JP2006274409A - Apparatus for manufacturing galvannealed steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a galvannealed steel sheet in which a playting nonuniformity in the transverse direction of the steel sheet can be iomproved and thereby the degree of alloying in the transverse direction of the stainless steel can be uniformed by preventing the alloying defect near the edges of the steel sheet and reducing the warping of the steel sheet in a plating restriction section. <P>SOLUTION: The apparatus for manufacturing the galvannealed steel sheet comprises a plating restriction device and an an electromagnetic induction heating alloying furnace arranged above the device. A flame burner which blows combustion gas and air for combustion from a tangent direction of the tubular burner is disposed below the electromagnetic induction heating alloying furnace movably to a position corresponding to the neighborhood of each edge of both sides of the steel sheet. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  The alloyed hot-dip galvanized steel sheet is manufactured by the apparatus shown in FIG. That is, the steel plate 1 immersed in the zinc pot 3 filled with molten zinc is pulled up by changing the plate passing direction by the sink roll 4, and excess zinc is removed from the wiping nozzle 5 provided above the zinc pot 3. Then, a high pressure gas such as air or nitrogen gas is blown and squeezed to be adjusted to a predetermined adhesion amount. The hot dip galvanized steel sheet having a predetermined zinc adhesion amount is introduced into the alloying furnace 8 and heated to about 500 to 600 ° C., so that the alloying treatment of the plating film is performed and the galvannealed steel sheet is alloyed. A strip is manufactured. The alloying furnace 8 includes a method using an open flame burner and an electromagnetic induction heating method, and the electromagnetic induction heating method is excellent from the point of view of responsiveness.

  In the alloyed hot dip galvanized steel sheet, the amount of adhesion tends to increase at the plating drawn portion in the vicinity of the steel sheet edge, and the steel sheet edge part is more easily cooled than the central part in the steel sheet width direction. Therefore, there is a problem that alloying defects (free zinc) are likely to occur near the edge of the steel plate during the alloying treatment.

  In recent years, the use of galvannealed steel sheets has expanded, and the amount of plating has been wide ranging from thin to thick, and the steel types and steel sheet sizes have become more diverse. For this reason, there is a problem that the warpage (C warpage) of the steel plate at the plating drawn portion is increased, and the amount of adhesion in the steel plate width direction tends to be uneven. If the amount of adhesion in the steel plate width direction becomes non-uniform, the degree of alloying in the steel plate width direction becomes non-uniform.

In order to prevent alloying failure in the vicinity of the steel plate edge, as shown in FIG. 2, by arranging an edge burner 21 below the alloying furnace 8 and locally heating the steel plate edge where alloying failure is likely to occur, It has been proposed to prevent poor alloying in the vicinity of the steel plate edge (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 5-25604

  However, the prior art document 1 is insufficient in the effect of preventing poor alloying near the steel plate edge. Further, the cited document 1 does not describe anything to improve the unevenness of the plating amount in the steel plate width direction.

  The object of the present invention is to improve the above-mentioned problems, prevent alloying failure in the vicinity of the steel plate edge, or reduce the warpage of the steel plate at the plating drawn portion, thereby reducing the unevenness of the plating amount in the steel plate width direction. It is an object of the present invention to provide an apparatus for producing an alloyed hot-dip galvanized steel sheet that can be improved and thereby have a uniform degree of alloying in the steel sheet width direction.

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

  The first invention includes a plating drawing apparatus and an electromagnetic induction heating alloying furnace disposed above the plating drawing apparatus, and fuel gas and combustion air are supplied from the tangential direction of the tubular burner below the electromagnetic induction heating alloying furnace. An apparatus for producing an alloyed hot-dip galvanized steel sheet, wherein a tubular flame burner to be blown is provided so as to be movable to a position corresponding to each edge vicinity of both surfaces of the steel sheet.

