PSI - Issue 54

ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000 Structural Integrity Procedia 00 (2023) 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 54 (2024) 233–240

© 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 the scientific committee of the ICSI 2023 organizers Abstract It is well known that the presence of hydrogen in steel structures can cause a degradation of their mechanical properties, such as fracture toughness. This phenomenon, commonly called hydrogen embrittlement (HE), poses a potentially serious challenge for structural steels subjected to cathodic protection or pipelines transporting high-pressure hydrogen gas. The repurposing of natural gas pipelines for hydrogen gas transport has gathered much interest in the past few years, and it is evident that these pipeline steels should be qualified for hydrogen service. Fracture toughness is an important property for these steels. The single edge notched tension (SENT) test can be used to quantify the fracture toughness of a steel and this test has been shown to induce a constraint level comparable to that of a pipe with through-thickness or surface cracks. LS-oriented SENT specimens, extracted from an API 5L X70 pipe, are hydrogen pre-charged in an aqueous 0.1M NaOH solution under a current density of 0.8 mA/cm² for 48h to obtain saturation and subsequently tested either ex-situ or with concurrent hydrogen charging (in-situ). For the latter case, a significant shift in fracture mode takes place, with most of the crack growth appearing to occur through quasi-cleavage. For the former, only limited quasi-cleavage is found. Furthermore, cracking along the microstructural banding proved to show a significant influence on the cracking behavior during the test, complicating the test result interpretation for qualifying hydrogen gas pipelines. © 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 the scientific committee of the ICSI 2023 organizers Keywords: Hydrogen embrittlement; Pipeline steels; SENT; Fracture toughness International Conference on Structural Integrity 2023 (ICSI 2023) Hydrogen-assisted degradation of an X70 pipeline steel evaluated by single edge notched tension testing Margo Cauwels a , Robin Depraetere b , Wim De Waele b , Stijn Hertelé b , Tom Depover a *, Kim Verbeken a* a Ghent University, Department of Materials, Textiles and Chemical Engineering, Sustainable Materials Science, Technologiepark 46, B-9052 Zwijnaarde, Belgium b Ghent University, Department of Electromechanical, Systems and Metal Engineering, Soete Laboratory, Technologiepark 46, B-9052, Belgium Abstract It is well known that the presence of hydrogen in steel structures can cause a degradation of their mechanical properties, such as fracture toughness. This phenomenon, commonly called hydrogen embrittlement (HE), poses a potentially serious challenge for structural steels subjected to cathodic protection or pipelines transporting high-pressure hydrogen gas. The repurposing of natural gas pipelines for hydrogen gas transport has gathered much interest in the past few years, and it is evident that these pipeline steels should be qualified for hydrogen service. Fracture toughness is an important property for these steels. The single edge notched tension (SENT) test can be used to quantify the fracture toughness of a steel and this test has been shown to induce a constraint level comparable to that of a pipe with through-thickness or surface cracks. LS-oriented SENT specimens, extracted from an API 5L X70 pipe, are hydrogen pre-charged in an aqueous 0.1M NaOH solution under a current density of 0.8 mA/cm² for 48h to obtain saturation and subsequently tested either ex-situ or with concurrent hydrogen charging (in-situ). For the latter case, a significant shift in fracture mode takes place, with most of the crack growth appearing to occur through quasi-cleavage. For the former, only limited quasi-cleavage is found. Furthermore, cracking along the microstructural banding proved to show a significant influence on the cracking behavior during the test, complicating the test result interpretation for qualifying hydrogen gas pipelines. © 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 the scientific committee of the ICSI 2023 organizers Keywords: Hydrogen embrittlement; Pipeline steels; SENT; Fracture toughness International Conference on Structural Integrity 2023 (ICSI 2023) Hydrogen-assisted degradation of an X70 pipeline steel evaluated by single edge notched tension testing Margo Cauwels a , Robin Depraetere b , Wim De Waele b , Stijn Hertelé b , Tom Depover a *, Kim Verbeken a* a Ghent University, Department of Materials, Textiles and Chemical Engineering, Sustainable Materials Science, Technologiepark 46, B-9052 Zwijnaarde, Belgium b Ghent University, Department of Electromechanical, Systems and Metal Engineering, Soete Laboratory, Technologiepark 46, B-9052, Belgium

* Corresponding author. Tel.: +32 9 331 04 53; E-mail address: Kim.Verbeken@UGent.be * Corresponding author. Tel.: +32 9 331 04 53; E-mail address: Kim.Verbeken@UGent.be

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 the scientific committee of the ICSI 2023 organizers 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 the scientific committee of the ICSI 2023 organizers

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 the scientific committee of the ICSI 2023 organizers 10.1016/j.prostr.2024.01.078