JP2574547Y2 - Continuous hot-dip plating equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot-dip plating apparatus for plating a corrosion-resistant metal such as zinc, tin, lead-tin or aluminum or an alloy thereof on a steel sheet running while being continuously annealed.

[0002]

2. Description of the Related Art A continuous hot-dip galvanizing apparatus includes a pre-oxidation furnace for activating the surface of a running steel strip, a reduction annealing furnace for reducing and softening in a reducing gas atmosphere, and a duct-shaped furnace for holding and cooling in a reducing atmosphere. It is composed of a snout and a hot-dip metal bath. Such a continuous hot-dip plating apparatus
By changing the running speed of a steel strip, various types of plated steel sheets having different plating weights from thin plating to thick plating can be stably and easily manufactured as compared with the brazing method, and thus are widely used.

However, for example, Japanese Patent Application Laid-Open No. 63-473
No. 55 and Japanese Unexamined Patent Publication (Kokai) No. 63-118057 disclose a continuous hot-dip coating apparatus in which foreign substances in an annealing furnace carried by a steel strip and dross generated in a hot-dip bath are hot-dipped in a snout. Floating on a metal bath,
There is a problem that the plating adheres to the strip and significantly impairs the plating appearance. In addition, steam generated from the hot-dip metal bath surface in the snout adheres to and accumulates on the inner wall of the snout or the annealing furnace, and falls onto the steel strip or hot-dip metal bath surface to cause a flaw or an external flaw called non-plating. There were also problems that occurred.

[0004] From these problems, Japanese Patent Publication No. 63-4974
A continuous hot-dip plating apparatus using a foreign matter removing technique has been developed as disclosed in Japanese Patent Publication No. 3 (JP-A) No. 3 (1999). This plating apparatus is a "technology for creating a gap between the tip of the snout and the hot-dip metal bath while supplying an inert gas into the snout and removing foreign matter from the gap". The present invention provides a snout apparatus which is connected to the outlet side of a furnace and moves up and down a snout whose tip is immersed in a hot-dip plating metal bath, and which can easily remove foreign substances. Such an apparatus is, as compared with a continuous hot-dip plating apparatus that has been widely used as described above,
There is a reason that foreign matter floating on the hot-dip metal bath in the snout can be easily removed.

[0005] However, when it becomes necessary to remove foreign matter from the snout, the plating operation is temporarily interrupted, the snout is moved upward, and a gap is created between the tip of the snout and the hot-dip metal bath. Since the method is a method for removing foreign matter in the snout from the gap, there is a problem that the operation must be stopped when a large amount of foreign matter is generated despite the plating operation under the same conditions. In addition, since snout is always used by immersing it in a hot-dip metal bath, there is also a problem of melting out.

Also, as disclosed in Japanese Utility Model Laid-Open No. 3-78049, "The steel strip is oxidized by keeping the tip of the snout at a constant gap from the plating bath surface without immersing it in the hot-dip plating bath. A continuous hot-dip galvanizing device that performs plating without plating has also been developed, but this device also oxidizes the steel strip by entraining the surrounding air with the gas in the snout ejected from the tip of the snout and approaching the steel strip. In addition, there is a problem in that hot-dip plating in the vicinity thereof is oxidized, thereby causing non-plating and pressing flaws.

[0007]

Due to such problems, the present invention does not oxidize a steel strip or a hot-dip metal to cause appearance defects such as non-plating, and also causes the tip of the snout to melt. It is intended to provide a continuous hot-dip plating apparatus without any problems.

