KR101517782B1 - Apparatus for strip flatness correction in hot dip galvanizing process - Google Patents

Abstract

The present invention relates to an apparatus for calibrating the flatness of a steel sheet passing through an air knife in a hot dip galvanizing process. The apparatus according to the present invention is an upper calibration unit and a lower calibration unit which are respectively provided on the upper and lower sides of the air knife, respectively including a front calibration unit and a rear calibration unit arranged on the front surface and the rear surface of the steel sheet, respectively, A shaft extending along the entire width of the steel sheet at one side of the steel sheet; a plurality of electrodes mounted on the shaft so as to be arranged along the width direction of the steel sheet and facing the steel sheet at a predetermined interval; And a wire extending along the shaft to supply electric power for generating the electric power; A power supply unit connected to the wires to supply electric power to the electrodes of the calibration units; An input unit for receiving information on the strength, thickness, and warping of the steel sheet; And a controller for controlling the intensity of the magnetic force generated in each of the electrode plates of the calibration units according to the information input through the input unit.

Description

TECHNICAL FIELD [0001] The present invention relates to a steel plate flatness correcting apparatus for a hot dip galvanizing process,

The present invention relates to a hot-dip galvanizing process for plating a steel sheet with zinc, and more particularly, to a method for maintaining the flatness of a steel sheet to prevent a variation in the amount of plating plated on the steel sheet due to warping of the steel sheet during the hot- The present invention relates to a flatness maintaining apparatus.

In the case of a steel sheet produced in a steel mill, it is common to perform plating on the surface in order to improve physico-chemical properties such as corrosion resistance and to improve the appearance. In recent years, the plating process has been classified as a very important work process in the process of producing electric steel sheets and automobile steel sheets used for special purposes.

As a typical plating process, a hot dip coating method in which a steel sheet is passed through a bath containing a hot dip coating solution and an electroplating method using an electrolytic solution are exemplified. As a typical plating work of electrons, a hot dip galvanizing step of a galvanized steel sheet can be mentioned.

Since the plating operation is performed in such a manner that the molten plating solution is adhered to the surface of the steel sheet while the steel sheet passes through the bath containing the molten plating solution such as molten zinc in the molten plating step, Equipment is needed.

Normally, the amount of plating adhered to the surface of the steel sheet is adjusted according to the demand of the customer by spraying air of appropriate pressure using the air knife on the surface of the steel sheet passed through the bath, The method of controlling the amount of plating using a knife is called an air wiping method.

In the air-wiping system, as shown in Fig. 1, the steel sheet 1 is moved vertically upward after passing through the zinc bath 2. In this way, air is supplied to both sides of the coated steel sheet 1, The knife 100 is installed and the air 101 is sprayed on both sides of the plated steel sheet 1 which is vertically upwardly moved at a pressure set in accordance with the amount of custom plating of the demand value to cut off the molten zinc adhering to the surface of the steel plate 1 To control the amount of plating. 1, reference numeral 116 denotes a sink roll for guiding the movement of the steel plate 1. [

Tension is generated on the surface of the steel sheet 1 which moves vertically upward through the plating liquid 102 contained in the molten state in the zinc bath 2 so that the steel sheet 1 has a wave shape It may happen that it is twisted. The gap between the nozzle of the air knife 100 and the surface of the steel plate 1 is changed according to the position of the steel plate 1 and thus the air 101 discharged from the air knife 100 The amount of zinc scraped off the surface of the steel sheet 1 varies depending on the position of the steel sheet 1 and the amount of the zinc 1-1 coated on the front and back surfaces of the steel sheet 1 is different .

In order to solve such a problem, conventionally, a pair of permanent magnets were installed on both sides of the steel plate in front of the air knife 100, and the flatness of the steel plate was maintained by pushing the steel plate with a magnetic force. However, these conventional solutions also have problems. That is, conventionally, by using a permanent magnet, it is impossible to adjust the magnetic force according to the twisted shape of the steel sheet, so that the flatness can not be maintained for the high-strength steel sheet or for the thick steel sheet. Further, since the conventional flatness maintaining apparatus is provided only in front of the air knife, the steel sheet becomes flat while passing through the flatness maintaining apparatus. However, at the time when the steel sheet passes through the air knife, most of the steel sheet is twisted again, There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a device for calibrating a flatness of a steel sheet so as to minimize warping of a steel sheet passing through an air knife in a hot- .

