KR102538119B1 - Method and apparatus for refining magnetic domains grain-oriented electrical steel - Google Patents

Abstract

By optimizing equipment and processes, through which the efficiency of magnetic domain refinement can be increased and workability can be improved to increase processing capacity. A steel sheet support roll position adjustment step of controlling the vertical position of the steel sheet while supporting the steel sheet progressing along the production line, and a laser irradiation step of melting the steel sheet by irradiating a laser beam to the surface of the steel sheet to form grooves on the surface of the steel sheet. It provides a magnetic domain refining method for grain-oriented electrical steel sheet, including blocking, and blocking the reflected light and scattered light of the laser beam irradiated on the surface of the steel sheet from entering the optical system for irradiating the laser beam.

Description

Magnetic domain refinement method of grain-oriented electrical steel sheet and its device

It relates to a magnetic domain refinement method of grain-oriented electrical steel sheet and an apparatus for permanently refining magnetic domains of a grain-oriented electrical steel sheet by irradiating laser to the grain-oriented electrical steel sheet.

For example, in order to reduce power loss and improve efficiency of electric devices such as transformers, grain-oriented electrical steel sheets having magnetic characteristics of low iron loss and high magnetic flux density are required.

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

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

The temporary domain refining method has a disadvantage in that the domain refining effect is lost after stress relief annealing. In the temporary magnetic domain refining method, the magnetic domains are refined by forming localized compressive stress areas on the surface of the steel sheet. However, since this method causes damage to the insulating coating layer on the surface of the steel sheet, re-coating is required, and the manufacturing cost is high because the domain refining treatment is performed in an intermediate process rather than the final product.

The permanent domain refining method can maintain the iron loss improvement effect even after heat treatment. For the permanent magnetic domain refinement treatment, techniques using an etching method, a roll method, or a laser method are mainly used. In the case of the etching method, it is difficult to control the depth or width of the groove formation, it is difficult to guarantee the iron loss characteristics of the final product, and it is not environmentally friendly because it uses an acid solution. In the case of a method using rolls, there are disadvantages in terms of stability, reliability, and complicated process for machining.

In the method of permanent magnetic domain refinement of a steel sheet using a laser, a laser beam is irradiated on the surface of the steel sheet in a state in which the steel sheet is supported and the tension is adjusted to form molten grooves on the surface of the steel sheet to refine the magnetic domains. In this way, in miniaturizing magnetic domains using a laser, it is required to improve and optimize a more effective process to reduce iron loss and increase magnetic flux density of an electrical steel sheet while enabling high-speed processing.

By optimizing equipment and processes, it provides a magnetic domain refinement method and device for grain-oriented electrical steel sheet that can increase the efficiency of magnetic domain refinement and improve workability through which the processing capacity can be increased.

Provided is a method and apparatus for refining grain-oriented electrical steel sheets capable of preventing damage to an optical system due to reflection of a laser beam and radiant heat.

Provided is a method and device for refining grain-oriented electrical steel sheet, which can more effectively remove contaminants such as heel-up and spatter formed by laser irradiation to improve product quality.

Provided is a method and device for refining grain-oriented electrical steel sheet capable of providing an optimal operating environment required for a process.

The magnetic domain refinement method of the present embodiment includes the step of adjusting the position of a steel sheet support roll for controlling the position of the steel sheet in the vertical direction while supporting the steel sheet progressing along the production line, and the surface of the steel sheet by irradiating a laser beam to the surface of the steel sheet and melting the steel sheet. It may include a laser irradiation step of forming a groove in the laser irradiation process, and a blocking step of blocking reflected light or scattered light and radiant heat of the laser beam irradiated on the surface of the steel sheet from entering the optical system of the laser irradiation equipment during the laser irradiation process.

The blocking step includes a step of shielding reflected light and scattered light with a polarizing filter disposed in the optical system, a cooling step of preventing the temperature of the optical system from rising due to the reflected light and scattered light, and a heat intake step for preventing moisture generation due to a temperature difference in the polarizing filter. can do.

In the blocking of the reflected light and the scattered light, reflected light and scattered light out of a range of ±5° in a direction perpendicular to the plane of the polarization filter may be blocked.

In the laser irradiation step, with respect to the surface of the steel sheet proceeding in contact with the surface of the steel sheet support roll in an arc shape, the laser beam irradiation position when the irradiation direction of the laser beam passes through the central axis of the steel sheet backup roll as a reference point, the steel sheet at the reference point A laser beam may be irradiated at a position spaced apart from the center of the support roll at an angle along the outer circumferential surface.

In the laser irradiation step, the laser beam may be irradiated in a range of 3 to 7° along the outer circumferential surface from the center of the steel sheet support roll with respect to the reference point.

The magnetic domain refinement method may further include a tension control step of applying tension to the steel sheet to maintain the steel sheet in a flat unfolded state.

The magnetic domain refinement method may further include a meandering control step of moving the steel sheet left and right along the center of the production line without bias.

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

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 temperature, pressure, and humidity inside the laser room.

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

The post-processing step may include a brush step of removing spatter and heel-up on the surface of the steel sheet with a brush roll.

The post-processing step includes a cleaning step in which heel-up and spatter remaining on the surface of the steel plate are additionally removed by electrolytic reaction of the steel plate with an alkali solution, and foreign substances removed from the steel plate and included in the alkali solution are filtered out from the alkali solution in the cleaning step. A filtering step may be further included.

In the meandering control step, the meandering amount measuring step of measuring the meandering amount in which the central position of the steel plate is out of the center of the production line, and the meandering amount measured in the meandering amount measuring step, adjust the axis of the steering roll according to the meandering amount. A meandering amount control step of controlling the meandering amount of the steel plate by adjusting the moving direction of the steel plate by rotating and moving the steel plate may be included.

In the meandering amount control step, the meandering amount of the steel sheet may be controlled within ±1 mm.

The tension control step includes a steel sheet tension applying step of applying tension to the steel sheet by the tension bridle roll, a steel sheet tension measuring step for measuring the tension of the steel sheet after performing the steel sheet tension applying step, and A steel sheet tension control step of controlling the steel sheet tension by adjusting a speed of the tension bridle roll according to the steel sheet tension measured in the steel sheet tension measuring step may be included.

The steel plate support roll position adjusting step includes a steel plate support step of supporting the steel plate positioned in the laser irradiation step with the steel plate support roll, a luminance measurement step of measuring the brightness of a spark generated when laser irradiating the steel plate in the laser irradiation step, and The steel sheet backup roll position control step of controlling the steel sheet to be located within the depth of focus of the laser by adjusting the position of the steel sheet support roll by the steel sheet support roll position control system according to the brightness of the flame measured in the luminance measurement step. can include

In the laser irradiation step, the laser beam irradiated from the laser oscillator is irradiated onto the surface of the steel sheet by the received optical system to form grooves having an upper width, a lower width, and a depth of 70 μm or less, 10 μm or less, and 3 to 30 μm, respectively. At the same time, when the laser beam is irradiated, a laser irradiation and energy transfer step of transferring a laser beam energy density within the range of 1.0 to 5.0 J / mm2 necessary for melting the steel sheet to the steel sheet so that a re-solidification portion remaining on the inner wall of the groove of the melting unit is generated. can

In the laser irradiation step, the laser oscillator controls the laser oscillator to turn on the laser oscillator that oscillates the laser beam under normal working conditions and to turn the laser oscillator off when the amount of meandering of the steel sheet is greater than 15 mm. A beam oscillation control step may be included.

