DETECTION FOR CENTER CRACK OF CAST INGOT IN CONTINUOUS CASTING

摘要

PURPOSE:To detect the generation of center cracks by measuring displacements on the both-side faces of a cast ingot and by detecting sine wave state displacements of the period corresponding to the circumferential length of a pinch roller. CONSTITUTION:The displacements at the same position are detected respectively by each detecting device 8, 9 of displacements at the top or rear faces of a cast ingot 1. One-end parts 12 of arms 10 are in contact with the top or rear faces of the cast ingot 1 and the other-end parts 13 are turned around a fulcrum 11 and their movements are converted to electrical signals by differential transformers 14 connecting with the end 13. As to the output from the transformers 14, only the frequency components which are decided with the transmitting speed of the ingot and the circumferencial length of the pinch rollers with filter circuits 16, are passed. Then, the output is inputted to an adding circuit 17 and an output signal corresponding to the total dispplacement is obtained. In a comparison circuit 18, a slice level corresponding to the total displacement generating the central cracks, is set, and thereby a pulse signal is outputted when a input signal is outputted when a input signal exceeding the slice level is inputted.