JPS59126768A - Continuous hot-dipping device - Google Patents

Abstract

PURPOSE:To prevent the formation of a rippled surface on a plating surface in the stage of subjecting slightly thickly a strip to hot-dipping by performing cooling with cooling water by means of coating rolls in the position where the plating metal after the passage through a gas squeezing device is in a molten state. CONSTITUTION:A strip 1 is passed through a molten Zn bath 4 to stick molten Zn on the surface thereof, and thereafter compressed gas is ejected thereto by a gas squeezing device 7 to adjust the amt. of the molten Zn sticking on the surface thereof to a specified thickness. Both surfaces of the strip are brought into contact with coating rolls 11, 11 in the position where the Zn sticking on both surfaces of the strip 1 is still in a molten state. The cooling water in van 14 is always supplied via pickup rolls 15, to the surface of the rolls 11, 11, and the Zn in a molten state is cooled to solidify by such cooling water, where the flat and relatively thick Zn plating layer having no rippled surface is continuously formed on the surface of the strip 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a continuous hot-dip galvanizing device such as a continuous hot-dip galvanizing device, and in particular, plating on the surface of an IJ tube after it has been lifted from a molten metal bath and wiped by a gas throttling device. The object of the present invention is to provide a continuous hot-dip plating apparatus that can uniformly cool a coating and smooth the surface of the plated coating.

In a hot dip metal plating manufacturing process such as a continuous galvanizing line, a continuously fed strip is pasted after passing through a molten metal bath to adhere the molten metal to the strip surface, and the upward progress position after passing through the molten metal bath is A tampering device is used which is configured to adjust the amount of molten metal coating by means of a gas throttling device installed in the molten metal coating. In hot-dip galvanizing, the thickness of the plating layer is specified.
In order to control the thickness of the plating layer, a wiping method is adopted in which gas is injected into the plating layer that is still in a molten state to control the plating layer thickness to a specified thickness. This is a device used for

FIG. 1 is a diagram illustrating the configuration of a continuous hot-dip plating apparatus of the type described above.

In FIG. 1, a strip 1 whose surface has been surface-cleaned by a cleaning process such as degreasing and pickling is continuously passed from a town-down roll 2 through a snout 3 into a molten metal bath (for example a molten zinc bath) 4. After passing through the zinc roll 5 installed in the metal bath 4, the feeding awn changes its direction of movement upward, is lifted out of the metal bath, and passes through the deflector roll 6 installed above. The molten metal that adheres to the surface of the strip while passing through the molten metal bath 4 is reduced by the amount of molten metal adhered to the strip by a gas throttle device 7 installed at an upwardly advancing position after passing through the molten metal bath 4. (
The coating thickness may be adjusted accordingly. As mentioned above, this gas squeezing device 7 injects compressed gas into the plating layer which is still in a molten state to adjust the coating amount to a constant value.

In the conventional continuous hot-dip plating apparatus as explained above with reference to FIG. Part of the still molten coating metal 8 flows downward.

There is a problem in that the solidification occurs as it is, resulting in a wavy pattern (hereinafter referred to as hot water wrinkles) 9 on the plating surface.

These hot water wrinkles 9 not only damage the appearance of the plated surface, but also appear even after painting, and seriously reduce the product value. The disadvantage was that it caused problems. Note that the reference numeral 10 in FIG. 2 indicates an alloy layer formed at the interface between the strip 1 and the coating metal 8, and when a galvanized layer is formed on the steel strip, an Fe--Zn alloy layer can be completely formed.

The molten metal wrinkles 9 are caused by the metal still in a molten state flowing vertically downward due to its own weight after passing through the gas throttle device 7. Likely to happen. In addition, (c) If the progressing speed of the IJ bulge is fast, the hot water lines 9 will become small, and if the progressing speed is slow, they will become large.

