METHOD OF CALIBRATING ULTRASONIC FLAW DETECTION, AND QUALITY CONTROL METHOD AND MANUFACTURING METHOD OF TUBE

摘要

PROBLEM TO BE SOLVED: To adequately determine flaws with a penetrator. SOLUTION: A flaw on a welded part 2 of a tube 1 is detected by ultrasound at least in a tube axis direction. A flaw determination threshold is set based on a difference in signal strength between a total area of flaws existing in a region of an ultrasonic beam in the welded surface and an artificial flaw, and quality of the tube is controlled by the flaw determination threshold. The flaw determination threshold is set based on the signal strength difference between an equivalent flaw diameter and the artificial flaw, wherein the equivalent flaw diameter is determined based on the total area of the flaws existing in the region of the ultrasonic beam from a flaw density on the welded surface of the welded part in the tube axis direction of the tube determined from a desired quality level, and an area of the ultrasonic beam on the welded surface. COPYRIGHT: (C)2008,JPO&INPIT