Abstract: The present invention relates to an ultrasonic testing apparatus with a variable frequency, which can automatically change the frequency according to thickness and thereby detect internal defects in objects having various thicknesses. The ultrasonic testing apparatus may comprise: a nozzle jetting a medium toward an object so as to form a medium column; and a plurality of probes disposed in the nozzle so as to generate ultrasonic waves.

Abstract: The present invention provides an apparatus for cutting a material, comprising: a frame body installed on a conveying path of a material; a cutting means, mounted on the frame body, for cutting an end portion of the material being conveyed; a laser preheating means for preheating the material by irradiating a laser beam onto the material before being conveyed to the cutting means; and a blocking and reflection means for blocking the laser beams reflected to the cutting means and re-reflecting the laser beam to the material.

Abstract: A side trimming device according to an embodiment of the present invention may comprise: a cutting unit for mechanically cutting a transferred steel plate; a groove forming unit for forming a groove in a cutting-scheduled area in front of the cutting unit with reference to the steel plate transfer direction; and a washing unit arranged adjacent to the groove forming unit so as to suction molten material accumulating in the groove in the side direction of the steel plate.

Abstract: A grain-oriented electrical steel plate of an exemplary embodiment of the present invention has a groove formed on a surface, wherein a curvature radius RBb at a position where a depth of the groove is maximum is 0.2 ?m to 100 ?m, and a curvature radius RSb on the groove surface from the position where the depth of the groove is maximum to a quarter-way position of the depth D of the groove is 4 ?m to 130 ?m.

Abstract: A dimension measuring device includes: a rail for moving two sheets of material; a plurality of range finders arranged at a preset interval along a direction of traveling of the material, so as to measure a distance from side surfaces of the material; and an imaging device for taking images between the first and second range finders, which are disposed at the first and second locations with reference to the entry side of the material, respectively.

Abstract: An apparatus for measuring a crystal grain size of a steel plate according to an embodiment of the present invention may comprises: an ultrasound generating unit for applying ultrasound to one point of a steel sheet; an ultrasound receiving unit for receiving propagated ultrasound at two points spaced different distances apart from the one point of the steel sheet; and a crystal grain size calculating unit for calculating an average crystal grain size of the steel sheet according to intensities of the ultrasound propagated to the two points and an attenuation coefficient according to a distance between the two points. The apparatus can calculate an attenuation coefficient, regardless of a change of surface characteristics, such as surface reflectance, surface roughness, or the like.

Abstract: The present invention provides an apparatus for cutting a material, comprising: a frame body installed on a conveying path of a material; a cutting means, mounted on the frame body, for cutting an end portion of the material being conveyed; a laser preheating means for preheating the material by irradiating a laser beam onto the material before being conveyed to the cutting means; and a blocking and reflection means for blocking the laser beams reflected to the cutting means and re-reflecting the laser beam to the material.

Abstract: A side trimming apparatus including a cutting unit which is installed on at least one side of a steel plate being transferred and trims a side of the steel plate by mechanical cutting and a laser processing unit which is installed in front of the cutting unit and emits a laser beam to a portion of the steel plate to be cut to form a groove at the portion to be cut or preheat the portion to be cut, and a side trimming method using the same are provided.

Abstract: The present invention relates to a dimension measuring device and a dimension measuring method, the dimension measuring device comprising: a moving unit for moving two sheets of material; a plurality of range finders installed at a preset interval along the direction of traveling of the material, so as to measure the distance from the side surfaces of the material; and an imaging device installed to take images between the first and second range finders, which are installed at the first and second locations with reference to the entry side of the material, respectively.

Abstract: Provided is a method and device for refining a magnetic domain of a grain-oriented electrical steel plate. The magnetic domain refining method of a grain-oriented electrical steel plate for stable permanent magnetic domain refining processing even if a steel plate is transferred at high speed of 2 m/s or more includes zigzag controlling for straightly transferring the steel plate without being inclined in right and left directions along a production line center, tension controlling for applying tension to the steel plate to maintain the steel plate in a flat state, steel plate support roll position adjusting for controlling a predetermined position of the steel plate in up and down directions while supporting the steel plate, and laser irradiating for irradiating a laser beam to melt the steel plate to form a groove in a surface of the steel plate.