An object of the present invention is to provide a continuous hot-dip plating apparatus Z that can eliminate the drawbacks of the prior art as described above and effectively prevent the occurrence of hot water wrinkles.

In the present invention, the coating roll 7 is installed at a position where the plating layer is still in a molten state after passing through a gas throttling device, and the coating roll is brought into contact with the plating layer while applying cooling water to the surface of the coating roll. By continuously cooling the plating layer.

This aims to achieve the above objectives.

That is, according to the present invention, a continuously fed strip is caused to pass through a molten metal bath so that the molten metal is deposited on the surface of the strip, and a gas constriction is provided at an upwardly advancing position after passing through the molten metal bath. In a plating device that adjusts the amount of molten metal coating using a device, a fl is placed on the coating roll at a position where the plating layer is still in a molten state after passing through the gas expansion device.
There is also provided a continuous hot-dip plating apparatus characterized in that the plating layer is continuously cooled by bringing the coating roll into contact with the plating layer while applying cooling water to the surface of the coating roll.

The present invention will be described in detail below with reference to FIGS. 4 and 5.

FIG. 4 is a view showing the essential parts of the first embodiment of the apparatus of the present invention, in which a coating roll 11 is installed at a position where the tight layer that has passed through the gas expansion device 7 is still in a molten state. In the illustrated example, the coating roll 11 is
They are installed on both sides of the tube 1 and are arranged so as to abut against each of the plating layers on the five surfaces.

On the other hand, water is supplied from the cooling water tank 12 via a pump 13'.
Cooling water is supplied to each of the holes 14 provided inside the IJ tube 1. A pick-up roll 15 is provided in each nozzle 14, and the lower half of this pick-up roll 15 is immersed in the cooling water inside the nozzle 14, and the surface force on the surface of the cooling water is applied. It is arranged so as to be in contact with the roll 11.

Therefore, the cooling water supplied into each pan 14 adheres to the surface of each pickup roll 15 and is applied to the surface of the coating roll 11. Since the coating rolls are in contact with the plating layers on both sides of the strip 10, the cooling water applied to each coating roll 11 moves to each plating layer and can continuously cool the plating layers. The aqueous solution after cooling the plating layer is stored in each pan 14, and the aqueous solution (cooling water) stored in the pan 14 overflows and is returned to the cooling water tank 12 and pumped up again. It is supplied to the pan 14.

The plating layer of the strip 1 can be continuously cooled by such a cooling water circulation system for the coating roll 11.

As the cooling water applied to the coating roll 11, water or a known minimum spangle solution can be used. Further, the coating roll 1 is for applying an aqueous solution to the surface of a high-temperature molten metal (e.g. zinc) coating, and furthermore, in order to prevent the molten metal from pinking up on the coating roll and to facilitate the application of the aqueous solution. It is preferable to use water-cooled iron rolls.

It is preferable to control the amount of cooling water (aqueous solution) applied depending on the solidification state of the molten metal coating.
This can be done by adjusting the gap with 5.

In addition, the pickup O-LE I5 TOL-TEHA,
In order to facilitate the movement of cooling water to the coating roll 11, it is preferable to use a felt roll.

It is preferable that each of the coatings 11% 11 be rotated in the same direction as the traveling direction of the strip, as shown, in order to prevent surface damage to the molten metal coating.

According to the first embodiment described above with reference to FIG. 4, 11 coating rolls are used and the cooling water applied to the surface of the coating rolls is applied to the molten metal film. The plating layer can be forcedly cooled continuously without causing uneven cooling in any direction. Considering the cause of the generation of hot water wrinkles mentioned above, it is necessary to instantly solidify the molten metal coating after wiping by forced cooling to prevent the molten metal from flowing down. However, according to the embodiment shown in FIG. Since the layer can be effectively cooled uniformly and instantaneously, the occurrence of such hot water wrinkles can be extremely effectively prevented. By the way, the direct cooling method for molten metal plating is
A method of spraying an aqueous solution onto the surface of the IJ tube may be considered, but such a method tends to cause uneven cooling in the width direction, and since the liquid contains gas, the cooling effect is small, as shown in Figure 4. Example 7 cannot obtain any of the hot water wrinkle prevention effects. In the embodiment shown in FIG. 4, a uniform cooling water film can be formed on the surface of the coating roll 11, and since this is brought into contact with the surface of the strip 10, the molten metal on the strip surface is uniformly and effectively cooled. It is possible to do so.

