JPH06322500A - Vibration preventive device for galvanized steel strip - Google Patents

Abstract

PURPOSE:To more exactly prevent the vibration of a plated steel strip in a gas wiping position by clamping the plated steel strip pulled up from the inside of a galvanizing bath from both sides by means of clamping mechanisms via dross suspended on the bath surface. CONSTITUTION:The plated steel strip 21 pulled up from the galvanizing bath 31 is clamped from both sides via the dross 32 suspended on the surface of the plating bath 31 by the clamping mechanisms 4 installed near the plating bath surface. The clamping mechanisms 4 hold both sides of a pair of clamping rods 6, 6a longer than the width of the steel strip by means of arms 7, 7a and arms 8, 8a respectively. These arms 8, 8a are constituted to be freely passable and slidable into holding cylindrical bodies 9, 9a. These holding cylindrical bodies 9, 9a is fitted into vertical cylindrical bodies 11, 11a via supporting members 10, 10a and are fixed to a plating cell 1 by means of stoppers 12, 12a. As a result, the vibration of the plated steel strip 21 by gas wiping is prevented and the variations in the plating adhesion are decreased. The steel strip 21 is clamped via the dross 32, by which the generation of flaws on the surface of the steel strip 21 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration preventing device for hot-dip galvanized steel strip in a galvanized steel sheet plating process.

[0002]

2. Description of the Related Art When manufacturing hot-dip galvanized steel strip,
While pulling up the plated steel strip fed into the hot dip galvanizing bath in the plating tank, a control gas is sprayed on both sides of the galvanized steel strip from a gas spray nozzle pair located at the top of the plating bath. It is common practice to control the amount of plating adhered to a predetermined amount with a gas wipe.

[0003]

From the above, during gas wiping, the ascending plated steel strip is vibrated with respect to the center position of the gas spray nozzle pair and is offset, and the plated steel strip surface is plated. A thick portion and a thin portion of the coating amount appear periodically, and this variation in the coating amount causes a marked deterioration in quality such as generation of a pattern called a tram mark on the plating surface. As an attempt to prevent such vibration, Japanese Patent Laid-Open No. 62-
As described in Japanese Patent No. 185667 and the like, it is disclosed that static pressure is generated on both sides of the plated steel strip to prevent vibration, but it is difficult to prevent reliable vibration even by this. There is a strong demand for the development of an anti-vibration device for hot-dip galvanized steel strip that can more accurately prevent vibration at the gas wiping position.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a vibration preventing device for hot dip galvanized steel strip which meets the above-mentioned demands, in which a galvanized steel strip pulled up from a galvanizing bath is arranged at the upper part of the bath. In a hot dip galvanizing device that gas wipes with a pair of gas spraying nozzles, a nipping mechanism that nips the galvanized steel strip from both sides via dross floating on the galvanizing bath is provided near the galvanizing bath. It is characterized by.

[0005]

[Function] Such a vibration preventive device for hot-dip galvanized steel strips is operated by the mechanism of the nipping mechanism when the hot-dip galvanized steel strip is pulled up and passes over the surface of the hot-dip galvanized bath. Since it is sandwiched from both sides via the dross floating on the bath surface, it is possible to reliably prevent the galvanized steel strip from vibrating while preventing scratches from being generated on the galvanized steel strip surface.

The dross generated in the galvanizing bath is roughly classified into Fe-containing dross and Al-containing dross. The Fe-containing dross precipitate on the bath bottom and the Al-containing dross float on the plating bath surface. The floating Al-containing dross does not cause a flaw even when it is soft and contacts the plated steel strip.

The present invention effectively prevents vibration of the plated steel strip by effectively utilizing the soft floating dross that does not cause a flaw even when it comes into contact with the plated steel strip. In addition to being able to suppress it, by sandwiching it with the action of the sandwiching mechanism via a soft floating dross, the plated steel strip does not generate any scratches and prevents vibration while maintaining high quality. It is possible to surely eliminate the above-mentioned difficulties due to occurrence.

