PSI - Issue 77

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2026) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 77 (2026) 484–489

© 2026 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 ICSI organizers Abstract The hydrogen economy continues to develop, with persistent technical barriers in pipeline infrastructure hindering large-scale hydrogen transportation. The repurposing of natural gas pipeline network for hydrogen transport offers a strategic pathway for decarbonizing energy systems. However, material compatibility challenges persist, particularly hydrogen embrittlement in aged infrastructure. This study evaluates hydrogen embrittlement susceptibility in pipeline steels considering two states: as-received and post-operated (after long-term service). Mechanical testing and fractographic analysis, combined with electrolytic hydrogen charging, reveal critical dependencies on material condition and hydrogen exposure. Post-operated steel exhibited pronounced hydrogen embrittlement sensitivity, with higher fracture toughness reductions under hydrogen charging, compared to as-received specimens. A displacement rate dependence was identified, where lower rates reduced fracture toughness compared to quasi-static conditions. These findings provide critical insights for safe gas pipeline repurposing, addressing both technical and strategic dimensions of the hydrogen economy. © 2026 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 ICSI organizers Keywords: Hydrogen; embrittlement; pipe steel; fracture toughness; gas pipeline, serviceability; fracture 1. Introduction The hydrogen economy continues to develop, with persistent technical barriers in pipeline infrastructure hindering large-scale hydrogen transportation. Hydrogen pipelines have been in safe operation for many decades, and International Conference on Structural Integrity Hydrogen Embrittlement and Fracture Behavior of Aged Pipeline Steels: Challenges for Hydrogen Transport in Gas Infrastructure Olha Zvirko* Karpenko Physico-Mechanical Institute of the NAS of Ukraine, Naukova St. 5, Lviv 79060, Ukraine

* Corresponding author. Tel.: +380-32-263-2133. E-mail address: olha.zvirko@gmail.com

2452-3216 © 2026 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 ICSI organizers

2452-3216 © 2026 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 ICSI organizers 10.1016/j.prostr.2026.01.061