FIG. 5 is a diagram showing a second embodiment of the apparatus of the present invention, in which a slit type spray 16 is used instead of the pickup roll 15 in FIG. 4, and a cooling water tank 12 is passed through a pump 13. This modification has been made so that the supplied cooling water can be directly sprayed onto the surface of the coating roll 1 from the spray 16 to keep the coating roll surface constantly wet. The rest of the structure is substantially the same as the embodiment shown in FIG. 4, and corresponding parts are denoted by the same reference numerals and detailed description thereof will be omitted.

According to the embodiment shown in FIG. 5, the same effects as in the embodiment shown in FIG. 4 described above can be achieved.

By omitting 15 baby rolls compared to the embodiment shown in FIG. 4, the structure can be simplified. Note that the spray 16 can also be installed above the coating roll 11 as shown by the dotted line.

Next, test results when the embodiment of the present invention shown in FIG. 4 is applied to an actual continuous hot-dip galvanizing line will be described.

In this test, a strip with a thickness of 0.8 m and a width of 1219 m + width was operated at a line speed of 60 m/min, and the zinc coating amount was 300 W/n? Continuous hot-dip galvanizing was carried out with l. When the plated coating, which was still in a molten state, was cooled after passing through the gas expansion device 7 using the apparatus shown in FIG. 4, a plated product with a smooth surface without hot water wrinkles was obtained.

In this test, the temperature of the galvanized steel plate in the area in contact with coating roll 1 was 420°C ± 10°C, and the amount of water (cooling water) supplied by coating roll 11 was 10μ to 15μ in terms of water film thickness. Ta. This water film thickness corresponds to a cooling water supply amount of 713 to 1097 P/min when converted from the size of the S h II tube (steel plate) and line speed described above.

As is clear from the above description, according to the present invention.

Continuous hot-dip plating equipment is capable of manufacturing plated products with smooth surfaces without creases by uniformly and effectively cooling the plating layer, which is still in a molten state after passing through a gas throttling device, and promoting its solidification. can get.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram illustrating the configuration of a continuous hot-dip plating apparatus suitable for applying the present invention, Fig. 2 is an explanatory diagram illustrating hot water wrinkles generated on the hot-dip plating surface, and Fig. 3 is a front view of Fig. 2. 4 is an explanatory diagram showing the main part structure of the first embodiment of the continuous hot-dip plating apparatus according to the present invention, and FIG. 5 is an explanatory diagram showing the main part structure 7 of the second embodiment of the continuous hot-dip plating apparatus according to the present invention. It is a diagram. 1... Strip, 4... Molten metal bath, 7
... Gas throttle device, 8... Covered metal, 9...
Hot water lines. 11°°゛Coating roll (water-cooled iron roll), 12
...Cooling water tank, 13...Pump, 14
...Bread, 15°゛°Pick-a-Sprout,
16...Spray. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A gas throttling device that is continuously fed by passing the IJ tube through the molten metal bath and attaching it to the surface of the IJ tube and installed at a position where it moves upward after passing through the molten metal bath. In a plating device that adjusts the amount of molten metal coating by a method, a coating roll is installed at a position where the plating layer is still in a molten state after passing through the gas expansion device, and the coating roll is heated while applying cooling water to the surface of the coating roll. 1. A continuous hot-dip plating device, characterized in that the plating layer is continuously cooled by contacting the plating layer with the plating layer.