JPH093619A - Method and equipment for continuous plating of steel strip - Google Patents

Abstract

PURPOSE: To provide a method and equipment for manufacturing the plated cold-rolled steel sheet unnecessary for annealing and hot-rolled steel sheet inexpensively with high productivity. CONSTITUTION: A pickling equipment 2, an Ni electric plating equipment 5, a heating equipment 8, and a plating equipment on which a spray nozzle 12 to blow fine particles of the molten metal on the surface of the steel strip are successively arranged in the traveling direction of the steel strip 1. After the steel strip 1 is pickled, the nickel coating layer is formed on the surface of the steel strip in the range of 0.5-2.0g/m<2> , and the nickel coating layer on the surface of the steel strip is heated in the range of a temp. between the melting point o the molten metal ±200 deg.C to be plated without oxidizing the nickel coating layer on the surface of the steel strip, and then, the fine particles of the molten metal are sprayed to plate the steel strip. The plated cold-rolled steel sheet unnecessary for annealing and the pickled hot-rolled steel sheet which are referred to the full-hard sheet can be manufactured inexpensively with high productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for hot-dip galvanizing strip-shaped steel sheet, and more particularly to a method and apparatus for hot-rolled steel sheet without annealing and pickling hot-rolled steel sheet, which is called a full-hard material.

[0002]

2. Description of the Related Art Conventionally, a hot-dip galvanized steel sheet is generally heat-treated in a weakly oxidizing atmosphere to oxidize the steel sheet surface, and then is uniformly reduced in a reducing atmosphere to activate the steel sheet surface. It is manufactured by a method of cooling in a reducing atmosphere to a temperature suitable for hot dip coating (usually at or above the melting point of hot dip metal), and dipping the steel sheet directly in a hot dip bath to perform plating.
However, in such a method, the plating adhesion cannot be ensured unless the active steel sheet surface is obtained by soaking and reducing in a reducing atmosphere. Even in the case of hot dip plating, high-concentration hydrogen atmosphere, for example, atmosphere N ₂ + 15%
It has to be reduced in H ₂ state at about 600 ° C. for 2 to 3 minutes. Moreover, when soaking in a hot dip plating bath, after soaking reduction, it must be cooled to a temperature suitable for plating in a reducing atmosphere.

When hot-rolled cold-rolled steel sheets requiring no annealing or hot-pickled hot-rolled steel sheets, which are called full-hard materials, are hot-dipped, the soaking reduction step and cooling step are omitted, and the material is immediately heated to a temperature suitable for hot-dip coating. If plating can be performed, the energy consumption rate and the reducing gas consumption rate are reduced, and the manufacturing cost can be greatly reduced. In addition, the equipment cost of the continuous hot dip galvanizing equipment can be significantly reduced.

Such a hot-dip reduction / cooling-free hot-dip galvanizing method is disclosed in Japanese Patent Publication No. 63-48925 / 1988.
-133106. The content of these proposals is that after the Ni pre-plating, the steel sheet is heated in a non-oxidizing atmosphere by using an indirect heating furnace or by directly energizing the steel sheet between the conductor roll and the hot dip bath. That is, the steel sheet is directly immersed in a hot dip plating bath in a state of being heated to a temperature equal to or higher than the melting point of (1) to perform plating.

However, in any of these methods, the step of plating is to immerse directly in a hot dip plating bath and to control the amount of adhesion by gas wiping. Due to problems such as splashing, the line speed is set to 1
50 m / min. The above high speed cannot be achieved and high productivity cannot be expected. Further, in order to separately produce a steel sheet that has not been plated but only pickled and a steel sheet that has been plated on the same line, it is necessary to change the pass line.

On the other hand, a spray plating method of atomizing a molten metal such as molten zinc by spraying and adhering the atomized molten metal to the surface of a strip-shaped steel sheet which is continuously fed to perform plating is conventionally known from JP-A-1-201456. It is known in Japanese Patent Application Laid-Open No. 2-410878 and Japanese Patent Application Laid-Open No. 4-52261. Since this spray plating method does not use gas wiping, the spray plating method can be sped up without the problem of splash due to the gas restriction of the excessive film thickness. Furthermore, spray is turned on and off in the same pass line.
It is possible to easily make steel plates that have been plated and steel plates that have not been plated.

