JPH0665768A - Pickling device - Google Patents

Abstract

PURPOSE:To avoid the direct contact of a steel sheet to be treated with weirs provided on the lower surface at the inlet side of a pickling vessel and to prevent the generation of scratching flaw on the steel sheet caused by the weirs in the improvement of the box type structural pickling vessel for removing oxidized layer on the surface of the hot rolled steel sheet. CONSTITUTION:The hot rolled steel sheet S being the material to be treated and sticking the oxidized layer on the surface is run into the pickling vessel from a left side in figure, and acid liquid is supplied from an inlet side nozzle 12 provided on the upper surface side of the steel sheet at the inlet side and shifted toward the outlet side according to advancing of the steel sheet. The new acid liquid 6 is always supplied in the vessel to promote the pickling work. In the vessel, further, the upper weir 7 and the lower weirs 3, 5 are arranged in the same interval, and by liquid stirring action with the weirs, the pickling is further promoted. In the lower weir 3 arranged at the lower surface side and at the inlet side of the steel sheet, an acid liquid supplying nozzle 20 is incorporated and since the acid liquid is made flow out toward the lower surface of the steel sheet from this nozzle 20, the steel sheet S is prevented from the direct contact with the upper surface of the lower weir 3 and the development of the scratching flaw on the lower surface of the steel sheet is surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickling tank for removing an oxide layer on the surface of a hot rolled steel sheet with an acid solution, and more particularly to a box having a structure in which the upper, lower, left and right sides of the steel sheet to be treated are surrounded by solid walls. -Type pickling tank improvement

[0002]

2. Description of the Related Art The structure of a conventional box type pickling tank will be described with reference to FIG. In the figure, S is a hot-rolled steel strip to be treated,
Reference numeral 1 is a can body that forms the lower surface of the box wall, and 2 is a cover that forms the upper surface.

Denoted at 3 and 4 are weirs provided on the lower surface of the box-type pickling tank on the inlet side and the outlet side of the steel strip, for maintaining stable running level of the steel strip and filling the box-type pickling tank with acid solution. 6
Plays the role of a seal.

Reference numeral 5 is a weir provided in the middle of the pickling tank in the longitudinal direction, which is a concentration boundary layer which keeps the running level of the strip steel stable and is generated on the surface of the strip steel S to suppress the pickling reaction. It plays a role in suppressing development and promoting pickling reaction.

Reference numeral 7 is a weir provided on the upper surface side of the strip in the middle portion in the longitudinal direction in the tank to destroy the concentration boundary layer formed on the upper side surface of the strip and promote pickling.

Reference numeral 12 is an inlet side nozzle provided on the upper surface of the inlet side of the steel strip for supplying an acid solution, and 13 and 14 are outlets for supplying an acid solution provided on the upper and lower surfaces of the steel strip outlet side of the tank. It is a nozzle.

In the pickling tank, the liquid pressure gradually increases in the traveling direction of the steel strip S, and the liquid pressure is highest at the steel strip tank outlet (right side in the drawing). Liquid leaks. Therefore, in order to reduce this leakage amount, nozzles 13 and 14 for acid solution sealing are provided at both the upper and lower surfaces of the strip steel at the strip steel outlet.

Reference numeral 16 denotes a pool of liquid leaked from the tank body provided on the inlet side and the outlet side of the tank, respectively, and the stored acid solution R is led through the outlet pipe 17 to the nozzle groups 12 to 12 on the inlet side and the outlet side. 14
It is designed to be reused in circulation.

[0009]

As described above, in the conventional box-type pickling tank, the acid liquid supply nozzle is provided only on the upper surface side of the strip steel on the strip steel inlet side.

However, since the acid solution in the tank is transferred from the left side to the right side in FIG. 4 by the steel strip, the acid solution in the vessel near the inlet of the steel strip becomes insufficient.

Accordingly, the lower surface side of the strip steel when passing over the weir 3 provided on the lower surface side of the tank inlet side comes into direct contact with the weir 3 in the absence of the acid solution, and There is a problem that scratches easily occur on the lower surface side.

Particularly, at the point of entering the final tank where the pickling is in progress (normally a plurality of tanks of the same type are provided in a box type pickling tank), the oxide layer is almost removed from the surface of the steel strip. In addition, since the ratio of the area where the background is exposed is large, there is a problem that scratches easily occur.

An object of the present invention is to provide a new pickling equipment which can solve these problems and reliably prevent the occurrence of scratches on the lower surface of the steel strip.

[0014]

As a structure for achieving the above object, the pickling equipment of the present invention has a lower surface weir that is filled with an acid solution and supports the steel plate on the lower surface, and an upper surface wall that blocks the liquid flow on the upper surface. In a pickling facility with a box structure for removing the oxide layer on the surface of the steel strip by passing the hot-rolled steel strip in a container surrounded by solid walls on four sides, the steel strip bottom surface of the pickling tank is inserted into It is characterized in that a weir having a nozzle capable of flowing out and supplying the acid solution is provided.

[0015]

The pickling equipment of the present invention is such that when the strip steel to be treated passes over the weir provided on the lower surface side of the inlet side of the box type pickling tank filled with the acid solution, The acid solution flowing out from the nozzle acts to avoid direct contact between the steel strip and the weir.

As a result, it is possible to avoid the occurrence of scratches on the lower surface side of the steel strip.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional side view of the main part on the inlet side of a pickling tank.

In FIG. 1, 1 is a can body that forms the lower surface of the box wall, and 2 is a cover that forms the upper surface, and these constitute a box-type pickling tank. Drive in the direction of the arrow shown.

