Steel material quality evaluation method and quality evaluation device

摘要

pA steel material quality evaluation device is provided with: a probe control unit (11) which scans a scan surface (S2) facing a mill scale surface (S1) of a steel material (1) including a surface layer portion by an ultrasonic signal and receives an echo signal from the steel material (1) the echo signal being generated with the scanning by the ultrasonic signal; a mill scale surface shape profile calculation unit (14) which calculates the propagation distance of the echo signal from the mill scale surface (S1) using waveform data relating to the echo signal and calculates the shape profile of the mill scale surface (S1) in the direction of the scanning by the ultrasonic signal from the calculated propagation distance; and a flaw indication imaging unit (15) and a flaw indication output unit (16) which set as a flaw detection gate the detection range of the echo signal resulting from a flaw in the steel material (1) on the basis of the shape profile of the mill scale surface (S1) and generates and outputs a flaw indication image in which the maximum value of the echo signal in the set flaw detection gate is mapped./p