JPS63162847A - Method for coating steel strip with molten metal - Google Patents

Abstract

PURPOSE:To change over a coating metal to other coating metal in a short time, by jetting a molten metal on the surfaces of coating rolls brought into contact with a steel strip on a vertical pass line and by changing over the molten metal to other molten metal or mixed molten metals including the molten metal. CONSTITUTION:Two kinds of molten metals such as molten Al and molten Zn are separately poured into molten metal tanks 16, 16'. A steel strip 2 is sent, valves 17 are opened to feed molten Al from the tank 16 and the fed molten Al is jetted from slit nozzles 12 on the surfaces of coating rolls 11 brought into contact with the steel strip 2 to coat the strip 2 with Al. The valves 17 are then closed, residual molten Al in pipes 14 and on the rolls 11 is removed and valves 17' are opened to feed molten Zn from the tank 16' to the nozzles 12. Molten Al and molten Zn may be simultaneously fed to the nozzles 12.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a hot-dip metal plating method for steel strips, and in particular, it is possible to perform various types of plating in one line, and it is possible to change to different types of plating solutions. The present invention relates to a hot-dip metal plating method that can be easily implemented in a short time.

<Prior art> Conventionally, when continuously applying hot-dip metal plating to a steel strip, as schematically shown in FIG. After being coated, both surfaces of the steel strip 2 are plated while being passed through a pot 5 filled with a molten metal plating solution 4 via a turn roll 6, and the plated steel strip 2 is coated with a plurality of layers. It is taken out of the tank by a deflection roll 7, wound up by a tension roll 8, and then shipped as a product. In addition, annealing furnace 3
and pot 5 is a snout 3a with a non-oxidizing atmosphere.
covered with.

In such conventional methods, when applying different types of plating, the following method is used.

(a) As shown in FIG.
horizontally (or vertically) to the path line of
How to line them up and slide them to switch.

(b) As shown in FIG.
A method of lining up vertically with respect to the pass line and switching by changing the pass line.

(C) Method of replacing the molten metal plating solution in the bot with a pump, etc.

<Problems to be Solved by the Invention> Although it is possible to perform different types of plating using any of the above methods, however, these methods have the following problems.

■ In any of the above methods (a), (b), and (c), it takes several hours to several tens of hours to change the plating solution, which leads to a decrease in efficiency, a worsening of the basic unit, and a decrease in yield. .

■ As the number of types of plating increases, it is necessary to increase the number of spare pots, and sliding the pot or changing the pass line becomes complicated, so there is a limit to the number of types available.

■ Conventional pots contain tens of tons to hundreds of tons.
), the burden of managing unused pots is heavy.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molten metal plating method that allows easy switching to a different type of plating solution in a short time.

<Means for Solving the Problems> The present invention is a method of continuously applying hot-dip metal plating to the surface of a steel strip, in which a pair of plating rolls is provided on a perpendicular pass line of the steel strip. There is a process in which the copper strip is plated by spraying a molten metal plating solution onto the surface that comes into contact with the plating roll, and a process in which multiple different types of molten metal plating solutions are switched alone or mixed and fed. A method for hot-dip metal plating of a copper strip, characterized by comprising the following steps.

<Function> The present invention provides a plating roll, and uses a pump to switch the molten metal plating solution from a plurality of molten metal plating tanks capable of melting only a small amount onto the plating roll depending on the application. Alternatively, since a plurality of plating solutions are mixed and fed, switching to a different type of plating solution can be easily performed in a short time.

<Example> An example of the plating equipment according to the method of the present invention will be described below based on FIGS. 1 to 3.

FIG. 1 schematically shows the entire plating equipment according to the present invention, and the same members as in FIG.

In the figure, a pair of plating rolls 11 are arranged on a pass line between a turn roll 6 and a first deflector roll 7, and a pair of slit nozzles 12 are installed above them on a steel strip 2.
are provided diagonally opposite each other on both sides. This slit nozzle 12 has piping 14 and pumps 15, 15'.
It is connected to a plurality of different types of hot-dip metal plating baths 16, 16' installed outside the pass line of the copper strip through the valves 17, 17'. Here, the number of pumps 15, 15' and hot-dip metal plating tanks 16, 16' can be further increased depending on the type of plating required in this line. Since the entire plating roll 11 needs to be in a non-oxidizing atmosphere, the plating chamber including the turn roll 6 and slit nozzle 12 is enclosed in a non-oxidizing atmosphere from the exit side of the snout 3a for one day.

