KR20170088250A - Method and apparatus for refining magnetic domains grain-oriented electrical steel - Google Patents

Abstract

The present invention relates to a method of refining a magnetic domain of a grain-oriented electrical steel sheet, capable of improving processing ability by improving efficiency of refining a magnetic domain and workability by optimizing facilities and process. To this end, the method of refining the magnetic domain of the grain-oriented electrical steel sheet comprises: a step of adjusting a location of a steel sheet support roll controlling a vertical direction location of the steel sheet while supporting the steel sheet proceeding along a production line; a step of irradiating a laser to form a groove on a surface of the steel sheet by melting the steel sheet by irradiating a laser beam on the surface of the steel sheet; and a step of cooling to cool a surface of a light concentration mirror of an optical system which reflects the laser beam to the surface of the steel sheet in a process of irradiating the laser wherein the cooling step includes a step of primarily cooling the light concentration mirror through a cooling jacket disposed on a rear surface of the light concentration mirror of an optical system; and a step of secondarily cooling the light concentration mirror through an auxiliary cooling block installed in the light concentration mirror.

Description

[0001] METHOD AND APPARATUS FOR REFINING MAGNETIC DOMAINS [0002] GRAIN-ORIENTED ELECTRICAL STEEL [

The present invention relates to a method of microminiaturizing a magnetic steel sheet and a method of micromachining the directional electric steel sheet.

For example, a directional electric steel sheet with low iron loss and high magnetic flux density is required in order to reduce power loss and improve efficiency of electric devices such as a transformer.

In order to reduce the iron loss of the grain-oriented electrical steel sheet, there is disclosed a technique of reducing the iron loss by irradiating the surface of the steel sheet with a mechanical method or a laser beam to miniaturize a magnetic domain in a direction perpendicular to the rolling direction.

The magnetic microfabrication method can be broadly classified into microstructure of the temporary magnetic domain and microstructure of the permanent magnetic domain depending on whether the effect of improving the magnetic domain refinement after the stress relief annealing is maintained or not.

The method of microminiaturization of the temporary magnetic domain has a disadvantage of losing the effect of miniaturization of the magnetic domain after stress relieving annealing. In the method of microminiaturizing the temporary magnetic domain, a local compressive stress portion is formed on the surface of the steel sheet to miniaturize the magnetic domain. However, such a method requires re-coating because it causes damage to the insulating coating layer on the surface of the steel sheet, and there is a disadvantage that the manufacturing cost is high because the micro-processing is performed in the intermediate process, not the final product.

The permanent magnet finer method can maintain the iron loss improving effect even after the heat treatment. Techniques using an etching technique, a roll technique, and a laser technique are mainly used for the permanent magnetic microfabrication process. In the case of the etching method, it is difficult to control the groove forming depth and width, it is difficult to guarantee the iron loss characteristic of the final product, and it is disadvantageous in that it is not environmentally friendly because an acid solution is used. In the case of a roll-based method, there is a disadvantage in that the stability, reliability, and process for machining are complicated.

In the method of making the steel sheet finer by using a laser, a laser beam is irradiated to the surface of the steel sheet while the steel sheet is supported and the tension is adjusted, thereby forming a molten groove on the surface of the steel sheet. As described above, in order to miniaturize the magnetic domain using the laser, it is required to improve and optimize the process more effectively so that high-speed processing can be performed, iron loss of the electric steel sheet can be lowered, and magnetic flux density can be increased.

The present invention provides a method of miniaturizing a magnetic steel sheet for directional electric steel sheet, which is capable of increasing the miniaturization efficiency of the magnetic steel sheet and improving the workability by optimizing the equipment and the process.

Provided is a method for miniaturizing a magnetic field of a directional electric steel sheet and an apparatus for cooling the condensing mirror that reflects a laser more effectively.

Provided is a method for miniaturizing a magnetic field of a directional electric steel sheet and an apparatus for minimizing a temperature deviation of a condensing mirror that reflects a laser.

Provided is a method of miniaturizing a magnetic steel sheet for directional electric steel sheet and an apparatus for removing contaminants such as heal-up and spatter formed by laser irradiation more effectively to improve the quality of a product.

The present invention also provides a method of miniaturizing a magnetic field of a directional electric steel sheet and an apparatus therefor, which are capable of providing an optimal operating environment necessary for the process.

The method includes a step of adjusting a position of a steel plate supporting roll to control a position of the steel plate in the vertical direction while supporting a steel plate running along a production line, a step of irradiating a laser beam on the surface of the steel plate to melt the steel plate, And a cooling step of cooling the condensing mirror surface of the optical system for reflecting the laser beam to the surface of the steel sheet in the laser irradiation process.

The cooling step may include a step of first cooling the condensing mirror through the cooling jacket disposed on the rear side of the condensing mirror of the optical system and a step of second cooling the condensing mirror through the auxiliary cooling block installed in the condensing mirror .

The cooling step includes the steps of: detecting a temperature difference between the inlet side and the outlet side of the cooling jacket in a first cooling process; and controlling the secondary cooling temperature of the condensing mirror by the auxiliary cooling block when the temperature difference is out of a predetermined temperature deviation range The method comprising the steps of:

The cooling step may cool the condensing mirror so that a temperature deviation between both ends of the condensing mirror is maintained at 0 to 2 DEG C along the laser irradiation direction.

Wherein the laser irradiating step irradiates the surface of the steel sheet contacting and advancing in the form of a circular arc on the surface of the steel sheet supporting roll with the laser beam irradiation position when the irradiation direction of the laser beam passes the central axis of the steel sheet supporting roll as a reference point, It is possible to irradiate the laser beam at a position at an angle apart from the center of the support roll along the outer circumferential surface.

In the laser irradiation step, the laser beam may be irradiated to the reference point in a range of 3 to 7 degrees apart from the center of the steel plate supporting roll along the outer circumferential surface.

The magnetic domain refinement method may further include setting and maintaining an internal operating environment of the laser room in which laser irradiation is performed.

The magnetic domain refinement method may further include a tension control step of applying a tension to the steel plate so that the steel plate is kept flat and spread.

The magnetic domain refinement method may further include a skew control step of causing the steel strip to move left and right along the center of the production line without shifting.

The setting maintenance step may include isolating the inside of the laser room from the outside to block the inflow of external contaminants, and controlling the laser room internal temperature, pressure, and humidity.

The magnetic domain refining method may further include a post-processing step for removing a hill up and a spatter formed on a surface of the steel plate through a laser irradiation step.

The post-treatment step may include a step of healing the surface of the steel sheet with a brush roll and a brush step of removing the spatter.

The post-treatment step may include a cleaning step of electrolytically reacting the steel sheet with an alkali solution to further remove the healing and spatter remaining on the surface of the steel sheet, a step of removing foreign substances contained in the alkali solution, And a filtering step for receiving the data.

The meandering control step may include a meander amount measuring step of measuring a meandering amount of the central position of the steel plate which is deviated from the center of the production line and a meandering amount measuring step of measuring the amount of meandering of the steered roll, And controlling a direction in which the steel sheet moves by rotating and moving the steel sheet so as to control the amount of meander of the steel sheet.

The amount of meandering of the steel sheet can be controlled within +/- 1 mm.

The tension control step may include a steel plate tension applying step of applying a tension to the steel plate by the tension bridle roll, a steel plate tension measuring step of measuring a tension of the steel plate subjected to the steel plate tension application step, And a steel plate tension control step of controlling the steel plate tension by adjusting the speed of the tension brick roll according to the tension of the steel plate measured in the steel plate tension measuring step.

The step of adjusting the position of the steel plate supporting roll may include a step of supporting a steel plate positioned in the laser irradiation step with a steel plate supporting roll, a brightness measuring step of measuring brightness of a flame generated upon laser irradiation of the steel plate in the laser irradiation step, A step of controlling the position of the steel plate supporting roll by the steel plate supporting roll position control system according to the brightness of the flame measured in the brightness measuring step and controlling the position of the steel plate in the depth of focus of the laser .

The laser irradiating step irradiates the laser beam irradiated by the laser oscillator onto the surface of the steel sheet by the optical system to form grooves having an upper width, a lower width and a depth of not more than 70 μm, not more than 10 μm, and 3 to 30 μm, respectively And a laser irradiation energy transfer step of transferring a laser beam energy density within a range of 1.0 to 5.0 J / mm 2 required for melting the steel sheet to the steel sheet so that a re-welding portion remaining on the inner wall surface of the groove of the molten portion during the laser beam irradiation is generated .