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

In the laser irradiation step, the optical system may control the laser scanning speed to adjust the distance between 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 an angle of the irradiation line of the laser beam irradiated onto the surface of the steel sheet.

In the angle conversion step, the irradiation angle of the laser beam with respect to the width direction of the steel sheet may be converted into a range of ±4°.

The laser irradiation step may further include a dust collection step of suctioning and removing fume and molten iron generated during laser beam irradiation. The dust collecting step may include a blowing step for removing molten iron remaining in the grooves by blowing compressed dry air into the grooves of the steel sheet.

The magnetic domain refinement device of the present embodiment includes a steel sheet support roll position adjusting device that controls the vertical position of the steel sheet while supporting the steel sheet moving along the production line, and melts the steel sheet by irradiating a laser beam to form grooves on the surface of the steel sheet. It may include a laser irradiation facility to form, and a shielding portion that blocks reflected light, scattered light, and radiant heat of the laser beam irradiated on the surface of the steel sheet from entering the optical system of the laser irradiation facility.

The shielding unit may include a polarization filter disposed below the optical system of the laser irradiation equipment to shield reflected light and scattered light.

The shielding unit may further include a cooling unit preventing an increase in temperature of the optical system due to reflected light and scattered light.

The cooling unit may include a cooling passage installed in the polarization filter to supply cooling water into the polarization filter, and a supply unit circulating and supplying a cooling medium through a cooling pipe connected to the cooling passage.

The shielding unit may further include a dust collecting hood for preventing moisture generation by suctioning and removing heat around the polarization filter.

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

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

The laser irradiation equipment may have a structure in which a laser beam is irradiated in a range 3 to 7° apart from the center of the steel sheet support roll along the outer circumferential surface with respect to the reference point.

It may further include a tension control device for imparting tension to the steel sheet so that the steel sheet is maintained in a flatly spread state.

It may further include a meander control facility that allows the steel plate to move left and right along the center of the production line without bias.

It may further include a laser room that accommodates the steel plate support roll position adjusting facility and the laser irradiation facility in isolation from the outside and provides an operating environment for laser irradiation.

The laser room accommodates the laser irradiation equipment and the steel plate support roll position control equipment and forms an internal space to isolate it from the outside, and an entrance and an exit are formed on both sides along the traveling direction of the steel plate, and inside the laser room. It may include a positive pressure device to increase the pressure higher than the outside, an optical system lower frame to separate the upper space where the optical system of the laser irradiation facility is located from the lower space where the steel plate passes, and a constant temperature and humidity controller to control the temperature and humidity inside the laser room.

A post-processing facility for removing hill-up and spatter formed on the surface of the steel sheet may be further included.

The post-processing facility may include a brush roll disposed at the rear of the laser room to remove spatter and heel-up on the surface of the steel plate.

The post-processing facility includes a cleaning unit disposed at the rear end of the brush roll to further remove heel-up and spatter remaining on the surface of the steel sheet by electrolytic reaction of the steel sheet with an alkali solution, and a cleaning unit connected to the cleaning unit and included in the alkali solution of the cleaning unit. A filtering unit for filtering out foreign substances from the alkaline solution may be further included.

The meander control facility includes a steering roll for changing the moving direction of the steel plate, a meander measurement sensor for measuring the extent to which the central position of the width of the steel plate deviates from the center of the production line (meander amount), and the meander measurement. A strip center position control system for adjusting the moving direction of the steel sheet by rotating and moving the shaft of the steering roll according to the output value of the sensor may be included.

The tension control device includes a tension bridle roll for inducing movement while applying tension to the steel sheet, a steel sheet tension measuring sensor for measuring the tension of the steel sheet passing through the tension bridle roll, and the steel sheet A strip tension control system may be included to adjust the speed of the tension bridle roll according to the tension of the steel sheet measured by the tension measuring sensor.

The steel plate support roll position adjusting device includes a steel plate support roll for supporting the steel plate at the location of the laser irradiation facility, a luminance measuring sensor for measuring the brightness of a flame generated when laser irradiating the steel plate in the laser irradiation facility, and the luminance measurement. A steel sheet support roll position control system for controlling the position of the steel sheet support roll according to the brightness of the flame measured by the sensor may be included.

The laser irradiation equipment is a laser oscillator for oscillating a continuous wave laser beam, and the laser beam oscillated from the laser oscillator is irradiated to the surface of the steel sheet so that the upper width, lower width, and depth are within 70 μm, within 10 μm, and 3 to 30 μm, respectively. It will include an optical system that transfers the laser energy density within the range of 1.0 to 5.0 J/mm2 necessary for melting the steel sheet to the steel sheet so that a 30㎛ groove is formed and at the same time a re-solidification portion remains on the inner wall of the groove of the molten portion during laser irradiation. can

The laser irradiation equipment may further include a laser oscillator controller that turns the laser oscillator on under normal working conditions and turns the laser oscillator off when the meandering amount of the steel plate exceeds 15 mm.

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

The optical system may control the laser scanning speed to adjust the distance between the laser irradiation lines to 2 to 30 mm along the rolling direction.

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

The molten iron removal facility may include an air knife that removes molten iron remaining in the groove by spraying compressed dry air into the groove of the steel sheet, and a dust collection hood that sucks and removes fume and molten iron.

As described above, according to the present embodiment, the magnetic domain refinement process by laser is stably performed while the steel sheet is advanced at a high speed of 2 m/sec or more, and the iron loss improvement rate before and after heat treatment of the electrical steel sheet is 5% or more and 10%, respectively. more can be obtained.

In addition, equipment damage can be prevented by appropriately blocking and cooling the laser beam and radiant heat from entering the optical system.

In addition, it is possible to increase the magnetic domain refinement processing capability by increasing the efficiency of magnetic domain refinement and improving workability.

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

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

1 is a diagram schematically showing the configuration of an apparatus for refining magnetic domains of a grain-oriented electrical steel sheet according to an embodiment.
2 is a schematic diagram showing a steel sheet subjected to magnetic domain refinement treatment according to the present embodiment.
Figure 3 is a schematic diagram showing the configuration of the optical system of the laser irradiation equipment equipped with a shield according to the present embodiment.
4 is a schematic diagram showing a shielding unit installed in an optical system according to the present embodiment.
5 is a view showing the cooling action of the shielding unit according to this embodiment compared to the conventional one.

The terminology used below is only for referring to specific embodiments and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" specifies specific characteristics, regions, integers, steps, operations, elements, and/or components, and other specific characteristics, regions, integers, steps, operations, elements, elements, and/or groups. does not exclude the presence or addition of

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described so that those skilled in the art can easily practice it. As can be easily understood by those skilled in the art to which the present invention pertains, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Accordingly, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

In the following description, the present embodiment will be described as an example of equipment for permanent domain refinement of grain-oriented electrical steel sheet used as a material for transformer iron core.

