PSI - Issue 68

ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 68 (2025) 1010–1016

European Conference on Fracture 2024 Numerical assessment of cold crack susceptibility of X65 pipe steel during in-service repair welding of pipeline in transportation of gas hydrogen blends Oleksii Milenin a,b, *, Olena Velykoivanenko a , Galyna Rozynka a , Nina Pivtorak a a E.O. Paton Electric Welding Institute of the NAS of Ukraine, 11, Kazymyr Malevych str., Kyiv, 03150, Ukraine b Kyiv Academic University, 36, Akad. Vernadskoho Blvd., Kyiv, 03142, Ukraine Abstract Transporting green hydrogen through existing gas pipelines presents a promising pathway for sustainable energy technologies. However, hydrogen’s interaction with pipeline steels can impact the operability and reliability of the infrastructure. Blending green hydrogen with natural gas mitigates the risk of hydrogen embrittlement, yet excess diffusible hydrogen within the pipeline material, while not significantly impairing mechanical properties, must be addressed in maintenance strategies. In-service repair welding is a viable approach for restoring pipeline integrity without interrupting gas flow. However, the risk of cold cracking due to hydrogen diffusion necessitates precautions, such as preheating or optimizing welding parameters. This study evaluates the risk of cold cracking during in-service welding on pipelines carrying gas-hydrogen blends. By employing multiphysics modelling, the analysis incorporates factors like temperature distribution, microstructural evolution, stress-strain behaviour, and hydrogen diffusion. Weibull criterion is applied to predict fracture probability based on hydrogen concentration, martensitic transformation, and tensile stress. A case study on repair welding of a corroded X65 pipeline examines the effects of diffusible hydrogen and preheating temperatures. The findings offer recommendations for ensuring safe in-service welding on pipelines transporting gas-hydrogen blends. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: gas-hydrogen blends; main pipelines; hydrogen embrittlement; in-service repair; cold cracking; computer simulation; reliability. European Conference on Fracture 2024 Numerical assessment of cold crack susceptibility of X65 pipe steel during in-service repair welding of pipeline in transportation of gas hydrogen blends Oleksii Milenin a,b, *, Olena Velykoivanenko a , Galyna Rozynka a , Nina Pivtorak a a E.O. Paton Electric Welding Institute of the NAS of Ukraine, 11, Kazymyr Malevych str., Kyiv, 03150, Ukraine b Kyiv Academic University, 36, Akad. Vernadskoho Blvd., Kyiv, 03142, Ukraine Abstract Transporting green hydrogen through existing gas pipelines presents a promising pathway for sustainable energy technologies. However, hydrogen’s interaction with pipeline steels can impact the operability and reliability of the infrastructure. Blending green hydrogen with natural gas mitigates the risk of hydrogen embrittlement, yet excess diffusible hydrogen within the pipeline material, while not significantly impairing mechanical properties, must be addressed in maintenance strategies. In-service repair welding is a viable approach for restoring pipeline integrity without interrupting gas flow. However, the risk of cold cracking due to hydrogen diffusion necessitates precautions, such as preheating or optimizing welding parameters. This study evaluates the risk of cold cracking during in-service welding on pipelines carrying gas-hydrogen blends. By employing multiphysics modelling, the analysis incorporates factors like temperature distribution, microstructural evolution, stress-strain behaviour, and hydrogen diffusion. Weibull criterion is applied to predict fracture probability based on hydrogen concentration, martensitic transformation, and tensile stress. A case study on repair welding of a corroded X65 pipeline examines the effects of diffusible hydrogen and preheating temperatures. The findings offer recommendations for ensuring safe in-service welding on pipelines transporting gas-hydrogen blends. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: gas-hydrogen blends; main pipelines; hydrogen embrittlement; in-service repair; cold cracking; computer simulation; reliability. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

* Corresponding author. Tel.: +38-067-457-95-99. E-mail address: asmilenin@ukr.net * Corresponding author. Tel.: +38-067-457-95-99. E-mail address: asmilenin@ukr.net

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 10.1016/j.prostr.2025.06.163