| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method and an apparatus in which the flaw of a cylindrical body as a whole can be detected with uniform sensitivity in a short time and with good efficiency, by a method wherein an array-type probe which is constituted by arraning a plurality of ultrasonic vibrators is used as a surface- wave probe. SOLUTION: For example, four ultrasonic flaw detection circuits 31 to 34 are connected to a surface-wave probe 20. Twenty ultrasonic vibrators are divided into four groups I to IV while five adjacent elements are used as a unit. Five elements inside every group are connected to one common ultrasonic flaw detection circuit. The four ultrasonic flaw detection circuits 31 to 34 are synchronized, they transmit electric pulses used to transmit surface waves to the four groups I to IV simultaneously, and they simultaneously receive signals captured by the four groups I to IV so as to be amplified to a proper level. An irregularity in the intensity of a surface-wave beam which is transmitted to, and received from, the surface-wave probe 20 is hardly generated, and the flaw of a cylindrical body can be detected with uniform sensitivity in the range of a wide beam width of about 30 mm. |
