Relationship between fatigue crack growth behaviour and local hydrogen concentration near crack tip in pipeline steel

Dmytrakh, І. М.; Smiyan, O. D.; Syrotyuk, А. М.; Bilyy, Orest

doi:10.1016/j.ijfatigue.2012.05.017

Cited by 35 publications

(19 citation statements)

References 13 publications

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“…The constants n and C of the "material-medium" system (namely, the "16GS steel-hydrogen-containingmedium" system) [8] and the constants K th and K fc (in what follows, they are used in the calculations) were determined from the experimental results (Table 1). The critical values of the SIF used to determine the safe and inadmissible depths of the cracklike defect are also presented in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the Durability of a Pipeline Weakened by Internal Defect in the Process of Transportation of Hydrogen-Containing Media

Bilyi¹

2016

Mater Sci

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We propose a method aimed at the evaluation of the durability of pipeline systems weakened by elliptic internal defects in the process of transportation of hydrogen-containing media. For the analysis of defects, we apply the criteria of fracture mechanics based on the determination of the safe and inadmissible depths of cracklike defects and on the characteristics of crack-growth resistance of structural elements characterized by the rate of changes in the stress intensity factor near the crack tip in the process of crack growth in the structural element. Examples of evaluation of the durability of feed pipeline systems in the presence of internal cracklike defects are presented.Keywords: pipeline systems, hydrogen-containing media, cracklike defects, stress intensity factors, characteristics of crack-growth resistance of a structural element, threshold and critical sizes of cracks, durability of structural elements.At present, the problem of influence of hydrogen-containing media on steel pipeline systems proves to be quite urgent due to the extensive use of these objects for the transportation of hydrogen and hydrogen-containing media. In the last decade, the number of various publications dealing with this problem noticeably increased both in the international and Ukrainian journals [1-3]. In the process of operation, the pipeline systems suffer the joint action of mechanical loads and hydrogen-containing media. This leads to the development of damage and the appearance of cracklike defects of various shapes and geometries, which, in turn, increases the probability of fracture of the object. These processes are also intensified due to the contamination of the environment, which leads to the appearance of unpredicted anthropogenic impurities in the working media and to the additional unforeseen formation of cracklike defects in the critical structures [4,5]. This is caused by the deterioration of the quality of water supply of thermal power plants (ТPP), especially pronounced near industrial centers due to pollution of the environment with various waste products as a result of which the water carriers are contaminated.In what follows, as an example, we consider feed pipelines of power-generating units of supercritical pressure of thermal power plants. The analyzed pipes are made of 16GS steel and have different standard sizes (526 × 50, 467 × 45, and 405 × 40 mm). They contain cracklike defects of different configurations. We investigate the possibility of their safe operation under the influence of anthropogenic organic impurities modeled by different volume concentrations of hydrogen in the metal C H(v) (1.97, 2.07, 2.20, and 2.47 ppm). As the research tool for the investigation of defects, we use fracture mechanics of materials [6] parallel with the nondestructive methods of monitoring of the objects with the help of which one can record and then reproduce the configuration of existing defects as a result of mathematical modeling.

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Section: Resultsmentioning

confidence: 99%

Evaluation of the Durability of a Pipeline Weakened by Internal Defect in the Process of Transportation of Hydrogen-Containing Media

Bilyi¹

2016

Mater Sci

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“…Therefore, the fatigue lifeassessment through crack growth prediction is acceptable; considering that the crack growth life was almost comparablewith the fatigue life itself [44]. Dmytrakh et al [45] studied an FCG on low alloyed pipeline steel under hydrogenating conditions. The empirical relationship was derived for fracture risk assessment of defect pipelines.…”

Section: = ∆mentioning

confidence: 99%

The Effect of Dent Under Fatigue Loading in Pressurized Pipeline: A Review

2015

IJAERD

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“…The (da/dN) HAC term takes account for both the HEDE theory and Lynch's theory, where the former expects the accumulation of H at the crack front direction to diminish the free surface energy and cause crack propagation [16,17] and the latter considers the coalescence of the minor defects with cracks due to H effects [18][19][20]. As hydrogen atoms saturate in the plastic zone, two mechanisms will enhance the crack propagation rate to reach maximum rate, as suggested by the recent experiments [15].…”

Section: Introductionmentioning

confidence: 99%

“…The hydrogen concentration in the steel is somehow difficult to quantify and can range from 0 to 5n10 À 4 atomic ratio [25]. To simplify the calculation, the c 0 here is taking a constant at 10 appm which is a reasonable amount around crack tips in steel [16,17].…”

Section: Introductionmentioning

confidence: 99%

Prediction of crack propagation under cyclic loading based on hydrogen diffusion

2015

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Relationship between fatigue crack growth behaviour and local hydrogen concentration near crack tip in pipeline steel

Cited by 35 publications

References 13 publications

Evaluation of the Durability of a Pipeline Weakened by Internal Defect in the Process of Transportation of Hydrogen-Containing Media

Evaluation of the Durability of a Pipeline Weakened by Internal Defect in the Process of Transportation of Hydrogen-Containing Media

The Effect of Dent Under Fatigue Loading in Pressurized Pipeline: A Review

Prediction of crack propagation under cyclic loading based on hydrogen diffusion

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