METHOD FOR MAGNETIC FLAW DETECTION AND MAGNETIC FLAW DETECTOR

摘要

An objective of the present invention is to provide a magnetic testing method and apparatus, which can accurately detect a flaw by magnetizing a test object to such a degree that the object becomes magnetically saturated while solving a problem that a large magnetizing device is required when only a DC magnetic field is applied and a problem that the test object generates heat when only an AC magnetic field is applied. A magnetic testing apparatus 100 according to the present invention comprises: a first magnetizing device 1 for applying a DC bias magnetic field to a test object P in substantially parallel to the direction in which a flaw F to be detected extends; a second magnetizing device 2 for applying an AC magnetic field to the test object P substantially perpendicularly to the direction in which the flaw F to be detected extends; and a detecting device 3 for detecting leakage flux produced by the magnetization of the test object P accomplished by the first magnetizing device 1 and the second magnetizing device 2.