  2nd invention is equipped with the plating roll apparatus, the touch roll which has arrange | positioned the position shifted with respect to the advancing direction of a steel plate on both sides on both sides of the steel plate, and an electromagnetic induction heating alloying furnace in order, and further the touch roll and the electromagnetic Between the induction heating alloying furnace, a tubular flame burner for blowing fuel gas and combustion air from the tangential direction of the tubular burner is movably installed at a position corresponding to each edge vicinity of both surfaces of the steel sheet. It is a manufacturing apparatus of a galvannealed steel plate.

  A third invention is the alloyed molten zinc according to the first or second invention, wherein the tubular flame burner is configured to be able to tilt the flame shape obliquely upward in the steel plate traveling direction with respect to the steel plate surface. It is a manufacturing apparatus of a plated steel plate.

  According to the present invention, poor alloying in the vicinity of the steel plate edge can be prevented. Further, by installing a touch roll, it is possible to improve the non-uniformity in the amount of adhesion in the steel plate width direction and make the degree of alloying in the steel plate width direction uniform. In addition, the problem of quality degradation caused by zinc powder generated by using touch rolls can be solved with inexpensive equipment, and the production equipment for alloyed hot-dip galvanized steel sheets can be made compact. Therefore, it is easy to implement the present invention.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 3 is a schematic view for explaining one embodiment of an apparatus for producing an alloyed hot-dip galvanized steel sheet according to the present invention. In FIG. 3, 1 is a steel plate (plated steel plate), 2 is an annealing furnace, 3 is a zinc pot, 4 is a sink roll, 5 is a wiping nozzle, 6 is a touch roll, 7 is a tubular flame burner, and 8 is an alloying furnace (electromagnetic) Induction heating furnace), 9 is a zinc powder removing device. The touch roll 6 is disposed on both sides of the steel plate 1 with the position shifted with respect to the traveling direction of the steel plate 1 and is a chrome-plated hollow steel roll that is internally water-cooled. The zinc powder removing device 9 is provided in the middle of the duct 13, a suction hood 11 disposed near the upper peripheral surface of each touch roll 6, a suction blower 12, a duct 13 connecting the suction hood 11 and the suction blower 12. A dust remover (cyclonic dust remover) 14 is provided, and a discharge duct 15 is provided on the outlet side of the suction blower 12.

By adjusting the pushing amount of the touch roll 6 in the pass line direction, the warp (C warpage) of the steel sheet 1 at the wiping nozzle 5 is corrected. As a result, even if the steel plate size changes, the amount of adhesion in the steel plate width direction can be made uniform. However, when the steel plate 1 passes through the touch roll 6, fine zinc is scraped off from the plated surface in the molten state. This fine zinc (hereinafter referred to as zinc powder) rises on the upward flow of gas injected from the gas wiping nozzle 5 (steel plate accompanying flow) and accumulates in the alloying furnace or temporarily rises. Then, it descends and accumulates on the upper part of the gas wiping nozzle, causing the following problems.
(1) The zinc powder deposited in the alloying furnace adheres to the plated steel sheet and causes a defect such as a scratch, and the current of the induction heating coil leaks through the zinc, causing a power trip and the like.
(2) Zinc powder deposited on the upper part of the gas wiping nozzle adheres to the steel plate, resulting in sticking of foreign substances and free zinc.

  The zinc powder removing device 9 sucks and removes the zinc powder scraped off by the touch roll 6. That is, by driving the suction blower 12, the zinc powder scraped off by the touch roll 6 is sucked from the suction hood 11 and separated and removed by the dust remover 14. The sucked gas after the zinc powder is removed is released from the discharge duct 15 into the atmosphere. Accumulation of zinc powder scraped off by the touch roll 6 in the alloying furnace and deposition on the gas wiping nozzle is prevented, and the above-mentioned problems caused by the zinc powder generated from the touch roll 6 are eliminated.

  The tubular flame burner 7 heats the vicinity of the steel plate edge to prevent free zinc generated in the vicinity of the steel plate edge. The tubular flame burner 7 is installed between the touch roll 6 and the alloying furnace (electromagnetic induction heating furnace) 8, that is, below the alloying furnace. As shown in FIG. 4, the tubular flame burners 7 are arranged on both surfaces in the vicinity of both edges of the steel plate, and each tubular flame burner 7 is movable in the steel plate width direction to the burner guide 16 provided along the steel plate width direction. Are configured so as to be individually movable in the steel plate width direction by the driving device 17.

