion coefficient is 11.2×10 -6 / K.

[0142] (Invention Example 1)

[0143] In the invention example 1, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 4 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 4As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 12mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, the first nozzle member 11 and the second nozzle member 12 are assembled separately. At this time, the adjacent nozzle members 11A, 11B; 11B, 11C; 12A, 12B; 12B, 12C are fixed to each other with an adhesive having zirconium oxide and silicon dioxide as the main component. Next, the assembled first nozzle member 11 is arranged on the upper side, and the assembled second nozzle member 12 is arranged on the lower side, and the same adhesive material as described above is applied to the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12, respectively, and the rectangular spacer member 30 is inserted into the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12. Finally, the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0144] (Invention Example 2)

[0145] In the second embodiment of the invention, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 4 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 4 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 78mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0146] (Invention Example 3)

[0147] In the invention example 3, the materials of the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all silicon aluminum oxynitride ceramics, and the material of the nozzle manifold 15 is chromium molybdenum steel. Figure 7 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 7 As shown, the shape of the dividing surface 20 is a tapered shape, and E1=32 mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T=20 mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina·silicon dioxide as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0148] (Invention Example 4)

[0149] In Example 4, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 7 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 7 As shown, the shape of the dividing surface 20 is a tapered shape, and E1=98 mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T=20 mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina·silicon dioxide as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0150] (Invention Example 5)

[0151] In the fifth embodiment of the invention, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.13As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Fig.13 As shown, the shape of the dividing surface 20 is a shape with a step difference 20b, D1 = 10mm, D2 = 12mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. The definitions of D1, D2, D3, and T are the same as Figure 4 Similarly. Moreover, on the dividing surface 20 of each of the first nozzle component 11 and the second nozzle component 12, two holes are drilled in the nozzle depth direction Y with a tolerance of 8mm+10μm. Next, for each of the first nozzle component 11 and the second nozzle component 12, the adjacent nozzle components 11A, 11B; 11B, 11C; 12A, 12B; 12B, 12C are fixed to each other on the dividing surface 20 with an adhesive containing zirconium oxide and silicon dioxide as the main component. Next, an adhesive containing zirconium oxide and silicon dioxide as the main component is applied to the hole-drilling portion, and a pin 32 made with a tolerance of 8mm-10μm in diameter is placed as shown in FIG. Fig.13 and Fig.15 As shown, the two openings are inserted in the slit depth direction Y. Next, the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive having alumina and silica as the main components. Finally, the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0152] (Invention Example 6)

[0153] In the invention example 6, the materials of the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all silicon aluminum oxynitride ceramics, and the material of the nozzle manifold 15 is chromium molybdenum steel. Fig.14 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Fig.14 As shown, the shape of the dividing surface 20 is a tapered shape, and E1 = 32 mm. The thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20 mm. The definitions of E1 and T are the same as Figure 7Similarly. Then, on the dividing surface 20 of each of the first nozzle component 11 and the second nozzle component 12, two holes are drilled in the nozzle depth direction Y with a tolerance of 8mm+10μm. Next, for each of the first nozzle component 11 and the second nozzle component 12, the adjacent nozzle components 11A, 11B; 11B, 11C; 12A, 12B; 12B, 12C are fixed to each other on the dividing surface 20 with an adhesive containing zirconium oxide and silicon dioxide as the main component. Next, an adhesive containing zirconium oxide and silicon dioxide as the main component is applied to the hole-drilling portion, and a pin 32 made with a tolerance of 8mm-10μm in diameter is placed as shown in FIG. Fig.14 and Fig.15 As shown, the two openings are inserted in the slit depth direction Y. Next, the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive having alumina and silica as the main components. Finally, the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0154] (Invention Example 7)

[0155] In Inventive Example 7, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 4 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 4 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 82mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0156] (Invention Example 8)

[0157] In Inventive Example 8, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 7As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 7 As shown, the shape of the dividing surface 20 is a tapered shape, and E1=102 mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T=20 mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina·silicon dioxide as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0158] (Invention Example 9)

