An Indicator for the Suppression of Fatigue Crack Growth by Hybrid Peening

概要

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Peening techniques are used to introduce compressive residual stress into the surface of a metal in order to improve the fatigue properties and resistance to stress corrosion cracking of the metal. The present paper focuses on the effect of peening on the fatigue crack growth behavior in austenitic stainless steel. An indicator which can be used to determine by how much the fatigue crack growth can be suppressed was found. Regardless of the type of peening technique used, a much closer correlation to the number of cycles to failure was found with the area of integration under the compressive residual stress curve with respect to depth than with the compressive residual stress at the surface. Moreover hybrid peening, which is a combination of different peening techniques, was developed in this study in order to enhance the favorable effects of peening. Hybrid peening increased the area of integration under the compressive residual stress curve and, as a result, a further increase in the number of cycles to failure compared to single peening was obtained.