Reference numeral 3 denotes a lower surface weir provided on the lower surface side of the strip steel tank on the inlet side. The weir 3 is provided with an acid solution supply nozzle 20 capable of letting out an acid solution, and the nozzle 20 supplies the acid solution. It communicates with the through hole 21 which plays the role of a header for

Reference numeral 5 denotes a lower surface weir provided at an intermediate position in the longitudinal direction of the pickling tank. Like the conventional apparatus, the lower surface weir 5 maintains the running level of the strip steel S stable and the surface of the strip steel S. It plays the role of promoting the pickling reaction by suppressing the development of the concentration boundary layer that is generated and suppresses the pickling reaction.

Reference numeral 7 denotes an upper surface weir provided on the upper surface side of the strip steel at an intermediate portion in the longitudinal direction in the tank, 12 is an inlet nozzle for supplying an acid solution provided on the upper surface of the strip steel at the inlet side, and 16 is a tank main body. In the pool of the leaked liquid, the pooled acid liquid R is configured to be circulated and reused to the nozzle groups on the inlet side and the outlet side via the outlet pipe 17. An outlet nozzle (13, 14 in FIG. 4) is provided on the outlet side of the tank as in the conventional device.

The operation will be described below. In the pickling tank of the present invention having such a structure, the hot-rolled steel S, which is a material to be treated having an oxide layer adhered to its surface, is changed to the pickling tank according to the left side of the drawing. enter.

At the inlet of the strip steel S of the tank body, an acid solution supply nozzle 12 is provided on the upper surface side of the strip steel, and as the strip steel advances, the acid solution is directed toward the right side of the drawing, that is, toward the exit side of the strip steel. Be transferred.

This transfer amount increases as the traveling speed of the steel strip increases. That is, when the traveling speed is about 300 m / min, the liquid pressure in the tank rises as it moves in the traveling direction with this transfer, and when the normal tank length is about 20 m, the tank pressure near the outlet of the strip steel is 500. Approximately 600 mm water column.

Accordingly, if the acid solution is discharged outside the tank at the strip steel outlet, the acid solution is gradually taken out from the upper and lower surfaces of the strip steel by the outlet nozzles 13 and 14 shown in FIG. Eject and seal the liquid.

For the amount of the acid liquid leaking from the strip steel outlet, the acid liquid is basically supplied by the inlet nozzle provided on the upper surface of the strip steel at the strip steel inlet side. As a result, fresh acid solution is constantly supplied to the tank to promote pickling.

Further, weirs are provided in the tank at a pitch of 3 to 6 m on the upper wall side and the lower wall side as in the conventional apparatus, and the pickling is further promoted by the liquid stirring action of these weirs.

Since the acid solution flows out toward the lower surface of the strip steel from the nozzle 20 built in the lower surface weir 3 provided on the lower side of the strip steel on the inlet side of the strip steel, the strip steel S is directly supplied to the weir 3. It is possible to reliably prevent the occurrence of scratches on the lower surface unlike the conventional case without contact.

FIGS. 2 and 3 show different embodiments of the bottom weir of the strip steel inlet side. In the case of the embodiment of FIG. 2, a liquid pool 22 is provided at the outlet of the acid solution supply nozzle 20. The cushioning effect of the liquid can more reliably prevent the lower surface of the steel strip from contacting the upper surface of the weir.

FIG. 3 shows another embodiment. In this case, the acid solution is supplied to the acid solution supply nozzle 20 by using the liquid pressure of the acid solution 6 accumulated in the box without using a pump. In order to be able to do so, a communication hole 23 to the box-type pickling tank is provided below the lower surface weir 3, and the hole 23 is made into the communication hole 23.
It is configured to communicate with 0.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made within the scope of the technical idea of the present invention.
All of these belong to the technical scope of the present invention.

[0032]

As described above, in the pickling equipment of the present invention, when the steel strip to be treated is introduced into the main body of the pickling tank, the acid liquid flowing out from the weir on the steel strip lower surface side on the steel strip inlet side is introduced. Is discharged toward the lower surface of the steel strip, the lower surface of the steel strip and the upper surface of the weir form a liquid film of the acid liquid on the surface, and it is possible to avoid direct contact between the two due to the cushioning effect of the liquid.
No scratches due to the weir and no loss of product value.

[Brief description of drawings]

FIG. 1 is a side sectional view of a main part of a pickling tank in a pickling facility according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing the structure of another embodiment of the inlet-side lower surface weir in the pickling equipment of the present invention.

FIG. 3 is a side sectional view of yet another embodiment of the inlet-side lower surface weir.

FIG. 4 is a side sectional view showing a configuration of an example of conventional pickling equipment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Can body 2 Cover 3,5 Lower surface dam 6 Acid liquid 7 Upper surface dam 12 Inlet side nozzle 16 Leakage liquid reservoir 20 Acid liquid supply nozzle 22 Liquid reservoir 23 Communication hole S Hot rolled steel strip

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Shoji Nagai 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Saka Adult 6-22 Kannon-shinmachi, Nishi-ku, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Yuji Furusawa 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute (72) Masaki Aihara 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Company Chiba Works (72) Inventor Hikosaku Matsunaga 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Chiba Works Co., Ltd. (72) Mano Sawa, Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Co., Ltd. Chiba Works

Claims (1)

[Claims] 1. A hot rolled steel sheet is passed through a container surrounded by a solid wall on four sides having a lower surface weir for supporting a steel sheet on the lower surface and an upper surface wall for blocking a liquid flow on the upper surface, filled with an acid solution. According to the above, in a pickling facility having a box structure for removing the oxide layer on the surface of the strip steel, the pickling is characterized in that a weir having a nozzle capable of supplying outflow of the acid solution is provided on the inlet side of the bottom surface of the strip steel of the pickling tank. Facility.