In-Service Degradation of Pipeline Steels

Nykyforchyn, Hryhoriy

doi:10.1007/978-3-030-58073-5_2

Cited by 10 publications

(3 citation statements)

References 24 publications

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“…All the obtained data formed a single narrow data scatter band, which indicated that at the corresponding levels of ∆K, almost no impacts of both stress ratio R and relative location of the examined pipe metal on the crack growth rate da/dN exist. The insensitivity of crack growth resistance characteristics relative to steel degradation in the Paris' law region is consistent with the conclusion of other authors, particularly [32,47]. A slight deviation of the da/dN-∆K diagrams from linearity was only observed for the steel in the AR state tested at R = 0.5 when approaching the crack growth rate relative to that corresponding to the critical stress intensity factor range ∆K fc , which quantitatively characterizes the fracture toughness of the material.…”

Section: The Results Of the Fcg Resistance Test Of 17h1s Steelsupporting

confidence: 91%

“…Therefore, the negative effect of operational degradation of the steel was more pronounced in the lower part of the pipe. The scheme for the development of the gas pipeline steel degradation proposed in studies [32,33] was used to estimate a degradation stage for the studied steel. Since both the strength characteristics (especially the yield strength) of the LTO steel decreased, this was evaluated according to the mentioned scheme as the stage of damage coalescence that occurred in the steel during operation.…”

Section: Mechanical Properties Of 17h1s Steel Estimated Under Tension...mentioning

confidence: 99%

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Peculiarities of Fatigue Crack Growth in Steel 17H1S after Long-Term Operations on a Gas Pipeline

et al. 2023

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This work presents the results of metallographic studies and the tensile, impact, and fatigue crack growth (FCG) resistance tests of 17H1S main gas pipeline steel in the as-received (AR) state and after a long-term operation (LTO). A significant number of non-metallic inclusions forming chains stretched along the direction of pipe rolling were found in the microstructure of the LTO steel. The lowest values of elongation at break and impact toughness of the steel were determined for the lower part of the pipe close to its inner surface. FCG tests at a low stress ratio (R = 0.1) did not reveal a significant change in its growth rate in degraded 17H1S steel compared to steel in the AR state. During tests at a stress ratio R = 0.5, the effect of degradation was more pronounced. The Paris’ law region of the da/dN—∆K diagram for the LTO steel corresponding to the lower part of the pipe close to its inner surface was higher than those for the steel in the AR state and the LTO steel corresponding to the higher part of the pipe. Fractographically, a significant number of delaminations of non-metallic inclusions from the matrix were recognized. Their role in the embrittlement of steel, especially steel from the lower part of the pipe close to its inner surface, was noted.

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Section: The Results Of the Fcg Resistance Test Of 17h1s Steelsupporting

confidence: 91%

Section: Mechanical Properties Of 17h1s Steel Estimated Under Tension...mentioning

confidence: 99%

Peculiarities of Fatigue Crack Growth in Steel 17H1S after Long-Term Operations on a Gas Pipeline

et al. 2023

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“…Gomes et al (2013) addresses the optimal inspection planning for onshore pipelines subject to external corrosion. In recent years, several researchers have studied degradation assessment and Failure prevention of pipeline systems (Nykyforchyn, 2021), also the optimization of inspection programs and maintenance actions based on the reliability level concept (Ben Seghier et al, 2020).…”

Section: Reliability-based Maintenance Strategymentioning

confidence: 99%

The optimum use of high-strength steel in the construction of gas transmission pipeline

Guillal

Abdelbaki

2023

IJSI

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PurposeThe aim of this study is to assess the opportunity for the development of hydrocarbon transportation using high-strength steel (HSS) in pipeline construction in terms of cost savings and reliability.Design/methodology/approachSeveral optimizations of pipeline design and operations were performed to estimate the total life-cycle cost variation associated with different grades of high-strength steel. The generalized reduced gradient (GRG) method was used in an Excel table to determine optimal total life cycle each pipeline. Variables used in this optimization with respect to each steel grade were as follows: pipeline external diameter, wall thickness, number of compression stations and installed power in each compression station. The reliability of a pipeline with optimal cost was assessed to highlight the impact of steel grade on pipeline reliability.FindingsThe study showed that the cost reduction is strongly dependent on the adopted gas pipeline configuration. The number of compression stations and external diameter are the main factors influencing the pipeline total life cycle cost, while the steel price seems to have a minor effect, the reduction of the gas pipeline total life cycle does not exceed 5% even with a 50% difference in pipe steel prices between X70 and X100 steels. On the other side, for the same external diameter, X100 steel presents better pipeline reliability against carbonic corrosion compared to X70 steel.Practical implicationsThe main contribution of this study is to provide a decision-support tool to help pipeline constructors enhance the profitability of natural gas transmission pipelines. The optimization method used is simple to use for design engineers during a feasibility study.Originality/valueThe present study presents one step to fill the gap concerning the question of balancing the trade-off between cost savings and structural reliability in high-strength steel pipelines during the early stages of feasibility studies. The optimal design and operations parameters ensuring cost savings on total life cycle costs are identified via an optimization method. The impact of selected optimal parameters on the long-term pipeline service life was estimated via a structural reliability analysis.

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3D Scan of Hardness Imprints for the Non-destructive In-Situ Structural Assessment of Operated Metal Components

Bolzon,

Talassi

2023

J Nondestruct Eval

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The structural integrity of operated components can be assessed by non-destructive mechanical tests performed in-situ with portable instruments. Particularly promising in this context are small scale hardness tests supplemented by the mapping of the residual imprints left on metal surfaces. The data thus collected represent the input of inverse analysis procedures, which determine the material characteristics and their evolution over time. The reliability of these estimates depends on the accuracy of the geometry scans and on the robustness of the data filtering and interpretation methodologies. The objective of the present work is to evaluate the accuracy of the 3D reconstruction of the residual deformation produced on metals by hardness tests performed at a few hundred N load. The geometry data are acquired by portable optical microscopes with variable focal distance. The imperfections introduced by the imaging system, which may not be optimized for all ambient conditions when used in automatic mode, are analysed. Representative examples of the output produced by the scanning tool are examined, focusing attention on the experimental disturbances typical of onsite applications. Proper orthogonal decomposition and data reduction techniques are applied to the information returned by the instrumentation. The essential features of the collected datasets are extracted and the main noise is removed. The results of this investigation show that the accuracy achievable with the considered equipment and regularization procedures can support the development of reliable diagnostic analyses of metal components in existing structures and infrastructures.

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In-Service Degradation of Pipeline Steels

Cited by 10 publications

References 24 publications

Peculiarities of Fatigue Crack Growth in Steel 17H1S after Long-Term Operations on a Gas Pipeline

Peculiarities of Fatigue Crack Growth in Steel 17H1S after Long-Term Operations on a Gas Pipeline

The optimum use of high-strength steel in the construction of gas transmission pipeline

3D Scan of Hardness Imprints for the Non-destructive In-Situ Structural Assessment of Operated Metal Components

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