The laser irradiating step includes turning on a laser oscillator for oscillating a laser beam under normal operation conditions by a laser oscillator controller and controlling the laser oscillator to be turned off when a steel sheet meandering amount of 15 mm or more occurs And a beam oscillation control step.

In the laser irradiation step, the laser oscillator can oscillate a single mode continuous wave laser beam.

In the laser irradiation step, the optical system controls the laser scanning speed to adjust the interval of the laser beam irradiation lines to 2 to 30 mm in the rolling direction.

The laser irradiation step may further include an angle conversion step of converting the angle of the irradiation line of the laser beam irradiated on the surface of the steel sheet.

The angle conversion step may convert the angle of the irradiation line of the laser beam to the range of +/- 4 degrees with respect to the width direction of the steel sheet.

The laser irradiation step may further include a blocking step for blocking the scattered light and the heat of the laser beam from entering the optical system of the laser irradiation facility.

The laser irradiation step may further include a dust collecting step of sucking and removing fumes and molten iron generated when the laser beam is irradiated. The dust collecting step may include a spraying step of spraying compressed dry air into the grooves of the steel sheet to remove molten iron remaining in the grooves.

The magnetic domain refining apparatus of this embodiment includes a steel plate support roll position adjusting device for controlling the position of the steel plate in the vertical direction while supporting the steel plate moved along the production line and a laser beam irradiating device for melting the steel plate, And a cooling unit provided in a condensing mirror provided in an optical system of the laser irradiation equipment for reflecting the laser beam onto the surface of the steel sheet and cooling the surface of the condensing mirror.

The cooling section may include a cooling jacket disposed on a rear surface of the condensing mirror of the optical system for primarily cooling the condensing mirror, and an auxiliary cooling block disposed on a side surface of the condensing mirror to cool the condensing mirror secondarily.

Wherein the auxiliary cooling block includes a plurality of side cooling portions disposed on each side of the condensing mirror for cooling the side surface of the condensing mirror, a connecting portion connecting the side cooling portions, and a cooling portion formed along the inside of the side cooling portion, And the like.

The cooling unit may further include a supply unit for circulating and supplying the cooling medium to the auxiliary cooling block.

The supply unit includes a heat exchanger installed on the cooling medium circulation line for cooling the cooling medium passed through the auxiliary cooling block, a supply pump for supplying the cooling medium passed through the heat exchanger to the cooling block, and a temperature difference between the inlet side and the outlet side of the cooling jacket And controlling the temperature of the cooling medium supplied to the auxiliary cooling block by controlling the heat exchanger when the temperature deviation is out of the reference range.

The laser irradiating equipment has a laser beam irradiating position when the irradiation direction of the laser beam passes through the central axis of the steel plate supporting roll as a reference point with respect to the surface of the steel plate contacting and advancing in the form of an arc on the surface of the steel plate supporting roll, It may be a structure in which a laser beam is irradiated at a position spaced apart at an angle from the center of the support roll along the outer circumferential surface.

The laser irradiation equipment may be configured to irradiate the laser beam to the reference point in a range of 3 to 7 degrees apart from the center of the steel sheet supporting roll along the outer circumferential surface.

The apparatus may further include a laser room for isolating the steel plate supporting roll position adjusting device and the laser irradiation equipment from the outside and providing an operating environment for laser irradiation.

And a tension control device for applying a tension to the steel sheet so as to maintain the steel sheet flatly spread.

The steel sheet may further include a skew control device that allows the steel sheet to move left and right along the center of the production line without tilting.

The laser room accommodates the laser irradiation equipment and the steel plate support roll position control equipment to form an inner space to isolate the laser irradiation equipment and the steel plate support roll position control equipment from each other. An optical system lower frame for separating the upper space where the optical system of the laser irradiation equipment is located from the lower space through which the steel sheet passes, and a constant temperature and humidity controller for controlling the laser room internal temperature and humidity.

And a post-treatment facility for removing hill-up and spatter formed on the surface of the steel sheet.

The post-treatment equipment may include a brush roll disposed at a rear end of the laser room to remove the heel-up and spatters of the steel sheet surface.

The post-treatment facility includes a clean unit disposed at the rear end of the brush roll and electrolytically reacting the steel plate with the alkali solution to further remove the healing and spatter remaining on the surface of the steel plate, and a clean unit connected to the clean unit, And a filtering unit for filtering foreign matters from the alkali solution.

Wherein the meander control facility comprises a steering roll for switching the moving direction of the steel strip, a meander measuring sensor for measuring the degree of deviation of the central position of the steel strip from the center of the production line (meandering amount) And a strip center position control system for adjusting a moving direction of the steel sheet by rotating and moving the axis of the steering roll according to an output value of the sensor.

The tension control device includes a tension bridge roll for guiding movement of the steel plate while applying tension to the steel plate, a steel plate tension measuring sensor for measuring a tension of the steel plate passed through the tension brick roll, And a steel strip control system for adjusting the speed of the tension brick roll according to the tension of the steel strip measured by the tension measuring sensor.

Wherein the steel plate supporting roll position adjusting device includes a steel plate supporting roll for supporting the steel plate at the position of the laser irradiation equipment, a brightness measuring sensor for measuring the brightness of the flame generated upon laser irradiation of the steel plate in the laser irradiation equipment, And a steel plate support roll position control system for controlling the position of the steel plate support roll according to the brightness of the flame measured by the sensor.

The laser irradiating equipment includes a laser oscillator for oscillating a continuous wave laser beam, a laser oscillator for irradiating the laser beam onto the surface of the steel plate, And an optical system for transferring the laser energy density within a range of 1.0 to 5.0 J / mm 2 required for melting the steel sheet to the steel sheet so as to form a groove having a thickness of 30 탆 and to generate a re-welded portion remaining on the inner wall surface of the groove of the molten portion during laser irradiation .

The laser irradiation equipment may further include a laser oscillator controller that turns on the laser oscillator under normal working conditions and controls the laser oscillator to be off when the steel sheet steepness exceeds 15 mm.

The laser oscillator may oscillate a single mode continuous wave laser beam.

The optical system controls the laser scanning speed so that the interval of the laser irradiation lines can be adjusted to 2 to 30 mm along the rolling direction.

The laser irradiation equipment may have a structure in which an optical system for irradiating a laser beam to a steel plate is rotatable by a driving unit and the optical system rotates with respect to the steel plate to change the angle of the irradiation line of the laser beam with respect to the width direction of the steel plate.

The laser irradiation equipment may further include a shielding part for shielding laser scattered light and heat from flowing into the optical system.

The laser irradiation equipment may further include a molten iron removing facility for removing fumes and spatter generated by the laser beam irradiation on the steel plate.

The apparatus for removing molten iron may include an air knife for removing the molten iron remaining in the grooves by spraying compressed dry air into the grooves of the steel sheet, and a dust collecting hood for sucking and removing fumes and molten iron.

As described above, according to the present embodiment, the magnetic iron oxide microfabrication process is stably performed at a high speed of 2 m / sec or more, and the iron loss reduction rates before and after the heat treatment of the electrical steel sheet are respectively 5% Or more.

Further, it becomes possible to cool the condensing mirror for reflecting the laser beam more effectively, thereby preventing the condensing mirror from being thermally deformed and being damaged.

In addition, the temperature deviation of the entire condensing mirror is minimized to maintain a uniform temperature, thereby reducing the condensed mirror thermal distortion and preventing the irradiation path of the laser beam from being changed. Thus, it is possible to maintain the initial operating state and to stabilize the magnetic billet quality of the steel sheet.

In addition, it is possible to increase the microfabrication efficiency of the magnetic domain and improve the workability.

In addition, it is possible to more effectively remove contaminants such as heal-up and spatter formed by laser irradiation, thereby improving the quality of the product.

In addition, by providing an optimum operating environment necessary for the process, it is possible to mass-produce high-quality products.

