JPH0564231B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a method for plating a metal strip by a meniscus coating method using a plating nozzle having a protruding weir inside an opening to narrow the gap between the openings. The present invention relates to a method for controlling the amount of plating deposited by adjusting the amount of molten metal sucked out from the plating nozzle.

(Prior art) As a method of applying melt plating to a metal strip, a plating nozzle is provided in a molten metal bath, and the metal strip is run while being brought very close to the nozzle, so that the plating bath between the metal strip and the nozzle opening is heated. There is a method of plating a metal strip by meniscus coating by sucking out molten metal by the wet adhesion force with the metal. In the case of melt plating using this meniscus coating, the amount of plating deposited is mainly determined by the running speed of the metal strip, the distance between the metal strip and the nozzle opening, and the amount of molten metal sucked out. This method has been used because it is easy to keep the speed constant and adjust the distance between the metal strip and the nozzle opening and the amount of molten metal sucked out.

(Problem to be solved by the invention) However, when controlling the amount of plating by adjusting the distance between the metal strip and the nozzle opening, the amount of plating is determined by the distance between the metal strip and the nozzle opening. As shown in Fig. 4, there is a tendency for the temperature to change rapidly, but not to change much before and after that point. Therefore, for stability of control, the distance between the metal strip and the nozzle opening must be set in a range where the amount of plating does not vary greatly, and there are cases where it is not possible to set the amount of plating to the desired amount.

On the other hand, when controlling the amount of plating deposited by the amount of molten metal sucked out, conventionally a weir 3 is provided protruding inside the flat opening 2 with the upper and lower surfaces of the nozzle 1 parallel to each other, as shown in FIG. This was done by narrowing the gap inside the opening 2. Cough here 3
The reason for protruding into the inside of the opening 2 is that the gap at the tip of the opening 2 needs to be widened to some extent in order to form a meniscus of molten metal. However, since the spout 3 was fixed and protruded from the nozzle 1, it was necessary to temporarily stop plating and replace the nozzle 1 in order to adjust the amount sucked out.

In addition, in the case of a method in which a weir 3 is provided protruding inside the opening 2 to adjust the amount of molten metal sucked out, if the gap is narrowed by the weir 3, the nozzle is likely to become clogged, and the molten metal will not be sucked out. There were times when things did not go smoothly.

(Means for Solving the Problems) The present invention provides a method for controlling the amount of plating that does not cause the above-mentioned problems when the amount of plating is controlled by the amount of molten metal sucked out. The protruding opening portion is partially closed to control the amount of molten metal sucked out. That is, the present invention includes a weir in which a plurality of strip-shaped divided bodies of the same width are arranged in close contact with each other in a plate shape in the width direction of the opening, and each insertion end is spaced from the bottom surface of the opening at equal intervals from the upper side of the outside of the nozzle to the inside of the opening. The split body is inserted over the entire width of the opening, and each divided body is individually slidable in the insertion direction. By protruding at equal intervals on the lower surface side, the gap in the weir part is partially closed,
The amount of molten metal sucked out was controlled.

(Function) The divided bodies constituting the weir are inserted into the entire width of the opening in close contact with each other, so that molten metal does not pass between the divided bodies. Moreover, since the insertion ends of each divided body are spaced apart from the lower surface of the opening at equal intervals, the molten metal passing through the weir portion is uniform over the entire width direction. In this state, if some of the divided bodies are made to protrude to the bottom side of the opening at equal intervals, the width of each divided body is the same, so the gaps in the weir part can be closed evenly at equal intervals, and the width direction The amount of molten metal passing through can be uniformly reduced.

Although the present invention alone may be used to control the amount of glazing deposited, it is also possible to use the present invention together with adjustment of the traveling speed of the metal body and the distance between the metal body and the nozzle opening.

The present invention will be explained below with reference to Examples.

(Example) FIG. 1 shows a nozzle 1 used in the present invention, and in FIG. The weir 3 is formed by arranging a plurality of strip-shaped divided bodies 4 of the same size closely in a row in the width direction of the opening 2 to form a plate wider than the width of the opening 2, and the lower side of the plate is connected to the upper nozzle wall of the nozzle 1. It is inserted perpendicularly into the opening 2 through the groove-shaped hole provided in 5. The divided bodies 4 are inserted so as to be in close contact with the nozzle wall 5, and each divided body 4 can be slid in the vertical direction. Further, the insertion end of each divided body 4 is spaced apart from the lower surface of the opening 2 at equal intervals. Furthermore, an operating rod 6 is fixed to the upper part of each divided body 4 projecting from the nozzle 1, so that each divided body 4 can be individually slid.

