The influence of microstructure on the fatigue crack growth rate in marine steels in the Paris Region

Abstract

This paper presents a study on the effect of microstructure on the fatigue crack growth (FCG) rate in advanced S355 marine steels in the Paris Region of the da/dN versus ΔK log–log plot. The environments of study were air and seawater (SW), under constant amplitude sinewave fatigue loading. Fundamentally, three phenomena (crack tip diversion, crack front bifurcation and metal crumb formation) were observed to influence the rate of FCG. These phenomena appear to be a function of the material microstructure, environment and crack tip loading conditions. The three factors retarded the crack growth by reducing or redistributing the effective driving force at the main active crack tip. A crack path containing extensively the three phenomena was observed to offer strong resistance to FCG. In SW, the degree of the electrochemical dissolution of the microplastic zone appears to be an additional primary factor influencing FCG in the steels.

Comparison of high‐ and low‐frequency fatigue properties of structural steels S355J0 and S355J2

“…Many works dealing with the study of high-strength and high-performance steels focus on the fatigue properties of welded parts, 3,4 whereas the others study the basic material. 5,6 Steel S355 is one of the structural steels often used in civil engineering industry. However, even in the case of S355 steel, most of the previous analysis focused only on studying the fatigue properties of welded components.…”

Assessment of mechanical and fatigue crack growth properties of wire + arc additively manufactured mild steel components

“…These fluctuations in the crack growth could be a result of crack diversion and bifurcation due to the localized microstructure and texture, which have been reported previously for other steels. 34 It has been observed in the literature that the presence of bainitic structure has been reported to slow down the crack growth rate that causes softening by dislocation rearrangement and annihilation during the strain-induced martensitic transformation. 35,36 The raw data from FCG tests were further analyzed to plot the FCG rate, da/dN, against the SIF range, ΔK, and the results are shown in Figure 7B.…”

Análise de Bolhas Desprendidas Durante o Ensaio por Fadiga Realizado em Ambiente Subaquático

“…Autores relatam [19,20,30,31] que o fenômeno de aceleração da trinca em ambiente aquoso também apresenta o mesmo padrão, de aumento e diminuição de intensidade na propagação da trinca com o aumento de ΔK, ou seja, com o aumento da trinca, semelhante ao encontrado neste trabalho e apresentado na Figura 11.…”