However, each of the proposals relates to a spray plating method and a spray plating apparatus for atomizing molten metal and adhering it to the surface of a steel sheet.
It does not show a concrete configuration of a method and a device for producing a cold-rolled steel sheet requiring no annealing or a galvanized steel sheet of pickled hot-rolled steel sheet, which is referred to as a full-hard material by a spray plating method while omitting cooling.

[0008]

DISCLOSURE OF THE INVENTION The present invention uses a melt spray plating method, which is inexpensive and enables high productivity.
An object of the present invention is to provide a method and an apparatus for producing a cold-rolled steel sheet that does not require annealing and is known as a full-hard steel sheet or a pickled hot-rolled steel sheet.

[0009]

In order to achieve this object, the present invention has as its gist the following method and apparatus. (1) A strip steel sheet is continuously pickled to clean its surface, and then a nickel coating layer of 0.5 to 2.0 g is provided on the surface.
Melting point of the molten metal to be plated −2, which is formed in the range of ² / m ² and is subsequently oxidized without oxidizing the nickel coating layer on the surface of the steel sheet in an inert and / or reducing gas atmosphere.
Continuous heating spray plating of strip steel sheet, characterized in that after heating to a range of 00 ° C to melting point + 200 ° C, fine particles of the molten metal to be plated in an inert and / or reducing gas atmosphere are spray-plated on the surface. Method.

(2) A pickling device is installed in the running direction of the strip steel plate,
Spray for spraying fine particles of molten metal onto the surface of a strip-shaped steel sheet that continuously passes through a Ni electroplating apparatus, a heating apparatus in an inert and / or reducing gas atmosphere, and a plating chamber hermetically connected to an already heated apparatus. It is a continuous hot-dip galvanizing apparatus for strip-shaped steel sheets, which is characterized by sequentially arranging plating apparatuses having nozzles.

[0011]

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows the outline of the apparatus of the present invention. A pickling device 2, a pickling rinse device 3, a pickling dryer device 4, a Ni electroplating device 5, in the running direction of the strip steel plate 1.
A rinsing device 6 for electroplating, a drier device 7 for electroplating, a heating device 8 in an inert and / or reducing gas atmosphere, and a plating device 9 in which a spray nozzle airtightly connected to the heating device 8 is arranged. The strip-shaped steel sheet 1 is arranged so that the oxide scale and the like on the surface thereof are cleaned by the pickling device 2, washed with water by the pickling rinse device 3, and dried through the pickling dryer device 4. After that, by the Ni electroplating device 5, 0.5 to 2.
A nickel coating layer of 0 g / m ² is formed. This nickel coating layer serves to enhance the adhesion to the molten metal to be plated (for example, molten zinc), and the thicker it is, the wider the appropriate strip-shaped steel plate temperature range in which a steel plate having good plating adhesion can be obtained. However, the thicker the nickel coating layer, the higher the input power cost of the electroplating apparatus,
The proper range of the nickel coating layer is preferably 0.5 to 2.0 g / m ² .

Subsequently, the strip-shaped steel sheet 1 is washed with water by the electroplating rinsing device 6 and dried by the electroplating drier device 7, and then by the heating device 8 in an inert and / or reducing gas atmosphere, the nickel on the surface of the steel plate. The coating layer is heated to a predetermined temperature without being oxidized, and is guided to the plating apparatus 9 in which a spray nozzle is arranged without being exposed to the atmosphere. In order to obtain a plated steel sheet having good adhesion, the strip steel sheet temperature is 0.5 which is an appropriate range of the nickel coating layer.
In the range of up to 2.0 g / m ² , the melting point of the molten metal to be plated is -200 ° C to the melting point + 200 ° C. The heating method used in the heating device 8 may be any of an indirect heating method using a radiant tube, a reduction direct flame heating method, and an electric heating method by induction or direct energization. The electric heating method is preferable in consideration of properties and the like.

