JPH0578871A - Steel strip pickling device - Google Patents

Abstract

PURPOSE:To efficiently scatter the scales deposited on a steel strip by providing a deaerator for the water to be supplied to a pickling soln. tank to the water supply line to the tank. CONSTITUTION:A steel strip 3 is passed through a pickling tank 1 filled with a pickling soln. 2 supplied from a pickling soln. tank 8 in this pickling device. The strip 3 in the soln. 2 is irradiated with an ultrasonic wave from ultrasonic vibrators 6A and 6B to remove the scales on the strip 3 surface. A deaerator 14 for deaerating the water to be supplied to the pickling soln. tank 8 is provided in the water supply line 11 of the picking soln. tank 8 in which acid and water are mixed to obtain the pickling soln. 2. Consequently, a strong impact force is obtained by the cavitation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel strip pickling apparatus for continuously pickling a running steel strip to remove scale on its surface.

[0002]

2. Description of the Related Art As a method for removing oxide scale adhered to a hot-rolled steel strip, there is a method of passing the steel strip through a hydrochloric acid solution and pickling it. And the recent trend of increasing steel strip production, as well as steel sheet Top (before) and End (after)
In order to deal with the difficulty of descaling the oxide scale of Edge and Edge (edge), there is a pickling device that accelerates descaling by irradiating a steel strip in a hydrochloric acid solution with ultrasonic waves.

An example of such a pickling apparatus will be described with reference to FIG. In FIG. 4, 1 is a pickling tank,
The pickling tank 1 is filled with an acid solution 2 such as hydrochloric acid, and a steel strip 3 is passed through the solution. At the inlet 1a and the outlet 1b of the steel strip 3 of the pickling tank 1, seal rolls 4A and 4B for holding the steel strip 3 are provided.
A and the outlet 1b are sealed by seal rolls 4A and 4B so that the acid solution 2 does not leak outside. Also,
Vibration plates 5A and 5B for irradiating ultrasonic waves are attached to the upper and lower outer surfaces of the pickling tank 1, and ultrasonic vibrators 6A and 6A for generating ultrasonic waves are attached to these vibration plates 5A and 5B.
B is stuck. In addition, these ultrasonic transducers 6A,
6B is driven by the high frequency power supply 7.

On the other hand, the acid solution 2 filled in the pickling tank 1 is circulated between the acid solution tank 8 and the circulation pumps 9A and 9A.
It is circulated through B. The acid solution 2 is prepared in the acid solution tank 8 and kept at a constant concentration. Therefore, the water supply source 10 is connected to the acid solution tank 8 via the water supply path 11, and the acid supply source 12 is connected to the acid solution tank 13 via the acid supply path 13.

In such an apparatus, the steel strip 3 is dipped and passed through the acid solution 2 in the pickling tank 1. At that time, ultrasonic waves are applied to both sides of the steel strip 3 from the vibrating plates 5A and 5B. Irradiation is performed to promote the removal of scale attached to the surface of the steel strip 3.

[0006]

However, in the above-mentioned pickling apparatus, even if the ultrasonic wave is irradiated, it is not possible to obtain an impact pressure sufficient to scatter the scale adhered to the steel strip 3, and the scale is removed. There is a problem in that the promotion of

In view of such circumstances, it is an object of the present invention to provide a steel strip pickling apparatus capable of sufficiently exerting the effect of ultrasonic irradiation.

[0008]

A steel strip pickling apparatus according to the present invention which achieves the above object, comprises a steel strip which is passed through a pickling tank filled with an acid solution supplied from an acid solution tank. The steel strip pickling device removes the scale on the surface of the steel strip by irradiating the steel strip in the acid solution with ultrasonic waves while immersing the steel strip in the acid solution. A deaerator for deaerating the water supplied to the acid solution tank is provided in the water supply path of the acid solution tank.

[0009]

In the above construction, the acid solution prepared by degassing with the degassing device and the acid having a low air content is supplied to the pickling tank. Therefore, when ultrasonic waves are applied to the steel strip immersed in the acid solution in the pickling tank, strong cavitation occurs and sufficient impact pressure can be applied to the steel strip. The scale attached to the belt is scattered.

This action will be described in more detail. Cavitation that occurs when ultrasonic waves are radiated into a liquid includes a vapor type and a gas type. Here, it is considered that the gaseous one is generated by the air contained in the liquid as a nucleus and the impact pressure is generally small. In the pickling apparatus having the above-mentioned configuration, since the air content in the acid solution is lowered as described above, it is considered that the cavitation generated by ultrasonic waves is mainly cavitation. Therefore, the impact pressure generated when the cavitation collapses is large, and the scattering effect of the scale becomes sufficiently large.