FIG. 5 shows the structure of a tubular flame burner. The tubular flame burner 7 is attached around a shaft 18 fixed to the burner guide 16 so as to be tiltable upward in the steel plate traveling direction. Fuel gas and combustion air are blown into the tubular combustion chamber 19 from its tangential direction. The tubular flame burner can complete combustion in the combustion cylinder compared to a general turbulent diffusion flame burner in which the flame extends in the axial direction of the burner, and can stably burn even at a high air ratio. Flame shape control is easy. Therefore, the narrow area | region of a steel plate can be heated efficiently in a short time. Moreover, the flame shape which collided with the steel plate can be mainly set to the upward direction by tilting the burner body 22 upward in the steel plate traveling direction to make the flame shape obliquely upward. An appropriate fuel can be used as the fuel. As an example, the COG flow rate can be about 25 Nm ³ / h with a tube diameter of 25 mmφ.

  FIG. 6 is a schematic view showing a flame shape, in which (a) is a torch type burner and (b) is a tubular flame burner. The suction hood needs not to suck the burner flame from the viewpoint of heat resistance. Since the torch type burner is inferior in flame shape controllability, the heating rate is inferior to that of the tubular flame burner even when the end of the steel plate is heated, and the interval between the burner and the suction hood is brought closer to about 500 mm. Then, as shown in FIG. 6B, the flame is sucked into the suction hood, and it is difficult to bring the burner and the suction hood close to the interval.

  On the other hand, since the flame shape control of the tubular flame burner is easy, as shown in FIG. 6 (b), by directing the burner flame shape obliquely upward with respect to the steel plate surface, Therefore, even if the interval between the spray burner and the suction hood is reduced to about 500 mm, the flame can be prevented from being sucked into the suction door.

  The tubular flame burner is moved to the vicinity of the edge of the steel plate, and the vicinity of the edge of the steel plate can be heated and heated efficiently in a short time. Therefore, for example, the appearance in the vicinity of the steel sheet edge after the alloying treatment is visually observed to evaluate the suitability of alloying, and the gas flow rate of the tubular flame burner and the corresponding air flow rate are adjusted to appropriate flow rates based on the evaluation results. Thus, it is possible to accurately prevent the occurrence of alloying failure (free zinc) in the vicinity of the steel plate edge.

  As described above, according to the apparatus of FIG. 3, the occurrence of alloying failure (free zinc) in the vicinity of the steel plate edge can be accurately prevented by using the tubular flame burner in the vicinity of the steel plate edge. Moreover, since the tubular flame burner used by this invention is excellent in controllability of a flame shape, a flame direction can be mainly formed only in a steel plate running direction. Therefore, even if a touch roll and a zinc powder removal device that sucks and removes zinc powder generated from the touch roll are installed below the tubular flame burner, the flame shape is mainly limited to the steel plate traveling direction (upward). The heat influence on the zinc powder removing device disposed below is small, the heat resistance required for the device material used for the suction hood of the zinc powder removing device, etc. is alleviated, and an inexpensive material can be used. In addition, since both can be arranged close to each other, the space for installing the touch roll, zinc powder removing device, and tubular flame burner (the length in the traveling direction of the steel plate) can be reduced, and the present invention can be easily made by modifying the existing equipment. Can be implemented.

  Next, a method for producing an alloyed hot-dip galvanized steel sheet using the apparatus of the present invention will be described.

  A steel plate subjected to a predetermined heat treatment in the annealing furnace 2 is dip-plated with a zinc pot 3 filled with molten zinc, pulled up from the zinc pot 3, and from a wiping nozzle 5 provided above the zinc pot 3, air and nitrogen gas The zinc adhesion amount is adjusted to a predetermined adhesion amount by spraying high pressure gas such as. Next, after passing the touch roll 6, the vicinity of the steel plate edge is heated with a tubular flame burner disposed in the vicinity of the steel plate edge, and the alloying treatment of the plating film is subsequently performed in the alloying furnace 8. Subsequently, it is cooled by a cooling device (not shown), or further subjected to necessary treatments such as temper rolling and post-treatment to obtain a required alloyed hot-dip galvanized steel sheet.