If the weir 3 is constructed from a plurality of divided bodies 4 as described above, and some of the divided bodies 4 are lowered at equal intervals with the operating rod 6 as shown in FIG. is partially closed, so the area through which molten metal can pass becomes smaller, and the amount sucked out is reduced.

Note that even if the gap in the weir 3 of the opening 2 is partially closed with the dividing body 4, the flow of molten metal will be uniform by the time it reaches the tip, so that the plating will not adhere in the width direction of the metal strip. The quantity distribution becomes constant. Furthermore, the operation rod 6 may be moved manually or automatically when lowering the divided body 4.

FIG. 2 shows an embodiment of a plating device in which the actuating rod 6 is automatically moved and the nozzle 1 shown in FIG. 1 performs plating while controlling the coating amount. The operating rod 6 of each divided body 4 constituting the weir 3 is pivotally connected to one end of each lever 10 provided on the box 9, which is protruded from the lower side of the molten metal tank 8 of the plating bath 7. An air cylinder 11 is pivotally attached to the other end of each lever 10, and each divided body 4 constituting the weir 3 is moved up and down by this air cylinder 11.

A deflector roll 12 is disposed in front of the nozzle 1 protruding as described above, and the steel strip 1 is moved horizontally by the deflector roll 12.
3 is turned upward so that the steel strip 13 is close to the tip of the nozzle 1. In this state, the steel strip 13
When the opening 2 of the nozzle 1 is moved by the steel strip,
The steel strip 13 is plated as the molten metal is sucked out. Note that 14 is a plating bath supply device,
Inside box 9, an inert or reducing atmosphere is created.

Next, a case will be described in which hot-dip galvanizing is applied to a steel strip by controlling the amount of plating deposited using the galvanizing device shown in FIG. In this case, the nozzle body of the nozzle 1 is made of isotropic electrographite, and when the weir 3 is slid, the part that the weir 3 contacts is reinforced with ceramics made of aluminum titanate crystal, and the weir 3 is made of 25 A structure made up of two divided bodies 4 was used. When plating, set the gap between the weir 3 to 0.7 mm, the width of the opening 2 to 100 mm, the temperature of the molten zinc in the nozzle 1 to 480°C, and the distance between the opening 2 and the metal strip to 0.8 mm. Also, the running speed of the steel strip
The speed was set at 60 m/min, and during plating, the divided bodies 4 were partially lowered at equal intervals to partially close the gap between the weirs 3 and the amount of plating deposited. As a result, we were able to control the amount of plating to 10 to 90 μm.

(Effects) As described above, the present invention does not narrow the gap between the weir parts, but partially closes the gap while keeping the gap constant to control the amount of plating. There is no need to stop plating when changing the amount, and nozzle clogging does not occur.

[Brief explanation of the drawing]

Figure 1 shows the plating nozzle used in the present invention, where A is a perspective view, B is a front view, and C is A of B.
It is a sectional view at -A. FIG. 2 shows an embodiment of a plating apparatus for controlling the amount of plating deposited according to the present invention. FIG. 3 shows a conventional plating nozzle, in which A is a front view and B is a sectional view taken along line B-B. FIG. 4 is a graph showing changes in the amount of plating deposited depending on the distance between the opening of the plating nozzle and the metal strip. 1... Nozzle, 2... Opening, 3... Weir, 4
...Divided body, 5... Nozzle wall, 6... Operating rod, 7
... plating bath, 8 ... molten metal tank, 9 ... box, 10 ... lever, 11 ... air cylinder,
12... Deflector roll, 13... Steel strip, 1
4...Plating bath supply device.

Claims (1)

[Claims] 1. A plating nozzle having an opening for supplying molten metal with a flat bottom surface is provided protrudingly in the molten metal tank, and a weir (weir) is provided protrudingly on the upper surface of the opening to narrow the gap between the openings, and the metal strip is In a meniscus coating method in which the metal band is moved very close to the tip of the nozzle opening, and the molten metal is sucked out by the wet adhesion force between the metal band and the plating bath at the nozzle opening and the metal band is plated, the weir is A plurality of strip-shaped divided bodies of the same width are arranged closely in a plate shape in the width direction of the opening and are inserted from the upper side outside the nozzle into the opening so that each insertion end is spaced equally apart from the lower surface of the opening over the entire width of the opening. It is provided by inserting and making each divided body individually slidable in the insertion direction, and part of the divided body is placed at equal intervals on the underside of the opening while the other divided bodies are held at a fixed position. A method for controlling the amount of plating deposited in a meniscus coating method, which comprises partially closing a gap in a weir portion by protruding and controlling the amount of molten metal sucked out.