[0011]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 conceptually shows a steel strip pickling apparatus according to one embodiment. In FIG. 1, members having the same functions as those in FIG. 4 are designated by the same reference numerals.

As shown in the figure, the pickling tank 1 is filled with an acid solution such as a hydrochloric acid solution, and a steel strip 3 is threaded through an inlet 1a and an outlet 1b. Further, at the inlet 1a and the outlet 1b, a seal roll 4A sandwiching the steel strip 1,
4B is provided, and the acid solution 2 is sealed so as not to leak outside. Further, diaphragms 5A and 5B are attached to the upper and lower outer surfaces of the pickling tank 1, and these diaphragms 5A and 5B
Ultrasonic transducers 6A and 6B are fixed to A and 5B, and the ultrasonic transducers 6A and 6B are driven by a high frequency power source 7.

The acid solution 2 in the pickling tank 1 is circulated with the acid solution tank 8 via circulation pumps 9A and 9B. Further, the acid solution 2 is prepared by combining water supplied from the water supply source 10 and acid such as hydrochloric acid supplied from the acid supply source 12 in the acid solution tank 8 and is kept at a constant concentration. ..

In this embodiment, a deaerator 14 is provided in the water supply passage 11 for supplying the water from the water supply source 10 to the acid solution tank 8. That is, the acid solution tank 8 is supplied with degassed water. Here, the deaerator 14 can be variously adopted, such as one that heats water to deaerate it and then cools it, or deaerate under reduced pressure. However, this structure is not particularly limited.

In such an apparatus, when the steel strip 3 is dipped and passed through the acid solution 2 in the pickling tank 1, ultrasonic waves are applied to both surfaces of the steel strip 3 from the vibrating plates 5A and 5B. ..
Here, since the acid solution 2 was prepared using degassed water as described above, the amount of air contained was remarkably lower than that in the conventional case where industrial water was used as it is. The pressure is large and the scale is scattered efficiently.

FIG. 2 shows the relationship between the air content in water and the pressure generated by ultrasonic irradiation. As shown in the figure, when the air content rate is 4 to 5 ppm or more, the generated pressure by ultrasonic waves does not change much, but when it is less than that, the generated pressure becomes remarkably large.

FIG. 3 shows the relationship between the temperature of water and the air content. As shown in the figure, it is necessary to raise the temperature of water to around 90 ° C. in order to set the air content of water to 4 to 5 ppm as described above. It has been found that, once heated to this temperature, the air content rate does not rapidly deteriorate even if the temperature is lowered. Therefore, as the deaerator 14 described above, an apparatus that once heats water such as industrial water to 90 ° C. or higher and then cools it is effective.

[0019]

As described above, in the steel strip pickling apparatus according to the present invention, since the pickling tank is supplied with the acid solution having a low air content, ultrasonic irradiation causes strong cavitation. The impact pressure can be obtained, and the scale attached to the steel strip can be efficiently scattered.

[Brief description of drawings]

FIG. 1 is a schematic view of a steel strip pickling apparatus according to an embodiment.

FIG. 2 is a graph showing the relationship between the air content in water and the pressure generated by ultrasonic waves.

FIG. 3 is a graph showing the relationship between temperature and air content in water.

FIG. 4 is a schematic view of a conventional steel strip pickling apparatus.

[Explanation of symbols]

 1 Pickling device 2 Acid solution 3 Steel strip 4A, 4B Seal roll 5A, 5B Vibration plate 6A, 6B Ultrasonic transducer 7 High frequency power supply 8 Acid solution tank 10 Water supply source 11 Water supply path 12 Acid supply source 14 Degassing device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Ideue 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Hiratsue Etsuro Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture 6-22 No. 6 Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Motomi Nakajima 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Hiroshima Prefecture (72) Inventor Etsushi Hino, Kurashiki Okayama Prefecture 1-chome, Kawashima-dori, Mizushima City, Kawashima Steel Co., Ltd., Mizushima Works (72) Inventor: Hiroshi Tsunoda 1-chome, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture (Mizushima Steel Works, Ltd.)

Claims (1)

[Claims] 1. A steel strip is passed through a pickling tank filled with an acid solution supplied from an acid solution tank, the steel strip is immersed in the acid solution, and ultrasonic waves are applied to the steel strip in the acid solution. In a steel strip pickling device that removes scale on the surface of the steel strip by irradiation, the water supplied to the acid solution tank is removed to the water supply path of the acid solution tank that mixes acid and water into an acid solution. A pickling device for steel strips, characterized by being equipped with a degassing device.