JP4700527B2 - Continuous molten metal plating equipment - Google Patents

Description

  The present invention relates to a continuous molten metal plating facility in which a steel strip is heat-treated in a continuous annealing furnace and subsequently immersed in a molten metal pot to continuously perform molten metal plating such as hot dip galvanization or molten aluminum containing galvanization. is there.

  The continuous molten metal plating facility is a steel strip that has been heat-treated in a continuous annealing furnace under a reducing atmosphere gas and turned diagonally downward with a turn-down roll, passing through a snout and molten metal plating such as zinc or zinc containing aluminum. It is immersed in a bath, and continuous molten metal plating is performed by adjusting the plating thickness and alloying treatment.

  In a continuous molten metal plating facility, the dross discharge pump for discharging dross in the snout is replaced at a frequency of about once per month due to corrosion or wear caused by molten zinc or the like. The snout tip is also replaced due to corrosion. When reducing the dross discharge pump, replacing the tip of the snout, or cleaning the inside of the snout, if the reducing atmosphere gas in the continuous annealing furnace blows out from the snout, there is a safety problem, so replace the atmosphere gas in the continuous annealing furnace with air. To ensure safety. Then, after the maintenance is completed, it is necessary to replace the inside of the continuous annealing furnace with the atmospheric gas, warm up, and make it operable again. If maintenance work can be performed without replacing the reducing atmosphere gas in the continuous annealing furnace with air, the maintenance time can be greatly shortened.

  In order to shorten the maintenance time and increase the operating rate of the equipment, Patent Document 1 provides a receiving seat having a receiving groove having an arc-shaped cross section in the snout wall portion, and a wall facing the receiving seat with a steel strip interposed therebetween. A snout seal device is disclosed in which a valve member is provided in a portion so as to be capable of moving back and forth in a receiving seat, and an atmospheric gas from an annealing furnace is shut off by fitting the valve member to the receiving seat.

Patent Document 2 discloses that in a continuous molten metal plating facility, metal vapor flows into the continuous annealing furnace through the snout and adheres to the surface of the steel strip. On the side or downstream side, a partition plate is provided above and below the steel strip so that the gap with the steel strip is 30 mm or less, and the space between the inside of the snout and the continuous annealing furnace is sealed, and the metal steam is supplied to the continuous annealing furnace. Preventing intrusion is disclosed.
Japanese Patent Laid-Open No. 4-128353 JP-A-11-286762

  In patent document 1, in order to shut off the atmospheric gas from the annealing furnace by stopping the running of the steel strip and pressing it against the snout wall surface by the sealing device, the atmospheric gas from the annealing furnace is used while the steel strip is running. It cannot be blocked. Further, since the sealing device cannot be operated while the steel strip is traveling, it is difficult to prevent the metal vapor from the molten metal pot from entering the annealing furnace.

  Patent Document 2 is for suppressing the amount of zinc fume generated in the snout in the hot dipping process. When the snout part is opened to the atmosphere, the presence of a gap in the partition plate causes the entry of air or the atmosphere. The gas cannot be shut off reliably.

  Therefore, the present invention reliably shuts off the atmospheric gas in the continuous annealing furnace regardless of whether the steel sheet is running or the steel sheet is stopped, and also when the metal vapor enters the continuous annealing furnace and the snout portion is opened to the atmosphere. It is an object of the present invention to provide a continuous molten metal plating facility equipped with an atmosphere gas seal that can prevent the atmosphere from entering.

  The present invention relates to a continuous molten metal plating facility in which a steel strip is annealed in a reducing atmosphere of a continuous annealing furnace and is introduced into a molten metal plating bath through a snout to perform plating on an upstream side or a downstream side of a turndown roll. A labyrinth seal having an inert gas introduction pipe for blowing out an inert gas toward the steel strip, which can adjust a gap with the steel strip by raising and lowering, is provided on both sides of the steel strip. Furthermore, you may provide a damper on both sides of the labyrinth seal with a steel strip.