[0159] In the invention example 9, the materials of the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all silicon aluminum oxynitride ceramics, and the material of the nozzle manifold 15 is chromium molybdenum steel. Fig.11 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into four nozzle members 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D in the longitudinal direction X of the slit is 450 mm). Fig.11 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 12mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0160] (Invention Example 10)

[0161] In the inventive example 10, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.11As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into four nozzle members 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D in the longitudinal direction X of the slit is 450 mm). Fig.11 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 78mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0162] (Invention Example 11)

[0163] In the invention example 11, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.11 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into four nozzle members 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D in the longitudinal direction X of the slit is 450 mm). Fig.11 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 82mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0164] (Invention Example 12)

[0165] In the invention example 12, the materials of the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all silicon aluminum oxynitride ceramics, and the material of the nozzle manifold 15 is chromium molybdenum steel. Fig.12 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into five nozzle members 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E along the length direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E in the slit length direction X is 450 mm). Fig.12 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 12mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0166] (Invention Example 13)

[0167] In Inventive Example 13, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.12 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into five nozzle members 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E along the length direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E in the slit length direction X is 450 mm). Fig.12 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 78mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0168] (Invention Example 14)

[0169] In the invention example 14, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.12 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into five nozzle members 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E along the length direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E in the slit length direction X is 450 mm). Fig.12 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 82mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0170] (Comparative Example 1)

[0171] In Comparative Example 1, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 5 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 5As shown, the shape of the dividing surface 20 is a straight line parallel to the nozzle thickness direction, and the length of each dividing surface 20 is T=20 mm, which is the same as the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section. Then, the first nozzle member 11 and the second nozzle member 12 are respectively coated with an adhesive containing alumina·silicon dioxide as a main component and assembled, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via the adhesive containing alumina·silicon dioxide as a main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0172] (Comparative Example 2)

[0173] In Comparative Example 2, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 4 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 4 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 8mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0174] (Comparative Example 3)

[0175] In Comparative Example 3, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Figure 7 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into three nozzle members 11A, 11B, 11C; 12A, 12B, 12C along the longitudinal direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C; 12A, 12B, 12C in the longitudinal direction X of the slit is 600 mm). Figure 7As shown, the shape of the dividing surface 20 is a tapered shape, and E1=28 mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T=20 mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina·silicon dioxide as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0176] (Comparative Example 4)

[0177] In Comparative Example 4, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.11 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into four nozzle members 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D along the length direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D; 12A, 12B, 12C, 12D in the slit length direction X is 450 mm). Fig.11 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 8mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0178] (Comparative Example 5)

[0179] In Comparative Example 5, the first nozzle member 11, the second nozzle member 12 and the gasket member 30 are all made of silicon aluminum oxynitride ceramics, and the nozzle manifold 15 is made of chromium molybdenum steel. Fig.12 As shown, the first nozzle member 11 and the second nozzle member 12 are equally divided into five nozzle members 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E along the length direction X of the slit 14 (the length of each nozzle member 11A, 11B, 11C, 11D, 11E; 12A, 12B, 12C, 12D, 12E in the slit length direction X is 450 mm). Fig.12 As shown, the shape of the dividing surface 20 is a shape having a step difference 20b, D1 = 10mm, D2 = 8mm, D3 = 10mm. Here, the thickness T1 of the first nozzle member 11 and the thickness T2 of the second nozzle member 12 in the cut section are both T = 20mm. Then, as in Example 1 of the invention, the first nozzle member 11 and the second nozzle member 12 are assembled separately, and the rectangular spacer member 30 is embedded in the grooves 28 and 29 of the first nozzle member 11 and the second nozzle member 12 via an adhesive with alumina and silica as the main component, and the nozzle manifold 15 is fixed to the first nozzle member 11 and the second nozzle member 12.

