JP2006265684A - Device and method for pickling steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for pickling a steel sheet where more stable descaling can be performed, and the trouble of the insufficiency in pickling at a high speed and that of overpickling at a low speed can be prevented. <P>SOLUTION: The pickling equipment for a steel sheet is equipped with a plurality of pickling tanks. Each pickling tank is provided with: a means for measuring the quantity of catenary in the steel sheet; a means for measuring a bath level; and a means for controlling the dipping length of the steel sheet in respective pickling tanks per pickling tank based on the measured results from each measuring means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steel plate pickling apparatus and a pickling method.

  In pickling equipment for removing iron oxide (scale) on the surface of a steel sheet, a method of continuously immersing the steel sheet in an acid solution in a plurality of continuously arranged pickling tanks is generally performed. .

  In immersion type pickling equipment, the length of the steel sheet immersed in the acid solution is controlled before and after the pickling tank so that the steel sheet tension measured by the tension meter installed on the inlet side of the pickling tank becomes the specified tension. The tension is controlled by the driven roll, or the catenary position of the steel plate in the tank is detected by the magnet type detector installed at the lower part of the pickling tank, and the predetermined catenary is detected by the driving roll arranged before and after the pickling tank. This is done by controlling the position.

  However, in the above-described control method, for example, when there is a change in the sheet passing state of the steel sheet due to mechanical loss of the Ringer roll disposed between the pickling tanks or fluctuation in resistance in the liquid, the desired descaling cannot be performed. There is. In order to deal with such problems, Patent Document 1 discloses the total value of each height by measuring the height of each catenary of the steel strip immersed in each pickling tank. A method of measuring the distance between the top of the steel strip catenary in the pickling tank and the bottom of the pickling tank and adjusting the pickling speed of the steel strip based on the total value of the catenary height and the spacing is proposed. ing.

In the steel plate pickling equipment, the upstream pickling tank is often set to have a high acid concentration, and therefore, the pickling degree (degree of descaling) of each tank is generally different. Therefore, the method of adjusting the pickling speed based on the total value of the amount of catenary proposed in Patent Document 1 cannot perform stable descaling. In addition, the dipping length setting is constant, and there is a problem that pickling tends to be insufficient at high speeds and over pickling at low speeds.
Japanese Patent Laid-Open No. 2-192811

  The present invention provides a steel plate pickling apparatus and a pickling method capable of solving the above-mentioned problems, performing more stable descaling, and preventing problems of insufficient pickling at high speeds and problems of over pickling at low speeds. The purpose is to provide.

  The gist of the present invention for solving the above problems is as follows.

  1st invention is the pickling equipment of the steel plate provided with a plurality of pickling tubs, and each pickling tub is provided with a means to measure the amount of catenary of a steel plate, or a means to further measure a bath level, and further, A steel plate pickling facility comprising means for controlling the immersion length of a steel plate in the pickling tank for each pickling tank based on the measurement result of each measuring means.

  2nd invention is the method of pickling a steel plate with the pickling equipment provided with a plurality of pickling tubs, measures the amount of catenary of the steel plate in each pickling tub or further the bath level, and based on the measurement result, The steel plate pickling method is characterized in that the dipping length of the steel plate in the pickling tank is controlled for each pickling tank.

  The third invention is characterized in that, in the second invention, the immersion length of the steel sheet for each pickling tank is controlled by reflecting the equipment speed so that the steel plate immersion time in each pickling tank becomes constant. It is the pickling method of the steel plate to perform.

According to the present invention, the following effects are exhibited.
(1) By independently controlling the immersion length of each pickling tank in the acid solution of the steel plate, for example, even when the state of each tank (ringer roll mechanical loss between tanks or resistance in the liquid) changes, Since the immersion length of each tank can be maintained at a desired size, more stable descaling can be performed.

  (2) In the case of short pickling, per pickling, etc., in addition to the conventional control of the immersion length of the entire pickling section, the control is performed by changing the immersion length of the steel plate in the pickling tank with high acid concentration. By doing so, it became possible to take more effective measures for pickling and over pickling.

  (3) By reflecting the equipment speed in the immersion length control, the immersion time of the steel sheet can be made constant regardless of the equipment speed, thereby preventing insufficient pickling when the equipment speed is high. It became possible to prevent peracid washing when the speed was low.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a diagram for explaining the main part configuration and control flow of a pickling facility for steel sheets used in the practice of the present invention. In FIG. 1, S is a steel plate, 1 is an entrance roll (line drive roll), 2 is an exit roll, 3 is an equipment speed control device, 4 is a tension meter, 5 is a tension control device, 6 and 8 are drive motors, 7 and 9 are drive devices, 11 to 14 are pickling tanks for storing an acid solution for removing scales on the steel sheet surface, 21 to 25 are ringer rolls, 31 to 35 are drive motors, 41 to 45 are drive devices, 51 to 51 54 is an immersion length controller, 61 to 64 are steel plate level meters for detecting the amount of catenary of the steel plate, 71 to 74 are bath level meters, and 81 to 84 are pH meters.