However, when the plated steel strip is sandwiched via the floating dross, the dross gradually accumulates on the plated steel strip and the upper part of the sandwiching mechanism for sandwiching the stripped steel strip from both sides, and a part of the dross adheres to the plated steel strip. Since the quality may be deteriorated, when such a deposit occurs, the sandwiching of the galvanized steel strip is temporarily released, the dross is returned to the bath surface, and then the dross near the galvanized steel strip is scraped and sandwiched again. It is preferable to operate as described above. Therefore, it is necessary to provide the mechanism for sandwiching the plated steel strip near the surface of the plating bath.

[0009]

The present invention will now be described with reference to the illustrated embodiments. In FIGS. 1 and 2, 1 is a plating tank containing a zinc plating bath 31, 2 and 3 and 3 a are sink rolls 2 and support rolls installed in the plating tank 1,
Reference numeral 4 denotes a nipping mechanism provided near the galvanizing bath surface of the galvanizing bath 31, and the galvanized steel strip 21 moves to the galvanizing bath 31 through the sink roll 2 and the support rolls 3 and 3a in the galvanizing bath 1. After being guided and plated, gas is wiped by a gas spray nozzle pair (not shown) arranged in the upper part of the plating bath while being pulled up, and when passing between the sandwiching mechanisms 4 provided near the plating bath surface during this pulling up. Dross 3 floating on the surface of galvanizing bath 31
The plated steel strip 21 is clamped from both sides by this clamping mechanism 4 via 2. The holding mechanism 4 holds both sides of a pair of holding rods 6 and 6a longer than the width of the steel strip by arms 7 and 7a and arms 8 and 8a, respectively, and the arms 8 and 8a slide through the holding cylinders 9 and 9a. With a flexible structure, the holding cylinders 9 and 9a are connected to the vertical cylinders 11 via the support members 10 and 10a.
It is fitted to 11a.

Therefore, the height of the holding rods 6 and 6a is fixed by the stoppers 12 and 12a when the support members 10 and 10a are moved up and down to be positioned near the bath surface, and the arms 8 and 8a.
a is moved forward and backward to adjust the holding rods 6 and 6a to positions where the plated steel strip 21 is held, and then fixed by the stoppers 12b and 12c. When the dross gradually accumulates on the plated steel strip 21 and the upper portions of the holding rods 6 and 6a of the holding mechanism 4 for holding the steel strip 21 from both sides, it is necessary to return the dross to the galvanizing bath 31 once. 12b and 12C are loosened and the arms 8 and 8a are moved backward to release the nipping of the galvanized steel strip 21 by the nipping rods 6 and 6a, and the dross 5 is widely dispersed on the bath surface of the galvanizing bath 31, and then the nipping rod 6 and 6a is moved forward to press the dross 32 floating near the plated steel strip 21 against the plated steel strip 21, thereby sandwiching the plated steel strip 21 with the sandwiching mechanism 4 via the dross 32 to prevent vibration of the plated steel strip 21. It is intended to surely prevent and uniformize the control of the coating amount by the gas wipe from the gas spray nozzle pair at the upper part to improve the quality.

[0011]

As is apparent from the above description, the present invention is as follows.
By providing a clamping mechanism for clamping the plated steel strip from both sides via dross floating on the bath surface near the plating bath surface, vibration of the plated steel strip pulled up from the plating bath and gas wiped is eliminated, It is possible to obtain an excellent effect such that the variation in the amount of plating adhered is reduced, the yield is improved, and the quality is improved. Therefore, the present invention contributes to the development of the industry as a vibration preventing device for a hot-dip galvanized steel strip, which can completely eliminate the inconvenience caused by vibration of the galvanized steel strip in the conventional galvanizing steel sheet plating process. There is.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an embodiment of the present invention.

FIG. 2 is an explanatory view according to a side of an embodiment of the present invention.

[Explanation of symbols]

 1 plating tank 2 sink roll 3 support roll 3a support roll 4 clamping mechanism 21 galvanized steel strip 31 galvanizing bath 32 dross

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidefumi Kikuchi 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Nagoya Steel Works

Claims (1)

[Claims] 1. A hot dip galvanizing apparatus in which a galvanized steel strip to be pulled up from a hot dip galvanizing bath is gas-wipe by a gas spray nozzle pair arranged above the galvanizing bath. An anti-vibration device for hot-dip galvanized steel strip, comprising a sandwiching mechanism for sandwiching the plated steel strip from both sides via a dross floating on the surface.