Fig. 1 is a view schematically showing a configuration of a magnetic domain refinement apparatus of a grain-oriented electrical steel sheet according to the present embodiment.
Fig. 2 is a schematic view showing a steel plate subjected to the micro-finishing process according to the present embodiment.
Fig. 3 is a schematic view showing an optical system configuration of a laser irradiation equipment having an absorption part according to the present embodiment.
Fig. 4 is a schematic view showing a configuration in which a cooling block is installed in an optical system under the present embodiment.
5 is a view showing a structure in which an auxiliary cooling block is installed in a condensing mirror of an optical system according to the present embodiment.
6 and 7 are schematic views showing an auxiliary cooling block according to the present embodiment.
8 is a schematic configuration diagram showing a structure for supplying a cooling medium to the auxiliary cooling block according to the present embodiment.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. 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 invention. Accordingly, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the following description, the present embodiment will be described by taking as an example a facility for finer permanent magnetic ball of a grain-oriented electrical steel sheet used for iron core material of a transformer.

FIG. 1 schematically shows a magnetic microfabrication apparatus for a directional electrical steel sheet according to the present embodiment, and FIG. 2 shows a steel plate subjected to magnetic microfabrication according to the present embodiment. In the following description, the rolling direction or the steel sheet moving direction means the x-axis direction in Fig. 2, the width direction means the y-axis direction in Fig. 2 in a direction orthogonal to the rolling direction, and the width in the y- Length. In Fig. 2, reference numeral 31 denotes a radiation line continuously formed on the surface of the steel plate 1 by being cut into a groove shape by a laser beam.

Referring to FIG. 1, the magnetic field refinement apparatus for a directional electric steel sheet according to the present embodiment stably performs permanent magnetic domain refinement even if the steel sheet 1 advances at a high speed of 2 m / s or higher.

The magnetic domain refining apparatus of the present embodiment includes a steel plate supporting roll position adjusting device for controlling the position of the steel plate in the vertical direction while supporting the steel plate 1 moved along the production line, And a cooling unit provided on a condensing mirror (see 35 in FIG. 3) provided in the optical system of the laser irradiation equipment for reflecting the laser beam onto the surface of the steel sheet and cooling the surface of the condensing mirror .

In addition, the magnetic domain refining apparatus may further include a laser room 20 for isolating the steel plate supporting roll position adjusting facility and the laser irradiation facility from the outside and providing an operating environment for laser irradiation.

In addition, the magnetic domain refinement apparatus may further include a tension control device for applying a tension to the steel strip so that the steel strip is not struck but spread flat.

In addition, the magnetic domain refinement apparatus may further include a warp control device for allowing the steel strip to move left and right along the center of the production line without tilting.

In addition, the magnetic domain refining apparatus may further include a post-treatment facility for removing hill-up and spatter formed on the surface of the steel sheet in accordance with the laser beam irradiation.

The hill up refers to a portion where molten iron is accumulated on both sides of the groove portion at a predetermined height or more when the groove is formed by irradiating the surface of the steel sheet with a laser beam. Spatter refers to molten iron generated during laser beam irradiation and solidified on the surface of a steel sheet.

Steering rolls 2A and 2B for switching the direction of movement of the steel strip 1 are disposed at the center of the width of the steel strip 1, (4) for calculating a detection signal of the meandering measurement sensor (4) and for rotating and moving the axis of the steering rolls (2A, 2B) to adjust the moving direction of the steel plate (1) And a position control system (Strip Center Position Control System) 3.

The meandering measurement sensor 4 is disposed at the rear end of the steering roll 2B to detect in real time the actual meandering amount of the steel plate passed through the steering roll.

It is possible to form grooves on the surface of the steel sheet over the full width of the steel sheet by moving the steel sheet straightly along the center of the production line without side-to-side bias.

In the meander control facility, the meandering amount of the steel sheet is measured by the meander measuring sensor 4 in the pre-formation step of the steel sheet surface by laser irradiation. The value measured by the meander measurement sensor 4 is output to the steel plate central position control system. The steel plate central position control system calculates the output value of the meander measurement sensor and rotates and rotates the axes of the steering rolls 2A, 2B according to the calculated degree of meandering. . As described above, the steering rolls 2A and 2B are rotated and moved, whereby the moving direction of the steel sheet wound around the steering roll is adjusted. Therefore, the meandering amount of the steel sheet is controlled, and the meandering amount of the steel sheet 1 can be controlled within +/- 1 mm.

The tension control facility includes tension braille rolls (TBR) 5A and 5B for guiding movement of the steel strip 1 while applying a predetermined tension to the steel strip 1, 5B according to the tension of the steel strip 1 measured by the steel strip tension measuring sensor 7 and the steel strip tension measuring sensor 7 for measuring the tension of the tension bridle rolls 5A, And a steel strip control system 6 for controlling the tension of the steel strip.

The steel plate tension measuring sensor 7 is disposed at the rear end of the tension bridle roll 5B and measures the actual tension of the steel plate subjected to the tension via the tension bridle roll 5B in real time.

In the present embodiment, the tensile force of the steel sheet can be set so that the surface of the steel sheet at the laser irradiation position of the laser irradiation equipment is made flat, and the steel sheet is not broken due to excessive tension.

In order to operate the steel plate tension within a predetermined range, the tension control facility is controlled by a steel strip tension control system 6 according to the tension of the steel plate measured by the steel plate tension measurement sensor 7, TBR) (5A, 5B). Thus, the tension control device controls the tension error of the steel strip 1 to be within the set range to apply tension to the steel strip.

The steel plate having passed through the tension control facility flows into the laser room 20, is finely processed through the steel plate supporting roll position adjusting facility and the laser irradiation equipment, and then exits to the outside of the laser room 20. The laser room will be described later.

In this embodiment, a steel plate supporting roll 9 is disposed in the laser room 20 immediately below the laser irradiation equipment, and deflector rolls 8A and 8B are provided on both sides of the steel plate supporting roll, .

The moving direction of the steel strip 1 is switched to the steel strip supporting roll 9 by the deflector rolls 8A and 8B. The steel plate 1 is moved to the side of the steel plate supporting roll 9 through the deflector roll 8A so as to be moved toward the deflector roll 8B after the steel plate 1 is contacted with the steel plate supporting roll 9, Lt; / RTI >

The steel plate 1 is wound in the form of an arc along the steel plate supporting roll 9 by the deflector roll and passes over the steel plate supporting roll while being in surface contact. In order to minimize the fluctuation of the laser beam focal length due to the vibration of the steel sheet and the wave during the irradiation of the laser beam, the steel sheet must sufficiently contact the surface of the steel sheet supporting roll. In this state, You must investigate. In this embodiment, since the steel plate is in surface contact with the steel plate supporting roll as described above, the laser beam can be accurately irradiated to the steel plate.

The steel plate supporting roll position adjusting device includes a steel plate supporting roll 9 for supporting the steel plate 1 to the laser irradiation position of the laser irradiation equipment, And a steel plate support roll (SPR) position control system 12 for controlling the position of the steel plate support roll 9 according to the brightness of the flame measured by the brightness measurement sensor 10 ).

The steel plate supporting roll position adjusting apparatus is configured such that the steel plate 1 is supported by the steel plate supporting roll 9 to the position of the laser irradiation portion and the steel plate 1 is supported on the steel plate so that the steel plate is positioned within the depth of focus The position of the steel plate supporting roll 9 is adjusted up and down as a whole so that the brightness of the flame generated in the laser irradiation becomes the best. The brightness of the flame generated when the steel plate is laser-irradiated is measured by using the luminance measurement sensor 10. [

In this embodiment, the steel plate supporting roll position adjusting device may further include a distance measuring sensor 11 for measuring an actual distance between the optical system of the laser irradiation equipment and the steel plate surface. The steel plate supporting roll position control system 12 calculates the brightness of the flame detected from the brightness measuring sensor 10 and the distance between the optical system and the surface of the steel sheet actually measured from the distance measuring sensor 11, As shown in FIG.

The meander control facility, the tension control facility, and the steel plate support roll position adjustment facility serve to make the steel plate condition at the laser irradiation position so that the laser groove can be precisely formed by the laser irradiation equipment. The steel plate at the laser irradiation position should have the center position of the steel plate at the center position of the production line and the distance from the optical system should be maintained at the set value.

The laser irradiation equipment may include a laser oscillator controller 13, a laser oscillator 14 for oscillating the continuous wave laser beam 16, and an optical system 15.

