METHOD FOR DETECTING SURFACE DEFECT ON CONTINUOUS CASTING ROUND CAST BILLET

摘要

PURPOSE:To detect surface defect on a round cast billet by dividing wall face of a mold into plural steps to height direction and also arranging thermocouples at the same level to circular direction in each division. CONSTITUTION:The wall face of the mold 1 is divided into three to the height direction and the thermocouples 2a-, 3a-, 4a-, are embedded at almost equal interval to the circular direction in each division. Measured temp. values to the height direction t2i, t3i, t4i... show temp. hysteresis at the same position of the cast billet, respectively, and these difference rates t2i-t3i, t3i-t4i... show changing degree of cooling and at the time of being large difference, the crack can be detected. Further, by comparing the measured results to the circular direction and at each step, the crack caused by second factor can be detected.