| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method, for marking a surface defect onto a steel plate, in which the surface defect can be detected with good accuracy even when the surface of the steel plate is coated with a rust preventive oil and in which a marking operation by an oily ink can be performed. SOLUTION: A steel plate 1 whose surface is coated with a rust preventive oil is passed through a part between suction ringer rolls 13, the rust preventive oil is absorbed by the suction ringer rolls 13 so as to be removed, and the remaining rust preventive oil is made uniform. After that, a surface defect is detected by a surface-defect detector 3 which is arranged at the rear of the suction ringer rolls 13, the detected surface defect is tracked, and a marking operation by an oily ink is executed by a marking device 12 which is arranged at the rear of the surface-defect detector 3.</p> |