3 and 4, the optical system 15 includes a module plate 37 rotatably installed to impart an angle of the laser beam irradiation line with respect to the width direction of the steel plate, A header 39 provided on the module plate 37 and adapted to emit a laser beam applied from the laser oscillator 14 to the inside of the optical system 15, A polygon mirror 32 for reflecting the laser beam emitted from the header 39, a rotation motor 33 for rotating the polygon mirror 32, a polygon mirror 32 mounted on the module plate 37, A condenser mirror 35 for reflecting the laser beam 16 reflected by the condenser lens 35 toward the steel plate and condensing the condensed laser beam onto a steel plate, (34), the module plate And a shutter 38 which is installed in the shutter 37 and selectively blocks the module plate 37 according to whether the laser beam is irradiated or not.

The optical system 15 is a body in which a header 39, a polygon mirror 32, a condenser mirror 35 and a shutter are disposed in a module plate 37 constituting an optical box. The laser oscillator 14 and the header 39 are connected to the optical cable 41, for example. Thus, the laser beam emitted from the laser oscillator 14 is transmitted to the header 39 via the optical cable 41. A header 39, a polygon mirror 32 and a condensing mirror 35 are disposed in a correct position to reflect the laser beam 16 to a desired position inside the module plate 37 constituting the optical box. 3, for example, the header 39 may be disposed on both sides of the polygon mirror 32, and may emit a laser beam toward the polygon mirror 32, respectively. Two condenser mirrors 35 are arranged in accordance with the respective laser beams reflected by the polygon mirror 32. [ The laser beam emitted from the header 39 is reflected by the polygon mirror 32 which rotates in accordance with the driving of the rotation motor 33 and is sent to the condensing mirror 35. The laser beam 16 reflected by the condenser mirror 35 is reflected from the condenser mirror 35 to the steel plate through the shutter 38 and condensed on the surface of the steel plate 1. [ Thus, the surface of the steel sheet is irradiated with the laser beam periodically to form continuous grooves in the width direction.

The entire focal distance of the laser beam 16 by the optical system 15 is adjusted by the upward and downward movement of the steel plate supporting roll 9 and the right and left focal lengths are not matched by the drive motor 34 ).

The shutter 38 is installed under the module plate 37 to open and close the module plate 37. The shutter 38 is opened when the laser beam is irradiated downward from the condensing mirror 35 to prevent interference with the laser beam. When the laser beam is not irradiated, the shutter 38 is closed so that external fumes or foreign substances are generated inside the optical system 15 .

The condensing mirror 35 of the optical system 15 includes a mirror plate 351 having a reflecting surface for reflecting the laser beam and a cooling jacket 352 for cooling the mirror plate 351 ) Are combined with each other.

The mirror plate 351 may be made of a copper material as a portion that directly contacts and reflects the laser beam. Since the condensing mirror 35 must focus and reflect the 15 kW class laser on the steel sheet, the focal point of the laser beam may be varied even with small deformation. However, since the condensing mirror 35 is continuously exposed to high heat by the direct heating by the laser and the reflected light reflected by the steel plate, the possibility of thermal deformation is very high. When the condensing mirror 35 is thermally deformed, the focus of the laser beam is changed. If the focal point of the laser beam on the steel sheet is changed, the groove depth formed on the steel sheet may be uneven and the performance of the product may be deteriorated.

Accordingly, in the present embodiment, the condensing mirror 35 includes a cooling part including the cooling jacket 352 and the auxiliary cooling block 140, thereby minimizing thermal deformation of the condensing mirror 35.

The cooling jacket 352 is installed to cool the mirror plate 351 primarily in contact with the rear surface of the mirror plate 351. The cooling jacket 352 may have a structure in which a flow path is formed in the inside of the cooling jacket 352 to circulate the cooling medium along the flow path. The internal flow path forming structure of the cooling jacket 352 may be variously modified and is not particularly limited. The cooling medium may be, for example, cooling water, and any heat-exchangeable fluid is applicable without any particular limitation. As the cooling medium flows into the cooling jacket 352, heat exchange is performed between the mirror plate 351 and the cooling jacket 352. The condenser mirror 35 including the mirror plate 351 is heat-exchanged with the cooling jacket 352 to be cooled.

The auxiliary cooling block 140 minimizes the temperature deviation between the opposite ends of the condensing mirror 35 by cooling both ends of the condensing mirror 35 that the cooling jacket 352 can not cover primarily.

Figs. 5 to 7 illustrate the structure of the auxiliary cooling block 140 installed in the condensing mirror 35. Fig. Hereinafter, the auxiliary cooling block 140 will be described with reference to FIGS.

The auxiliary cooling block 140 includes a plurality of side cooling portions 141 disposed on both sides of both ends of the condensing mirror 35 along the width direction of the steel plate for cooling the side surface of the condensing mirror 35, A connection part 142 connecting the side surface cooling part 141 and the side surface cooling part 141, and a flow path formed along the inside of the side surface cooling part 141 and the connection part 142 to move the cooling medium.

As mentioned above, the condensing mirror 35 is heated by direct heating of the laser and radiant heat of the reflected light, and is primarily heat-exchanged by the cooling jacket 352 to be cooled. However, the cooling medium flowing into the inlet of the cooling jacket 352 is gradually heated while moving toward the outlet of the cooling jacket 352, so that the temperature rises. Accordingly, a temperature deviation occurs in an area between the inlet side of the cooling jacket 352 into which the cooling medium flows and the outlet side from which the cooling medium is discharged.

 In particular, since the condensing mirror 35 is also elongated in the width direction of the steel plate so as to irradiate the laser in the width direction of the steel plate, the condensing mirror 35 is formed along the steel plate width direction even if cooled by the cooling jacket 352, A large temperature deviation occurs between the both side ends of the heater.

When the temperature of the condensing mirror 35 becomes non-uniform, the condensing mirror 35 is distorted such that the laser beam is not irradiated properly.

Accordingly, the auxiliary cooling block 140 cools both side surfaces of the condensing mirror 35 to minimize the temperature deviation between both ends.

The connection portion 142 connects and supports the plurality of side cooling portions 141 and serves as a passage through which the cooling medium flowing to the side cooling portion 141 moves. The connection portion 142 is formed to extend along the condensing mirror 35. The side cooling part 141 is connected to the connection part 142 to form a body and extends at a right angle to the side of the condensing mirror 35 at the connection part 142. The side cooling part 141 may be formed to correspond to the side surface of the condensing mirror 35 so as to be in surface contact with the side surface of the condensing mirror 35.

The side cooling section cools the condensing mirror 35 on both sides of the condensing mirror 35 in contrast to the structure in which the cooling jacket 352 cools the mirror plate 351 on the rear surface of the condensing mirror 35. The side surface of the condensing mirror 35 where the side cooling portion 141 is in contact with and heat-exchanged may be a side surface of the cooling jacket 352 disposed on the rear surface of the mirror plate 351, for example. Or the side surface of the bracket coupled with the mirror plate 351 of the condensing mirror 35.

In this embodiment, as shown in FIGS. 5 and 6, the condensing mirrors 35 are disposed at two intervals along the width direction of the steel plate, so that the auxiliary cooling block 140 is divided into three side cooling portions 141). The side cooling portion 141 disposed in the middle is sandwiched between the two condenser mirrors 35 to come in contact with the opposite side surfaces of the two condenser mirrors 35 to cool the side of the condenser mirror 35. The intermediate cooling unit 141 may be formed to have a size corresponding to the size of the space between the two condenser mirrors 35. The side cooling portion 141 disposed at both ends is in contact with the side surface of the outer end of each condensing mirror 35 to cool the side surface of each condensing mirror 35. The number of the side cooling units 141 may vary according to the number of the condensing mirrors 35 and may be variously modified as long as they can be disposed on both sides of all the condensing mirrors 35.

FIG. 7 illustrates a flow path formed in the auxiliary cooling block 140. FIG.

In this embodiment, the flow path is formed by a cooling flow path 143 formed to circulate the front surface of each side cooling portion 141 of the auxiliary cooling block 140 and a connection path 142 formed in the connection portion 142, (144). The cooling medium flows through the side cooling portion 141 disposed on one side of the auxiliary cooling block 140 and circulates the side cooling portion 141 along the cooling flow passage 143, And then to the next side cooling part 141 through the connecting flow path 144 and then to the cooling flow path 143 of each side cooling part 141 in turn. The formation structure of the flow path may be variously modified.

As shown in FIG. 8, the cooling unit may further include a supply unit connected to the flow path to circulate and supply the cooling medium to the auxiliary cooling block 140.