  The amount of push in the direction perpendicular to the pass line of the touch roll 6 disposed across the steel plate 1 is adjusted so as to reduce the warpage of the steel plate at the wiping nozzle 5 part, and the amount of adhesion in the steel plate width direction becomes non-uniform. To prevent. At the same time, the zinc powder generated from the touch roll 6 is sucked from the suction hood 9 of the zinc powder removing device 9 and removed out of the system, thereby preventing the generation of quality defects due to the zinc powder. By heating an appropriate amount in the vicinity of the steel plate edge using a tubular flame burner, alloying failure in the vicinity of the steel plate edge that occurs after the alloying treatment is prevented.

  FIG. 7 is a schematic view illustrating another embodiment of the apparatus for producing an galvannealed steel sheet according to the present invention. In the apparatus of FIG. 7, the touch roll 6 and the zinc powder removing apparatus 9 which are arranged by the apparatus shown in FIG. 3 are not arranged. As is apparent from the above description, this apparatus also has an effect of preventing poor alloying in the vicinity of the steel plate edge.

  The apparatus of the present invention can be used as a facility apparatus for producing an alloyed hot-dip galvanized steel sheet that can reduce the occurrence of poor alloying near the edge of the steel sheet.

  Moreover, the apparatus of the present invention is used as an apparatus for producing an alloyed hot-dip galvanized steel sheet that is excellent in uniformity of the degree of alloying in the width direction of the steel sheet and can reduce the occurrence of poor alloying in the vicinity of the edge of the steel sheet. Can do.

It is a figure of the manufacturing apparatus of the galvannealed steel plate of the conventional method. It is a figure of the manufacturing apparatus of the galvannealed steel plate described in patent document 1. It is the schematic explaining one Embodiment of the manufacturing apparatus of the galvannealed steel plate which concerns on this invention. It is a figure explaining embodiment of the apparatus which moves the tubular flame burner installed in the apparatus of FIG. 3 to a steel plate width direction. It is a figure which shows the structure of the tubular flame burner used by the temperature rising rate investigation test. It is a schematic diagram which shows each flame shape of a tubular flame burner and a torch type burner, (a) is a torch type burner, (b) is a tubular flame burner. It is the schematic explaining another embodiment of the manufacturing apparatus of the galvannealed steel plate which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel plate 2 Annealing furnace 3 Zinc pot 4 Sink roll 5 Wiping nozzle 6 Touch roll 7 Tubular flame burner 8 Alloying furnace (electromagnetic induction heating furnace)
9 Zinc powder removal device 11 Suction hood 12 Suction blower 13, 15 Duct 14 Dust remover (Cyclone type dust remover)
16 Burner guide 17 Drive device 21 Edge burner

Claims (3)

  A tubular flame burner comprising a plating squeezing device and an electromagnetic induction heating alloying furnace disposed above, and injecting fuel gas and combustion air from the tangential direction of the tubular burner below the electromagnetic induction heating alloying furnace Is movably provided at a position corresponding to the vicinity of each edge on both sides of the steel sheet.   A plating drawing device, a touch roll disposed on both sides of the steel plate with a position shifted with respect to the traveling direction of the steel plate, and an electromagnetic induction heating alloying furnace are sequentially provided, and the touch roll and the electromagnetic induction heating alloying furnace are further provided. An alloyed hot-dip galvanized plating characterized in that a tubular flame burner that blows fuel gas and combustion air from the tangential direction of the tubular burner is movably installed at positions corresponding to the vicinity of each edge on both sides of the steel plate Steel plate manufacturing equipment.   The apparatus for producing an galvannealed steel sheet according to claim 1 or 2, wherein the tubular flame burner is configured to be able to tilt a flame shape obliquely upward in the steel sheet traveling direction with respect to the steel sheet surface. .

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