According to an aspect of the present invention, there is provided an apparatus for calibrating a flatness of a steel sheet passing through an air knife of a hot dip galvanizing process, the apparatus comprising: a front calibrating unit and a rear calibrating unit, And an upper calibration unit and a lower calibration unit provided on the upper and lower sides of the air knife, respectively, wherein the calibration units each include a shaft extending along one of the entire width of the steel sheet from one side of the steel sheet, And a wire extending along the shaft to supply electric power for generating a magnetic force to the plurality of electrodes, the calibration unit comprising: a plurality of electrodes; A power supply unit connected to the wires to supply electric power to the electrodes of the calibration units; An input unit for receiving information on the strength, thickness, and warping of the steel sheet; And a controller for controlling the intensity of the magnetic force generated in each of the electrode plates of the calibration units according to the information input through the input unit.

Preferably, the calibration section further comprises additional electrodes mounted symmetrically with the electrodes on opposite sides of the steel sheet, and a rotation motor coupled to one end of the shaft for rotating the shaft to change the position of the electrodes and further electrodes . Preferably, the electrodes and the additional electrodes may be formed in the shape of a semicircular segment. Further, preferably, one end of the shaft and the rotary motor may be connected via a belt.

Preferably, the calibration section may further include a zinc removal section for removing zinc from the electrodes during operation. The zinc removing part may include a semi-cylindrical case installed to surround the additional electrodes, and an electric heating line attached to the inner surface of the case facing the additional electrodes and connected to the power source through the electric wire.

Preferably, each of the calibration units may further include a position control mechanism for adjusting the position of the caliper relative to the steel plate. The position control mechanism includes a movable block for supporting one end of the shaft, a guide rod extending in a direction orthogonal to the width direction of the steel plate to guide the movement of the movable block, and a drive motor for moving the movable block along the guide rod And may include a plurality of spacing adjusters. Preferably, the movable block and the guide rod can be ball-screw-engaged.

Preferably, the position control adjusting mechanism may further include a plurality of widthwise position adjusting portions including a seating plate on which the guide rod and the movable block are mounted, and a cylinder for moving the seating plate back and forth along the width direction of the steel plate. Preferably, the seating portion can be configured to simultaneously seat the guide rods and the movable blocks of the front and rear calibrations of each of the calibration units.

According to the steel sheet flatness correcting apparatus for hot dip galvanizing according to the present invention, it is possible to flatten the warping of the steel sheet by using the magnetic force generated from the electrodes disposed on the front and rear surfaces of the steel sheet, It is possible to precisely correct the flatness of the steel sheet by adjusting the intensity of the magnetic force, the distance between the electrode and the steel sheet, and the position of the electrode relative to the width direction of the steel sheet. As a result, the variation of the plating amount on the surface of the steel sheet can be minimized, and the thickness of the plating layer can be maintained uniformly. Further, upper and lower calibration units and a lower calibration unit are provided on the upper and lower sides of the air knife, respectively, to calibrate the flatness of the steel plate on the upper and lower sides of the air knife so that the flattened steel plate is twisted again It is possible to obtain a plated steel sheet of even higher quality.

1 is a perspective view schematically showing a general hot dip galvanizing process.
FIG. 2 is a view for explaining the distortion of the steel plate and the deviation of the plating amount according to the position of the steel plate caused by the distortion.
3 is a perspective view illustrating a steel plate flatness maintaining apparatus according to an embodiment of the present invention.
4 is a plan view showing a steel plate flatness maintaining apparatus according to an embodiment of the present invention.
FIG. 5 is a view showing a state in which a steel sheet flattened by the steel plate flatness maintaining apparatus according to the present invention passes through an air knife of a hot-dip galvanizing system.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 and 4 show a steel sheet flatness correcting apparatus in a hot dip galvanizing process according to an embodiment of the present invention.

The steel plate flatness correcting apparatus in the hot dip galvanizing process according to an embodiment of the present invention includes a lower calibrating unit 200, an upper calibrating unit 300, a power unit (not shown), an input unit And a control unit (not shown).

The lower calibrating unit 200 includes a front calibrating unit 200a and a rear calibrating unit 200b disposed on the front and rear surfaces of the steel plate 1 below the air knife 100 of the hot dip galvanizing system. The lower calibration unit 200 may further include a position controller 250 for adjusting the position of the front calibration part 200a and the rear calibration part 200b with respect to the steel plate 1. [

The frontal control unit 200a includes a shaft 212a extending in the width direction of the steel strip 1, a plurality of electrodes 214a arranged along the shaft 212a so as to face the steel strip 1 at a predetermined interval, A plurality of electrodes 216a (hereinafter referred to as a spare electrode) additionally arranged to face the opposite side of the electrodes 214a of the shaft 212a, that is, a direction opposite to the steel plate 1, (Not shown) connected to the power supply unit to supply power to the power supply units 216a.

