| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detection device and an ultrasonic flaw detection method, which allow for detecting surface defects with good repeatability, and to provide a method of manufacturing steel.SOLUTION: In one embodiment of the present invention, an ultrasonic flaw detection device 1 includes: a transmitter unit 2 configured to electromagnetically excite an ultrasonic signal on a surface layer of steel; a receiver unit 3 configured to receive the ultrasonic signal; an amplifier unit 6 configured to detect the ultrasonic signal traveling directly to the receiver unit 3 from the surface layer of the steel, and amplifies a reflection signal of the ultrasonic signal from a surface defect D of the steel received by the receiver unit 3 based on intensity of the detected ultrasonic signal; and a signal evaluation unit 7 configured to detect the surface defect of the steel based on the amplified reflection signal. Such a configuration allows for detecting the surface defect with good repeatability even when the amplitude of the ultrasonic vibration is altered by a change in flux density of a static magnetic field B imparted on the surface layer, by correcting sensitivity to reflection echoes from the surface defect D.SELECTED DRAWING: Figure 1 |
