Ultrasonic flaw detector, ultrasonic flaw detection method, welded steel pipe manufacturing method, and welded steel pipe quality control method

摘要

The ultrasonic flaw detector 1 is focused in the axial direction of the pipe disposed via the wedge 3 at a position on the outer peripheral surface of the welded steel pipe S where ultrasonic waves can be incident perpendicularly to the welding root surface. A matrix array probe 2 that transmits ultrasonic waves to the welding root surface and receives ultrasonic waves reflected on the welding root surface, and a matrix array probe 2 that receives reflected ultrasonic waves reflected on the welding root surface. An ultrasonic transmission / reception unit 4 to be controlled and an evaluation unit 5 for detecting a plane defect based on a reflected wave of the ultrasonic wave received by the ultrasonic transmission / reception unit 4 are provided.