JP2010180456A - Sink roll for continuous hot-dip metal plating, apparatus of continuous hot-dip metal plating, and method of producing continuously hot-dip metal plated steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sink roll for continuous hot-dip metal plating, which prevents a flow in raising bottom dross from forming by an opening hole provided in a side plate of the sink roll; in addition, to provide an apparatus of the continuous hot-dip metal plating; and a method of producing a continuously hot-dip-plated steel sheet, which improves a problem that the dross is deposited on a surface of the steel sheet. <P>SOLUTION: The sink roll 1 for the continuous hot-dip metal plating is formed of a hollow cylindrical shape by providing with a cylindrical sack body 2, and one pair or two or more pairs of side plates 3 installed to be substantially perpendicular to an axis core line of the body 2, and also the side plates 3 have rod-shaped shafts 4 attached to extend along outsides of a hollow cylindrical part 5, and have at least one opening 6 for communicating an inside and the outside of the hollow cylindrical part 5, on exterior periphery sides of the side plates 3. The cylindrical sack body 2 and the side plates 3 are not integrated, but the cylindrical sack body 2 is outwardly rotatable on the exterior peripheries of the side plates 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sink roll for continuous molten metal plating, a continuous molten metal plating apparatus, and a method for producing a continuous molten metal plated steel sheet.

  In the continuous molten metal plating apparatus, as shown in FIG. 5, a sink roll 22 as a roll in the bath is disposed in the lower part of the plating bath 21 filled with the molten metal. The sink roll 22 is supported in a horizontal state on a roll support portion 23 of a continuous molten metal plating apparatus, and is rotatably arranged through a bearing. The steel plate 24 that has entered the plating bath 21 at a predetermined plate passing speed turns around the outer periphery of the sink roll 22 at the bottom of the bath, changes its traveling direction, and is pulled up to the outside of the bath, so that the plating adheres continuously. Processing is performed.

  There are various types of sink rolls, and a sink roll having a hollow cylindrical shape is known in which a pair of side plates are integrally attached to both ends of a cylindrical body. A sink roll of this shape is usually provided with an opening hole in the side plate so that the hollow part of the roll communicates with the outside, and when placed in the plating bath, molten metal is allowed to flow into the hollow part of the roll from the opening hole. The generation of buoyancy is suppressed, and the pulling operation is facilitated by discharging the molten metal in the roll hollow portion from the opening hole to the outside when pulling up from the plating bath.

  By the way, when performing molten metal plating such as molten Zn-based plating and molten Al-based plating, in a plating bath for performing molten metal plating, Fe eluted from the steel plate reacts with the molten metal in the plating bath and is called dross. Impurities are generated. A part of this dross accumulates at the bottom of the plating bath to form a bottom dross.

  The bottom dross deposited on the bottom of the plating bath is wound up in the plating bath by the accompanying flow of the sink roll and the steel plate and adheres to the surface of the steel plate. The adhering dross causes uneven plating on the surface of the steel sheet, which not only deteriorates the appearance but also deteriorates the corrosion resistance. Therefore, it is necessary to prevent the dross from adhering.

  One of the reasons why the bottom dross deposited on the bottom of the plating bath is rolled up in the plating bath is that a flow of winding up the bottom dross in the molten metal is generated by the opening hole provided in the side plate of the rotating sink roll. In order to improve the product quality, it is necessary to prevent the flow of winding up the bottom dross from the opening hole in the sink roll having the opening on the side plate.

  Japanese Utility Model Laid-Open No. 5-54547 proposes that a baffle plate having a smooth surface is arranged in the opening hole of the side plate of the sink roll so as not to generate a flow of winding up the bottom dross. However, since the baffle plate is installed so as to protrude from the side surface of the side plate, the rotational resistance of the sink roll is increased, and the sink roll may idle and the steel plate may be scratched.

Japanese Utility Model Publication No. 5-54547

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sink roll for continuous molten metal plating that can prevent the flow of winding up the bottom dross from the opening hole provided in the sink roll side plate. To do. Moreover, an object of this invention is to provide the manufacturing method of the continuous hot-dip metal plating steel plate which can improve the problem of the dross adhesion to the steel plate surface, and a continuous hot-dip metal plating steel plate.

  It is considered that the flow of winding up the bottom dross by the opening hole provided in the side plate of the sink roll is generated as follows. Since the molten metal existing in the opening hole is surrounded by the wall surface of the opening hole, the molten metal rotates together with the opening hole, and as a result receives a strong centrifugal force. The molten metal that has been subjected to centrifugal force flows out of the opening hole vigorously, becomes a flow in the plating bath, winds up the dross, and transports it.