1 schematically illustrates an apparatus for domain refining of a grain-oriented electrical steel sheet according to the present embodiment, and FIG. 2 illustrates a steel sheet subjected to domain refining treatment according to the present embodiment. In the following description, the rolling direction or the steel plate moving direction means the x-axis direction in FIG. 2, the width direction means the y-axis direction in FIG. 2 as a direction perpendicular to the rolling direction, and the width is the means length. In FIG. 2 , reference numeral 31 denotes a radiation line continuously formed on the surface of the steel sheet 1 by being dug in the form of a groove by a laser beam.

Referring to FIG. 1 , the device for refining the magnetic domain of a grain-oriented electrical steel sheet according to the present embodiment stably performs a permanent domain refining process even when the steel sheet 1 proceeds at a high speed of 2 m/s or more.

The magnetic domain refinement apparatus of the present embodiment supports the steel sheet 1 moving along the production line, and controls the position of the steel sheet in the vertical direction of the steel sheet. It may include a laser irradiation facility that forms grooves, and a shielding portion that blocks reflected light, scattered light, and radiant heat of the laser beam irradiated onto the surface of the steel sheet from entering the optical system of the laser irradiation facility.

In addition, the magnetic domain refinement device may further include a laser room 20 that accommodates the steel sheet support roll position adjusting facility and laser irradiation facility in isolation from the outside and provides an operating environment for laser irradiation.

In addition, the magnetic domain refinement device may further include a tension control device for applying tension to the steel sheet so that the steel sheet is maintained in a flat unfolded state without sagging.

In addition, the magnetic domain refinement device may further include a meandering control facility that allows the steel sheet to move left and right along the center of the production line without bias.

In addition, the magnetic domain refinement device may further include a post-processing facility for removing spatter and hill-up formed on the surface of the steel sheet according to laser beam irradiation.

Hill-up refers to a portion in which molten iron in the steel sheet is piled up to a certain height or higher on both sides of the groove when forming a groove by irradiating a laser beam on the surface of the steel plate. Spatter refers to molten iron that is generated during laser beam irradiation and solidified on the surface of the steel sheet.

The meandering control facility controls steering rolls (2A, 2B) for changing the moving direction of the steel plate 1, and the degree (meandering amount) that the central position of the width of the steel plate 1 deviates from the center of the production line. A meander measurement sensor 4 for measuring, a steel plate center for adjusting the direction in which the steel plate 1 moves by calculating the detection signal of the meander measurement sensor 4 and rotating and moving the axes of the steering rolls 2A and 2B A strip center position control system (3) may be included.

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

Since the steel sheet is moved straight along the center of the production line by the meandering control facility without left-right bias, it is possible to form grooves on the surface of the steel sheet over the entire width of the steel sheet.

The meandering control facility measures the amount of meandering of the steel sheet by the meandering measuring sensor 4 in the process before forming grooves on the surface of the steel sheet by laser irradiation. The value measured by the meander measurement sensor 4 is output to the steel plate center position control system, and the steel plate center position control system calculates the output value of the meander measurement sensor and rotates and rotates the shafts of the steering rolls 2A and 2B according to the calculated meandering degree. will move In this way, by rotating and moving the steering rolls 2A and 2B, the moving direction of the steel sheet wound around the steering roll and moving is adjusted. Accordingly, the amount of meandering of the steel plate is controlled so that the amount of meandering of the steel plate 1 can be controlled within ±1 mm.

The tension control device includes tension bridle rolls (TBR) (5A, 5B) for inducing movement while applying a certain amount of tension to the steel sheet 1, and the steel sheet passing through the tension bridle roll ( 1) Adjust the speed of the tension bridle rolls 5A and 5B according to the tension of the steel sheet 1 measured by the steel sheet tension sensor 7 for measuring the tension, and the steel sheet tension sensor 7 It may include a strip tension control system 6 for

The steel sheet tension sensor 7 is disposed at the rear end of the tension bridle roll 5B and measures the actual tension of the steel sheet tensioned through the tension bridle roll 5B in real time.

In this embodiment, the tension of the steel sheet can be set so as not to cause breakage of the steel sheet due to excessive tension while flattening the surface shape of the steel sheet at the laser irradiation position of the laser irradiation equipment.

In order to operate with the steel sheet tension within the set range, the tension control facility uses the strip tension control system 6 according to the steel sheet tension measured by the steel sheet tension measuring sensor 7. Tension Bridle Roll: Adjust the speed of TBR) (5A, 5B). Accordingly, the tension control device applies tension to the steel sheet by controlling the tension error of the steel sheet 1 to be within the set range.

The steel sheet passing through the tension control facility is introduced into the laser room 20, undergoes magnetic domain refinement through a steel sheet support roll position adjusting facility and a laser irradiation facility, and then exits the laser room 20. The laser room will be described again later.

In this embodiment, in the laser room 20, a steel plate support roll 9 is disposed right below the laser irradiation equipment, and deflector rolls 8A and 8B are placed on both sides with the steel plate support roll in between. are placed

The moving direction of the steel sheet 1 is switched to the steel sheet support roll 9 by deflector rolls 8A and 8B. The steel plate 1 passes through the deflector roll 8A, the moving direction is changed toward the steel plate support roll 9, and after coming into contact with the steel plate support roll 9, the direction is changed again toward the deflector roll 8B, and the deflector roll 8B is moved past

The steel sheet 1 is wound in an arc shape along the steel sheet backup roll 9 by the deflector roll, and passes while being in surface contact with the steel sheet backup roll. In order to minimize the change in the focal length of the laser beam due to the vibration and wave of the steel sheet during laser beam irradiation, the steel sheet must pass through the steel sheet support roll in sufficient surface contact. You have to investigate. In this embodiment, as the steel sheet is brought into surface contact with the steel sheet support roll as described above, the laser beam can be accurately irradiated to the steel sheet.

The steel sheet support roll position adjusting facility includes the steel sheet support roll 9 supporting the steel sheet 1 at the laser irradiation position of the laser irradiation facility, and the brightness of the flame generated when the laser irradiation is performed on the steel sheet 1 in the laser irradiation facility. A luminance measurement sensor 10 for measuring , and a steel sheet support roll (SPR) position control system 12 for controlling the position of the steel sheet support roll 9 according to the brightness of the flame measured by the luminance measurement sensor 10 ) may be included.

The steel sheet support roll position adjusting facility supports the steel sheet 1 to the position of the laser irradiation unit by the steel sheet support roll 9, and places the steel sheet within the depth of focus with high laser steel irradiation efficiency. Adjust the position of the steel sheet support roll 9 up and down as a whole so that the brightness of the flame generated during laser irradiation is the best. In addition, the brightness of a flame generated when the steel sheet is irradiated with a laser is measured using the luminance measuring sensor 10 .

In this embodiment, the steel sheet support roll position adjusting facility may further include a distance measurement sensor 11 for measuring the actual distance between the optical system of the laser irradiation facility and the surface of the steel sheet. The steel plate support roll position control system 12 calculates the distance between the optical system and the surface of the steel plate actually measured from the brightness of the flame detected from the luminance measurement sensor 10 and the distance measurement sensor 11 to position the steel plate support roll 9 control more precisely.

The meandering control facility, the tension control facility, and the steel sheet support roll position adjusting facility play a role in creating conditions for the steel sheet at the position of laser irradiation so that laser grooves can be precisely formed in the steel sheet by means of the laser irradiation facility. For the steel plate at the laser irradiation position, the central position of the steel plate should be in the central position of the production line and the distance from the optical system should be maintained at a set value.

