Completion of solidification position of continuous casting slab detection method and detection device and manufacturing method of continuous casting slab

摘要

PROBLEM TO BE SOLVED: To accurately detect a crater end only from a value measured by a sensor without needing calibration based on a slab rivet method.;SOLUTION: An ultrasonic shear wave sensor 6, 8 for transmitting an ultrasonic shear wave to a cast product 1 and receiving it and an ultrasonic longitudinal wave sensor 7, 9 for transmitting an ultrasonic longitudinal wave to the cast product and receiving it are installed at the same position in a continuous casting machine or at two positions apart in a casting direction. A casting velocity is increased, and a crater end 4 is moved to the downstream side than the installed position of the ultrasonic shear wave sensor. From variations in strength of a signal received by the ultrasonic shear wave sensor at that time, it is detected that the position at which the solid phase ratio of the central part in the cast product reaches 1 is matched with the installed position of the ultrasonic shear wave sensor. A calculation formula for determining the crater end from a propagation time of an ultrasonic longitudinal wave signal is calibrated such that the crater end computed from the propagation time of the ultrasonic longitudinal wave signal at that time is matched with the installed position of the ultrasonic shear wave sensor. After the calibration, the crater end is determined from the propagation time of the ultrasonic longitudinal wave signal based on the calibrated calculation formula.;COPYRIGHT: (C)2010,JPO&INPIT