  The present inventors conducted various studies on the shape of the side plate of the sink roll and the flow in the plating bath due to the rotation of the side plate. As a result, it has been found that when the sink roll side plate and the body are separate structures and the side plate is not rotated, the flow of winding up the dross is reduced.

  Means of the present invention for solving the above problems are as follows.

  (1) A cylindrical body and a pair or a plurality of pairs of side plates installed so as to be substantially orthogonal to the axial center line of the body form a hollow cylindrical shape, and the side plate is outside the hollow cylindrical portion. A continuous roll metal plating sink roll having a rod-shaped shaft attached to extend to the outer periphery and having at least one opening communicating the inside and the outside of the hollow cylindrical portion on the outer peripheral side of the side plate, A sink roll for continuous molten metal plating, wherein the barrel portion and the side plate are not integrated, and the barrel portion can be rotated around the outer periphery of the side plate.

  (2) A continuous molten metal plating apparatus comprising the sink roll according to (1), wherein the shaft is fixed so as not to rotate to a sink roll support portion supporting the shaft. Continuous molten metal plating equipment.

  (3) A method for producing a continuous molten metal plated steel sheet, comprising subjecting the steel sheet to a molten metal plating treatment using the continuous molten metal plating apparatus according to (2).

  In the sink roll for continuous molten metal plating according to the present invention, the body portion and the side plate are not integrated, and the body portion is configured to be able to rotate around the outer periphery of the side plate. By fixing the shaft of the side plate of the sink roll to the sink roll support portion of the continuous molten metal plating apparatus so as not to rotate, the side plate does not rotate when the steel plate travels, and only the trunk portion rotates. Since the flow which winds up a bottom dross by the opening part of a side plate does not generate | occur | produce, the hoisting of a bottom dross is suppressed and the dross defect of a steel plate can be reduced.

It is a figure which shows 1st Embodiment of the sink roll of this invention, (a) is a perspective view, (b) is an axial sectional view. It is a figure which shows various embodiment of the sink roll of this invention, and is a cross-sectional enlarged view of the side plate vicinity of the one side of a sink roll. It is a numerical fluid analysis model used for simulation on a computer. It is a figure explaining the flow velocity evaluation of the molten zinc by the simulation on a computer, (a) shows a flow velocity evaluation place, (b) is the absolute value (maximum) of the distance from the trunk | drum outer periphery in the lower part of a sink roll trunk | drum end, The flow rate) relationship is shown. It is the schematic which shows the principal part of a continuous molten metal plating apparatus.

  An embodiment of a sink roll of a continuous molten metal plating apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing a first embodiment of a sink roll according to the present invention, in which (a) is a perspective view and (b) is an axial sectional view. The sink roll 1 of the present embodiment includes a roll hollow portion 5 including a cylindrical barrel portion 2 and a pair of left and right circular side plates 3 and 3 that closes both end openings of the barrel portion 2. The side plate 3 is formed with one or a plurality of opening holes 6 for communicating the roll hollow portion 5 with the outside. A shaft 4 is attached and fixed to the center of the side plate 3 so as to extend outside the hollow portion of the roll. A groove 7 is formed in the circumferential direction in the vicinity of the inner peripheral side end of the body portion 2, and the outer peripheral portion of the side plate 3 is loosely fitted into the groove 7, and the body portion 2 freely abducts the outer periphery of the side plate 3. It has a possible structure. As the material constituting the body portion 2, the side plate 3, and the shaft 4, known materials conventionally used for the body portion, the side plate, and the shaft of the sink roll can be used.

  When the sink roll 1 is mounted on a continuous molten metal plating apparatus, the shaft 4 is fixed to a sink roll support portion that is a structure that supports the sink roll so that the shaft 4 does not rotate. For example, the shaft 4 is formed in a shape having a polygonal cross section, and the sink roll support portion forms a hole having a dimension corresponding to the cross sectional shape of the shaft 4, and the shaft 4 is inserted into the hole and does not rotate. To fix.

  The hot dip plating method using the continuous hot dip plating apparatus equipped with the sink roll of the present invention may be a conventional method. When the steel plate is immersed in the plating bath, the side plate 3 does not rotate, and only the body portion 2 rotates around the outer periphery of the side plate 3. Since the side plate 3 does not rotate, centrifugal force is not received on the wall surface of the opening hole 6 of the side plate 3, that is, generation of a flow of winding up the bottom dross by the opening of the side plate is prevented. The flow rate of the molten zinc flowing out from the opening hole 6 in the side plate is lower than that in the case of the conventional apparatus in which the side plate rotates, thereby suppressing the bottom dross from being rolled up and reducing the dross adhesion on the plated steel plate.

