| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and device for rapidly comprehending the state of wall thickness reduction of an inspection object by using an eddy current flaw detection method. SOLUTION: In measurement A (step 17), the magnetic flux density of the inspection object is brought into a saturated state and the eddy current flaw detection method is applied to the inspection object in the saturated state. In measurement B (step 19), the flux density of the inspection object is brought into an unsaturated state and the eddy current flaw detection method is applied to the inspection object in the unsaturated state. An electric signal S<SB>(saturated)</SB>obtained in the measurement A is compared with an electric signal S<SB>(unsaturated)</SB>obtained in the measurement B (step 20) to find a relation "S<SB>(saturated)</SB>> S<SB>(unsaturated)</SB>". If the relation is confimed (yes), it is determined that the wall thickness of the inspected body is reduced. If not (no), it is assumed to equate with the intensity of an electric signal detected as a change in magnetic characteristics not based on a wall thickness reduction and a predetermined threshold value L is compared to S<SB>(unsaturated)</SB>(step 21) to see if a relation "S<SB>(unsaturated)</SB>> L" is satisfied. If "yes", it is determined that the wall thickness of the inspected body is reduced. If "no", it is determined that no damage exists. COPYRIGHT: (C)2004,JPO&NCIPI
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