Quasiperiodic change of microhardness during cyclic loading of structural steels

Authors: Bolotnikov A.I.
Published in issue: #10(27)/2018
DOI: 10.18698/2541-8009-2018-10-384
Category: Metallurgy and Science of Materials | Chapter: Metal Science, Thermal Processing of Metals and Alloys
Keywords: microhardness, non-destructive testing, fatigue, microcracks, electrical resistance, eddy current, structural steels, strength
Published: 12.10.2018

The article conducts a statistical study of the change in microhardness in the process of cyclic loading of structural steels on samples of steel 20, steel 45 and 12X18H9T. The values of the dependence of the mean square deviation of microhardness and the coefficient of heterogeneity of the structure of the relative durability are calculated. The obtained statistical characteristics are nonlinear, which agrees well with the previously determined changes in the physical properties of the tested samples. The dependence of the number of cracks of various lengths on the relative number of loading cycles is plotted. The data obtained are correlated with previously published data. As a result, the maximum of microhardness, as well as statistical and physical parameters, is observed at the same value of relative durability, corresponding to the beginning of the stage of fusion of microcracks.

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