PSI - Issue 54

Magdalena Eškinja et al. / Procedia Structural Integrity 54 (2024) 123–134 M. Eškinja et al./ Structural Integrity Procedia 00 (2019) 000 – 000

134 12

4. Conclusions 1. High Mo content enables formation of the Mo carbides for tempered martensitic steels. Mo carbides can be characterized as medium-strong traps which can trap diffusible hydrogen and reduce its deteriorating effect on the mechanical properties of steel. 2. Mo carbides show trapping ability, resulting in decreased effective diffusion coefficient for the steel with higher Mo content. Additionally, hydrogen desorption spectra showed higher desorption rate and shift of the peaks to higher temperature. 3. No indication of intergranular fracture was found, and quasi-cleavage fracture features with serrated markings were observed in investigated steels prevailing HE mechanism was hydrogen enhanced-localized plasticity (HELP). 4. Under simulated field conditions HMoS exhibited higher hydrogen uptake compared to LMoS, due to the higher amount of hydrogen traps and uptake was higher in case of the specimens loaded in plastic region. 5. Double Q&T treatment of the alloy with higher Mo content revealed superior behavior compared to single Q&T alloy. Origin of this improved HE resistance can be correlated with two effects: higher quantity and more uniform distribution of Mo carbides and reduced dislocation density. [1] A. Conde, J.J. De Damborenea, J.M. López-Escobar, C. Pérez-Arnaez, Slow strain rate technique for studying hydrogen induced cracking in 34CrMo4 high strength steel, International Journal of Hydrogen Energy. 46 (2021) 34970 – 34982. https://doi.org/10.1016/j.ijhydene.2021.08.026. [2] J. Venezuela, Q. Liu, M. Zhang, Q. Zhou, A. Atrens, A review of hydrogen embrittlement of martensitic advanced high-strength steels, Corrosion Reviews. 34 (2016) 153 – 186. https://doi.org/10.1515/corrrev-2016-0006. [3] B.N. Popov, J.-W. Lee, M.B. Djukic, Hydrogen Permeation and Hydrogen-Induced Cracking, in: Handbook of Environmental Degradation of Materials, Elsevier, 2018: pp. 133 – 162. https://doi.org/10.1016/B978-0-323-52472-8.00007-1. [4] M. Moshtaghi, E. Maawad, A. Bendo, A. Krause, J. Todt, J. Keckes, M. Safyari, Design of high-strength martensitic steels by novel mixed metal nanoprecipitates for high toughness and suppressed hydrogen embrittlement, Materials & Design. (2023) 112323. https://doi.org/10.1016/j.matdes.2023.112323. [5] Y. Nie, Y. Kimura, T. Inoue, F. Yin, E. Akiyama, K. Tsuzaki, Hydrogen Embrittlement of a 1500-MPa Tensile Strength Level Steel with an Ultrafine Elongated Grain Structure, Metall Mater Trans A. 43 (2012) 1670 – 1687. https://doi.org/10.1007/s11661-011-0974-7. [6] C.-M. Liao, J.-L. Lee, Effect of Molybdenum on Sulfide Stress Cracking Resistance of Low-Alloy Steels, CORROSION. 50 (1994) 695 – 704. https://doi.org/10.5006/1.3293546. [7] M. Moshtaghi, M. Safyari, Temperature mitigates the hydrogen embrittlement sensitivity of martensitic steels in slow strain rates, Vacuum. 202 (2022) 111187. https://doi.org/10.1016/j.vacuum.2022.111187. [8] M. Safyari, M. Moshtaghi, S. Kuramoto, Effect of strain rate on environmental hydrogen embrittlement susceptibility of a severely cold rolled Al – Cu alloy, Vacuum. 172 (2020) 109057. https://doi.org/10.1016/j.vacuum.2019.109057. [9] M. Moshtaghi, B. Loder, M. Safyari, T. Willidal, T. Hojo, G. Mori, Hydrogen trapping and desorption affected by ferrite grain boundary types in shielded metal and flux-cored arc weldments with Ni addition, International Journal of Hydrogen Energy. 47 (2022) 20676 – 20683. https://doi.org/10.1016/j.ijhydene.2022.04.260. [10] M. Moshtaghi, M. Safyari, Different augmentations of absorbed hydrogen under elastic straining in high-pressure gaseous hydrogen environment by as-quenched and as-tempered martensitic steels: combined experimental and simulation study, International Journal of Hydrogen Energy. 48 (2023) 27408 – 27415. https://doi.org/10.1016/j.ijhydene.2023.03.396. [11] Devanathan M. A. V. Stachurski Z., The adsorption and diffusion of electrolytic hydrogen in palladium, Proc. R. Soc. Lond. A. 270 (1962) 90 – 102. https://doi.org/10.1098/rspa.1962.0205. [12] X.Y. Cheng, H.X. Zhang, A new perspective on hydrogen diffusion and hydrogen embrittlement in low-alloy high strength steel, Corrosion Science. 174 (2020) 108800. https://doi.org/10.1016/j.corsci.2020.108800. [13] S. Komazaki, K. Kobayashi, T. Misawa, T. Fukuzumi, Environmental embrittlement of automobile spring steels caused by wet – dry cyclic corrosion in sodium chloride solution, Corrosion Science. 47 (2005) 2450 – 2460. https://doi.org/10.1016/j.corsci.2004.10.008. [14] K. Takai, R. Watanuki, Hydrogen in Trapping States Innocuous to Environmental Degradation of High-strength Steels, ISIJ International. 43 (2003) 520 – 526. https://doi.org/10.2355/isijinternational.43.520. [15] M. Moshtaghi, M. Safyari, Temperature mitigates the hydrogen embrittlement sensitivity of martensitic steels in slow strain rates, Vacuum. 202 (2022) 111187. https://doi.org/10.1016/j.vacuum.2022.111187. [16] S. Pichler, A. Bendo, G. Mori, M. Safyari, M. Moshtaghi, