JP2012219356A - Wiping device and hot dip plating apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiping device which improves the flow of a wiping gas on an edge part of a steel sheet, thereby prevents edge over coat and splash, and to provide a hot dip plating apparatus using the wiping device.SOLUTION: The wiping device 1 includes a couple of wiping nozzles 2a, 2b which are arranged at both sides of and across a steel sheet P pulled up from a hot dip plating tank and toward the sheet surface of the steel sheet P, and the wiping device 1 blows wiping gas to the steel sheet P from the couple of wiping nozzles 2a, 2b. The wiping device 1 further includes masks 3 which cover parts, located on both outer sides in the width direction of the steel sheet P, of one or both of the couple of wiping nozzles 2a, 2b. Thereby, the collision of the wiping gas blown from the couple of the wiping nozzle 2a, 2b at parts on the both outer sides in the width direction of the steel sheet P between the wiping nozzles is inhibited, and the generation of a turbulent flow is prevented.

Description

  The present invention relates to a wiping apparatus and a hot dipping apparatus using the same.

  FIG. 6 is a cross-sectional view showing an outline of a continuous hot dip plating apparatus. As shown in FIG. 6, in the continuous hot dip plating apparatus 11, the steel plate P that has been pickled is immersed in the hot dip plating bath 12 to plate the hot metal through the sink roll 13. After gas wiping by the wiping nozzle 14, plating is performed by introducing it into the alloying furnace 15 and rapidly heating, holding, and cooling.

  The gas wiping by the wiping nozzle 14 is performed by wiping gas from the wiping nozzles 14 disposed on both sides of the steel plate P so that the molten metal adhering to the surface of the steel plate P has a uniform plating thickness in the plate width direction and the plate longitudinal direction. By spraying, the excess molten metal is wiped off and the adhesion amount of the molten metal is controlled. The wiping nozzle 14 ejects wiping gas from a slit extending in the width direction of the steel sheet P, and this slit is longer than the width of the steel sheet P in order to correspond to various widths of the steel sheet P. The steel plate P extends outward from the edge portion.

  The wiping gas blown from such a wiping nozzle 14 is separated in the vertical direction after colliding with the steel plate P as a high-speed jet, so that excess molten metal is wiped in the vertical direction, and the pressure distribution in the plate width direction is Uniform plating thickness is realized by making it uniform. However, as for the edge portion of the steel plate P, the jet flow colliding with the edge portion escapes in the lateral direction, so that the collision force of the jet flow is reduced and the plating thickness of the edge portion becomes thicker than that of the center portion. The overcoat is generated, or a so-called splash is generated in which the molten metal scatters around due to the disturbance of the jet colliding with the edge portion, and the surface quality of the steel sheet P is deteriorated.

  As an attempt to solve such a problem, for example, Patent Document 1 describes that an auxiliary nozzle is provided on the wiping nozzle in order to compensate for the collision pressure of the wiping gas in the vicinity of the edge portion of the steel plate. Further, in Patent Document 2, in order to prevent edge overcoat caused by a decrease in the wiping force of the edge portion due to collision of gas outside the steel plate edge portion of the wiping gas sprayed on the steel plate, a plate is provided in the vicinity of the edge portion. It is described that it is installed and the collision between wiping gases is eliminated. Moreover, as described in Patent Document 3, an apparatus has been proposed in which a suction nozzle is provided opposite to the side end surface of a steel plate and molten metal is removed by using air pressure.

Japanese Patent Laid-Open No. 10-265930 JP 2005-248243 A JP-A-9-143663

  When the auxiliary nozzle is arranged on the wiping nozzle as described in Patent Document 1, the gas discharged from the wiping nozzle and the auxiliary nozzle does not match at one point on the steel plate due to the displacement of the steel plate, Occurs, the wiping force of the edge of the steel sheet is reduced, and edge overcoat is generated. Further, when the plate is installed as described in Patent Document 2, the impinging pressure of the wiping gas to the edge portion of the steel plate increases, so the splash of molten metal increases, and the edge adheres between the steel plate and the plate. Cause poor quality. Moreover, in the apparatus described in Patent Document 3, since the molten metal is sucked by the suction nozzle, the sucked molten metal adheres to the nozzle and closes the nozzle, resulting in the wiping force of the edge portion of the steel plate. There is a problem that the edge overcoat occurs due to the decrease.

  Accordingly, an object of the present invention is to provide a wiping apparatus capable of preventing edge overcoat and splash by improving the flow of wiping gas at the edge of a steel sheet, and a hot dipping apparatus using the same. And

  The wiping device of the present invention is a wiping device that blows wiping gas to a steel plate from a pair of wiping nozzles arranged on both sides of the steel plate pulled up from a hot dipping bath toward the plate surface of the steel plate. It is provided with a mask that covers portions located on both outer sides in the width direction of one or both steel plates.

  According to the wiping device of the present invention, the portions of the pair of wiping nozzles located on one side or both sides of the steel sheet on the both sides in the width direction are covered with the mask, so that the wiping gas blown from the pair of wiping nozzles is It is possible to prevent collisions at both outer portions in the width direction of the steel sheet between the wiping nozzles, and to prevent the occurrence of turbulence.

