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) 880–886

European Conference on Fracture 2024 Fracture behaviour of pipeline steel depending on hydrogen content in material Andriy Syrotyuk*, Ihor Dmytrakh, Rostyslav Leshchak, Oleh Malyk Karpenko Physico-Mechanical Institute of National Academy of Sciences of Ukraine, 5 Naukova Street, Lviv, 79060, Ukraine Abstract The effect of hydrogen in pipeline steel on its fracture behaviour has been evaluated based on the failure tests of the notched and cracked beam specimens with different hydrogen content in the material. We propose a special index showing the loss of the resistance to fracture of the steel depending on the hydrogen content in the steel. Three characteristic ranges of the hydrogen content that correspond to different features of the hydrogen influence on the microstructural fracture specificity of pipeline steel have been found, namely: the zone of enhanced deformability of material, the transition zone with the mixed mechanism of hydrogen effect, and the zone of hydrogen embrittlement. It has been found that the ratio of diffusible/residual (trapped) hydrogen in the steel defines such microstructural fracture behaviour. The SEM examination of the fracture surfaces confirmed this relationship. © 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: pipeline steel; notch; crack; hydrogen content; microstructural fracture. 1. Introduction The pipeline networks, both main and secondary, are the critical components of the industrial and transport infrastructure of many countries. The problem of ensuring their reliable and accident-free operation has always been on the agenda of engineering practice (Bolzon et al. (2021)). The importance of this problem is permanently increasing with the large-scale use of hydrogen as an energy source (Mulder et al. (2007)). As a result of the above, during recent years European Conference on Fracture 2024 Fracture behaviour of pipeline steel depending on hydrogen content in material Andriy Syrotyuk*, Ihor Dmytrakh, Rostyslav Leshchak, Oleh Malyk Karpenko Physico-Mechanical Institute of National Academy of Sciences of Ukraine, 5 Naukova Street, Lviv, 79060, Ukraine Abstract The effect of hydrogen in pipeline steel on its fracture behaviour has been evaluated based on the failure tests of the notched and cracked beam specimens with different hydrogen content in the material. We propose a special index showing the loss of the resistance to fracture of the steel depending on the hydrogen content in the steel. Three characteristic ranges of the hydrogen content that correspond to different features of the hydrogen influence on the microstructural fracture specificity of pipeline steel have been found, namely: the zone of enhanced deformability of material, the transition zone with the mixed mechanism of hydrogen effect, and the zone of hydrogen embrittlement. It has been found that the ratio of diffusible/residual (trapped) hydrogen in the steel defines such microstructural fracture behaviour. The SEM examination of the fracture surfaces confirmed this relationship. © 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: pipeline steel; notch; crack; hydrogen content; microstructural fracture. 1. Introduction The pipeline networks, both main and secondary, are the critical components of the industrial and transport infrastructure of many countries. The problem of ensuring their reliable and accident-free operation has always been on the agenda of engineering practice (Bolzon et al. (2021)). The importance of this problem is permanently increasing with the large-scale use of hydrogen as an energy source (Mulder et al. (2007)). As a result of the above, during recent years © 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.: +38-032-263-14-00; fax: +38-032-264-94-27. E-mail address: syrotyuk@ipm.lviv.ua (Andriy Syrotyuk). * Corresponding author. Tel.: +38-032-263-14-00; fax: +38-032-264-94-27. E-mail address: syrotyuk@ipm.lviv.ua (Andriy Syrotyuk).

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.2025.06.145