A detailed study of the relationship between fatigue crack growth rate and striation spacing in a range of low alloy ferritic steels

Bulloch, J.H.; Callagy, A.G.

doi:10.1016/j.engfailanal.2009.04.028

Cited by 21 publications

(5 citation statements)

References 11 publications

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“…Moreover, this correspondence was better manifested at higher (up to 650 • C) test temperatures during the determination of the FCG resistance [38]. It was also confirmed for low-alloy ferritic steel and recommendations were formulated for the residual lifetime assessment of steam generator elements [39].…”

Section: Introductionsupporting

confidence: 53%

Estimation of Fatigue Crack Growth Rate in Heat-Resistant Steel by Processing of Digital Images of Fracture Surfaces

Maruschak

Vorobel

Student

et al. 2021

Metals

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The micro- and macroscopic fatigue crack growth (FCG) rates of a wide class of structural materials were analyzed and it was concluded that both rates coincide either during high-temperature tests or at high stress intensity factor (SIF) values. Their coincidence requires a high level of cyclic deformation of the metal along the entire crack front as a necessary condition for the formation of fatigue striations (FS). Based on the analysis of digital fractographic images of the fatigue fracture surfaces, a method for the quantitative assessment of the spacing of FS has been developed. The method includes the detection of FS by binarization of the image based on the principle of local minima, rotation of the highlighted fragments of the image using the Hough transform, and the calculation of the distances between continuous lines. The method was tested on 34KhN3M steel in the initial state and after long-term operation (~3 × 105 h) in the rotor disk of a steam turbine at a thermal power plant (TPP). Good agreement was confirmed between FCG rates (both macro and microscopic, determined manually or using digital imaging techniques) at high SIF ranges and their noticeable discrepancy at low SIF ranges. Possible reasons for the discrepancy between the micro- and macroscopic FCG rates at low values of the SIF are analyzed. It has also been noted that FS is easier to detect on the fracture surface of degraded steel. Hydrogen embrittlement of steel during operation promotes secondary cracking along the FS, making them easier to detect and quantify. It is shown that the invariable value of the microscopic FCG rate at a low SIF range in the operated steel is lower than observable for the steel in the initial state. Secondary cracking of the operated steel may have contributed to the formation of a typical FS pattern along the entire crack front at a lower FCG rate than in unoperated steel.

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Section: Introductionsupporting

confidence: 53%

Estimation of Fatigue Crack Growth Rate in Heat-Resistant Steel by Processing of Digital Images of Fracture Surfaces

Maruschak

Vorobel

Student

et al. 2021

Metals

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“…Recently, Bulloch and Callagy (2010) have found evidences that, in Phase II of the crack propagation process, the value of s allows for the prediction of the macroscopic Crack propagation in steel weldments crack growth rate, da/dN, with small errors. The results presented in this paper describe a different situation, i.e.…”

Section: Discussionmentioning

confidence: 99%

Fatigue crack propagation behaviour in thick steel weldments

Albuquerque

Miranda

Richter-Trummer

et al. 2012

Int Jnl of Struct Integrity

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If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The purpose of this paper is to study the fatigue crack growth (FCG) behaviour of the steel and weldments of a railway bridge. Design/methodology/approach -Tests were carried out on compact tension (CT) specimens using the thickness (B ¼ 32 mm) of a structural detail. The test matrix included three R values and three material conditions: base material (BM), heat affected zone (HAZ) and weld metal (WM). An evaluation of opening load behavior was carried out. The full field measurement of the residual stress perpendicular to the crack plane was performed using the contour technique. A simplified finite element analysis supported the interpretation of the results. Scanning electron microscopy (SEM) observation of the fracture surface of BM and HAZ specimens was carried out. Findings -Extensive crack closure effects were found in the welded specimens. Important through-the-thickness variation of residual stress was found using the contour technique. The residual stress fields of HAZ and WM specimens led to slowing down the FCG rate in the initial stages of crack propagation and to uncommon fracture surfaces. When the opening load effect was taken into consideration it was found that the da/dN vs DK of the different types of specimens are approximately identical. The ratio (striation spacing)/(da/dN) decreases up to approximately unity as a/W increases. In the specimens analyzed, FCG rates below approximately 2E-7 to 3E-7 m/cycle are associated with approximately constant striation spacing values, which could be considered a conservative upper bound of the real crack growth rate. Originality/value -Fatigue crack growth behavior of thick welded steel CT specimens was analyzed on the basis of tests including full field residual stress measurements, crack closure behavior and striation spacing, allowing for the simultaneous consideration of all those aspects. It is shown that the striations spacing provides no more than a conservative upper bond of the real crack propagation rate.

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“…Previous researchers [27,28] suggested that the correlation between fatigue striation spacing and the crack growth rate (CGR) is one-to-one correlation in ductile materials, especially in stable growth regions. According to this view, the CGR of LM will be larger than that of BM.…”

Section: Fracture Surface Morphology Analysismentioning

confidence: 99%

Effect of microstructure on high cycle fatigue behavior of Ti–5Al–5Mo–5V–3Cr–1Zr titanium alloy

Huang

Zhang

Xin

et al. 2017

International Journal of Fatigue

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A detailed study of the relationship between fatigue crack growth rate and striation spacing in a range of low alloy ferritic steels

Cited by 21 publications

References 11 publications

Estimation of Fatigue Crack Growth Rate in Heat-Resistant Steel by Processing of Digital Images of Fracture Surfaces

Estimation of Fatigue Crack Growth Rate in Heat-Resistant Steel by Processing of Digital Images of Fracture Surfaces

Fatigue crack propagation behaviour in thick steel weldments

Effect of microstructure on high cycle fatigue behavior of Ti–5Al–5Mo–5V–3Cr–1Zr titanium alloy

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