[0008]

The gist of the present invention is to connect a snout provided with an atmosphere gas introduction pipe on the discharge side of an annealing furnace strip of a continuous hot-dip plating line at a distance from a hot-dip bath, and to form a hot-dip coating of the snout. This is a continuous hot-dip plating apparatus provided with a gas injection slit nozzle which extends outwardly around the entire lower end of the bath surface side and surrounds a part or the whole of the hot-dip plating bath surface.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. FIG.
Shows an embodiment of the present invention. Reference numeral 1 denotes an annealing furnace, which shows a part on the outlet side. 2 is a steel strip. Reference numeral 3 denotes a turn-down roll, which is a furnace roll provided near the outlet of the annealing furnace 1. That is, the steel strip 2 is connected to the annealing furnace 1.
It is provided so as to go around the turndown roll 3 and run while being softened.

Reference numeral 4 denotes a snout, which is connected to the steel strip outlet side of the annealing furnace 1. The snout 4 is a duct-shaped pipe provided with an atmosphere gas introducing pipe 5 for supplying an inert gas such as nitrogen or argon gas or other gas. They are connected with a gap.

That is, the snout 4 is provided so as to guide the steel strip 2 having traveled through the annealing furnace 1 into the bath of the hot-dip metal 7 while protecting the steel strip 2 with the atmospheric gas. 8
Is a sink roll, which rotates the steel strip 2 passing through the hot-dip metal bath.

Reference numeral 9 denotes a gas injection slit nozzle, which is provided on the entire periphery of the lower end of the snout 4 on the hot-dip plating bath surface and is slightly inclined outward. That is, the gas injection slit nozzle 9
Is provided so that a gas such as an injected inert gas surrounds a part or the whole surface of the hot-dip plating bath to prevent oxidation near the hot-dip bath and the plating surface of the traveling steel strip 2. It is. Reference numeral 10 denotes a gas wiping nozzle which wipes off excess hot-dip galvanized metal adhering through the hot-dip metal bath 6 to control the weight per unit area. 11 'indicates the flow direction of the wiping gas.

According to the continuous hot-dip coating apparatus of the present invention as described above, the traveling steel strip 2 is softened in the annealing furnace 1 and then filled with an arbitrary atmospheric gas and passes through the snout 4 ejected from below. Through the hot-dip metal bath 6,
The coated steel sheet is manufactured by wiping to a predetermined basis weight.

In this case, the gas injected from the gas injection slit nozzle 9 does not oxidize the hot-dip plating bath near the steel strip 2 infiltration, and is discharged from the gas wiping nozzle 10 and flows down along the steel strip 2. A beautiful hot-dip coated steel sheet is manufactured while preventing the flow of the wiping gas 11 (arrow).

As shown in FIG. 2, foreign matter such as dross generated and floating on the hot-dip plating bath surface outside the gas surrounding of the gas injection slit nozzle 9 is attached to the hot-dip plating bath surface immediately below the snout 4 to prevent foreign matter from adhering. By floating 12, a hot-dip coated steel sheet having a beautiful surface can be stably manufactured.

[0016]

As described above, according to the present invention, the present invention does not interrupt the plating operation, move the snout upward, and do not melt the snout.
There is no non-plating due to oxidation of the steel strip before entering the bath, foreign substances floating on the hot-dip metal bath surface can be easily removed, and hot-dip coated steel sheets with beautiful appearance can be continuously produced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of the device of the present invention.

FIG. 2 is an explanatory view showing another embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Annealing furnace 2 Steel strip 3 Turndown roll 4 Snout 5 Atmospheric gas introduction pipe 6 Hot-dip plating metal tank 7 Hot-dip plating metal 8 Sink roll 9 Gas injection slit nozzle 10 Wiping gas nozzle 11 Wiping gas 11 'Wiping gas 12 Foreign matter prevention weir

Claims (1)

(57) [Scope of request for utility model registration] 1. A snout provided with an atmosphere gas introduction pipe on the outlet side of an annealing furnace strip of a continuous hot-dip galvanizing line is connected at a distance from a hot-dip plating bath surface, and is outwardly extended all around a lower end of the hot-dip bath surface side of the snout. A continuous hot-dip galvanizing apparatus characterized in that a gas jet slit nozzle is provided to surround a part or the entire surface of a hot-dip plating bath.