JPS5856028B2 - Single-sided molten metal plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuously plating one side of a steel plate with molten metal.

Many methods have been known for manufacturing single-sided galvanized steel sheets, which have been in increasing demand in recent years.

One of them is proposed in Japanese Patent Application Laid-Open No. 53-75124 (see Fig. 1), in which a strip 30 is run on the bath surface of a molten zinc tank, and a jet nozzle 31 is applied to the bath surface from below. There is a method in which the strip is heaped up or molten zinc is jetted above the bath surface, resulting in only the bottom surface of the strip coming into contact with the molten zinc, thereby performing single-sided plating.

In this case, the wetting length L between the molten zinc and the strip 30 is
) controls the contact time between zinc and the IJJ tube, and this contact time plays an extremely important role as the reaction time during hot-dip galvanizing.

However, according to the conventional method described above, the wetting length obtained from one stage nozzle varies by at most 3 to 5 times the nozzle width. For example, when a slit nozzle with a width of 10 mrrt is used, the wetting length L) is It's only about 30 to 50 degrees different.

In other words, in order to achieve a reaction time equivalent to the reaction time of the current continuous double-sided galvanizing line with a single-sided galvanizing line, it is necessary to either make the line speed extremely slow or to install the nozzles 31 in Fig. 1 in multiple stages toward the line. becomes.

However, the former method results in low productivity, while the latter method requires an extremely large total discharge flow rate of zinc, making it uneconomical and difficult to maintain.

- When performing such one-sided plating, it is extremely important and difficult to prevent zinc from going around the other side that is not plated (especially when the strip width is changed).

For this reason, in the conventional method described above, measures are taken to spray inert gas onto the top surface of the strip to prevent the zinc from going around from the strip edges, but in order to achieve this, it is necessary to There are problems such as the need for inert gas.

The present invention was proposed as a result of various studies to improve the above-mentioned problems.

That is, an object of the present invention is to increase the wetting length L) in order to prolong the reaction time during molten metal plating, and to increase the supply efficiency of molten metal.
without letting molten metal get to the other side that is not plated.
To provide an apparatus which can apply uniform and beautiful plating to one side of a strip and can easily cope with changing the width of the strip.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention.

In the figure, reference numeral 1 denotes a strike IJ tube, which runs while being held horizontally with respect to the bath surface by a pair of horizontal rolls disposed at the top of the plating bath.

In the device of the present invention, a nozzle plate 17 is disposed on the lower blade of the horizontally traveling I-IJ knob 1.

This nozzle plate 17 has a slit-shaped discharge port 1 extending in the width direction on the rear end side in the longitudinal direction (strip traveling direction).
5a, which are arranged parallel to the strip 1 and at a predetermined interval.

A nozzle header 15 communicating with the discharge port 15a is provided at the bottom of the nozzle plate 17, and molten metal is supplied between the strip 1 and the nozzle plate 17 from the nozzle header 15 through the discharge port 15a.

A baffle plate 21 extending in the width direction is provided at the front of the nozzle plate 17 in the steel plate traveling direction (at the front end in the longitudinal direction).

This baffle plate 21 functions to change the flow ejected from the discharge port 15a from the line direction to the width direction.

The discharge port 15a is provided so as to be inclined toward the front side in the strip traveling direction, and furthermore, in this embodiment, the discharge port 15a
A baffle plate 6 is provided protrudingly on the side opposite to the side where the nozzle plate is disposed, so that the molten metal flowing out from the discharge port 15a forms a smooth flow in the strip advancing direction.

Furthermore, nozzle masks 20 are provided at both ends of the slit-shaped discharge port 15a to be slidable in the width direction of the nozzle plate, respectively, for partially blocking both ends of the discharge port to an arbitrary length.

This nozzle mask 20 is used to adjust the length of the discharge port 15a as the width of the strip to be plated is changed, and in this embodiment is constituted by a plate member that slides over the discharge port 15a.

Note that the nozzle mask 20 is slid through the connecting rod 201 by a known means such as a fluid pressure cylinder or a mechanical feed device (not shown).

FIG. 3 shows an embodiment of the second invention of the present application, in which, in addition to the configuration shown in FIG. It is something that

This edge mask 22 prevents a large amount of molten metal supplied from the discharge port 15a from flowing out from the strip edge portion, and actively flows it toward the line to extend the wetting length of the strip. The distance between the strip and the nozzle plate is narrowed at the edge portion, and the nozzle plate is arranged to be slidable in the width direction according to changes in the strip width.

In this embodiment, the edge mask 22 is provided integrally with the nozzle mask 20 and extends a predetermined length from the nozzle mask 20 in the direction of the baffle plate 21 along the strip edge portion.

There is a gap between the edge mask 22 and the baffle plate 21, so that the molten metal flowing toward the line can finally flow from this portion toward the edge without resistance.

Note that the nozzle mask 20 and the edge mask 22 are slid by a known means such as a fluid pressure cylinder or a mechanical feed device (not shown) via the connecting rod 20L201.

FIG. 4 shows a cross section of the edge mask 22. The upper surface of the edge mask 22 is elevated in a mountain-like or streamlined shape toward the strip edge, and at the strip edge, the strip 1 and the nozzle plate 17 The edge mask 22 and the nozzle mask 2
0, and separate mechanical feed mechanisms may be provided for each.

Each of the embodiments described above is an example of the present invention, and for example, the nozzle plate is not limited to the one shown in the drawings, but as long as the plate is parallel to the lower surface of the strip, the design of the detailed structure etc. can be changed as necessary. It is possible.

