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) 52–58

International Conference on Structural Integrity 2023 (ICSI 2023) Hydrogen effects in high-strength lath martensite steel bars for structural engineering Mihaela Iordachescu a *, Patricia Santos a , Andrés Valiente a , Maricely De Abreu a a Material Science Dpt., ETSI Caminos, Universidad Politécnica de Madrid, 5 Prof. Aranguren St., 28040-Madrid, Spain Abstract The paper addresses the damage tolerance of high-strength lath martensite steel bars as assessed from tensile tests carried out on fatigue pre-cracked single edge notched tensile, SENT specimens, both under conventional conditions and at low strain rate with simultaneous hydrogen uptake. The experimental results were evaluated by means of a damage tolerance diagram that allowed them to be compared with the limit loads derived from plastic collapse solutions. The fractographic analysis of the broken samples revealed that the steel is singularly sensitive to hydrogen action, consisting of two-phase assisted cracking, namely initiation and propagation. The change from one phase to another roughly coincides with the end of the small scale yielding (SSY) regime and the propagation one occurs in the transition to the fully plastic regime. The cracking resistance strongly decreases in this phase, along which the embrittlement of the steel by the hydrogen action remains localized at the crack front and contributes to accelerating the ductile failure by plastic collapse of the resistant ligament. © 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: Lath martensite steel; Hydrogen-assisted cracking; Damage tolerance; 1. Introduction The incorporation of sustainability and resilience criteria for design, construction and maintenance in structural engineering requires an accurate geometrical configuration and a reliable loading control of structural members essential for safety assurance. The high-strength steel bars intended for use in pre- or post-stressed construction meet International Conference on Structural Integrity 2023 (ICSI 2023) Hydrogen effects in high-strength lath martensite steel bars for structural engineering Mihaela Iordachescu a *, Patricia Santos a , Andrés Valiente a , Maricely De Abreu a a Material Science Dpt., ETSI Caminos, Universidad Politécnica de Madrid, 5 Prof. Aranguren St., 28040-Madrid, Spain Abstract The paper addresses the damage tolerance of high-strength lath martensite steel bars as assessed from tensile tests carried out on fatigue pre-cracked single edge notched tensile, SENT specimens, both under conventional conditions and at low strain rate with simultaneous hydrogen uptake. The experimental results were evaluated by means of a damage tolerance diagram that allowed them to be compared with the limit loads derived from plastic collapse solutions. The fractographic analysis of the broken samples revealed that the steel is singularly sensitive to hydrogen action, consisting of two-phase assisted cracking, namely initiation and propagation. The change from one phase to another roughly coincides with the end of the small scale yielding (SSY) regime and the propagation one occurs in the transition to the fully plastic regime. The cracking resistance strongly decreases in this phase, along which the embrittlement of the steel by the hydrogen action remains localized at the crack front and contributes to accelerating the ductile failure by plastic collapse of the resistant ligament. © 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: Lath martensite steel; Hydrogen-assisted cracking; Damage tolerance; 1. Introduction The incorporation of sustainability and resilience criteria for design, construction and maintenance in structural engineering requires an accurate geometrical configuration and a reliable loading control of structural members essential for safety assurance. The high-strength steel bars intended for use in pre- or post-stressed construction meet © 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

* Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: mihaela.iordachescu@upm.es * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: mihaela.iordachescu@upm.es

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.2024.01.055