FIG. 2 is an enlarged perspective view of the vicinity of the plating roll 11. As shown in FIG. 2(a), a pair of plating rolls 1
Side seal members 21 are provided to prevent the plating solution from leaking from both sides of the plate. This side seal member 21 is movable by a driving means (not shown) according to the width of the steel strip. In addition, in order to be able to control the level of the plating solution on the plating roll 11, as illustrated in FIG. It is preferable to combine them to form a fence.

Further, it is preferable that the roll 11 and the side seal member 21 be subjected to electrical resistance heating in order to prevent attachment of hot-dip plated metal.

The operation of this embodiment will be explained below.

As the molten metal plating solution, for example, two types of molten aluminum plating solution and hot-dip galvanizing solution are used and placed in the molten metal plating baths 16 and 16' respectively, and the side seals 21 are prepared in advance according to the width of the plate. Position.

While passing the steel strip 2 through the turn roll 6, first close the pulp 17', open the pulp 17, and then start the pump 15 of the plating tank 16 containing the molten aluminum solution. As shown in FIG. 3, a molten aluminizing solution is sent out and sprayed from the slit nozzle 12 onto the contact area between the plating roll 11 and the steel strip 2 to apply aluminization. When the predetermined length of plating is completed, stop the line and
After stopping the pump 15 and closing the pulp 17, the residual aluminum plating solution in the pipe 14 is extracted and the valve 19 is opened to drain it into the drain tank 20. Also, the residual aluminum plating solution on the plating roll 11 is also not shown. Pull it out with a pump, etc.

Subsequently, while restarting the line, the pulp 17' is opened, the pump 15' is started, the hot-dip galvanizing solution is sent to the slit nozzle 12, and the steel strip 2 is similarly galvanized.

The time required to change the plating solution described above can be within several tens of minutes.

Furthermore, if the pumps 15 and 15' are operated at the same time to send out the same amount of hot-dip aluminum plating solution and hot-dip galvanization, it is possible to perform aluminum-zinc alloy plating, and the type of plating solution can also be changed. By increasing the number, it becomes possible to apply even more types of plating.

<Effects of the Invention> As explained above, according to the present invention, a pair of plating rolls are provided and a plating tank is provided to enable switching depending on the type of plating, so the following effects are achieved.

(1) Since the time required to switch to a different type of plating is very short, there is no need to stop the line for a long time, and it is possible to prevent the conventional efficiency drop, deterioration of basic unit, and yield drop.

(2) The plating tank to be placed only needs to have a small capacity, so it is easy to manage. Furthermore, since it is possible to prepare many tanks, it is possible to perform various types of plating.

(3) Since the composition of alloy plating can be easily changed, it is possible to perform various alloy platings.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram schematically showing an embodiment of plating equipment according to the method of the present invention, Fig. 2 is an enlarged perspective view of a plating roll, and Fig. 3 shows the state in which a steel strip is plated. The schematic diagrams shown in FIGS. 4, 5, and 6 are schematic diagrams schematically showing conventional plating equipment. 2... Steel strip, 4... Molten metal plating solution,
6... Turn roll, 7... Deflection roll, 11... Plating roll, 12... Slit nozzle, 14... Piping, 15... Pump, 16.
...Hot dip metal plating tank, 17...Pulp, 20.
...Drainage tank, 21...Side seal member Patent applicant Kawa V4 Steel Co., Ltd. Figure 1 Figure 3 Figure 2 Figure 1) Figure 4 Figure 5

Claims (1)

[Claims] A method of continuously applying hot-dip metal plating to the surface of a steel strip, in which a pair of plating rolls is installed on the perpendicular pass line of the steel strip, and a hot-dip metal plating solution is sprayed onto the surface of the steel strip in contact with the plating rolls. Hot-dip metal plating of a steel strip characterized by comprising a step of applying plating to the steel strip, and a step of feeding a plurality of different types of hot-dip metal plating solutions, either singly or in combination. Method.