In addition, the distance between the baffle plates 6, 21 and the strip 1 should be kept at a distance of about 5 degrees in consideration of the unevenness of the strip 1, but depending on the material of the baffle plate, if it does not damage the strip 1. The interval may be such that it can be touched lightly.

In the present invention, the molten metal effluent from the nozzle plate 17 may be directly received in the plating bath as in the conventional case, or may be temporarily received outside the nozzle plate 17.

Further, it is preferable that the nozzle mask 20 and the edge mask 22 be configured to automatically slide in response to changes in the strip width.

It goes without saying that the present invention can be applied to any molten metal plating other than molten zinc.

Next, the present invention will be explained in detail.

In the apparatus of the present invention, molten metal is ejected from the discharge port 15a to form a molten metal jet between the strip 1 and the nozzle plate 17, and the strip is plated.

This will be explained based on FIG. In the figure, 2 is the plating bath surface.

When molten metal such as zinc is ejected from the slit-shaped discharge port 15a, the molten metal collides with the lower surface of the strip 1, and then flows toward the line, filling the space between the nozzle plate 17 and the lower surface of the strip, and the wetting length increases. Plating can be performed with sufficient thickness.

That is, in the conventional method without the nozzle plate 17, the bath surface of the discharged molten metal becomes as shown by the dotted line in the figure, and the wetting length becomes short, whereas in the case of the present invention with the nozzle plate 17, the bath surface of the discharged molten metal becomes as shown by the dotted line in the figure. The wetting length can be made sufficiently long by making the amount of molten metal supplied from the outlet 15a larger than the amount flowing out from the outflow portion (■ in the figure).

This makes it possible to obtain a line speed for single-sided plating strips comparable to that for double-sided plating.

In addition to these basic functions, the present invention slides the nozzle mask 20 according to the strip width, adjusts the length of the discharge port 15a, and further controls the baffle plate 21 protruding from the front end of the nozzle plate 17. This action changes the flow of the molten zinc flowing out from the discharge port 15a from the line direction to the width direction, thereby ensuring sufficient wettability at the strip edge while preventing the molten metal from going around to the non-plated surface. It can definitely be prevented.

Based on the example shown in Figure 2, we conducted hot-dip galvanizing experiments under the conditions listed in the table below, and were able to achieve uniform single-sided galvanizing without zinc going around to the non-plated surface. .

Furthermore, in the apparatus shown in FIG. 3, in addition to the above-described effects, the flow path of the supplied molten metal is constricted at the strip edge portion by the edge mask 22, so that the molten metal flows out from the strip edge portion. This makes it possible to efficiently supply molten metal toward the line, and to appropriately plate the strip edges.

In addition, in the apparatus according to this embodiment, the edge mask 2
In an experiment, the width (11) of 2 was about 50 mm, and the maximum height 12) from the nozzle plate 17 was about 5 mm (the distance between the nozzle plate and the strip (13) was 10 mm). Under the same flow rate conditions as in the experiment using this method, a wetting length approximately 1.5 times longer could be secured, and line speeds up to 200 mpm were possible.

According to the present invention described above, it is possible to ensure a sufficient wetting length and to sufficiently lengthen the reaction time of molten metal plating. It has the excellent effect of being able to apply uniform plating in all directions, as well as properly preventing molten metal from going around the non-plated surface, thereby allowing uniform and beautiful plating to be applied to one side of the strip. It is.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a conventional single-sided mating type. FIG. 2 is a perspective view of essential parts showing one embodiment of the present invention and its usage situation. FIG. 3 is a perspective view of main parts showing another embodiment of the present invention and its usage situation, FIG. 4 is a sectional view taken along line B-B in FIG. 3, and FIG. 5 is a plating state according to the present invention. FIG. In the figure, 15a is a discharge port, 17 is a nozzle plate, 20 is a nozzle mask, and 22 is an edge mask. 21 is a baffle board,

Claims (1)

[Claims] 1. In an apparatus for plating molten metal on the lower surface of a horizontally traveling strip, a slit-shaped molten metal discharge port is provided which is inclined inwardly as the sl-IJ tube advances and extends in the width direction. A nozzle plate on the rear end side in the direction of stripping force is disposed on the lower strip blade parallel to the strip with a gap therebetween, and a baffle plate along the width direction of the nozzle plate is provided in front of the nozzle plate in the direction in which the strip moves. 1. A single-sided molten metal plating apparatus, characterized in that a nozzle mask is provided on both ends of the discharge port so as to be slidable in the width direction of the nozzle plate, and can close both ends of the discharge port to an arbitrary length. 2. In an apparatus for plating molten metal on the lower surface of a horizontally traveling steel plate, a slit-shaped molten metal discharge port that is inclined inward and runs along the width direction of the sl-IJ tube is located at the rear end of the slit-shaped molten metal discharge port in the direction of the stripping force. A nozzle plate on the side is arranged on the strip lower blade so as to be parallel to the strip and with a gap therebetween, and a baffle plate is protruded along the width direction of the nozzle plate in front of the nozzle plate in the strip traveling direction. On both sides of the nozzle plate, a nozzle mask that can close both ends of the discharge port to an arbitrary length, and an edge mask that narrows the gap between the sl-IJJ tube nozzle plates at the strip edge part can be slid in the width direction of the nozzle plate. Single-sided molten metal plating equipment characterized by the following: