PSI - Issue 54

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ScienceDirect

Procedia Structural Integrity 54 (2024) 172–179 Structural Integrity Procedia 00 (2023) 000–000 Structural Integrity Procedia 00 (2023) 000–000

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© 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 In the light of the energy transition, part of the European natural gas pipeline grid will be converted to hydrogen gas pipelines. One of the challenges of this conversion is the well-acknowledged reduction in mechanical properties of steel in the presence of hydrogen, commonly known as ‘hydrogen embrittlement’. The steels in-use are of variable characteristics (with respect to chemical, microstructural and mechanical properties), resulting in a variety of plasticity and fracture behaviors. The present work investigates the e ff ect of hydrogen on the fracture behavior of a relatively old grade API 5L X56 pipeline steel produced by normalized rolling which resulted in a banded microstructure. Tensile tests were performed on smooth and notched round bar specimens that were hydrogen pre-charged electrochemically (ex-situ), and compared to tests on uncharged specimens as a reference. The fractured specimens were scanned using high resolution X-ray computed tomography (X-ray micro-CT) to visualize and quantify the damage underneath the fracture surface. Statistics regarding the void size distribution and void shapes are provided. The fracture process in the absence of hydrogen is characterised by significant void development. The presence of hydrogen accelerates the fracture mechanisms without fundamentally altering them. This is in contrast with previous results obtained on a di ff erent pipeline steel grade, demonstrating the sensitivity of hydrogen embrittlement susceptibility to material characteristics. © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // 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 steel; Fracture; X-ray micro-CT International Conference on Structural Integrity 2023 (ICSI 2023) Damage evolution of a hydrogen charged grade X56 pipeline steel evaluated using X-ray micro-CT Robin Depraetere a , Wim De Waele a, ∗ , Margo Cauwels b , Tom Depover b , Kim Verbeken b , Stijn Hertele´ a a Ghent University, Department of Electromechanical, Systems and Metal Engineering, Soete Laboratory, Technologiepark-Zwijnaarde 46, 9052 Zwijnaarde, Belgium b Ghent University, Department of Materials, Textiles and Chemical Engineering, Sustainable Materials Science, Technologiepark-Zwijnaarde 46, 9052 Zwijnaarde, Belgium Abstract In the light of the energy transition, part of the European natural gas pipeline grid will be converted to hydrogen gas pipelines. One of the challenges of this conversion is the well-acknowledged reduction in mechanical properties of steel in the presence of hydrogen, commonly known as ‘hydrogen embrittlement’. The steels in-use are of variable characteristics (with respect to chemical, microstructural and mechanical properties), resulting in a variety of plasticity and fracture behaviors. The present work investigates the e ff ect of hydrogen on the fracture behavior of a relatively old grade API 5L X56 pipeline steel produced by normalized rolling which resulted in a banded microstructure. Tensile tests were performed on smooth and notched round bar specimens that were hydrogen pre-charged electrochemically (ex-situ), and compared to tests on uncharged specimens as a reference. The fractured specimens were scanned using high resolution X-ray computed tomography (X-ray micro-CT) to visualize and quantify the damage underneath the fracture surface. Statistics regarding the void size distribution and void shapes are provided. The fracture process in the absence of hydrogen is characterised by significant void development. The presence of hydrogen accelerates the fracture mechanisms without fundamentally altering them. This is in contrast with previous results obtained on a di ff erent pipeline steel grade, demonstrating the sensitivity of hydrogen embrittlement susceptibility to material characteristics. © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // 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 steel; Fracture; X-ray micro-CT International Conference on Structural Integrity 2023 (ICSI 2023) Damage evolution of a hydrogen charged grade X56 pipeline steel evaluated using X-ray micro-CT Robin Depraetere a , Wim De Waele a, ∗ , Margo Cauwels b , Tom Depover b , Kim Verbeken b , Stijn Hertele´ a a Ghent University, Department of Electromechanical, Systems and Metal Engineering, Soete Laboratory, Technologiepark-Zwijnaarde 46, 9052 Zwijnaarde, Belgium b Ghent University, Department of Materials, Textiles and Chemical Engineering, Sustainable Materials Science, Technologiepark-Zwijnaarde 46, 9052 Zwijnaarde, Belgium

1. Introduction 1. Introduction

Considering the potential role of hydrogen in the energy transition, it is expected that part of the European natural gas pipeline grid will be repurposed for hydrogen gas transport. However, the takeup of hydrogen atoms by metallic Considering the potential role of hydrogen in the energy transition, it is expected that part of the European natural gas pipeline grid will be repurposed for hydrogen gas transport. However, the takeup of hydrogen atoms by metallic

∗ Corresponding author. E-mail address: wim.dewaele@ugent.be ∗ Corresponding author. E-mail address: wim.dewaele@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 10.1016/j.prostr.2024.01.070 2210-7843 © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the ICSI 2023 organizers. 2210-7843 © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the ICSI 2023 organizers.