The electrodes 214a and the spare electrodes 216a are formed in the shape of a semicircular segment so that the electrodes 214a and the spare electrodes 216a facing each other form a circle. As a result, the front bridge unit 210a including the shaft 212a, the electrodes 214a, and the spare electrodes 216a has the shape of a cylindrical cylinder as a whole.

At one end of the shaft 212a, a rotary motor 220a for rotating the shaft 212a is provided. One end of the shaft 212a is connected to the drive shaft of the rotary motor 220a by a belt (not shown). Alternatively, one end of the shaft 212a may be directly connected to the rotary motor 220a. Reference numeral 230a denotes a support casing which rotatably supports one end of the shaft and accommodates the belt together with a belt connected to the motor without being exposed to the outside.

Since the shaft 212a can be rotated by the rotation motor 220a, the electrodes 214a and the spare electrodes 214b disposed on the shaft 212a are changed in position with rotation of the shaft 212a . That is, when the position of the electrodes 214a is referred to as an operation position and the position of the spare electrodes 216a is referred to as a preliminary position, the electrodes 214a and the spare electrodes 216a are moved in accordance with the rotation of the shaft 212a, The positions are alternately positioned between the positions.

Further, the front calibration unit 200a may further include a zinc removal unit. The zinc removing portion includes a semi-cylindrical case 218a provided so as to surround the spare electrodes 216a in a preliminary position, and a heating wire (not shown) disposed on the inner surface of the case. The heating wire is connected to a power source through an unillustrated electric wire. The zinc removal part is fixed so as not to move at that position despite the rotation of the shaft 212a.

The backside calibration unit 200b provided on the back side of the steel plate 1, that is, facing the front calibration unit 200a with the steel plate 1 interposed therebetween, Except that it is positioned symmetrically to the operating position of the electrodes 212a. Therefore, the backside calibration unit 200b is distinguished by adding "b" instead of "a" after the reference numerals, and will not be described in duplicate. It is to be understood that the parts indicated by reference numerals not having "a" or "b" in the following description refer to the parts of the front side calibration unit 200a and the rear side calibration unit 200b at the same time.

The position control unit 250 includes a gap adjusting unit for adjusting the distance between the calibration unit 200 and the steel plate 1 and a width direction position adjusting unit for moving the calibration unit 200 along the width direction of the steel plate 1 .

The gap adjusting portion includes a movable block 262, a guide rod 264, and a driving motor 266. The guide rod 264 is disposed on a seating plate 272 to be described later in a direction orthogonal to the width direction of the steel plate 1 and the movable block 262 is movable along a guide rod 264 ). ≪ / RTI > The drive motor 266 is coupled to one end of the guide rod 264. On the movable block 262, a rotary motor 220 of the calibration unit 200 and a support casing 230 for supporting one end of the shaft 212 are placed. When the guide rod 264 is rotated by the drive motor 266, the movable block 262 coupled to the guide rod 264 by the ball screw moves along the guide rod 264, The shaft 212 to which the one end portion is supported is moved in the direction perpendicular to the width direction of the steel plate 1 together with the movable block 262 in the support casing 230. As a result, the distance to the steel plate 1 of the caliper is adjusted.

The width direction position adjustment portion includes a seating plate 272 on which the guide rod 264 of the gap adjusting portion is disposed and a guide rail 274 on which the seating plate 272 is movable in the width direction of the steel plate 1, 276). The guide rail 274 and the drive cylinder 276 are seated on a support 280. Preferably, the interval adjusting unit adjusts the interval of the front calibrating unit 200a of the upper calibrating unit 200 with respect to the steel plate 1 and the interval adjusting unit adjusts the interval of the rear calibrating unit 200b with respect to the steel plate 1 And the seat is seated together on one seat plate 272. In this case, the front calibration part 200a and the rear calibration part 200b are simultaneously moved in the width direction of the steel plate 1 by the single cylinder 276. [

Preferably, the guide rod 264a of the gap adjusting portion for the front calibrating portion 200a and the guide rod 264b of the gap adjusting portion for the rear calibrating portion 200b are simultaneously driven by the single driving motor 266 . With such a configuration, the intervals between the front facsimile unit 200a and the rear facsimile unit 200b with respect to the steel plate 1 can be adjusted while maintaining the same interval at the same time.