  Here, it is desirable that the outer shape of the mask is convex toward the wiping nozzle on the facing side of the pair of wiping nozzles. As a result, when a mask is provided only on one side of the pair of wiping nozzles, the wiping gas blown from the wiping nozzle on the facing side is guided to the rear of the wiping nozzle, and the width direction of the steel sheet between the wiping nozzles It is possible to prevent a collision at a part and to prevent generation of turbulent flow.

(1) By providing a mask that covers a part of the pair of wiping nozzles located on one side or both sides of the steel sheet in the width direction on both sides, the wiping gas blown from the pair of wiping nozzles is between these wiping nozzles. It is possible to prevent collisions at both outer portions in the width direction of the steel sheet and to prevent the occurrence of turbulence. This prevents the wiping gas from colliding with the steel plate due to fluttering of the steel plate between the wiping nozzles and fluctuations in the plate position due to vibration, and prevents the splash from adhering to the plate, preventing edge overcoat and achieving a uniform plating thickness. it can.

(2) When a mask is provided only on one side of the pair of wiping nozzles by spraying from the facing wiping nozzle because the outer shape of the mask is convex toward the wiping nozzle on the opposite side of the pair of wiping nozzles The generated wiping gas is guided to the rear of the wiping nozzle, and can be prevented from colliding at both outer portions in the width direction of the steel plate between the wiping nozzles, thereby preventing the occurrence of turbulence.

It is a longitudinal cross-sectional view of the wiping apparatus in embodiment of this invention. It is a perspective view of the wiping apparatus of FIG. It is a figure which shows the relationship between the amount of wiping gas and the presence or absence of the coil shape defect of an overcoat. It is a figure which shows the relationship between the gap of a mask and a steel plate edge, and the presence or absence of the coil shape defect of an overcoat. It is a figure which shows the relationship between the width | variety of a mask, and the presence or absence of the coil shape defect of an overcoat. It is sectional drawing which shows the outline | summary of a continuous hot-dip plating apparatus.

  FIG. 1 is a longitudinal sectional view of a wiping device according to an embodiment of the present invention, and FIG. 2 is a perspective view of the wiping device of FIG.

  As shown in FIGS. 1 and 2, a wiping device 1 according to an embodiment of the present invention is provided in a continuous hot-dip plating device 11 as shown in FIG. A pair of wiping nozzles 2a and 2b disposed on both sides of the steel plate P, and a mask 3 that covers portions of the pair of wiping nozzles 2a located on both outer sides in the width direction of the steel plate P are provided.

  The wiping nozzles 2a and 2b are nozzles that eject wiping gas from linear slits 4a and 4b extending in the width direction of the steel plate P toward the plate surface of the steel plate P, respectively. The slits 4a and 4b are formed to be longer than the width of the steel plate P and extend outward from the edge E of the steel plate P as shown in FIG. The wiping gas blown onto the plate surface of the steel plate P from the wiping nozzles 2a and 2b is separated in the vertical direction after colliding with the steel plate P as a high-speed jet, and wipes off excess molten metal.

  The mask 3 is supported by a mask support bar 7 with respect to a moving gantry 6 provided so as to be movable in the width direction of the steel plate P by a ball screw 5. Further, the movable gantry 6 is provided with an edge positioning sensor 8 that detects the edge position of the steel plate P. The mask 3 is controlled so as to be arranged at a predetermined distance from the edge position of the steel sheet P based on the edge position of the steel sheet P detected by the edge positioning sensor 8. In FIG. 2, only one outer side in the width direction of the steel plate P is illustrated, but the mask 3 and the like are arranged symmetrically around the center of the steel plate on the other outer side.

  Further, the mask 3 covers the portions of the wiping nozzle 2a located on both outer sides in the width direction of the steel plate so that the wiping gas discharged from the wiping nozzle 2a does not collide with the wiping gas discharged from the facing wiping nozzle 2b. However, the outer shape of the mask 3 is convex toward the facing wiping nozzle 2b. In the example shown in the figure, the tip of the wiping nozzle 2b is pointed toward the wiping nozzle 2b. The wiping gas blown from the wiping nozzle 2b is separated vertically at the tip of the mask 3, and the wiping nozzle 2a Guided backwards.

  According to the wiping device 1 configured as described above, the portions of the wiping nozzle 2a located on both outer sides in the width direction of the steel plate P are covered with the mask 3, so that the wiping gas blown from the wiping nozzles 2a and 2b It is possible to prevent collision at both outer portions in the width direction of the steel sheet P between the wiping nozzles 2a and 2b, and to prevent generation of turbulent flow. As a result, it is possible to prevent a decrease in the collision pressure of the wiping gas and the adhesion of the splash to the steel plate P due to the fluctuation of the plate position due to the fluttering of the steel plate P between the wiping nozzles 2a and 2b and vibration, and to prevent the edge overcoat and uniform Can be achieved.