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

As shown in FIG. 3, the optical system 15 includes a module plate 37 that is rotatably installed to give an angle of a laser beam irradiation line with respect to the width direction of the steel sheet, and a driving unit for rotating the module plate 37. (36), a header 39 installed on the module plate 37 and emitting a laser beam applied from the laser oscillator 14 into the optical system 15, and a header 39 rotatably installed on the module plate 37 ( 39), a polygon mirror 32 that reflects the laser beam emitted from the polygon mirror 32, a rotation motor 33 that rotates and drives the polygon mirror 32, and is installed on the module plate 37 to reflect the polygon mirror 32. A condensing mirror 35 that reflects the laser beam 16 toward the steel plate and condenses it on the steel plate, and a driving motor 34 that is connected to the condensing mirror 35 and moves the condensing mirror 35 to adjust the focal length of the laser beam , It may include a shutter 38 installed on the module plate 37 to selectively block the module plate 37 according to whether a laser beam is irradiated.

In the optical system 15, a header 39, a polygon mirror 32, a condensing mirror 35, and a shutter are disposed in a module plate 37 constituting an optical box to form one body. The laser oscillator 14 and the header 39 are connected by an optical cable 41, for example. Thus, the laser emitted from the laser oscillator 14 is sent to the header 39 via the optical cable 41. Inside the module plate 37 constituting the optical box, the header 39, the polygon mirror 32, and the condensing mirror 35 are disposed in the right position to reflect the laser beam 16 to a desired position. As shown in FIG. 3 , for example, the header 39 may be disposed on both sides with the polygon mirror 32 interposed therebetween to emit laser beams toward the polygon mirror 32, respectively. Two condensing mirrors 35 are arranged to match each laser beam reflected by the polygon mirror 32 . The laser beam emitted from the header 39 is reflected by the polygon mirror 32 rotating according to the driving of the rotation motor 33 and sent to the condensing mirror 35 . The laser beam 16 reflected by the condensing mirror 35 is reflected from the condensing mirror 35 toward the steel sheet through the shutter 38 and is condensed on the surface of the steel sheet 1. Accordingly, a laser beam is periodically irradiated on the surface of the steel sheet to form continuous grooves in the width direction.

The overall focal length of the laser beam 16 by the optical system 15 is adjusted by the vertical movement of the steel plate support roll 9, and if the left and right focal lengths do not match, the driving motor 34 connected to the condensing mirror 35 ) is adjusted by

The shutter 38 is installed under the module plate 37 to open and close the module plate 37 . The shutter 38 is open when the laser beam is irradiated downward from the condensing mirror 35 to prevent interference with the laser beam, and is closed when the laser beam is not irradiated to prevent external fume or foreign substances from entering the optical system 15. block the inflow of

If the amount of meandering of the steel sheet is excessive, the steel sheet deviates from the laser irradiation position, and damage occurs as the laser is irradiated to the steel sheet support roll 9 . Therefore, in order to prevent damage to the steel sheet support roll, the laser oscillator controller 13 turns the laser oscillator on under normal working conditions and turns it off when the meandering amount of the steel sheet exceeds 15 mm. do.

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

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

The optical system 15 has a function of controlling the laser scanning speed, so that the distance between the laser irradiation lines (31 in FIG. 2) can be adjusted to 2 to 30 mm in the rolling direction. Accordingly, the iron loss of the steel sheet may be improved by minimizing the effect of the heat affected zone (HAZ) by the laser beam.

In addition, the laser irradiation equipment may have a structure that converts an irradiation angle of a laser beam irradiated onto 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 range of ±4° with respect to the width direction of the steel sheet.

To this end, the laser irradiation equipment has a structure in which the optical system 15 for irradiating the laser beam onto the steel sheet is rotatable by the driving unit 36, and the angle of the irradiation line of the laser beam formed on the surface of the steel sheet is converted with respect to the width direction of the steel sheet. It may be a structure that In this way, by changing the angle of the irradiation line of the laser beam by the optical system, the irradiation line 31 by the laser beam is formed inclined in a range of ±4° in a direction perpendicular to the rolling direction of the steel sheet. Therefore, it is possible to minimize the decrease in magnetic flux density due to the formation of the groove by the laser.

In addition, in this embodiment, the laser irradiation equipment controls the irradiation position of the laser beam with respect to the steel plate 1 to prevent the back reflection phenomenon in which the laser beam irradiated to the steel plate is reflected from the steel plate and enters the optical system or laser oscillator. structured.

To this end, as shown in FIG. 3, the laser irradiation equipment directs the irradiation direction of the laser beam emitted from the optical system 15 to the surface of the steel sheet that is in contact with the surface of the steel sheet support roll 9 in an arc shape. With the laser beam irradiation position when passing through the central axis of the roll 9 as the reference point P, the angle along the outer circumferential surface from the center of the steel sheet support roll 9 from the reference point P (separation angle for convenience of description below) R)) may be a structure in which a laser beam is irradiated to a spaced apart position.

The reference point P is a point where a line passing through the central axis of the steel plate support roll 9 in FIG. 3 and the steel plate meet. When the irradiation direction of the laser beam passes through the central axis of the steel plate support roll 9, the laser beam is focused on the reference point P. In this case, as the irradiation direction of the laser beam forms a right angle to the tangential line of the steel plate support roll 9 at the reference point P, the laser beam reflected by the steel plate enters the optical system and the laser oscillator as it is, causing damage. this occurs

As described above, the laser irradiation equipment according to the present embodiment irradiates the laser beam at a position spaced apart from the reference point P by the separation angle R, so that the laser beam reflected back from the steel plate is not incident to the optical system. Therefore, it is possible to prevent the back reflection phenomenon and to maintain the quality of the shape of the groove formed by the laser beam.

In this embodiment, the separation angle R may be set in the range of 3 to 7° from the center of the steel sheet support roll 9 along the outer circumferential surface with respect to the reference point P.

When the distance angle R, which is the irradiation position of the laser beam, is smaller than 3°, a part of the laser beam reflected back from the steel sheet may be introduced into an optical system or a laser oscillator. When the separation angle R exceeds 7°, groove formation by the laser beam is not properly performed, and groove formation defects may occur.

In this way, the laser irradiation equipment of the present embodiment irradiates the steel plate at a point spaced apart at a predetermined angle from the reference point P, thereby preventing the back reflection phenomenon and not interfering with the incident light path when the laser beam is reflected, and It is possible to stably maintain the quality of the groove shape formed by the

Figure 3 shows a shield provided in the optical system according to the present embodiment. Through the shielding portion 18, reflected light, scattered light, and radiant heat of the laser light reflected back from the steel plate can be more reliably blocked.

In this way, the optical system 15 is provided with a shielding part 18 at the bottom to block reflected light or scattered light of the laser beam irradiated on the surface of the steel plate and radiant heat from entering the optical system of the laser irradiation equipment, and the optical system is heated. It is structured to prevent this from happening.

Hereinafter, the structure of the shielding unit 18 of this embodiment will be described with reference to FIGS. 3 and 4 .