On the other hand, the upper calibration unit 300 has the same configuration as the lower calibration unit 200 described above, except that the upper calibration unit 300 is provided above the air knife 100. In the description of the present invention, a detailed description of the upper calibration unit 300 will be omitted in order to avoid redundant description.

The input unit receives the information on the thickness and the strength of the steel plate 1 and the distortion generated in the steel plate 1. [ The thickness and the strength of the steel sheet 1 are input by the operator every time the type of the steel sheet 1 in operation is changed. The distortion that occurs in the steel sheet 1 is grasped and input by the operator during the operation, It is often the case that the distortion of the same type of the steel plate 1 occurs in a constant pattern. Therefore, it is also good to store the distortion pattern according to the type of the steel plate 1 and input appropriate data. Otherwise, it is conceivable to detect the distortion generated in the steel strip 1 directly by using a laser or an ultrasonic wave and to input it to the input unit in real time.

The control unit applies power to the electrodes at the working position of the calibration unit 200 to generate a magnetic force capable of correcting the twist of the steel plate 1 based on the data input through the input unit.

Hereinafter, the operation of the steel plate flatness correcting apparatus according to an embodiment of the present invention will be described.

The steel plate 1 passes through the lower calibrating unit 200 before passing through the air knife 100 after being taken out of the zinc bath. At this time, a magnetic force is generated in the electrodes 214 at the working positions of the front calibration part 200a and the rear calibration part 200b of the lower calibration unit 200 and the steel plate 1 passing through the lower calibration unit 200, So that the steel plate 1 is flattened. The strength of the magnetic force generated in each of the electrodes 214 may be different depending on the position of the electrodes 214 arranged in the width direction of the steel plate 1 along the shaft 212, That is, a power of different intensity is applied to each of the electrodes 214 in the control unit so as to generate a magnetic force of a pattern capable of maximizing the flatness of the steel plate 1 according to the thickness, the strength, and the warping information of the steel plate 1 .

5, the steel plate 1 is pressed against the air knife 100 (see FIG. 5) in a flattened state by pushing the steel plate 1 with a magnetic force in accordance with the warp of the steel plate 1 at the front and rear of the steel plate 1, ). Accordingly, the plating amount to be cut by the air knife 100 becomes uniform, and the thickness of the plating layer on the surface of the steel sheet 1 can be made uniform.

Further, since the upper calibration unit 300 catches the warpage of the steel plate 1 again on the upper side of the air knife 100, after passing through the air knife 100 from the lower calibration unit 200, It can be maintained in a flattened state until it passes through the through-hole 300, so that a more excellent effect can be obtained in minimizing the variation of the plating amount.

During such a flatness correction operation, the spare electrodes 216 of each of the calibration units 200 are not operated in the preliminary position and are kept in a standby state.

When continuously operated, zinc removed from the surface of the steel plate 1 by the air knife 100 adheres to the surface of the working electrodes 214 of the calibration part 200 and solidifies. This is expected to be even more severe in the bottom calibration unit 200 located below the air knife 100 in particular. When the amount of zinc adhered to the working electrode 214 increases, the strength of the magnetic force generated at the electrodes 214 is weakened and the desired effect is not obtained.

In this case, the rotation motor 220 is operated to rotate the shaft 212 by 180 degrees. The positions of the electrodes 214 in the operating position and the spare electrodes 216 in the spare position are changed accordingly. That is, the spare electrodes 216 are moved to the operating position and the electrodes 214 are moved to the preliminary position. In the state where the positions of the electrodes 214 and 216 are changed, the control unit can continue the work of calibrating the flatness of the steel plate 1 by applying power to the spare electrodes 216 at the operating position.

On the other hand, the electrodes 214 moved to the preliminary position are not supplied with power from the control unit, so that the electrodes 214 are in a standby state. Then, power is applied to the heating wire of zinc removal by the control unit. As a result, the zinc adhering to the surfaces of the electrodes 214 is melted by the heat generated in the heating wire, and is recovered back to the zinc bath. When the operator judges that the zinc is completely removed from the surfaces of the electrodes 214, the operation of the heating wire is stopped.

When zinc is further attached to the electrodes 216 in the operating position by the continuous operation, the shaft 212 is again rotated by 180 degrees to change the positions of the electrodes 214 and the spare electrodes 216 to perform the same operation . There is no need to stop the line to remove the zinc attached to the electrodes 216.