  In this embodiment, the mask 3 is provided only on one wiping nozzle 2a of the pair of wiping nozzles 2a and 2b. However, the mask 3 is provided only on the other wiping nozzle 2b, and both the wiping nozzles 2a and 2b are provided. It is also possible to have a configuration provided in FIG. In this case, what is necessary is just to provide symmetrically with what was provided in the wiping nozzle 2a side in the wiping nozzle 2b side.

  In this embodiment, since the outer shape of the mask 3 is convex toward the facing wiping nozzle 2b, the mask 3 is provided only on one of the pair of wiping nozzles 2a and 2b. Even if it exists, the wiping gas blown from the wiping nozzles 2a and 2b on the opposite side is guided to the rear of the wiping nozzles 2a and 2b and collides with both outer portions in the width direction of the steel plate P between the wiping nozzles 2a and 2b. And the occurrence of turbulent flow can be prevented.

  A test was conducted on the relationship between the arrangement position of the mask 3 and the overcoat in the above embodiment. In the test, a steel plate P with a width of 1200 mm was pulled up at a speed of 120 mpm, the difference in plating thickness between the steel plate center in the width direction and the position 20 to 100 mm from the steel plate edge E, and the coil end portion by edge overcoat when coiled. Coil shape collapse due to bulging was investigated for each hot-dip type. As the hot-dip plating type, molten aluminum at a temperature of 650 to 670 ° C., molten zinc at a temperature of 450 to 480 ° C., and a tin-zinc alloy molten metal at a temperature of 270 to 300 ° C. were used.

  The test results are shown in FIGS. FIG. 3 shows the relationship between the amount of wiping gas and the presence / absence of a coil shape defect in the overcoat, and FIG. 4 shows the relationship between the gap between the steel plate center side edge of the mask 3 and the steel plate edge E FIG. 5 shows the relationship between the width in the extending direction of the wiping nozzle 2a of the mask 3 and the presence or absence of an overcoat coil shape defect.

As can be seen from FIG. 3, if the wiping gas amount is 180 Nm ³ / Hr · m or more per width of the wiping nozzles 2 a and 2 b, no overcoat coil shape defect has occurred.

  As can be seen from FIG. 4, the gap between the steel plate center side edge of the mask 3 and the steel plate edge E is -3 mm to 15 mm, that is, a range from 3 mm from the steel plate edge E to the steel plate center side to 15 mm outside the steel plate P. If it is inside, the gas turbulence accompanying the collision of the wiping gas outside the steel plate edge E by the mask 3 is suppressed, the wiping force of the steel plate edge E is ensured, and the plating thickness difference in the steel plate width direction is reduced. Shape defects are also eliminated.

  On the other hand, when the gap between the edge of the steel plate center side of the mask 3 and the steel plate edge E is −5 mm, the collision gas pressure of the wiping gas to the steel plate P is lowered, the wiping force is lowered, and the coil shape defect due to the overcoat occurs. did. If the gap between the edge of the steel plate center side of the mask 3 and the steel plate edge E is 20 mm, the masking effect of the wiping nozzle 2a is lost, and the wiping force of the steel plate edge E due to the influence of gas turbulence caused by the collision between the wiping gases. The coil shape was poor due to overcoating.

  Further, as can be seen from FIG. 5, when the width of the mask 3 is 50 mm or more, the wiping force of the steel plate edge E is ensured without being affected by the gas turbulence accompanying the collision of the wiping gas outside the steel plate edge E. Thus, the difference in plating thickness in the width direction of the steel sheet is reduced, and the defective coil shape is also eliminated. On the other hand, when the width of the mask 3 was 25 mm, the wiping force of the steel plate edge E decreased due to the influence of gas turbulence, and a coil shape defect due to overcoat occurred.

  INDUSTRIAL APPLICABILITY The wiping apparatus of the present invention is useful for an apparatus for preventing edge overcoat and splash at an edge portion of a steel plate in a hot dipping process and a hot dipping apparatus using the apparatus.

DESCRIPTION OF SYMBOLS 1 Wiping apparatus 2a, 2b Wiping nozzle 3 Mask 4a, 4b Slit 5 Ball screw 6 Moving mount 7 Mask support bar 8 Edge positioning sensor

Claims (4)

In the wiping device for blowing wiping gas to the steel plate from a pair of wiping nozzles arranged on both sides of the steel plate to be pulled up from the hot dipping bath, respectively, toward the plate surface of the steel plate,
The wiping apparatus provided with the mask which covers the part located in the both outer sides of the width direction of the said steel plate of the one side or both sides of said pair of wiping nozzles.   The wiping apparatus according to claim 1, wherein an outer shape of the mask is convex toward a wiping nozzle facing the pair of wiping nozzles. The mask has a width in the extending direction of the wiping nozzle of 50 mm or more,
The wiping apparatus according to claim 1 or 2, wherein a position of an edge of the mask on the steel plate center side is within a range from 3 mm from the edge of the steel plate to the center side of the steel plate to 15 mm to the outside of the steel plate.   The hot dipping apparatus provided with the wiping apparatus in any one of Claim 1 to 3.

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