JPH0669265U - Continuous hot dip coating equipment - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Continuous without causing appearance defects such as non-plating due to acidification of steel strip or hot-dip metal, and without melting the tip of the snout. A hot dip plating apparatus is provided. [Structure] A gas injection slit nozzle 9 is provided all around the tip of a snout 4 which is connected to the exit side of the annealing furnace 1 of the continuous hot dip coating apparatus and is kept at a slight distance from the surface of the hot dip metal bath 7 and is inert in the snout 4. A continuous hot-dip galvanizing apparatus characterized in that a pipe 5 for supplying gas is provided on a side wall of the snout 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuous hot-dip plating apparatus for plating a corrosion-resistant metal such as zinc, tin, lead-tin, or aluminium, or an alloy thereof, which has been melted on a steel sheet which is running while being continuously annealed.

[0002]

[Prior art]

 The continuous hot-dip galvanizing equipment is a pre-oxidizing furnace that surface-activates the running steel strip, a reduction annealing furnace that reduces and softens in a reducing gas atmosphere, a duct-shaped snout that is kept in a reducing atmosphere, and hot-dip galvanizing. It is composed of a metal tank. Such continuous hot dip galvanizing equipment produces various kinds of plated steel sheets with different coating weights, from thin to thick plating, by changing the running speed of the steel strip more stably and easily than the dopping method. It is commonly used because of its advantages.

However, the continuous hot-dip galvanizing apparatus as shown in, for example, Japanese Patent Laid-Open No. 63-47355 and Japanese Laid-Open Patent No. 63-118057, foreign matter in the annealing furnace carried by the steel strip and hot-dip galvanizing There was a problem that the dross formed in the bath floated on the surface of the molten plated metal bath in the snout and adhered to the strip, significantly impairing the plating appearance. In addition, the steam generated from the hot-dip metal bath surface inside the snout adheres to and accumulates on the inner wall of the snout and the annealing furnace, and falls onto the steel strip and hot-dip metal bath surface, resulting in appearance defects called imperfections and non-plating. There was also a problem that occurs.

Due to these problems, a continuous hot-dip galvanizing apparatus of foreign matter removing technology has been developed as disclosed in Japanese Patent Publication No. 63-49743. This plating equipment is a "technology that removes foreign substances from the gap by creating a gap between the tip of the snout and the surface of the hot-dip metal bath while supplying an inert gas into the snout." It provides a snout device that can easily remove foreign substances by moving a snout that is connected to the outlet side of the furnace and has its tip immersed in a hot dip metal bath up and down. Such an apparatus has a reason that foreign matters floating on the surface of the molten plating metal bath in the snout can be easily removed, as compared with the above-described conventional continuous hot dipping apparatus.

However, when it becomes necessary to remove the foreign matter in 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 surface, Since this is a method of extracting foreign matter from the snout through 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. Further, since the snout is always used by immersing it in the hot-dip metal bath, there is a problem of melting damage.

Further, as disclosed in Japanese Utility Model Laid-Open No. 3-78049, "a steel strip is oxidized by keeping a constant gap between the tip of the snout and the surface of the plating bath without immersing it in the hot dipping bath. A continuous hot dip galvanizing device for plating without a steel plate has also been developed, but this device also oxidizes the steel strip as the gas in the snout that is ejected from the tip of the snout approaches the steel strip and entrains the ambient air. In addition, there is a problem in that the molten solder in the vicinity thereof is oxidized and non-plating or a flaw is generated.

[0007]

[Problems to be solved by the device]

 Due to these problems, the present invention provides a continuous hot-dip galvanizing apparatus that does not oxidize steel strip or hot-dip galvanized metal to cause appearance defects such as non-plating, and does not melt the tip of the snout. It is provided.

[0008]

[Means for Solving the Problems]

 The gist is that a snout with an atmosphere gas introduction pipe installed on the outlet side of the annealing furnace of the continuous hot dip coating line is separated from the hot dip bath surface and connected, and the snout is outwardly directed to the entire lower end of the hot dip bath surface side. It is a continuous hot-dip galvanizing apparatus that is provided with a gas injection slit nozzle that surrounds part or all of the hot-dip bath surface.

[0009]

EXAMPLES The present invention will be described in detail below. FIG. 1 shows an embodiment of the present invention. Reference numeral 1 denotes an annealing furnace, which shows a part of the outlet side. 2 is a steel strip. Reference numeral 3 is a turndown roll, which is an in-furnace roll provided near the exit of the annealing furnace 1. That is, the steel strip 2 is provided so as to run around the turndown roll 3 while being softened in the annealing furnace 1.

Reference numeral 4 is 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 introduction pipe 5 for supplying an inert gas such as nitrogen or argon gas or another gas, and is arbitrarily selected from the bath surface of the hot dip metal 7 in the hot dip metal bath 6. It is connected with a gap.

That is, the snout 4 is provided so as to guide the steel strip 2 running in the annealing furnace 1 into the bath of the hot-dip metal 7 while protecting the steel strip 2 with the atmospheric gas. Numeral 8 is a roll for rotating 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 circumference of the lower end of the snout 4 on the hot dip bath surface side so as to be slightly inclined outward. That is, the gas injection slit nozzle 9 is provided so that the injected gas such as an inert gas surrounds a part or the whole of the hot dip bath surface, and the hot dip coating penetrates into the running steel strip 2 plating surface. It prevents oxidation near the bath. Reference numeral 10 denotes a gas wiping nozzle, which wipes off the surplus hot-dip galvanized metal that has passed through the hot-dip galvanized metal tank 6 and controls it to a predetermined basis weight. Reference numeral 11 'indicates the flow direction of the wiping gas.

According to the continuous hot-dip galvanizing apparatus of the present invention as described above, the running steel strip 2 is softened in the annealing furnace 1 and then passes through the snout 4 which is filled with an arbitrary atmospheric gas and jets from the lower part. Then, it passes through the hot dip metal bath 6 and is wiped to a predetermined basis weight to produce a plated steel sheet.

In this case, the gas sprayed from the gas spray slit nozzle 9 does not oxidize the hot dip plating bath in the vicinity where the steel strip 2 enters, and is sprayed from the gas wiping nozzle 10 along the steel strip 2. A beautiful hot-dip galvanized steel sheet is manufactured while preventing the inflow of the wiping gas 11 flowing down (arrow).

Further, as shown in FIG. 2, foreign matter such as dross generated and floating on the surface of the hot dip bath outside the gas surrounding of the gas injection slit nozzle 9 is a weir to prevent foreign matter from adhering to the hot dip bath surface directly below the snout 4, as shown in FIG. If 12 is floated, a hot-dip galvanized steel sheet with a beautiful surface can be stably manufactured.

[0016]

[Effect of device]

 As described above, according to the present invention, there is no interruption of plating operation, no upward movement of the snout, and no erosion of the snout. In addition, foreign matter floating on the surface of the hot-dip galvanized metal bath can be easily removed, and hot-dip galvanized steel sheets with a beautiful appearance can be continuously manufactured.

[Brief description of drawings]

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

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

[Explanation of symbols]

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

Claims (1)

[Scope of utility model registration request] 1. A snout having an atmosphere gas introduction pipe provided on the outlet side of an annealing furnace strip of a continuous hot dip coating line is separated from the hot dip bath surface and is connected to the snout, and the snout is outwardly directed to the entire lower end of the hot dip bath surface side. A continuous hot-dip galvanizing apparatus, which is provided with a gas injection slit nozzle that surrounds a part or the entire surface of the hot-dip galvanizing bath.