The supply unit includes a heat exchanger 151 installed on the cooling medium circulation line 150 to cool the cooling medium passed through the auxiliary cooling block 140 and a cooling medium passing through the heat exchanger 151 to the cooling block 140 A supply pump 152 for supplying cooling water to the cooling jacket 352 and a temperature difference between the inlet side and the outlet side of the cooling jacket 352 and controlling the heat exchanger 151 when the temperature deviation is out of the reference range, And a control unit 154 for controlling the temperature of the supplied cooling medium.

The supply unit may further include a thermostat (156) installed on the circulation line (150) to receive the cooled cooling medium through the heat exchanger (151) to maintain the temperature.

The supply pump 152 of the supply unit is installed at the rear end of the thermostatic chamber 156 and at least two of them are arranged in parallel and installed on the circulation line 150. Accordingly, when the one-side supply pump fails, the remaining supply pump is driven to continuously circulate and supply the cooling medium. The cooling medium may be, for example, cooling water, and any heat-exchangeable fluid is applicable without any particular limitation.

On the inlet side and the outlet side of the cooling jacket 352, a temperature sensor 153 for detecting the temperature of the cooling medium is provided, respectively. Each of the temperature sensors 153 detects the temperature of the cooling medium flowing into the inlet of the cooling jacket 352 and the temperature of the cooling medium discharged through the outlet through the flow path inside the cooling jacket 352 in real time. The control unit 154 compares the detected values of the respective temperature sensors 153 and calculates a temperature deviation between the inlet side and the outlet side of the cooling jacket 352. Since the cooling jacket 352 is provided along the condensing mirror 35 and the inlet and the outlet are located at both ends of the cooling jacket 352, the temperature deviation between the inlet side and the outlet side of the cooling jacket 352 is Means a temperature deviation between both ends of the condensing mirror 35. [

The control unit 154 has a reference range for an allowable temperature deviation value therein. In this embodiment, the reference range may be 0 to 2 占 폚. When the temperature deviation is out of the above range, the thermal deformation amount due to the temperature difference between the both ends of the condensing mirror 35 exceeds the allowable range, and irradiation of the laser beam is not properly performed.

The control unit 154 calculates whether the deviation value of the temperature detected through the two temperature sensors 153 is out of an allowable reference range to lower the temperature of the cooling medium supplied to the auxiliary cooling block 140 And controls the heat exchanger 151 to operate. The temperature difference between both ends of the optical system 15 can be reduced by supplying the cooling medium whose temperature is lowered in accordance with the control drive of the heat exchanger 151 to the auxiliary cooling block 140. [

As described above, the supply unit of the present embodiment continuously monitors the temperature deviation of the condensing mirror 35 and controls the temperature of the cooling medium of the auxiliary cooling block 140, thereby controlling the temperature of both ends of the condensing mirror 35 of the optical system 15 Minimize the deviation to minimize thermal deformation and prevent the quality of the steel sheet from deteriorating.

The cooling medium drawn by the supply pump 152 is removed from the impurities through the filter 157 installed on the circulation line 150 and is depressurized through the auxiliary valve 158 before the auxiliary cooling block 140, And is supplied to the auxiliary cooling block 140.

The cooling medium supplied to the auxiliary cooling block 140 passes through the side cooling part 141 along the cooling flow path 143 to intensively cool the opposite side surfaces of the condensing mirror 35. The rear surface of the condensing mirror 35 is cooled by the cooling jacket 352 and both side surfaces of the condensing mirror 35 having a small cooling effect by the cooling jacket 352 are additionally provided by the auxiliary cooling block 140 The cooling is uniformly performed over the entire light-collecting mirror 35. As a result, The cooling medium supplied to the auxiliary cooling block 140 is directly transferred to both side ends of the condensing mirror 35 and is cooled through the side cooling part 141 so that the cooling medium is supplied to the auxiliary cooling block 140 between the both ends of the condensing mirror 35 The temperature difference is reduced. Accordingly, the temperature deviation between both ends of the condensing mirror is reduced to within the predetermined reference range, and thermal deformation of the condensing mirror can be minimized.

If the steel sheet meandering amount is excessive, the steel sheet is deviated from the laser irradiation position, and the steel sheet support roll 9 is irradiated with a laser, and damage occurs. In order to prevent damage to the steel plate supporting roll, the laser oscillator controller 13 turns on the laser oscillator under normal working conditions and controls the laser oscillator to turn off when the steel sheet steepness exceeds 15 mm do.

The laser oscillator 14 can oscillate a single mode continuous wave laser beam and transmit it to the optical system 15. The optical system 15 irradiates the transferred laser beam 16 onto the surface of the steel sheet.

The laser oscillator 14 and the optical system 15 irradiate the surface of the steel sheet with a laser beam to form grooves with an upper width, a lower width and a depth of 70 mu m or less, 10 mu m or less, 3 to 30 mu m, The laser energy density in the range of 1.0 to 5.0 J / mm 2 necessary for melting the steel sheet can be transmitted to the steel sheet so that a re-welded portion remaining on the inner wall surface of the groove in the molten portion during irradiation is generated.

The optical system 15 has a function of controlling the laser scanning speed so that the interval of the laser radiation (31 in FIG. 2) can be adjusted to 2 to 30 mm in the rolling direction. Thus, the influence of the heat affected zone (HAZ, heat affected zone) by the laser beam can be minimized and the iron loss of the steel sheet can be improved.

Further, the laser irradiation equipment may be a structure for converting the angle of the irradiation line of the laser beam irradiated on the surface of the steel sheet with respect to the width direction of the steel sheet. In this embodiment, the laser irradiation equipment can convert the angle of the irradiation line of the laser beam in the width direction of the steel plate into the range of +/- 4 degrees.

To this end, the laser irradiation equipment is structured such that the optical system 15 for irradiating the steel plate with a laser beam is rotatable by the drive unit 36, and the angle of the irradiation line of the laser beam formed on the surface of the steel plate is changed Lt; / RTI > As the angle of the irradiation line of the laser beam by the optical system is changed as described above, the irradiation line 31 by the laser beam is formed by inclining in the range of +/- 4 degrees in the direction perpendicular to the rolling direction of the steel sheet. Therefore, it is possible to minimize the decrease in the magnetic flux density due to the groove formation by the laser.

Further, in this embodiment, the laser irradiation equipment controls the irradiating position of the laser beam on the steel plate 1 so as to prevent a back reflection phenomenon in which the laser beam irradiated on the steel plate is reflected by the steel plate and enters the optical system or the laser oscillator Structure.

4, the laser irradiating equipment is arranged such that the irradiation direction of the laser beam irradiated by the optical system 15 is applied to the surface of the steel sheet which contacts the surface of the steel plate supporting roll 9 in the form of an arc, The laser beam irradiation position when passing the central axis of the roll 9 is set as a reference point P and an angle from the reference point P to the center along the outer peripheral surface at the center of the steel plate supporting roll 9 R) (hereinafter referred to as " R ").

The reference point P is a point at which a line passing through the central axis of the steel plate supporting roll 9 meets the steel plate in FIG. When the irradiation direction of the laser beam passes the central axis of the steel plate supporting roll 9, the focal point of the laser beam is adjusted to the reference point P. In this case, as the irradiation direction of the laser beam is orthogonal to the tangent to the steel plate supporting roll 9 at the reference point P, the laser beam reflected by the steel plate is directly incident on the optical system and the laser oscillator, Lt; / RTI >

As described above, the laser irradiation apparatus according to this embodiment irradiates the laser beam at a position spaced apart from the reference point P by the spacing angle R, so that the laser beam reflected back from the steel plate is not incident on the optical system. Therefore, the above-described back reflection phenomenon can be prevented and the groove quality formed by the laser beam can be maintained.

In the present embodiment, the spacing angle R may be set in the range of 3 to 7 degrees along the outer peripheral surface at the center of the steel plate supporting roll 9 with respect to the reference point P. [

When the spacing angle R, which is a position at which the laser beam is irradiated, is smaller than 3 DEG, a part of the laser beam reflected back from the steel sheet may be introduced into the optical system or the laser oscillator. If the spacing angle (R) exceeds 7, grooves formed by the laser beam may not be formed properly and grooves may be formed defective.

As described above, the laser irradiation equipment according to the present embodiment prevents the back reflection phenomenon by irradiating the steel plate with the laser beam at a position spaced by a predetermined angle around the reference point P, and does not interfere with the incident optical path during laser beam reflection, So that it is possible to stably maintain the quality of the groove shape formed by the groove.