FIG. 2 is a detailed explanatory view of the plating apparatus 9,
A plating chamber 10 having inlet / outlet side sealing chambers 10, 11, a spray nozzle 12 arranged substantially symmetrically with the strip-shaped steel plate 1 sandwiched therebetween, and a molten metal pump 14 for supplying the molten molten metal to the spray nozzle 12 from a plating pot 13. The molten metal pipe 15 and the gas pipe 16 for supplying the non-oxidizing pressurized gas used for atomizing the molten metal to the spray nozzle 12. FIG.
In the above, a method of supplying the molten metal to the spray nozzle by a pump is shown, but a method of pressurizing the plating pot 13 and supplying the molten metal to the spray nozzle 12 may be used. The fine particles of the molten metal preferably have a cumulative weight average particle diameter of 50 μm or less, and this particle diameter is adjusted by the ratio of the molten metal and the pressurized gas supplied to the spray nozzle 12. Further, the coating weight of the plating is adjusted by the number of rotations of the pump for supplying the molten metal to the spray nozzle 12, the pressing force, the line speed of the strip-shaped steel sheet, and the number of nozzles arranged in the longitudinal direction of the strip-shaped steel sheet. The strip-shaped steel sheet 1 exiting the plating apparatus 9 is naturally cooled or forcedly cooled by using a gas jet cooler or the like and returned to room temperature.

[0014]

EXAMPLES Next, hot-dip galvanized steel sheets were produced according to the production conditions shown in Tables 1 to 3 by using the spray hot-dip galvanizing apparatus of the present invention shown in FIGS. The quality of was investigated. The strip steel plate has a thickness of 1.75 m.
A hot rolled steel plate of m × width 1200 mm, low carbon Al killed steel was used. The line speed is 300 m / min., Which is about twice that of a normal continuous hot-dip galvanizing line. And pickled, then Ni
It is adjusted to a predetermined nickel skin layer thickness shown in Tables 1 to 3 by an electroplating apparatus, and the steel sheet temperature is adjusted to a predetermined temperature shown in Tables 1 to 3 by induction heating in an N ₂ + 5% H ₂ atmosphere. It heated and spray-plated in the plating chamber. The plating metal is a molten Z containing 99.8% Zn and 0.2% Al.
An n-Al alloy (melting point 450 ° C.) was used.

FIG. 3 shows the results of an investigation of the plating adhesion of the products manufactured in this example. From this figure, the thicker the nickel coating layer is, the wider the temperature range of the strip-shaped steel sheet during plating is.
The melting point of the molten metal to be plated −200 ° C. to the melting point + 200 ° C., which is formed in the range of 0 g / m ² and which does not oxidize the nickel coating layer on the steel sheet surface in an inert and / or reducing gas atmosphere. It can be seen that if hot-dip galvanized hot-rolled steel sheets with good plating adhesion can be manufactured at a line speed significantly higher than that of a normal continuous hot-dip galvanizing line, by spray-plating the strip-shaped steel sheet in a heated range.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

According to the present invention described above, it is possible to obtain an apparatus for inexpensively and easily producing a plated steel sheet of a cold-rolled steel sheet requiring no annealing or a pickled hot-rolled steel sheet, which is called a full hard material, at low cost and with high productivity. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of the entire equipment of the present invention,

FIG. 2 is a diagram showing an outline of a spray plating apparatus of the equipment of the present invention,

FIG. 3 is a diagram showing the results of investigation of plating adhesion of products manufactured according to the present invention.

[Explanation of symbols] 1 strip steel plate 2 pickling device 3 pickling rinse device 4 pickling dryer device 5 Ni electroplating device 6 electroplating rinse device 7 electroplating dryer device 8 heating device 9 plating device 1 0 plating Inlet seal chamber 1 1 Plating chamber Outlet seal chamber 1 2 Spray nozzle 1 3 Plating pot 1 4 Molten metal pump 1 5 Molten metal pipe 1 6 Gas pipe

Claims (2)

[Claims] 1. A strip steel sheet is continuously pickled to clean its surface, and then a nickel coating layer of 0.5 to 0.5 is formed on the surface.
It is formed in a range of 2.0 g / m ^2, followed without oxidizing the nickel coating layer of the steel sheet surface with an inert and or reducing gas atmosphere, mp -200 ° C. ~ melting point of the molten metal to be plated +200 After heating to the range of ℃,
A continuous hot-melt spray plating method for strip steel plates, characterized in that fine particles of a molten metal to be plated are spray-plated on the surface in an inert and / or reducing gas atmosphere. 2. A pickling device, Ni, in the running direction of the strip steel plate.
Electroplating equipment, heating equipment in an inert and / or reducing gas atmosphere, and a spray nozzle for spraying fine particles of molten metal onto the surface of a strip-shaped steel sheet continuously passing through the interior in a plating chamber hermetically connected to this heating equipment. A continuous hot-dip galvanizing apparatus for strip-shaped steel sheets, which is characterized by sequentially arranging the galvanizing apparatuses that have been arranged.