In this embodiment, the shielding unit 18 may include a polarization filter 50 disposed under the optical system 15 to shield scattered light. In addition, the shielding unit 18 may further include a cooling unit to prevent the temperature of the optical system from rising due to reflected light and scattered light.

As shown in FIG. 3, a polarization filter 50 is disposed below the module plate 37 of the optical system. The polarization filter 50 is disposed at the lower part of the module plate at the shutter position through which the laser beam passes. Accordingly, the polarization filter 50 can shield reflected light and scattered light introduced into the optical system through the open shutter when the laser beam is irradiated.

The laser beam irradiated from the optical system to the steel plate is reflected back toward the shutter from the steel plate. The material processing efficiency by the high-power laser is about 40 to 60%, and the remaining energy is dissipated as scattered light or radiated as reflected light to the module plate 37 of the optical system, causing local temperature rise. As a result, thermal deformation occurs in the module plate of the optical system.

The thermal deformation of the module plate 37 in the optical system causes a change in the light path of the polygon mirror and the condensing mirror, causing a change in the focal length according to the temperature rise, and directly affecting the depth of the groove of the irradiation line processed in the material, thereby degrading the quality of the product. .

Therefore, in the device of this embodiment, thermal deformation of the module plate 37 can be prevented by installing the polarization filter 50 below the module plate as described above to block radiant light, scattered light, and heat.

The polarization filter 50 may be applied to both a filter surface capable of blocking reflected light and scattered light. In this embodiment, the polarization filter 50 has a structure to block reflected light and scattered light out of the range of ±5° in a direction perpendicular to the plane of the polarization filter.

The laser beam irradiated from the optical system 15 is irradiated onto the steel plate at a predetermined angle, that is, an angle of ±5° based on a direction perpendicular to the module plate 37 of the optical system, through a polygon mirror and a condensing mirror.

Accordingly, the polarization filter 50 may block reflected light and scattered light reflected back at angles other than the angle at which the laser is irradiated, that is, angles outside the range of ±5°, and thus energy. Accordingly, the laser beam irradiated through the shutter of the optical system is normally irradiated onto the steel plate without interfering with the polarization filter 50 . In addition, the polarization filter 50 blocks reflected light and scattered light that are reflected back at an angle outside the range of ±5° and thus energy, thereby preventing heat from being applied to the inside of the optical module or the module plate.

Scattered light, reflected light, and their energy blocked by the polarization filter 50 heat the polarization filter. The cooling unit is installed on the polarization filter to cool the polarization filter.

In this embodiment, the cooling unit circulates and supplies a cooling medium through a cooling passage 51 installed in the polarization filter 50 and supplying cooling water to the inside of the polarization filter, and a cooling pipe 52 connected to the cooling passage. (53) may be included.

The cooling medium may be, for example, cooling water, and any fluid capable of exchanging heat is not particularly limited and is applicable to all.

The supply unit 53 may include, for example, a pump, and forcibly circulates and supplies the cooling medium to the cooling passage.

The cooling passage 51 is disposed inside a polarization filter 50 made of glass. The end of the cooling passage 51 may be finished with thermal epoxy, which has a thermal expansion rate similar to that of glass, which is a polarizing filter material, and is resistant to heat. Accordingly, damage due to thermal expansion of the polarization filter can be minimized.

In addition, the shielding unit may further include dust collection hoods 19A and 19B for preventing moisture generation by suctioning and removing hot air around the polarization filter 50 .

In this embodiment, as shown in FIG. 1, the dust collecting hoods 19A and 19B are provided under the optical system to remove fume and spatter generated according to laser beam irradiation. available.

Moisture may be generated in the polarization filter due to a temperature difference between the heat blocked by the polarization filter 50 and the cooling passage 51 . Moisture generated at this time may scatter the laser beam passing through the polarization filter made of glass while changing into water vapor by scattered light or reflected light. Therefore, by sucking and removing heat around the polarization filter through the dust collection hoods 19A and 19B as described above, it is possible to prevent moisture generation and keep the surrounding area including the polarization filter in a dry state.

As described above, according to the present embodiment, reflected light, scattered light, and radiant heat are shielded from the lower part of the optical system and prevented from flowing into the optical system, thereby preventing deformation of the module plate and stably maintaining the irradiation state of the laser beam. It is possible to stably form an irradiation line with a constant groove depth.

In addition, the laser irradiation facility may further include a molten iron removal facility for removing fumes and spatter generated by irradiation of the laser beam on the steel sheet.

The molten iron removal facility includes an air knife 17 that removes molten iron remaining in the groove by spraying compressed dry air into the groove of the steel plate, and dust collection hoods 19A and 19B that suction and remove fume and molten iron. can include The fume generated during laser irradiation is removed through the air knife and the dust collection hood, so that the fume can be prevented from being introduced into the optical system. The air knife 17 sprays compressed dry air having a certain pressure (Pa) into the groove of the steel plate 1 to remove 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. This is because, when the pressure of the compressed dry air is less than 0.2 kg/cm ² , it is impossible to remove molten iron from the inside of the groove, so that the iron loss improvement effect cannot be secured. Fume and spatter removed by the air knife are removed by dust collection hoods 19A and 19B disposed before and after the laser irradiation position. The dust collection hoods 19A and 19B may also be used to remove molten iron such as fume and spatter, as well as to remove moisture generated during cooling of the polarization filter 50 as mentioned above. Accordingly, there is no need to provide a separate dust collection hood to remove moisture from the polarization filter, making it possible to further simplify the equipment.

The laser room 20 is a room structure having an internal space, and accommodates the laser irradiation equipment and the steel sheet support roll 9 position control equipment therein, isolates them from the outside, and provides an appropriate operating environment for their smooth operation. do.

An inlet and an outlet are formed on the inlet and outlet sides of the laser room 20 along the steel plate traveling direction, respectively. The laser room 20 is equipped with a facility to block the inflow of contaminants so that the interior space is not polluted by external dust. To this end, the laser room 20 is provided with a positive pressure device 23 for increasing the internal pressure than the external. The positive pressure device 23 maintains the internal pressure of the laser room 20 relatively higher than the external pressure. Thus, it is possible to prevent foreign substances from entering the inside of the laser room 20 . In addition, air curtains 22A, 22B, 22C, and 22D are installed at the entrance and exit of the steel plate. The air curtain forms a film by spraying air to the inlet and outlet, which are passages through which the steel plate enters and exits the laser room 20, thereby blocking dust from entering through the inlet and outlet. In addition, in order to prevent contamination of the inside of the laser room 20, a shower booth 21 may be installed at a door that is an entrance and exit of the laser room 20. The shower booth 21 removes foreign substances from the body of the person entering the laser room 20 .

The laser room 20 is a space in which a process of refining a magnetic domain of a steel sheet is substantially performed using a laser beam, and it is necessary to minimize changes in the internal environment and maintain an appropriate environment. To this end, the laser room 20 includes an optical system lower frame 24 that separates the upper space where the laser oscillator 14 and the optical system 15 of the laser irradiation facility are located from the lower space where the steel plate 1 passes, and the laser The room 20 is provided with a constant temperature and humidity controller 25 that controls the internal temperature and humidity.

