Characterizing the surface crack size by magnetic flux leakage testing

The work of this paper is mainly on evaluation the surface crack of different depth and width just like natural defects. First, the effect of slot width to the leakage flux is carefully studied using finite element method(FEM.). Then the ''Width model" about the influence of slot width is developed. Base on the research of the influence of width, a new quantitative testing method is advanced in order to size the surface cracks with different width and depth. The core of the new method is the consideration of the influence of width. The results of FEM. and the experiment show that: the characterizing result is very good after the correction of Byp-p (y component peak to peak value)by slot's width.