The laser irradiation equipment may further include a molten iron removing facility for removing fumes and spatter generated by the laser beam irradiation on the steel plate.

The molten iron removing apparatus includes an air knife 17 for spraying compressed dry air into the grooves of the steel sheet to remove molten iron remaining in the grooves, and dust collecting hoods 19A and 19B for sucking and removing fumes and molten iron . The fume generated during the laser irradiation through the air knife and the dust-collecting hood is removed and the fume can be prevented from being introduced into the optical system. The air knife 17 injects compressed dry air having a predetermined pressure Pa into the groove of the steel plate 1 to remove the molten iron remaining in the groove. The compressed dry air in the air knife 17 preferably has a pressure (Pa) of 0.2 kg / cm ² or more. When the pressure of the compressed dry air is smaller than 0.2 kg / cm ² , it is impossible to remove the molten iron in the groove and the iron loss improving effect can not be secured. The fumes and spatters removed by the air knife are removed by the dust collecting hoods 19A and 19B disposed before and after the laser irradiation position.

In addition, the laser irradiation equipment may further include a shielding portion 18 for shielding reflected light, scattered light, and radiant heat of the laser beam from entering the optical system. The shielding portion 18 shields the reflected light and the scattered light introduced into the optical system by reflection and scattering of the laser beam 16 irradiated on the steel plate to prevent the optical system from being thermally deformed by the radiant heat due to the reflected light and scattered light do.

The laser room 20 is a room structure having an internal space. The laser irradiation facility and the steel plate supporting roll 9 are accommodated in the inside of the room structure to isolate it from the outside and provide an appropriate operating environment for smooth driving do.

The entrance and exit of the laser room 20 are formed at the entrance and exit sides of the laser room 20 along the direction of the steel plate. The laser room 20 has a facility for blocking inflow of contaminants so that the internal space is not contaminated by external dust or the like. To this end, the laser room 20 is provided with a positive pressure device 23 for raising the internal pressure beyond the outside. The positive pressure device 23 maintains the pressure inside the laser room 20 relatively higher than the external pressure. Accordingly, it is possible to prevent foreign substances from entering into the laser room 20. In addition, air curtains 22A, 22B, 22C, and 22D are provided at the entrance and exit of the steel sheet. The air curtain blows air to the inlet and the outlet, which are passages through which the steel sheet enters and exits the laser room 20 to form a film, thereby blocking dust and the like from entering through the inlet and the outlet. In order to prevent contamination of the inside of the laser room 20, a shower booth 21 may be installed on the door, which is an entrance of the laser room 20. The shower booth 21 removes foreign matter adhering to the body of the passerby entering the laser room 20. [

The laser room 20 is a space in which the steel plate self-ballast finishing process by the laser beam proceeds, and it is necessary to minimize the change of the internal environment and maintain the proper environment. The laser room 20 includes an optical system lower frame 24 for separating the upper space in which the laser oscillator 14 and the optical system 15 of the laser irradiation facility are located from the lower space through which the steel plate 1 passes, And a constant temperature and humidity controller 25 for controlling the internal temperature and humidity of the room 20.

The optical system lower frame 24 makes it possible to more thoroughly manage the operation environment of the main equipment such as the laser oscillator 14 and the optical system 15. The optical system lower frame 24 is installed in the laser room 20 so as to separate the lower space of the optical system through which the steel plate passes, and the upper space of the optical system where the laser oscillator and the optical system mirrors are located. The upper space of the optical system is also separated from the inside of the laser room 20 by the optical system lower frame 24 to prevent contamination and temperature and humidity control of major facilities such as a laser oscillator and an optical system.

The constant temperature and humidity controller 25 adjusts the temperature and humidity inside the laser room 20 to provide a proper environment. In the present embodiment, the temperature and humidity controller 25 can maintain the internal temperature of the laser room 20 at 20 to 25 DEG C and maintain the humidity at 50% or less.

As described above, the inner space of the laser room 20 is maintained at a temperature and a humidity suitable for the working environment, so that the micro-miniaturization process can be performed on the steel sheet in the optimum condition. Therefore, a high-quality product can be mass-produced under the optimal operating environment required for the process.

The magnetic domain refining apparatus of the present embodiment may further include a post-treatment facility for removing hill-up and spatter formed on the surface of the steel sheet.

Since the heel-up and spatter cause deterioration of the insulation and viscosity of the product, the quality of the product can be improved by completely removing the product through the post-treatment equipment.

The post-treatment equipment may include brush rolls 26A and 26B disposed at the rear end of the laser room 20 along the steel sheet moving direction to remove the heel-up and spatters of the steel sheet surface. The brush rolls 26A and 26B are rotated at a high speed by a driving motor. The brush rolls 26A and 26B are controlled by a current control system that controls the current value of the driving motor generated during operation to a predetermined target value, The rotation speed and the distance between the steel plate are controlled by the control system. The brush roll may be disposed on only one side of the steel plate having grooves formed by the laser beam, or on both sides of the steel plate. The brush rolls 26A and 26B come into close contact with the surface of the steel sheet and rotate at a high speed to remove the heel-up and spatter attached to the surface of the steel sheet. As shown in Fig. 1, a dust-collecting hood 19C for discharging the heel-up and the spatters removed by the brush roll in the vicinity of the brush rolls 26A and 26B is further provided. The dust-collecting hood 19C sucks the heel-up and the molten iron which are separated from the steel plate by the brush rolls 26A and 26B and spatters and discharges the molten iron to the outside.

The post-treatment facility includes a cleaning unit 29 disposed at the rear end of the brush rolls 26A and 26B for electrolytically reacting the steel sheet with the alkali solution to further remove the healing and spatter remaining on the surface of the steel sheet, And a filtering unit 30 for filtering foreign substances contained in the alkali solution of the clean unit from the alkali solution.

The steel sheet is primarily healed and spatters are removed through the brush rolls 26A and 26B, and the remaining heal-up and spatters are secondarily removed through the clean unit 29. [ Thus, it is possible to more completely remove the heel-up and spatter attached to the surface of the steel sheet, thereby enhancing the product quality.

The clean unit 29 is filled with an alkali solution, and the filtering unit 30 is connected to one side. As the steel sheet is processed through the clean unit, the heel-up and spatters removed from the steel sheet are accumulated in the internal alkali solution, thereby deteriorating the cleaning performance of the steel sheet. The filtering unit 30 circulates the alkali solution of the cleaning unit and removes the healing and spatter contained in the alkali solution. The filtering unit 30 removes the heal-up and the spatter to control the iron content of the alkali solution to 500 ppm or less. In this way, deterioration of the cleaning performance of the clean unit can be prevented, and the steel sheet can be continuously treated.

Hereinafter, the process of miniaturization of the electric steel sheet according to the present embodiment will be described.

Continuous steel plates are passed through the meandering control equipment and the tension control equipment, enter the laser room, proceed at a speed of 2 m / sec or more, and finely processed. The steel sheet entering the laser room is finely processed through the laser irradiation equipment and then drawn out of the laser room. The steel sheet drawn to the outside of the laser room is passed through the post-treatment facility and the heal-up and spatter remaining on the surface are removed and sent to the post-process.

In this process, the laser room in which laser irradiation is performed on the surface of the steel sheet appropriately sets and maintains the internal operating environment so as to provide an optimum environment for microfabrication.

The laser room isolates the inside of the laser room from the outside and blocks the inflow of external contaminants, and controls the internal temperature, pressure, and humidity of the laser room according to the operating environment for miniaturization.

The inner pressure of the laser room is set higher than the external pressure, so that foreign substances such as dust can be prevented from entering into the laser room. In addition, by forming a film of air on the entrance and the exit, which are passages through which the steel sheet is moved, foreign substances such as dust can be prevented from flowing into the laser room during the process of the steel sheet through the entrance and exit.

The constant temperature and humidity controller installed in the laser room maintains the temperature inside the laser room at 20 to 25 DEG C and maintains the humidity at 50% or less, thereby providing an optimum condition for the magnetic domain refining treatment by laser irradiation.

In this way, the laser room provides the optimal environment for laser beam irradiation, and the steel sheet is accurately positioned at the laser irradiation position through the meander control facility, the tension control facility, and the steel plate support roll position adjustment facility.

