Employing magnetic sensor array for inspecting cracks in a pipeline

In this paper, an NDT method for detecting cracks in a rotor bore is proposed. A linearly integrated Hall sensor array (LIHaS) with a small yoke-type magnetizer measures the distribution of a magnetic field (DMF) in a rotor bore. The crack information is then extracted by analyzing the DMF. In the sample test, an axis-directional crack and an arc-directional crack with the length of 0.9 mm was detected with the width of the crack at 0.1 mm. The cracks had depths of 0.2 mm and 0.5 mm, respectively.