PSI - Issue 80

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 80 (2026) 392–402

© 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 Ferri Aliabadi Abstract The conversion of existing natural gas pipelines into hydrogen transport systems is crucial for the sustainable energy transition. To assess the impact of hydrogen-promoting environments on mechanical behavior, it is essential to conduct in-situ testing where hydrogen charging and mechanical testing are performed concurrently. Hydrogen can form on the surface of pipeline metals through dissociation from the gas phase or electrochemical reduction of hydrogen ions via cathodic protection or over protection. Once atomic hydrogen enters the material, it can diffuse rapidly through the metal lattice, accumulating at critical concentrations and leading to "hydrogen damage". The steels used in gas pipelines are immune to hydrogen embrittlement (HE), however HE phenomena can occur under conditions of slow plastic deformation, often due to soil movement. Therefore, it is necessary to perform hydrogen charging in conjunction with mechanical tests, such as elastic-plastic mechanical testing to simulate these conditions. This study investigates the mechanical behavior of API 5L grade X65 pipeline steel. An experimental setup was developed to conduct elastic-plastic fracture mechanics tests on SE(B) samples while concurrently performing electrochemical hydrogen charging. The hydrogen charging was carried out in an alkaline solution, simulating the presence of water in soils. Tests were conducted in both air and hydrogen environments, and the effects of hydrogen embrittlement were analyzed using the J integral approach. © 2023 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 Professor Ferri Aliabadi Keywords: Mechanical fracture tests, Cathodic protection, J-integral in environment, Hydrogen embrittlement, Pipeline steel Fracture, Damage and Structural Health Monitoring Investigation of J-integral in Hydrogen-promoting environment L.Gritti a *, D. Fiorona a , S. Ferrari a , M. Pelucchi a , M. Cabrini a , T. Pastore a a University of Bergamo, Dalmine (BG), 24044, Italy

* Corresponding author. Tel.: +39 035 205 2052. E-mail address: luca.gritti1@unibg.it

2452-3216 © 2023 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 Professor Ferri Aliabadi

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 Ferri Aliabadi 10.1016/j.prostr.2026.02.037