The lower frame 24 of the optical system allows the operating environment of major facilities such as the laser oscillator 14 and the optical system 15 to be managed more thoroughly. The optical system lower frame 24 is installed inside the laser room 20 to separate the lower space of the optical system where the steel plate passes and the upper space of the optical system where the laser oscillator and the optical system mirror are located. Even inside the laser room 20 by the optical system lower frame 24, the upper space of the optical system is separately separated, so that contamination prevention and temperature and humidity control for major facilities such as a laser oscillator or an optical system become easier.

The constant temperature and humidity controller 25 provides an appropriate environment by controlling the temperature and humidity inside the laser room 20 . In this embodiment, the constant temperature and humidity controller 25 can maintain the internal temperature of the laser room 20 at 20 to 25° C. and maintain the humidity at 50% or less.

In this way, the internal space of the laser room 20 is continuously maintained at the temperature and humidity suitable for the working environment, so that the magnetic domain refinement process can be performed on the steel sheet in an optimal state. Therefore, it is possible to mass-produce high-quality products under the optimal operating environment required for the process.

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

Since heel-up and spatter cause deterioration of insulation and spot rate of a product, the quality of the product can be improved by completely removing them through the post-processing facility.

The post-processing facility may include brush rolls 26A and 26B disposed at the rear end of the laser room 20 along the steel plate moving direction to remove spatter and heel-up on the surface of the steel plate. The brush rolls 26A and 26B are rotated at high speed by a drive motor, and a current control system controls the current value of the drive motor generated during operation to a set target value, and a brush position controlled by adjusting the distance between the brush roll and the steel plate. The rotational speed and the distance between the steel plates are controlled by the control system. The brush roll may be disposed on only one side of the steel sheet on which grooves are formed by the laser beam, or may be disposed on both sides of the steel sheet. The brush rolls 26A and 26B adhere to the surface of the steel plate and rotate at high speed to remove heel-up and spatter attached to the surface of the steel plate. As shown in FIG. 1, a dust collecting hood 19C for discharging spatter and heel-up removed by the brush rolls is further installed close to the brush rolls 26A and 26B. The dust collection hood 19C sucks molten iron, such as heel-up and spatter, separated from the steel sheet by the brush rolls 26A and 26B and discharges it to the outside.

In addition, the post-processing facility includes a cleaning unit 29 disposed at the rear end of the brush rolls 26A and 26B to additionally remove heel-up and spatter remaining on the surface of the steel sheet by electrolytic reaction of the steel sheet with an alkali solution, and a cleaning unit A filtering unit 30 connected to and filtering out foreign substances included in the alkali solution of the cleaning unit from the alkali solution may be further included.

The steel plate firstly removes heel-up and spatter through the brush rolls 26A and 26B, and secondarily removes residual heel-up and spatter while passing through the cleaning unit 29. Accordingly, it is possible to more completely remove heel-up and spatter attached to the surface of the steel sheet, thereby improving product quality.

The cleaning unit 29 is filled with an alkali solution, and a filtering unit 30 is connected to one side. As the steel sheet is processed through the cleaning unit, heal-up and spatter removed from the steel sheet are accumulated in the internal alkali solution, and the cleaning performance of the steel sheet is deteriorated. The filtering unit 30 circulates the alkali solution of the cleaning unit to remove heel-up and spatter contained in the alkali solution. The filtering unit 30 manages the iron content of the alkali solution to 500 ppm or less by removing heel-up and spatter. In this way, the cleaning performance of the cleaning unit is prevented from being deteriorated, and the steel sheet can be continuously processed.

Hereinafter, a process of refining the magnetic domain of the electrical steel sheet according to the present embodiment will be described.

The continuously transported steel plates pass through the meandering control facility and the tension control facility before entering the inside of the laser room and proceeding at a speed of 2m/sec or higher, undergoing magnetic domain refinement. The steel plate entered into the laser room is taken out of the laser room after being processed for permanent magnetic domain refinement through laser irradiation equipment. The steel sheet pulled out of the laser room goes through a post-processing facility to remove the heal-up and spatter remaining on the surface before being sent to the post-process.

In this process, the laser room where the laser irradiation is performed on the surface of the steel sheet properly sets and maintains an internal operating environment to provide an optimal environment for magnetic domain refinement.

The laser room isolates the inside from the outside to block the inflow of external contaminants, and controls the internal temperature, pressure, and humidity of the laser room according to the operating environment for forming magnetic domain refinement.

By setting and maintaining the pressure inside the laser room higher than that of the outside, foreign substances such as dust from the outside can be prevented from entering the inside of the laser room. In addition, by forming a film by air at the inlet and outlet, which are the passages through which the steel plate is moved, it is possible to block foreign substances such as dust from being introduced into the laser room during the course of the steel plate going through the inlet and the outlet.

In addition, the constant temperature and humidity controller installed in the laser room maintains the temperature inside the laser room at 20 to 25° C. and the humidity at 50% or less, thereby providing optimal conditions for the magnetic domain refinement process by laser irradiation.

As such, the optimal environment for laser beam irradiation is provided by the laser room, and the steel sheet is accurately positioned at the laser irradiation position through meandering control facilities, tension control facilities, and steel sheet support roll position adjusting facilities.

First, for the magnetic domain refinement process, the direction of movement of the steel sheet is controlled through a meandering control facility, so that it moves straight along the center of the production line without biasing left and right.

The meandering sensor continuously detects the meandering amount of the steel plate, and when the steel plate meanders, the signal detected by the meandering measuring sensor is calculated so that 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. In this way, by continuously controlling the steering roll according to the position of the steel sheet, it is possible to continuously move the steel sheet without departing from the center of the production line.

The steel plate passes through the steering roll and moves through the tension bridle roll for tension control. The tension of the steel sheet passing through the tension bridle roll is detected by the tension measuring sensor. The steel plate tension control system controls the speed of the tension bridle roll according to the set tension by calculating the measured value detected by the tension measuring sensor. Accordingly, it is possible to continuously maintain the tension of the moving steel sheet within a set range.

The steel plate that has gone through the tension bridle roll is introduced into the laser room through the entrance of the laser room. The direction of the steel plate is changed by the bridle roll inside the laser room and moved in close contact with the steel plate support roll located between the two bridle rolls.

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

When a laser beam is irradiated onto the steel sheet from the laser irradiation facility, the brightness measuring sensor detects the brightness of the flame on the surface of the steel sheet in real time, and the steel sheet support roll position control system moves the steel sheet support roll up and down according to the measured value detected by the brightness measuring sensor. Place the steel plate within the depth of focus of the laser beam. Accordingly, the laser beam is effectively irradiated on the surface of the steel sheet, and high-quality irradiation rays can be formed.

The laser oscillator controller turns on/off the laser oscillator according to the meandering degree of the steel sheet. The laser oscillator controller is connected to the meander measurement sensor and determines that the steel sheet deviates too much from the steel sheet support roll when the meandering amount of the steel sheet measured from the meander measurement sensor is, for example, 15 mm or more, and turns off the laser oscillator. Accordingly, it is possible to prevent the roll from being damaged by irradiating the laser beam to the surface of the steel sheet support roll passing through the meandering steel sheet.

According to the command of the laser oscillator controller, the laser beam generated by the laser oscillator is irradiated onto the surface of the steel sheet through an optical system. The laser oscillator oscillates the TEM ₀₀ continuous wave laser beam and transmits it to the optical system.