[0180] Then, in Inventive Examples 1 to 14 and Comparative Examples 1 to 5, the gap variation rate of the slit 14, the deviation of the coating adhesion amount in the width direction of the steel strip S, the linear mark generation rate, and the nozzle damage condition (crack) were evaluated. Here, the gap variation rate (%) of the slit 14 is a value (%) expressed by the maximum gap amount / the minimum gap amount in the longitudinal direction X of the slit 14 × 100, and it is acceptable when it is less than 110 (%). In addition, the coating adhesion amount deviation (%) in the width direction of the steel strip S is a value (%) expressed by the maximum coating adhesion amount / the minimum coating adhesion amount in the width direction of the steel strip S × 100, and it is acceptable when it is less than 120 (%). In addition, the linear mark generation rate (%) is the ratio of the length of the steel strip S visually determined to have a linear mark defect in the inspection process to the length of the steel strip S passing under each manufacturing condition, and it is acceptable when it is less than 0.4 (%).

[0181] Table 1 shows the results.

[0182]

[0183] It is obvious from Table 1 that Examples 1 to 14 of the invention with a dividing surface length of more than 1.5T can significantly reduce the gap change rate of the slit 14, the deviation of the coating adhesion amount in the width direction of the steel strip S, and the linear mark generation rate, compared with Comparative Examples 1 to 5 with a dividing surface length of 1 to 1.4T, and all are qualified.

[0184] In addition, for Comparative Example 1 in which the shape of the dividing surface is a straight line parallel to the nozzle thickness direction and the length of the dividing surface is 1T, Comparative Examples 2, 4, and 5 in which the shape of the dividing surface is a shape with a step difference but the length of the dividing surface is 1.4T, and Comparative Example 3 in which the shape of the dividing surface is a conical shape but the length of the dividing surface is 1.4T, any one of the gap change rate of the slit 14, the deviation of the coating adhesion amount in the width direction of the steel strip S, and the linear mark generation rate exceeds the qualified reference value and is unqualified.

[0185] It should be noted that, with regard to Invention Examples 7, 8, 11, and 14, the length of the dividing surface exceeds 5T, and in the nozzle disassembly inspection after manufacturing, cracks were observed in each of the first nozzle component 11 and the second nozzle component 12, but the gap change rate of the slit 14, the deviation of the coating adhesion amount in the width direction of the steel strip S, and the linear mark generation rate met the qualified criteria and were qualified.

[0186] In any of the inventive examples 1 to 14 and the comparative examples 1 to 5, the temperature of the wiping gas was controlled so that the temperature T (° C.) of the wiping gas immediately after being ejected from the slit 14 of the gas wiping nozzle 10 was equal to the melting point T (° C.) of the molten metal. M (℃) satisfies the relationship T M -150≤T≤T M +250. Therefore, in any of Inventive Examples 1 to 14 and Comparative Examples 1 to 5, no water mark defect occurred.

[0187] Therefore, it can be confirmed that: according to the gas wiping nozzle and the method for manufacturing a molten metal-coated metal strip of the present invention, when the slit 14 serving as a gas injection port is manufactured in a divided manner along the length direction X, even in a high-temperature atmosphere, the gap L3 in the width direction Z orthogonal to the length direction X of the slit 14 can be uniformly maintained along the length direction X of the slit 14, and the coating adhesion amount of the steel strip S along the width direction of the steel strip S can be made uniform.

[0188] Explanation of symbols

[0189] 1 Continuous molten metal coating equipment

[0190] 2. Nose

[0191] 3 Plating tanks

[0192] 4 Molten Metal Bath

[0193] 5 Sinking roller

[0194] 6 Support rollers

[0195] 10 Gas wipe nozzle

[0196] 11. First nozzle member

[0197] 11A, 11B, 11C, 11D, 11E Nozzle components

[0198] 11a Flat plate

[0199] 11b Flange

[0200] 11c Slanted end

[0201] 12. Second nozzle member

[0202] 12A, 12B, 12C, 12D, 12E Nozzle assembly

[0203] 12a Flat plate

[0204] 12b Flange

[0205] 12c Slanted end

[0206] 13 Hollow

[0207] 13a Hollow portion forming space

[0208] 13b Hollow portion forming space

[0209] 14 Slit

[0210] 15 Nozzle header

[0211] 16 Gas supply path

[0212] 17 Gas supply pipe

[0213] 20 Split surface

[0214] 20a First straight line portion

[0215] 20b Step Difference

[0216] 20c Second straight line portion

[0217] 20d Concave

[0218] 20e Convex

[0219] 28, 29 groove

[0220] 28a, 29a Corner

[0221] 30 Gasket component

[0222] 31 Offset

[0223] 32 Pins

[0224] 33 Pins

[0225] L1 Length of the slit

[0226] L2 Slit depth

[0227] L3 Slit width (slit gap)