First, the steel plate is controlled in a straight line through the meander control facility, and moves straight along the center of the production line.

The meander detection sensor continuously detects the meandering amount of the steel sheet. When the steel sheet meanders, the signal detected by the meandering sensor is calculated, and the steel plate central position control system rotates and moves the shaft of the steering roll to move the steel plate to the correct position do. By continuously controlling the steering roll according to the position of the steel sheet, the steel sheet can be continuously moved continuously without departing from the center of the production line.

The steel plate is moved past the steering roll through the tension bridle roll for controlling the tension. Tension The tension of the steel plate past the bridle roll is detected by the tension measuring sensor. The steel plate tension control system calculates the measured value detected by the tension measuring sensor and controls the speed of the tension bridle roll with the set tension. Thus, the tension of the steel sheet to be moved can be maintained constantly in accordance with the set range.

The steel plate passed through the tensile bridle roll enters the laser room through the entrance of the laser room. The steel sheet is turned inside the laser room by the bridle roll and moved in a state of being in close contact with the steel plate supporting roll located between the two bridle rolls.

The steel plate supporting roll moves the steel plate up and down to position the steel plate in the depth of focus of the laser beam.

When the laser beam is irradiated from the laser irradiation equipment to the steel plate, the brightness measuring sensor detects the brightness of the flame on the steel plate in real time, and the steel plate supporting roll position control system moves the steel plate supporting roll up and down according to the measured value detected by the luminance measuring sensor So that the steel sheet is positioned within the focal depth of the laser beam. Thus, the surface of the steel sheet is effectively irradiated with the laser beam, and high quality radiation can be formed.

The laser oscillator controller turns on / off the laser oscillator according to the degree of skew of the steel sheet. The laser oscillator controller is connected to the meander measurement sensor, and determines that the steel plate has deviated too much from the steel plate supporting roll when the amount of meander of the steel sheet measured by the meander measurement sensor is 15 mm or more, for example, and turns off the laser oscillator. Thus, it is possible to prevent the laser beam from being irradiated to the surface of the steel plate supporting roll through the meandered steel plate to damage the roll.

The laser beam generated by the laser oscillator is irradiated onto the surface of the steel plate through the optical system in response to the command from the laser oscillator controller. The laser oscillator oscillates the TEM ₀₀ continuous wave laser beam and transmits it to the optical system.

The optical system changes the direction of the laser beam and irradiates the surface of the steel sheet with a laser to continuously form a molten groove on the surface of the steel sheet to carry out micro-finishing.

 The surface of the steel sheet is melted by the laser beam irradiated to the steel sheet through the optical system, and a melted groove is formed along the irradiation line. In this embodiment, grooves having an upper width, a lower width and a depth of not more than 70 mu m, not more than 10 mu m, and 3 to 30 mu m, respectively, are formed on the surface of the steel sheet through laser beam irradiation, The laser oscillator and the optical system transmit the laser energy density within the range of 1.0 to 5.0 J / mm 2 to the steel sheet necessary for melting the steel sheet so that the re-irradiated portion is formed.

Also, by irradiating the laser beam at a position spaced apart from the reference point in the laser beam irradiation process through the optical system, the laser beam reflected back from the steel plate is not incident on the optical system. Therefore, the above-described back reflection phenomenon can be prevented, and the incident light path of the laser beam is not interfered by the reflected light, so that the groove quality formed by the laser beam can be maintained.

In this embodiment, in the laser irradiation process, the condensing mirror of the optical system is cooled to prevent the condensing mirror from being thermally deformed by the direct heating of the laser or the radiant heat of the reflected light reflected from the surface of the steel plate.

The cooling of the condensing mirror is performed by first cooling the condensing mirror through the cooling jacket disposed on the rear side of the condensing mirror of the optical system and secondly cooling the condensing mirror through the auxiliary cooling block installed in the condensing mirror.

The temperature difference between the inlet side and the outlet side of the cooling jacket is detected in the primary cooling process and the secondary cooling temperature of the condensing mirror by the auxiliary cooling block is adjusted when the temperature difference is out of the predetermined temperature deviation range.

In order that the irradiation path of the laser beam through the condensing mirror does not change, the deformation amount of the condensing mirror with respect to the steel plate width direction should be 16 μm or less and the temperature deviation between both ends of the condensing mirror must be maintained within the range of 0 to 2 ° C.

Thus, by further cooling the condensing mirror through the auxiliary cooling block, it is possible to cool the condensing mirror so that the temperature deviation between both ends of the condensing mirror is 0 to 2 占 폚 along the laser irradiation direction. Therefore, the amount of deformation of the condensing mirror can be reduced to 16 mu m or less to prevent defective irradiation of the laser beam.

Table 1 below shows the condensed mirror deformation amount according to this embodiment in comparison with the conventional one.

Deviation of temperature of condensing mirror (℃) Vertical deformation (탆) Transverse strain (탆) Allowable range Comparative Example 1 7 13.87 17.48 Departure Comparative Example 2 5 13.78 16.69 Departure Example 1 2 13.64 15.52 permit Example 2 0 13.55 14.77 permit

As shown in Table 1, in the case of the embodiments of the present invention, the temperature variation of the condensing mirror is maintained within the reference range of 0 to 2 DEG C so that the deformation amount (indicated by the horizontal deformation amount in Table 1) All were less than 16 ㎛.

In the comparative examples, unlike the present embodiment, only the first cooling by the cooling jacket is performed or the cooling is not performed at all. As a result, the temperature deviation of the orphaned mirror deviates from the reference range, Respectively.

Therefore, in the case of this embodiment, it can be confirmed that the effective cooling of the condensing mirror can reduce the temperature deviation of the condensing mirror and minimize the thermal deformation amount.

The optical system has a function of controlling the laser scanning speed so that the interval of the laser irradiation lines with respect to the rolling direction can be adjusted. Further, the optical system has a rotation function and can change the angle of the laser radiation line. In the present embodiment, the distance between the laser irradiation lines can be adjusted to 2 to 30 mm in the rolling direction by the optical system, thereby minimizing the influence of the heat affected zone (HAZ, heat affected zone) have. Further, in the laser beam irradiation process, the angle of the irradiation line of the laser beam irradiated on the surface of the steel sheet can be changed through the rotation of the optical system. In this embodiment, the optical system can convert the angle of the irradiation line of the laser beam into a range of +/- 4 degrees with respect to the width direction of the steel sheet. In other words, the irradiation line 31 of the laser beam can be formed so as to be inclined in the range of ± 4 degrees with respect to the y-axis direction in FIG. Therefore, the radiation rays formed on the surface of the steel sheet can be formed by inclining in the range of 86 to 94 degrees with respect to the rolling direction. By forming the irradiation line inclined with respect to the y-axis direction in this manner, it is possible to minimize the decrease in the magnetic flux density due to the formation of grooves by the laser.

In the laser beam irradiation process, a steel sheet is melted by a laser beam, and a large amount of fume and molten iron spatter are generated. The fume and spatter contaminate the optical system, and if molten iron remains in the groove, it is difficult to form a precise groove and damage of the iron loss is not made and the product quality is deteriorated. Thus, compressed dry air is sprayed into the grooves of the steel sheet to remove the residual iron in the grooves, and the fumes and molten iron are immediately sucked through the dust collecting hood to be removed. Accordingly, it is possible to prevent the fume from flowing into the optical system in the process of finishing the steel plate magnetic domain, and to rapidly remove the fume and the spatter, thereby improving the efficiency of microfabrication. In addition, it is possible to further prevent the scattered light and the heat of the laser beam from being introduced into the optical system of the laser irradiation equipment during the laser beam irradiation process.

Grooves are formed on the surface of the steel sheet through the laser beam irradiation, and the steel plate subjected to the micro-finishing process is continuously moved and discharged to the outside through the exit of the laser room.

The steel sheet discharged from the laser room is subjected to a post-treatment process to remove the heel-up and spatters attached to the surface of the steel sheet.

The steel plate is firstly passed through the brush roll disposed outside the laser room, and is firstly heel-up and spatters are removed by the brush roll which is closely attached to the steel plate and rotates at high speed.

The steel plate after the brush roll is finally passed through the clean unit, and the remaining healing and spatter are finally removed through the electrolysis reaction between the steel sheet and the alkali solution. The steel plate with the heel-up and spatter removed through the clean unit is transferred to the post-process.

