| 摘要 |
PURPOSE:To largely reduce change in ultrasonic wave beam width due to a defect position in a steel pipe, compensate an attenuation amount of ultrasonic waves and make uniform detection sensitivity with respect to various scanning lines. CONSTITUTION:A method for ultrasonic flaw detection of a pipe comprises steps for phase-controlling wave surfaces of ultrasonic beams 4 of a desired number of unit oscillators among a plurality of unit oscillators composing an array-type probe 1 so that the beams are focused to a scanning line 5 which is a center line of the ultrasonic beam 4 to detect flaws and for sequentially varying the desired number of unit oscillators to move a focus position of the ultrasonic beams. |