  In this equipment, as is also done in the prior art, the equipment speed control device 3 commands the equipment speed to the drive devices 7 and 9 to drive the entry side roll 1 and the exit side roll 2. The tension control device 5 adjusts the speed of the entrance roll 1 via the drive device 7 so that the steel plate tension of the tension meter 4 on the entrance side of the pickling bath becomes a predetermined tension, and thereby the steel plate in the pickling bath is adjusted. Control is performed so that the catenary amount becomes a predetermined catenary amount, in other words, the immersion length of the steel sheet in the acid solution becomes the predetermined immersion length. In this apparatus, the immersion length of the entire pickling section can be changed by changing the set value of the steel plate tension.

  In this facility, as described below, each pickling tank is independently an arbitrary tank, and the immersion length (catenary length) of the steel sheet in the acid solution in the tank can be controlled. It is configured. That is, for each pickling tank 11-14, the value of the signal of the steel plate level meters 61-64 (distance between the steel plate and the bottom of the pickling tank), the value of the signal of the bath level meters 71-74, and the immersion length of the steel plate The relationship is obtained, and the immersion length is obtained by approximating the catenary curve with a parabola from the immersion depth of the steel sheet in the acid solution, and these relationships are input to each immersion length controller 51-54.

  The ringer rolls 21 to 25 between the pickling tanks are independently driven by drive motors 31 to 35 and drive devices 41 to 45, respectively. The performance signals of the steel plate level meters 61 to 64 and the bath level meters 71 to 74 of the pickling tanks 11 to 14 are input to the immersion length controllers 51 to 54 of the pickling tanks 11 to 14, respectively. If the bath level is controlled to be constant, only the amount of catenary may be measured.

  It is possible to control the immersion lengths of the pickling tanks 11 to 14 independently by outputting the control outputs of the immersion length controllers 51 to 54 to the drive devices 41 to 45 and correcting the speeds of the ringer rolls 21 to 25, respectively. It was. Thereby, for example, even when the state (ringer roll mechanical loss between the tanks or resistance in liquid) varies in each of the pickling tanks 11 to 14, the immersion length of each of the pickling tanks 11 to 14 has a desired size. It became possible to hold on.

  In addition, in the case of insufficient pickling, over pickling, etc., in addition to controlling the overall immersion length of the entire pickling section, the immersion length of the pickling tank 11 having a high acid concentration should be intensively controlled. Thus, it has become possible to more effectively prevent the occurrence of acid pickling shortage, peracid pickling and the like.

  Also, the equipment speed control device 3 is interfaced to the immersion length controllers 51 to 54, that is, the output of the equipment speed control device 3 is input to the immersion length controllers 51 to 54, and the equipment speed is reflected in the parameters of the immersion length control. I let you. Each immersion length controller 51-54 adjusts the amount of catenary and / or the bath level so that the immersion time of the steel sheet is constant based on the input equipment speed. This makes it possible to make the immersion time of the steel sheet constant regardless of the equipment speed, to prevent deficiency in pickling when the equipment speed is high, and to prevent over pickling when the equipment speed is low. Became possible.

According to the present invention, the following effects are exhibited.
(1) By independently controlling the immersion length of each pickling tank in the acid solution of the steel plate, for example, even when the state of each tank (ringer roll mechanical loss between tanks or resistance in the liquid) changes, As a result of controlling the immersion length of each tank, descaling can be performed more stably.

  (2) In the case of short pickling, per pickling, etc., in addition to the conventional control of the immersion length of the entire pickling section, the control is performed by changing the immersion length of the steel plate in the pickling tank with high acid concentration. By doing so, it became possible to take more effective measures for pickling and over pickling.

  (3) By reflecting the equipment speed in the immersion length control, the immersion time of the steel sheet can be made constant regardless of the equipment speed, thereby preventing insufficient pickling when the equipment speed is high. It became possible to prevent peracid washing when the speed was low.

  The apparatus of the present invention can be used as a steel plate pickling apparatus that can perform more stable descaling. The method of the present invention can be used as a pickling method for steel sheets that can perform more stable descaling.

It is a figure explaining the principal part structure and control flow of the pickling equipment of the steel plate used for implementation of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS S Steel plate 1 Entry side roll 2 Outlet side roll 3 Equipment speed control device 4 Tension meter 5 Tension control device 6, 8 Drive motor 7, 9 Drive device 11-14 Pickling tank 21-25 Ringer roll 31-35 Drive motor 41- 45 Drive device 51-54 Immersion length controller 61-64 Steel plate level meter 71-74 Bath level meter 81-84 pH meter

Claims (3)

Steel pickling equipment comprising a plurality of pickling tanks, each pickling tank is provided with means for measuring the amount of catenary of the steel sheet, or further means for measuring the bath level, further measurement results of each measuring means And a means for controlling the immersion length of the steel plate in the pickling tank for each pickling tank. In the method of pickling steel sheets with pickling equipment comprising a plurality of pickling tanks, the catenary amount of the steel sheet or further the bath level is measured in each pickling tank, and for each pickling tank based on the measurement results A pickling method for a steel sheet, characterized by controlling the immersion length of the steel sheet in the pickling tank. The steel plate pickling method according to claim 2, wherein the immersion speed of the steel plate for each pickling bath is controlled so as to reflect the equipment speed so that the dipping time of the steel plate in each pickling bath is constant. .

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