Iron loss
Improvement rate (%) After laser irradiation After heat treatment 9.5 11.6 9.7 12.9 11.5 13.5 8.4 11.6 8.6 11.8 8.5 11.7

Table 2 shows the iron loss improvement ratio of the grain-oriented electrical steel sheet by grooves formed on the surface of the steel sheet of 0.27 mm thickness by the continuous wave laser beam irradiation according to the present embodiment. As shown in Table 2, it can be seen that, in the case of the steel sheet subjected to the micro-finishing treatment in the present embodiment, iron loss is improved both after the laser irradiation and after the heat treatment.

While the illustrative embodiments of the present invention have been shown and described, various modifications and alternative embodiments may be made by those skilled in the art. Such variations and other embodiments will be considered and included in the appended claims, all without departing from the true spirit and scope of the invention.

1: steel plate 2A, 2B: steering roll (SR)
3: Steel plate center position control system 4: Meander measurement sensor
5A, 5B: tension bridle roll 6: steel plate tension control system
7: Steel plate tension measuring sensor 8A: Deflector roll
8B: Deflector roll 8C: Medium deflector roll
9: steel plate supporting roll 10: luminance measuring sensor
11: distance measuring sensor 12: steel plate supporting roll position control system
13: laser oscillator controller 14: laser oscillator
15: optical system 16: laser beam
17: air knife 18: absorption part
19A, 19B, 19C: dust collecting hood 20: laser room
21: Shower booth 22A, 22B, 22C, 22D: Air curtain
23: positive pressure device 24: optical system lower frame
25: Constant temperature and humidity controller 26A, 26B: Brush roll
27: motor current control system 28: brush position control system
29: clean unit 30: filtering unit
31: Survey line 32: Polygon mirror
33: rotation motor 34: drive motor
35: condensing mirror 36:
37: module plate 38: shutter
39: Header 140: Auxiliary cooling block
141: side cooling section 142:
143: cooling channel 144: connecting channel
150: circulation line 151: heat exchanger
152: Feed pump 153: Temperature sensor
154: control unit 156: thermostatic chamber
157: Filter 158: Pressure reducing valve
351: mirror plate 352: cooling jacket

Claims (22)

A step of adjusting a position of a steel plate supporting roll to control a position of the steel plate in a vertical direction while supporting a steel plate running along a production line, a laser irradiation step of forming a groove on the surface of the steel plate by irradiating a laser beam onto the surface of the steel plate, And a cooling step of cooling the condensing mirror surface of the optical system reflecting the laser beam to the surface of the steel sheet in the laser irradiation process,
Wherein the cooling step includes a step of first cooling the condensing mirror through a cooling jacket disposed on the rear side of the condensing mirror of the optical system, and a step of secondarily cooling the condensing mirror through the auxiliary cooling block installed in the condensing mirror A method of finely dividing a steel plate. The method according to claim 1,
Wherein the laser irradiating step irradiates the surface of the steel sheet contacting and advancing in the form of a circular arc on the surface of the steel sheet supporting roll with the laser beam irradiation position when the irradiation direction of the laser beam passes the central axis of the steel sheet supporting roll as a reference point, And irradiating a laser beam at a position spaced apart at an angle from the center of the support roll along the outer circumferential surface. 3. The method of claim 2,
Wherein the laser beam is irradiated to the reference point in a range of 3 to 7 degrees apart from the center of the steel plate supporting roll along the outer circumferential surface thereof in the laser irradiation step. The method according to claim 1,
Wherein the laser irradiation step further comprises an angle conversion step of converting an angle of an irradiation line of the laser beam irradiated on the surface of the steel sheet. 5. The method of claim 4,
Wherein the angle conversion step converts the angle of the irradiation line of the laser beam in the width direction of the steel sheet into a range of +/- 4 degrees. 6. The method according to any one of claims 1 to 5,
Wherein the cooling step comprises the steps of: detecting a temperature difference between a cooling jacket inlet side and an outlet side in a primary cooling process; and controlling a secondary cooling temperature of the condensing mirror by the auxiliary cooling block when the temperature difference is out of a predetermined temperature deviation range The method further comprising the step of: The method according to claim 6,
Wherein the cooling step cools the condensing mirror so that the temperature deviation between both ends of the condensing mirror is maintained at 0 to 2 占 폚 along the laser irradiation direction. The method according to claim 6,
Further comprising a setting maintaining step of setting and maintaining an internal operating environment of the laser room in which laser irradiation is performed,
Wherein the setting and maintaining step includes the step of isolating the inside of the laser room from the outside to block inflow of external contaminants, and controlling the internal temperature, pressure, and humidity of the laser room. The method according to claim 6,
Further comprising a tension control step of applying a tension to the steel plate so as to maintain the steel plate in a flattened unfolded state. The method according to claim 6,
And a skew control step of causing the steel sheet to move left and right along the center of the production line without tilting. The method according to claim 6,
Further comprising a post-treatment step of removing hill-up and spatter formed on a surface of the steel sheet through the laser irradiation step. A steel plate support roll position adjusting device for controlling the position of the steel plate in the vertical direction while supporting the steel plate moved along the production line, and a laser irradiation equipment for forming a groove on the surface of the steel plate by melting the steel plate by irradiating the laser beam, And a cooling unit provided in an optical system of the laser irradiation equipment and provided in a condensing mirror for reflecting the laser beam onto the surface of the steel plate to cool the surface of the condensing mirror,
Wherein the cooling section includes a cooling jacket disposed on a rear surface of the condensing mirror of the optical system for primarily cooling the condensing mirror and an auxiliary cooling block disposed on a side of the condensing mirror for cooling the condensing mirror to secondarily cool the condensing mirror, . 13. The method of claim 12,
The laser irradiating equipment has a laser beam irradiating position when the irradiation direction of the laser beam passes through the central axis of the steel plate supporting roll as a reference point with respect to the surface of the steel plate contacting and advancing in the form of an arc on the surface of the steel plate supporting roll, Wherein the laser beam is irradiated at a position spaced at an angle from the center of the support roll along the outer circumferential surface. 14. The method of claim 13,
Wherein the laser irradiation equipment irradiates the laser beam to the reference point in a range of 3 to 7 degrees apart from the center of the steel plate supporting roll along the outer circumferential surface thereof. 13. The method of claim 12,
Wherein the optical system has a structure rotatable by a driving unit and rotates with respect to the steel plate to change the angle of the irradiation line of the laser beam with respect to the width direction of the steel plate. 16. The method according to any one of claims 12 to 15,
Wherein the auxiliary cooling block includes a plurality of side cooling portions disposed on each side of the condensing mirror for cooling the side surface of the condensing mirror, a connecting portion connecting the side cooling portions, and a cooling portion formed along the inside of the side cooling portion, And a flow path for flowing the magnetic field of the directional electric steel plate. 17. The method of claim 16,
Wherein the cooling section further comprises a supply section for circulating and supplying the cooling medium to the auxiliary cooling block,
The supply unit includes a heat exchanger installed on the cooling medium circulation line for cooling the cooling medium passed through the auxiliary cooling block, a supply pump for supplying the cooling medium passed through the heat exchanger to the cooling block, and a temperature difference between the inlet side and the outlet side of the cooling jacket And controlling the temperature of the cooling medium supplied to the auxiliary cooling block by controlling the heat exchanger when the temperature deviation is out of the reference range. 17. The method of claim 16,
Further comprising a laser room for isolating the steel plate supporting roll position adjusting facility and the laser irradiation facility from the outside and providing an operating environment for laser irradiation. 19. The method of claim 18,
The laser room accommodates the laser irradiation equipment and the steel plate support roll position control equipment to form an inner space for isolating the laser irradiation equipment and the steel plate support roll position control equipment from each other. The entrance and exit are formed on both sides along the progress direction of the steel plate, A directional electric steel plate including an optical system lower frame for separating the upper space in which the optical system of the laser irradiation equipment is located from the lower space through which the steel sheet passes, and a constant temperature and humidity controller for controlling the laser room internal temperature and humidity, . 17. The method of claim 16,
And a tensile force control device for applying a tensile force to the steel plate so as to maintain the steel plate in a flattened unfolded state. 17. The method of claim 16,
Further comprising a warp control device for causing the steel strip to move left and right along the center of the production line without tilting. 17. The method of claim 16,
Further comprising post-treatment equipment for removing hill-up and spatter formed on the surface of the steel sheet.

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