The optical system converts the direction of the laser beam and irradiates the surface of the steel sheet with a laser beam, thereby continuously forming molten grooves on the surface of the steel sheet to perform magnetic domain refinement.

As the surface of the steel sheet is melted by the laser beam irradiated onto the steel sheet through an optical system, melting grooves are formed along the irradiation line. In this embodiment, a groove having an upper width, a lower width, and a depth of 70 μm or less, 10 μm or less, and 3 to 30 μm, respectively, is formed on the surface of the steel sheet through laser beam irradiation, and at the same time, the laser beam is irradiated on the inner wall of the groove of the fusion part. A laser oscillator and an optical system deliver a laser energy density within the range of 1.0 to 5.0 J/mm 2 necessary for melting the steel sheet to the steel sheet so that the remaining re-solidified portion is created.

In addition, by irradiating the laser beam at a location spaced apart from the reference point in the process of irradiating the laser beam through the optical system, the laser beam reflected back from the steel plate is not incident to the optical system. Accordingly, the above-described back reflection phenomenon is prevented and the incident light path of the laser beam is not interfered with by the reflected light, so that the quality of the shape of the groove formed by the laser beam can be maintained.

In this embodiment, in the laser irradiation process, reflected light, scattered light, and radiant heat of the laser beam irradiated on the surface of the steel plate are blocked from entering the optical system of the laser irradiation equipment.

A polarization filter disposed below the optical system blocks reflected light and scattered light reflected back toward the optical system, thereby preventing the optical system from being heated by the reflected light and scattered light. In addition, the cooling medium supplied through the cooling tube cools the polarization filter while flowing along the cooling path inside the polarization filter. In this process, the heat flowing into the polarization filter and the moisture generated by the temperature difference as the polarization filter is cooled are discharged through the dust collection hood.

In this way, the module plate of the optical system can be prevented from being heated by appropriately blocking and removing reflected light, scattered light, and radiant heat flowing into the lower part of the optical system.

Figure 5 shows the cooling action of the shield according to this embodiment compared to the prior art.

The comparative example shows the temperature distribution of the optical system in a state without the shielding part in the conventional structure, and the embodiment shows the temperature distribution of the optical system in the state where the shielding part is provided under the optical system like the present invention.

As shown in FIG. 5, in the case of the comparative example, the temperature of the optical system shows a relatively very high distribution, and in the case of the embodiment, the reflected light, scattered light, and radiant heat are properly shielded, so that the temperature shows a relatively very low distribution.

The optical system has a function of controlling the laser scanning speed, and thus the distance of the laser irradiation line can be adjusted with respect to the rolling direction. In addition, the optical system may have a rotation function to change the angle of the laser irradiation line. In this embodiment, by enabling the optical system to adjust the distance between the laser irradiation lines in the rolling direction from 2 to 30 mm, the effect of the heat affected zone (HAZ) by the laser beam can be minimized to improve the iron loss of the steel sheet. there is. Also, in the process of irradiating the laser beam, the angle of the irradiation line of the laser beam irradiated to the surface of the steel sheet may be changed through rotation of the optical system. In this embodiment, the optical system may convert the angle of the irradiation line of the laser beam to a range of ±4° with respect to the width direction of the steel sheet. That is, in FIG. 2, the irradiation line 31 of the laser beam may be formed by tilting it in a range of ±4° with respect to the y-axis direction. Accordingly, the irradiation line formed on the surface of the steel sheet may be formed inclined at an angle of 86 to 94° with respect to the rolling direction. In this way, by forming the irradiation line to be inclined with respect to the y-axis direction, it is possible to minimize the decrease in magnetic flux density due to the formation of the groove by the laser.

During the laser beam irradiation process, a large amount of fumes and molten iron spatter are generated as the steel sheet is melted by the laser beam. Fume and spatter contaminate the optical system, and when molten iron remains inside the groove, it is difficult to form an accurate groove and damage to the iron loss is not achieved, thereby impairing product quality. Accordingly, compressed dry air is sprayed into the grooves of the steel sheet to remove the molten iron remaining in the grooves, and the fumes and molten iron are directly sucked and removed through a dust collection hood. Therefore, in the process of refining the magnetic domain of the steel sheet, it is possible to block fumes from flowing into the optical system, and to quickly remove fumes and spatter, thereby increasing the efficiency of the domain refining process. In addition, in the process of irradiating the laser beam, it is possible to further block reflected light, scattered light, and heat of the laser beam from entering the optical system of the laser irradiation equipment.

Grooves are formed on the surface of the steel sheet through laser beam irradiation, and the magnetic domain refinement process is performed, and the steel sheet subjected to magnetic domain refinement process is continuously moved and discharged to the outside through the exit of the laser room.

The steel plate discharged from the laser room goes through a post-processing process to remove spatter and heal-up attached to the steel plate surface.

The steel plate first passes through the brush roll placed outside the laser room, and the heel-up and spatter are primarily removed by the brush roll rotating at high speed in close contact with the steel plate.

The steel plate that has passed through the brush roll is secondarily passed through the cleaning unit, and the residual heal-up and spatter are finally removed through the electrolytic reaction between the steel plate and the alkali solution. After passing through the cleaning unit, the steel sheet with heel-up and spatter removed 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 1 shows the iron loss improvement rate of the grain-oriented electrical steel sheet by the grooves formed on the surface of the steel sheet having a thickness of 0.27 mm by continuous wave laser beam irradiation according to the present embodiment. As shown in Table 1, in the case of the steel sheet subjected to the magnetic domain refinement process through this example, it can be seen that iron loss is improved both after laser irradiation and after magnetic domain refinement and heat treatment.

Although exemplary embodiments of the present invention have been shown and described as described above, various modifications and other embodiments may be made by those skilled in the art. All of these modifications and other embodiments are to be considered and included in the appended claims, without departing from the true spirit and scope of the present invention.

1: steel plate 2A, 2B: steering roll (SR)
3: steel plate central position control system 4: meander measurement sensor
5A, 5B: Tension bridle roll 6: Steel plate tension control system
7: steel sheet tension measurement sensor 8A: deflector roll
8B: deflector roll 8C: intermediate deflector roll
9: steel plate support roll 10: luminance measurement sensor
11: Distance measurement sensor 12: Steel plate support roll position control system
13: laser oscillator controller 14: laser oscillator
15: optical system 16: laser beam
17: air knife 18: shield
19A, 19B, 19C: dust collection 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: cleaning unit 30: filtering unit
31: irradiation line 32: polygon mirror
33: rotation motor 34: drive motor
35: condensing mirror 36: driving unit
37: module plate 38: shutter
39: header 50: polarization filter
51: cooling oil 52: cooling pipe
53: supply unit

Claims (24)

