ULTRASONIC FLAW DETECTING METHOD AND DEVICE

PROBLEM TO BE SOLVED: To easily and precisely execute the ultrasonic flaw detecting work to a multilayered piping structure region. SOLUTION: At first, linear scanning is performed at a flaw detecting angle θ1 of refraction so that the ultrasonic beams from the respective vibrators of a phased array probe 1 can directly irradiate a flaw inspecting target region R. Subsequently, the same linear scanning is performed at a flaw detecting angle θ2 of refraction so that the ultrasonic beams are once reflected from the inner surface of a thick-walled part to arrive at the flaw inspecting target region R. In this case, one of the ultrasonic beams is reflected on one end side (crack opening position) of a flaw part (d). Then, the ultrasonic beams are once reflected from the inner surface of the thick-walled part and the same linear scanning is performed at a flaw detecting angle θ3 of refraction so that the ultrasonic beams are once reflected from the outer surface of the thick-walled part to arrive at the flaw inspecting target region R. In this case, one of the ultrasonic beams is reflected on the other end side (crack leading end position) of the flaw part (d). COPYRIGHT: (C)2010,JPO&INPIT