Multifractal analysis of the S235J2 steel structure with corrosion wear

Multifractal analysis has been used for quantitative evaluation of the corrosion pits areas of the ferrite-pearlite S235J2 steel. The multifractal analysis has been used due to complex geometrical shape of the corrosion products. Rényi dimensions spectrum increasing has been obtained from 11 to 20 % at corrosion pits areas increasing from 0.5 to 0.7 mm. Values of informational dimension of the microstructure D1 and light corrosion zone of metal surface D100 changes at 11 %. Therefore these dimensions are most sensitive to YTS of the steel. Dimension D-100 corresponds to dark areas of the microstructure with corrosion products and the value of the dimension changes at 20%. At the same time for dimension D1 coefficient of the pair correlation to YTS is 0.78 and for dimension D100 is only 0.61. Dimension D2 has a good correlation to YTS (0.91) and D-100 has enough correlation to YTS (0.87), but the lower is for D100 (0.61) and fractal dimension of corrosion zone D0 (0.72). Coefficients of correlation have been ranged and analyzed. Obtained results can be used as an additional method for prediction of remaining service life of steel constructions of the nuclear power plants.