A steel sheet support roll position adjusting step of controlling the vertical position of the steel sheet while supporting the steel sheet progressing along the production line; a laser beam irradiating the surface of the steel sheet to melt the steel sheet and forming grooves on the surface of the steel sheet; An irradiation step, and a blocking step of blocking reflected light and scattered light of the laser beam irradiated on the surface of the steel sheet from entering an optical system for irradiating the laser beam,
The blocking step includes shielding reflected light and scattered light with a polarization filter disposed in the optical system,
The optical system includes a module plate rotatably installed to give an angle of a laser beam irradiation line with respect to the width direction of the steel sheet, and a shutter installed on the module plate to selectively block the module plate depending on whether the laser beam is irradiated or not. do,
The polarization filter is disposed below the module plate at a position of the shutter through which the laser beam passes, and blocks reflected light and scattered light introduced into the optical system through the shutter opened when the laser beam is irradiated, thereby thermal deformation of the module plate. to prevent,
A setting maintenance step of setting and maintaining the internal operating environment of the laser room where laser irradiation is performed, and
A post-processing step for removing hill-up and spatter formed on the surface of the steel sheet through the laser irradiation step,
In the post-processing step,
Removing heel-up and spatter on the surface of the steel plate by a brush roll disposed at the rear end of the laser room along the moving direction of the steel plate;
A step of discharging the heel-up and spatter removed by the brush roll to the outside by a dust collection hood, and
The magnetic domain refining method of grain-oriented electrical steel sheet comprising the step of electrolytically reacting the steel sheet with an alkali solution by a cleaning unit disposed at the rear end of the brush roll to additionally remove heal-up and spatter remaining on the surface of the steel sheet. According to claim 1,
In the laser irradiation step, the laser beam irradiation position when the laser beam irradiation direction passes through the central axis of the steel sheet backup roll with respect to the surface of the steel sheet proceeding in contact with the surface of the steel sheet backup roll in an arc shape is used as a reference point. Magnetic domain refinement method of a grain-oriented electrical steel sheet by irradiating a laser beam at a position spaced apart from the reference point at an angle along the outer circumferential surface from the center of the steel sheet support roll. According to claim 2,
In the laser irradiation step, the laser beam is irradiated in a range of 3 to 7° apart from the center of the steel sheet support roll along the outer circumferential surface with respect to the reference point. According to claim 1,
The laser irradiation step further comprises an angle conversion step of converting an angle of the irradiation line of the laser beam irradiated to the surface of the steel sheet. According to claim 4,
The angle conversion step is a magnetic domain refinement method of a grain-oriented electrical steel sheet of converting the radiation angle of the laser beam in the range of ± 4 ° with respect to the width direction of the steel sheet. According to any one of claims 1 to 5,
The blocking step includes a cooling step for preventing temperature rise of the optical system due to reflected light and scattered light, and a hot air intake step for preventing moisture generation due to a temperature difference of the polarization filter. According to claim 6,
The reflected light and scattered light shielding step is a magnetic domain refinement method of grain-oriented electrical steel sheet for blocking reflected light and scattered light outside the range of ± 5 ° with respect to a direction perpendicular to the surface of the polarization filter. According to claim 6,
The setting maintenance step includes the step of isolating the inside of the laser room from the outside to block the inflow of external contaminants, and the step of controlling the internal temperature, pressure and humidity of the laser room. Method for refining grain-oriented electrical steel sheet. According to claim 6,
The magnetic domain refinement method of the grain-oriented electrical steel sheet further comprising a tension control step of applying tension to the steel sheet so that the steel sheet is maintained in a flat spread state. According to claim 6,
Magnetic domain refinement method of grain-oriented electrical steel sheet further comprising a meandering control step of allowing the steel sheet to move left and right along the center of the production line without bias. delete A steel sheet support roll position adjusting facility for controlling the vertical position of the steel sheet while supporting the steel sheet moving along the production line, and a laser irradiation facility for melting the steel sheet by irradiating a laser beam to form a groove on the surface of the steel sheet, and A shielding portion for blocking the reflected light and scattered light of the laser beam irradiated on the surface of the steel sheet from entering the optical system of the laser irradiation equipment;
The shielding unit includes a polarization filter disposed below the optical system to shield reflected light and scattered light;
The optical system includes a module plate rotatably installed to give an angle of a laser beam irradiation line with respect to the width direction of the steel sheet, and a shutter installed on the module plate to selectively block the module plate depending on whether the laser beam is irradiated, ,
The polarization filter is disposed below the module plate at a position of the shutter through which the laser beam passes, and blocks reflected light and scattered light introduced into the optical system through the shutter opened when the laser beam is irradiated, thereby thermal deformation of the module plate. to prevent,
A laser room that accommodates the steel plate support roll position adjusting facility and the laser irradiation facility in isolation from the outside and provides an operating environment for laser irradiation, and
Including a post-processing facility for removing hill up and spatter formed on the surface of the steel sheet,
The post-processing facility,
A brush roll disposed at the rear end of the laser room along the moving direction of the steel plate to remove heel-up and spatter on the surface of the steel plate;
A dust collection hood disposed at the rear end of the brush roll to discharge the heel-up and spatter removed by the brush roll to the outside;
A magnetic domain refining device for grain-oriented electrical steel sheet comprising a cleaning unit disposed at a rear end of the brush roll to further remove heel-up and spatter remaining on the surface of the steel sheet by electrolytic reaction of the steel sheet with an alkali solution. According to claim 12,
The laser irradiation equipment uses the laser beam irradiation position when the irradiation direction of the laser beam passes through the central axis of the steel sheet backup roll as a reference point with respect to the surface of the steel sheet that proceeds in contact with the surface of the steel sheet support roll in an arc shape. , Magnetic domain refinement device of a grain-oriented electrical steel sheet having a structure in which a laser beam is irradiated at a position spaced apart from the reference point at an angle along the outer circumferential surface from the center of the steel sheet support roll. According to claim 13,
The laser irradiation equipment is a magnetic domain refining device for grain-oriented electrical steel sheet having a structure in which the laser beam is irradiated to a range spaced from 3 to 7 ° along the outer circumferential surface from the center of the steel sheet support roll with respect to the reference point. According to claim 12,
The optical system is made of a rotatable structure by a driving unit, and the magnetic domain refining device of a grain-oriented electrical steel sheet having a structure that rotates with respect to the steel sheet to convert the angle of the irradiation line of the laser beam with respect to the width direction of the steel sheet. delete According to claim 12,
The shielding unit further comprises a cooling unit for preventing temperature rise of the optical system due to reflected light and scattered light. 18. The method of claim 17,
The cooling unit includes a cooling passage installed on the polarization filter to supply cooling water into the polarization filter, and a supply unit circulating and supplying a cooling medium through a cooling pipe connected to the cooling passage. 18. The method of claim 17,
The shielding unit further comprises a dust collection hood for preventing moisture generation by suctioning and removing heat around the polarizing filter. delete According to claim 12,
The laser room accommodates the laser irradiation equipment and the steel plate support roll position control equipment and forms an internal space to isolate it from the outside, and an inlet and an outlet are formed on both sides along the traveling direction of the steel plate. A positive pressure device to increase the pressure inside the laser room than the outside, an optical system lower frame to separate the upper space where the optical system of the laser irradiation facility is located from the lower space where the steel plate passes, and a constant temperature and humidity controller to control the temperature and humidity inside the laser room Magnetic domain refining device of grain-oriented electrical steel sheet comprising. According to claim 12,
Magnetic domain refinement device for grain-oriented electrical steel sheet further comprising a tension control facility for applying tension to the steel sheet to maintain the steel sheet in a flat spread state. According to claim 12,
Magnetic domain refinement device for grain-oriented electrical steel sheet further comprising a meandering control facility that allows the steel sheet to move left and right along the center of the production line without bias. delete

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