Development of the Detecting System for Steel Plate with Backside Defect Using an Array of AMR Sensor

摘要

Demand for detecting deep defects in the steel plate is increasing. We have reported a magnetic flux leakage testing (MFLT) system to detect deep defects and create magnetic imaging methods that indicate the backside defect. However, the developed system with one magnetic sensor requires XY automatic positioning stage and long measurement time. In this study, to realize fast measurement for practical use, we have developed a new system which can detect the magnetic field at several measurement points simultaneously using a multi-sensor array. Using the developed system, backside corrosion of steel plates having different depth was measured and two-dimensional images were created. The detected vector signal was analyzed by adjusting phase data. As a result, the developed MFLT system showed good performance of detection limit more than 7.2 mm in depth.