  In the present invention, a labyrinth seal that injects an inert gas from an inert gas introduction pipe toward a steel strip enables a non-contact seal with high sealing performance without generating flaws on a steel plate.

  Further, in the present invention, only the labyrinth seal can be used to adjust the gap between the labyrinth seal and the steel strip to prevent the metal vapor from entering the annealing furnace through the snout from the molten metal pot, and at the time of maintenance around the molten metal pot. The furnace atmosphere gas can be shut off, and it is not necessary to separately provide a sealing device for penetration of the metal vapor into the annealing furnace and a sealing device for shutting down the atmosphere gas, so that space can be saved. .

  Moreover, since the position of the labyrinth seal can be adjusted in consideration of the catenary of the steel strip by the labyrinth seal that can be raised and lowered, the contact between the steel strip and the labyrinth seal can be prevented, and the steel strip is not forced by the labyrinth seal.

  In addition, the gap between the labyrinth seal that can be moved up and down and the steel strip is opened to the atmosphere when the continuous molten metal plating facility is in operation, and the snout exit is opened to the atmosphere when the steel strip is stopped. It can be changed according to each situation of the steel strip traveling at a low speed.

  Further, by providing a damper on the entry side and / or the exit side of the labyrinth seal, the sealing performance is enhanced.

  FIG. 1 shows an embodiment of a continuous molten metal plating facility according to the present invention. FIG. 2 (a) is a view showing the position of the sealing device during steady operation in the continuous molten metal plating facility according to the present invention, and FIG. 2 (b) is a view showing the position of the sealing device when the snout portion is opened to the atmosphere. FIG. 3 is a diagram showing the distance between the catenary and the labyrinth seal.

  As shown in FIG. 1, a steel strip 2 that has been subjected to heat treatment such as heating, soaking, and cooling in a continuous annealing furnace 1 under a reducing atmosphere gas passes through a labyrinth seal 3 and is tilted downward by a turn-down roll 4. Change direction, pass through the snout 5 and immerse in the molten metal pot 6. Subsequently, the steel strip 2 is turned upward by the sink roll 7 and supported by the support roll 8 to suppress vibration, and the plating nozzle 9 adjusts the plating thickness.

  The snout 5 and the snout tip 10 are connected by a bellows 11, and when the snout tip 10 is immersed in the molten metal, the atmospheric gas does not leak. The snout tip 10 can be moved up and down by a snout telescopic device 12 driven by a fluid pressure cylinder or the like. When cleaning the inside of the snout, the snout tip 10 is moved upward by the snout telescopic device 12. Pull up. When the snout tip 10 rises above the molten metal liquid level, the inside of the snout is released to the atmosphere.

  A dross suction pipe 14 connected to a dross discharge pump 13 is installed in the snout to discharge dross on the molten metal surface.

  The labyrinth seal 3 is provided on both sides of the steel strip 2 so as to be lifted and lowered by a lifting device driven by a fluid pressure cylinder, a worm jack, an electric motor or the like (not shown). The labyrinth seal 3 is provided with an inert gas introduction hole 15 for injecting an inert gas toward the steel strip 2 at the center, and surrounds the inert gas introduction hole 15 to be parallel to the width direction of the steel strip 2. Plates 16 are provided at intervals.

  A damper 17 parallel to the width direction of the steel strip 2 is provided on the exit side of the labyrinth seal 3 with the steel strip 2 interposed therebetween. The damper 17 is rotated from outside the furnace by a rotating device (not shown) so that the opening degree of the damper 17 can be adjusted.

  Next, the operation of the continuous molten metal plating facility of the present invention will be described.

(1) During continuous operation of continuous molten metal plating As shown in FIG. 2 (a), the gap between the labyrinth seal 3 and the steel strip 2 installed on both sides of the steel strip 2 is 10 to 30 mm (20 ± 10 mm). By adjusting, metal vapor can be prevented from entering the continuous annealing furnace. In addition, at this time, for example, nitrogen of 50 Nm ³ / min is blown from the inert gas introduction hole 15 of the labyrinth seal 3 to ensure the penetration of the metal vapor from the molten metal pot 6 into the continuous annealing furnace. Can be prevented.