Abstract: A device according to an embodiment of the present invention for detecting an internal flaw in a steel plate by using a height-adjustable ultrasonic sensor may comprise: a spray nozzle installed a certain distance apart from the bottom of a steel plate, for spraying a medium toward the steel plate and forming a medium column; an ultrasonic sensor installed inside the spray nozzle, for transmitting and receiving ultrasonic waves for detecting flaws in the steel plate through the medium column; a flaw detecting unit for detecting the presence of internal flaws in the steel plate on the basis of the transmitted and received ultrasonic waves; and a driving unit installed inside the spray nozzle, for adjusting the distance between the ultrasonic sensor and the steel plate according to the thickness of the steel plate.

Abstract: An apparatus and a method for ultrasonic detection are provided. The apparatus includes an injection nozzle which is installed below a steel plate being transported and forms a medium column by jet a medium toward the steel plate, an ultrasonic probe which is installed in the injection nozzle and transmits and receives ultrasonic waves for detecting flaws in the steel plate through the medium column, and a medium circulation unit which reclaims the medium which falls from the medium column and circulates the reclaimed medium to the injection nozzle.

Abstract: A grain-oriented electrical steel plate of an exemplary embodiment of the present invention has a groove formed on a surface, wherein a curvature radius RBb at a position where a depth of the groove is maximum is 0.2 ?m to 100 ?m, and a curvature radius RSb on the groove surface from the position where the depth of the groove is maximum to a quarter-way position of the depth D of the groove is 4 ?m to 130 ?m.

Abstract: A side trimming apparatus including a cutting unit which is installed on at least one side of a steel plate being transferred and trims a side of the steel plate by mechanical cutting and a laser processing unit which is installed in front of the cutting unit and emits a laser beam to a portion of the steel plate to be cut to form a groove at the portion to be cut or preheat the portion to be cut, and a side trimming method using the same are provided.

Abstract: An apparatus and a method for ultrasonic detection are provided. The apparatus includes an injection nozzle which is installed below a steel plate being transported and forms a medium column by jet a medium toward the steel plate, an ultrasonic probe which is installed in the injection nozzle and transmits and receives ultrasonic waves for detecting flaws in the steel plate through the medium column, and a medium circulation unit which reclaims the medium which falls from the medium column and circulates the reclaimed medium to the injection nozzle.

Abstract: There is provided an on-line detection system and method for a weld of a steel strip, which can emit a laser beam onto the surface of a steel strip moving at a high speed and measure the reflectivity of the laser beam reflecting from the same, thereby detecting the weld of the steel strip easily on-line. In the on-line detection system, reflectivity measuring means emits a laser beam onto a moving steel strip and continuously measuring the reflectivity of the laser beam returning from the surface of the steel strip, and signal processing means detects a weld of the steel strip based on change in the reflectivity measured on the weld.

Abstract: There is provided an on-line detection system and method for a weld of a steel strip, which can emit a laser beam onto the surface of a steel strip moving at a high speed and measure the reflectivity of the laser beam reflecting from the same, thereby detecting the weld of the steel strip easily on-line. In the on-line detection system, reflectivity measuring means emits a laser beam onto a moving steel strip and continuously measuring the reflectivity of the laser beam returning from the surface of the steel strip, and signal processing means detects a weld of the steel strip based on change in the reflectivity measured on the weld.

Abstract: A method of measuring the degree of alloying of galvanized steel sheet through the use of laser beams includes the steps of directing a laser beam on a standard sample and reflecting and splitting the beam and detecting the intensity of specular reflection I.sub.0 (.alpha.) at an angle of reflection (.alpha.) and the intensity of scattering I.sub.0 (.beta.) at an angle of reflection (.beta.) to thus obtain the degree of alloying (X.sub.0) of the standard sample by the formula: ##EQU1## The above steps are repeated to obtain values I.sub.1 (.alpha.) and I.sub.2 (.beta.) to obtain a comparative degree of alloying (X.sub.1) of the standard sample using the above equation form. The arrangement of the laser, mirror and first and second beam splitters are corrected based on a comparison of the X.sub.0 and X.sub.1 values. The above steps are then repeated by directing the laser onto a galvanized steel sheet to obtain the degree of alloying (X.sub.2) of the galvanized steel sheet.