Abstract
A variety of defects in continuous steel strip may result in accidents. Traditional MFL (Magnetic flux leakage) testing method can lead to large blind area because steel strip is too broad to be rotated. A new MFL testing method that can inspect omni-directional cracks in steel strip is introduced in this paper. This method is characterized basically by the deep saturation state of steel strip generated. The property of inspection is investigated using 3-D finite element method. Waveform configurations of the experimental results agree with that of the theoretical predictions. Automatic inspecting equipment has been developed based on the new MFL method principle.