METHOD AND DEVICE FOR DETECTING SURFACE DEFECT OF SLAB

PROBLEM TO BE SOLVED: To provide a method for detecting the surface defect of a slab for precisely detecting the surface defect such as a blow-hole produced in the slab. SOLUTION: In the method for detecting the surface defect produced in the slab 6 from the data of the surface unevenness state of the slab measured by irradiating the surface of the slab 6 with a laser beam 8 from a plurality of the laser beam projectors 7a and 7b arranged in the width direction of the slab 6, the laser beam non-reflecting positions, where the data of the unevenness state becomes a missing value, of the surface of the slab 6 is extracted by a laser beam non-reflecting position extracting circuit 11 and, when a plurality of the laser beam non-reflecting positions extracted by the laser beam non-reflecting position extracting circuit 11 are continuously present in the lateral or longitudinal direction of the slab 6, the laser beam non-reflecting positions are determined as positions where the surface defect is produced by a determination device 12. COPYRIGHT: (C)2010,JPO&INPIT