  As shown in FIG. 3, the level of the steel strip 2 is at a position lower than the pass line due to the catenary c even when the steel strip 2 is in tension. Therefore, the center position of the labyrinth seal 3 on both sides of the steel strip is set to a position that is lowered by the catenary of the steel strip 2 from the pass line.

  Further, the dampers 17 provided on both sides of the steel strip on the labyrinth seal exit side are opened. In this case, it is more desirable to adjust the opening degree of the damper 17 to an opening degree that does not contact the steel strip.

(2) When the snout exit side is opened to the atmosphere and the steel strip is stopped. When the snout 5 is opened to the atmosphere, the gap between the labyrinth seal 3 and the steel strip 2 is adjusted to 5 mm (5 ± 5 mm), for example. , Sealability can be improved. At this time, in combination with the inert gas introduction pipe 16 of the labyrinth seal 3, more nitrogen, for example, 100 Nm ³ / min, is blown than in the steady operation to prevent the atmosphere from entering the continuous annealing furnace, It is possible to prevent the metal vapor from the molten metal pot from entering the continuous annealing furnace. Further, the dampers 17 provided on both sides of the steel strip on the labyrinth seal exit side are closed to further ensure the seal.

(3) When the snout exit side is opened to the atmosphere and the steel strip is run at a slow speed When the snout 5 is opened to the atmosphere, the steel strip 2 in the molten metal bath is broken by erosion of the molten metal pot 6 by the molten metal bath. The gap between the labyrinth seal 3 and the steel strip 2 is prevented when the steel strip 2 is moved at a slow speed of, for example, several m / min so that the steel strip in the annealing furnace for a long time does not creep rupture. Is adjusted to 10 mm (10 ± 5 mm), for example. Thereby, it can seal, avoiding the contact with the steel strip 2 and the labyrinth seal 3 which are drive | working. At this time, in addition, the inert gas introduction hole 15 of the labyrinth seal 3 is blown with nitrogen of, for example, 150 Nm ³ / min more than when the steel strip 2 is stopped, and enters the atmospheric continuous annealing furnace. It is desirable to prevent intrusion. At this time, as shown in FIG. 3, since there is a catenary c, the center position between the tips of the labyrinth seal 3 is a position that is lowered by the catenary of the steel strip 2 from the pass line. It is more desirable to adjust the opening of the damper 17 to an angle that does not contact the steel strip.

It is a figure which shows one Example of the continuous molten metal plating equipment which concerns on this invention. (A) is a figure which shows the position of the sealing apparatus at the time of steady operation in the continuous molten metal plating equipment which concerns on this invention, (b) is a figure which shows the position of the sealing apparatus at the time of open | release of a snout part atmosphere. It is a figure which shows the space | interval of a catenary and a labyrinth seal.

Explanation of symbols

1: Continuous annealing furnace 2: Steel strip 3: Labyrinth seal 4: Turn-down roll 5: Snout 6: Molten metal pot 7: Sink roll 8: Support roll 9: Injection nozzle 10: Snout tip 11: Bellows 12: Snout expansion / contraction Device 13: Dross discharge pump 14: Dross suction pipe 15: Inert gas introduction hole 16: Labyrinth seal plate 17: Damper

Claims (2)

In a continuous molten metal plating facility in which a steel strip is annealed in a reducing atmosphere of a continuous annealing furnace, and introduced into a molten metal plating bath through a snout to perform plating,
A labyrinth seal with an inert gas introduction pipe that blows inert gas toward the steel strip on both sides of the steel strip on the upstream side or downstream side of the turn-down roll. A continuous molten metal plating facility characterized by being provided.   The continuous molten metal plating facility according to claim 1, wherein a damper is provided on both the labyrinth seal inlet side and / or outlet side with a steel strip interposed therebetween.

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