  The side plate 3 of the sink roll 1 is formed with one or a plurality of opening holes 6 that allow the roll hollow portion 5 to communicate with the outside. When the sink roll 1 is placed in the plating bath of the continuous molten metal plating apparatus, the molten metal flows into the roll hollow portion 5 from the opening hole 6 and generation of buoyancy of the sink roll 1 is suppressed, and the sink roll 1 is pulled up from the plating bath. Since the molten metal in the roll hollow portion 5 is discharged to the outside through the opening hole 6, the sink roll 1 can be pulled up easily.

  FIG. 2 shows various embodiments of the sink roll 1 of the present invention, and is an enlarged sectional view showing one side portion of the pair of side plates 3. FIG. 2A is the same as that of the first embodiment of FIG. 1, and the side plate 3 of the sink roll 1 has a simple flat plate shape. In contrast, FIG. 2B shows a second embodiment of the present invention, in which the side plate 3 has a conical shape. Thus, the present invention can also be applied when the side plate 3 is not a flat plate. FIG. 2C shows a third embodiment of the present invention, which has a structure in which the thickness of the side plate 3 is not uniform and the thickness is increased near the shaft 4. FIG. 2 (d) shows a fourth embodiment of the present invention. Of the side plate 3, the portion close to the sink roll body 2 is a simple flat plate having the same thickness, and the portion close to the shaft 4 is centered. It has a structure that increases in thickness.

  Using the numerical fluid analysis model 8 shown in FIG. 3, the flow of the molten metal generated from the sink roll 1 of the first embodiment of FIG. 1 was evaluated by computer simulation. The numerical fluid analysis model 8 shown in FIG. 3 includes a bathtub 10 filled with molten zinc 11 and a sink roll 9 that rotates at a rotational speed of 8 rad / s. The sink roll 9 includes a side plate 12 and a body portion 13, and the side plate 12 is provided with eight opening holes.

  The sink roll of the present invention in which only the body portion rotates when the steel plate passes without integrating the body portion and the side plate, and the shaft, the side plate, and the body portion are integrated and rotate integrally when the steel plate passes. About the sink roll of the conventional example, the flow rate of the molten zinc below the sink roll barrel end portion was evaluated by changing the distance from the outer periphery of the sink roll barrel portion. FIG. 4A shows the location where the flow rate of molten zinc was evaluated. FIG. 4 (b) shows the relationship between the distance from the outer periphery of the trunk portion below the sink roll barrel end and the absolute value (maximum flow velocity) of the flow velocity.

  FIG. 4 shows that the sink roll of the present invention is compared with the sink roll of the conventional example by using the sink roll of the present invention at a location 5 cm away from the outer periphery of the sink roll body or at a location 50 cm away. It can be seen that the flow rate of molten zinc can be kept low.

  From this, the sink roll according to the present invention can reduce the drooping of the dross, so that the dross adhesion is reduced and it is effective for the production of a high-quality plated steel sheet.

  The sink roll of the present invention can be used as a sink roll attached to a continuous molten metal plating apparatus that can reduce dross adhesion to the steel sheet surface. The continuous molten metal plating apparatus of this invention can be utilized as a manufacturing apparatus of the high quality plated steel plate which can reduce the dross adhesion to the steel plate surface. The manufacturing method of the continuous molten metal plating steel plate of this invention can be utilized as a manufacturing method of the high quality plating steel plate which can reduce dross adhesion to the steel plate surface.

DESCRIPTION OF SYMBOLS 1 Sink roll 2 Body part 3 Side plate 4 Shaft 5 Roll hollow part 6 Opening hole 7 Groove 8 Numerical fluid analysis model 9 Sink roll 10 Bath 11 Hot-dip zinc 12 Sink roll side plate 13 Sink roll trunk 14 Flow rate measurement point 21 Plating bath 22 Sink Roll 23 Roll support 24 Steel plate

Claims (3)

A cylindrical body and a pair or a plurality of side plates installed so as to be substantially orthogonal to the axial center line of the body form a hollow cylindrical shape, and the side plate extends outside the hollow cylindrical portion. A sink roll for continuous molten metal plating having a rod-like shaft attached to the outer side of the side plate and having at least one opening communicating the inside and the outside of the hollow cylindrical portion on the outer peripheral side of the side plate, A sink roll for continuous molten metal plating, wherein the body and the side plate are not integrated, and the outer periphery of the side plate can be rotated around the outer periphery of the side plate. It is a continuous molten metal plating apparatus which equips the sink roll of Claim 1, Comprising: The said axis | shaft is fixed so that it may not rotate to the sink roll support part which supports this axis | shaft, The continuous melting characterized by the above-mentioned Metal plating equipment. A method for producing a continuous molten metal plated steel sheet, comprising subjecting a steel sheet to a molten metal plating treatment using the continuous molten metal plating apparatus according to claim 2.

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