FLAW DETECTION DEVICE

To detect a flaw in a steel plate deck from a pavement body side.SOLUTION: A flaw detection device 100 comprises: an excitation coil 132; a detection coil 134; an excitation unit 210 that applies AC current to the excitation coil 132 to generate induction current in a steel plate deck through electromagnetic induction; a detection unit 230 that detects a detection signal based on the induction current through the detection coil 134; a distance calculation unit 264 that calculates the distance from the steel plate deck on the basis of the detection signal; and a comparison unit 262 that compares the detection signal with a threshold based on the distance calculated by the distance calculation unit 264.SELECTED DRAWING: Figure 8 【課題】鋼床版のきずを舗装体側から検出する。【解決手段】探傷装置１００は、励磁コイル１３２と、検出コイル１３４と、励磁コイル１３２に交流電流を印加し、電磁誘導により鋼床版に誘導電流を発生させる励磁部２１０と、検出コイル１３４を通して、誘導電流に基づく検出信号を検出する検出部２３０と、検出信号に基づき、鋼床版との間の距離を算出する距離算出部２６４と、距離算出部２６４によって算出された距離に基づく閾値と、検出信号とを比較する比較部２６２と、を備える。【選択図】図８