On the other hand, if necessary, the position of the calibration part with respect to the steel plate 1 can be adjusted by using the position control mechanism. The movable block 262 is moved along the guide rod 264 when the guide rod 264 is rotated by the driving motor 266 of the gap adjusting portion so that the center portion 200 is also moved along the width direction of the steel plate 1 The interval of the electrode of the calibrating unit 200 with respect to the steel plate 1 can be adjusted. The strength of the magnetic force of the electrode 214 applied to the surface of the steel plate 1 can be adjusted by adjusting the gap. The strength of the magnetic force applied to the steel plate 1 can be controlled more finely by adjusting the gap between the electrode 214 and the steel plate 1 at the same time as adjusting the strength of the magnetic force generated at the electrode 214. [

It is also possible to adjust the position along the width direction of the steel plate 1 of the calibration part 200 by moving the seating plate 272 in the width direction of the steel plate 1 by the cylinder 276 of the width direction position adjuster have.

According to the steel plate flatness correcting apparatus for a hot dip galvanizing process according to an embodiment of the present invention, warpage of a steel sheet can be flatly corrected using the magnetic force generated from the electrodes disposed on the front and rear surfaces of the steel sheet, It is possible to precisely correct the flatness of the steel sheet by adjusting the strength of the magnetic force, the distance between the electrode and the steel sheet, and the position of the electrode with respect to the width direction of the steel sheet according to the thickness, As a result, the variation of the plating amount on the surface of the steel sheet can be minimized, and the thickness of the plating layer can be maintained uniformly. Further, upper and lower calibration units and a lower calibration unit are provided on the upper and lower sides of the air knife, respectively, to calibrate the flatness of the steel plate on the upper and lower sides of the air knife so that the flattened steel plate is twisted again It is possible to obtain a plated steel sheet of even higher quality.

In the foregoing, the present invention has been shown and described with reference to certain preferred embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept as defined by the appended claims. You can do it.

1: steel plate 100: air knife
200: lower calibration unit 200a: front correction unit
200b: rear surface calibration unit 212, 212a, 212b: shaft
214, 214a, 214b: electrodes 216, 216a, 216b:
220a: rotation motor 218a, 218b:
250: Position control unit 262:
264: Guide rod 266: Driving motor
272: seating plate 274: guide rail
276: driving cylinder 300: upper calibration unit

Claims (11)

An apparatus for calibrating the flatness of a steel sheet passing through an air knife in a hot dip galvanizing process,
An upper calibration unit and a lower calibration unit, which are respectively disposed on the upper and lower sides of the air knife, respectively including a front calibration unit and a rear calibration unit arranged on the front and rear surfaces of the steel sheet, A plurality of electrodes mounted on the shaft so as to be arranged along a width direction of the steel plate and facing the surface of the steel plate with a predetermined gap therebetween; A rotating motor coupled to one end of the shaft for rotating the shaft to change the position of the electrodes and the additional electrodes; and a power supply for supplying power to the plurality of electrodes and the additional electrode A calibration unit comprising a configuration having a wire extending along the shaft;
A power source connected to the wires to supply electric power to the electrodes and the additional electrodes of the calibration units;
An input unit for receiving information on the strength, thickness, and warping of the steel sheet; And
And a controller for controlling the intensity of the magnetic force generated in each of the electrode plates of the calibration units according to the information input through the input unit. delete The method according to claim 1,
Wherein the calibration unit further includes a zinc removing unit for removing zinc adhered to the electrodes during the operation of the galvanizing apparatus. The method of claim 3,
The zinc-
A cylindrical case mounted to surround the additional electrodes,
And a heating wire attached to an inner surface of the case facing the additional electrodes and connected to a power source through a wire. The method according to claim 1,
Wherein the electrodes and the additional electrodes are formed in the shape of a semicircular segment. The method according to claim 1,
Wherein one end of the shaft is connected to a rotating motor through a belt. The method according to claim 1,
Wherein each of the calibration units further comprises a position control mechanism for adjusting a position of the calibration unit with respect to the steel plate. 8. The method of claim 7,
The position control mechanism includes a movable block that supports one end of the shaft, a guide rod that extends in a direction perpendicular to the width direction of the steel plate to guide the movement of the movable block, And a plurality of spacing adjusting portions including a driving motor for the galvanizing process. 9. The method of claim 8,
Wherein the movable block and the guide rod are coupled in a ballscrew manner. 9. The method of claim 8,
The position control mechanism includes:
Further comprising a plurality of width direction position adjusting portions including a seating plate on which the guide rods and the movable blocks are seated and cylinders for moving the seating plates back and forth along the width direction of the steel plate. Calibration device. 11. The method of claim 10,
Wherein the seating plate is configured to simultaneously seat the guide rods and the movable blocks of the front and rear calibrating units of each of the calibration units.

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