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

Abstract

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.

Preventing hydrogen embrittlement in stainless steel by means of compressive stress induced by cavitation peening

“…Figure 7 plots area of compressive residual stress with respect to depth, S σ , respectively. The S σ has been defined in past literatures so as to represent suppressive effect on fatigue crack growth [15]. In cavitation peening, compressive residual stress is linearly introduced with respect to the depth due to its randomness [9].…”

Suppression of Fatigue Crack Propagation of Duralumin by Cavitation Peening

“…It is known that the compressive residual stress mitigates stress concentration around a crack tip due to crack closure effect [20] and reduces the stress intensity factor [21]. Also, it was reported that increase in integral intensity of compressive residual stress with respect to depth raises the resistance to the fatigue crack propagation regardless of the type of peening technique [22].…”

Combination of Laser Shock Peening with Cavitation, Shot, and Ultrasonic Impact Hardening for Stainless Steels Surface Characteristics Improving

“…Additionally, a study of stainless steel by Turski et al [20] established that as compared to the conventional SP process, the LSP, monopin UIP, and WjCP processes induced a greater depth of compressive residual stress. However, it is of interest that the combined peening techniques provide a better improvement of the surface characteristics as compared to the single peening process [27][28][29][30]. Wang et al [31] found favourable effects of the application of LSP followed by SP for surface enhancement of a martensitic stainless steel.…”

“…They have shown that the surface roughness is decreased after the SP process followed by the SB process. Soyama et al [27] established that a combination of WjCP + CP/CP + WjCP, SP + WjCP/WjCP + SP, and CP + SP/SP + CP induced the resistance to fatigue crack growth owning to a greater and deeper compressive residual stress in comparison with a single peening of AISI 316L austenitic stainless steel. Zhang et al [32] showed that the combined USB + SP + USB process increased the surface hardness value from ∼ 800 HV 0.2 to ∼ 1100 HV 0.2 and value of the surface compressive residual stress from about −350 MPa to −1000 MPa.…”