[0228] S Steel belt (metal belt)

[0229] X: Length direction of the slit (width direction of the steel strip)

[0230] Y Slit depth direction (steel strip thickness direction)

[0231] Z: width direction of the slit (length direction of the steel strip)

Claims

1. A gas wiping nozzle that sprays wiping gas onto a metal strip lifted from a molten metal bath to adjust the amount of molten metal attached to the surface of the metal strip, characterized in that: The gas wiping nozzle includes a first nozzle member and a second nozzle member. A slit serving as a gas injection port is formed between the first nozzle member and the second nozzle member at the end of the gas wiping nozzle on the metal belt side. The first nozzle member and the second nozzle member are each divided into two or more nozzle members in the length direction of the slit, When the thickness of the first nozzle member in the width direction of the slit is set to T1 and the thickness of the second nozzle member in the width direction of the slit is set to T2, the length of the dividing surface of the first nozzle member and the second nozzle member in their respective cross sections cut at least at one point in the depth direction orthogonal to the length direction of the slit along the length direction of the slit is greater than 1.5T1 for the first nozzle member and greater than 1.5T2 for the second nozzle member.

2. The gas wiping nozzle according to claim 1, characterized in that A spacer member is provided for adjusting a gap in a width direction perpendicular to the longitudinal direction of the slit.

3. The gas wiping nozzle according to claim 1 or 2, characterized in that: The length of the dividing surface of each of the first nozzle component and the second nozzle component is set to be greater than 1.5T1 for the first nozzle component and greater than 1.5T2 for the second nozzle component, and the area in the depth direction is an area greater than 1 / 3 of the total length of each of the first nozzle component and the second nozzle component in the depth direction.

4. The gas wiping nozzle according to claim 1 or 2, characterized in that: The upper limit of the length of the dividing surface of the first nozzle member is 5T1, and the upper limit of the length of the dividing surface of the second nozzle member is 5T2.

5. The gas wiping nozzle according to claim 3, characterized in that: The upper limit of the length of the dividing surface of the first nozzle member is 5T1, and the upper limit of the length of the dividing surface of the second nozzle member is 5T2.

6. The gas wiping nozzle according to claim 1 or 2, characterized in that: The shape of the dividing surface of each of the first nozzle member and the second nozzle member has a step difference.

7. The gas wiping nozzle according to claim 1 or 2, characterized in that: The shape of each of the dividing surfaces of the first nozzle member and the second nozzle member is a tapered shape inclined with respect to the width direction of the slit.

8. The gas wiping nozzle according to claim 1 or 2, characterized in that: The shape of the divided surface of each of the first nozzle member and the second nozzle member is a fitting surface shape in which the concave surface and the convex surface of the adjacent divided nozzle members fit together.

9. The gas wiping nozzle according to claim 2, characterized in that: The first nozzle component, the second nozzle component and the gasket component are made of ceramic material, carbon material, carbon fiber reinforced carbon composite material or ceramic matrix composite material.

10. The gas wiping nozzle according to claim 1 or 2, characterized in that: Pins are used to connect the divided nozzle members of the first nozzle member and the divided nozzle members of the second nozzle member.

11. A method for manufacturing a molten metal-coated metal strip, characterized in that: A pair of gas wiping nozzles as described in any one of claims 1 to 10 are arranged on both sides of a metal strip lifted from a molten metal bath, and wiping gas is sprayed toward each side of the metal strip from the respective slits of the pair of gas wiping nozzles to adjust the amount of molten metal attached to both sides of the metal strip, thereby continuously manufacturing a molten metal-coated metal strip.

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