METHOD AND DEVICE FOR DETECTING SLAG INCLUSION IN HOT FLAW DETECTION ON SURFACE OF CONTINUOUS CASTING MATERIAL

PURPOSE:To enable charging of a hot slab and hot direct feeding rolling thereof and to save energy and to improve yield by detecting the oscillation mark on the surface of a continuous casting slab, deciding the disturbance in the pattern thereof and detecting the slag inclusion thereof. CONSTITUTION:An optical distance sensor 10 is used for an oscillation mark detector 6. The sensor 10 measures the ruggedness of an oscillation mark, and the measuring signal thereof is converted by an A/D converter 29 to a digital signal 13 which is stored in a memory 14. When the inputting of data in the memory 14 is completed, the content is transferred at a high speed to a memory 2 (15). The data of the memory 2 (15) is buffered to a Fourier transform device 16, where one-dimensional Fourier transform is repeated 10 times, and after the passage through a frequency gate 24 determined according to the space frequency of the oscillation mark, the average for the ten transforms is calculated by an integrator 25. The value thereof is compared with a reference set value by a comparator 25 and a decided output 30 is obtd.