| 摘要 |
PROBLEM TO BE SOLVED: To provide a presuming method of the depth of local corrosion of a piping capable of grasping the maximum depth of corrosion simply and properly in a non-destructive state. SOLUTION: A plurality of measuring points P are set for each of regions S1, S2,...Sn on a piping 1, and the wall thickness ms of the piping 1 at these point P are measured ultrasonically, and on the basis of the obtained measurements, the maximum corroding depth xs in each region is determined, and the obtained value xs is applied to Gumbel distribution so that the position parameterαs and scale parameterλs in Gumbed distribution are determined, and the Gumbel distribution for the maximum value xo of the actual corroding depth in each region is presumed by applying the obtainedαs andλs to the calculation formula derived previously.
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