抄録
This paper proposes a quantitative evaluation method for the size of far-side corrosive flaws in steel plates or in pipe-wall by means of the magnetic flux leakage technique. For this purpose, an approach that considers both experimental and theoretical modeling works concerning the simplified model flaws of local corrosion or pitting has been adopted. The experiment has been carried out for steel plate specimens containing artificial flaws with various depths and widths, such as circular holes and rectangular grooves in the backside of specimen plates. These experimental results have suggested that the depth of flaw or residual plate thickness can be estimated by the measurements of strength and distribution of vertical component in magnetic leakage flux density arising from far-side flaws. This is confirmed by analytical model calculations, which have been proposed by the authors concerning far-side magnetic leakage field. Finally, a practical evaluation scheme for size of flaws or residual thickness of metal loss area using this technique has been presented.
