Study on the effects of yoke parameters on uniform magnetization for magnetic flux leakage testing

For the magnetic flux leakage (MFL) testing technique, the uniform magnetization to the measured specimen will result in smooth signals and reduce the dynamic influence caused by the relative motion between the magnetizing yoke and specimen. In this paper, a magnetic circuit model is established to analyze the effects of yoke parameters on the uniform magnetization. The theoretical analysis is verified by simulations. It shows that the magnetization amplitude of the uniform area is mainly determined by the magnet width and height. And the width of the uniform area is mainly determined by the gap between the magnets. The air reluctance and magnetizing source play the most important role in the magnetization.