Patent ID: 7248366

Claim:
A method for marking a defect, comprising the steps of: (a) arranging a surface defect tester to detect a surface flaw and an ink marker device having a felt impregnated with ink to mark the defect at a defect position, in a continuous processing line of a steel sheet; (b) detecting the surface flaw on the steel sheet using the surface defect tester; (c) determining a defect name, defect grade, defect length, and defect position in a width direction of the steel sheet, on the basis of information regarding the detected surface flaw, and identifying the surface defect in terms of harmful defect, injudicable defect, and harmless defect; (d) tracking the defect position for each harmful defect and injudicable defect; (e) marking the surface defect at the defect position by pressing the felt on the steel sheet to fix the ink on the surface of the steel sheet when the defect reaches the ink marker device; arranging an internal defect tester to detect a defect inside of the steel sheet; and determining the defect length and the defect position in the width direction of the steel sheet, on the basis of the detected flaw information, and identifying the defect in terms of harmful defect and harmless defect, wherein the step of marking comprises changing a defect marking position based on the defect information in the width direction of the steel sheet, given by the surface defect tester and the internal defect tester, and marking the defect.