| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inspecting a butt-welded parts of a steel sheet, capable of speedily and reliably detecting various defects, such as step failures of the butt-welded part, weld penetration faults, blow holes, and pinholes. SOLUTION: A detection part 1 is constituted of both a magnetic sensing element 2, such as a Hall element and a magnetizing unit 3 arranged, in such a way as to sandwich the magnetic sensing element 2. The detection part 1 is used to magnetize the butt-welded part of the steel sheet in the direction of a weld seam, while scanning the detection part 1 or the steel sheet in the direction of the weld seam of the steel sheet to detect leakage magnetic flux at a welding defect part. It is preferable that inspection be conducted, while maintaining a uniform distance between the detection part 1 and the welded part, by bringing the detection part 1 into close contact with the steel sheet via a non-magnetic material plate 9 of a prescribed thickness. COPYRIGHT: (C)2004,JPO&NCIPI
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