METHOD FOR DETECTING SOLIDIFICATION COMPLETION POSITION OF CONTINUOUS CASTING CAST PIECE, DETECTOR, AND METHOD FOR PRODUCING CONTINUOUS CASTING CAST PIECE

摘要

In steel continuous casting, the solidification completion position is accurately detected from only a measured value measured by a sensor without need for correction by driving a rivet into a cast piece. Specifically lateral ultrasonic sensors (6, 8) for transmitting a lateral ultrasonic wave into a cast piece (1) and receiving its reflected wave and longitudinal ultrasonic sensors (7, 9) for transmitting a longitudinal ultrasonic wave into the cast piece and receiving its reflected wave are installed at the same position of a continuous casting machine or at the same position in the direction of the width of the cast piece at two portions spaced in the casting direction. On the basis of the variations of the intensities of the received signals of the lateral ultrasonic sensors, the solidification completion potion (4) of the cast piece is detected to agree with the position where the lateral ultrasonic sensors are installed. The calculation formula for determining the solidification completion position from the propagation time of the longitudinal ultrasonic wave is corrected so that the solidification completion position calculated from the propagation time of the longitudinal ultrasonic wave at the time of detection may agree with the position where the lateral ultrasonic sensors are installed. After the correction, using the corrected calculation formula, the solidification completion position is determined from the propagation time of the longitudinal ultrasonic wave.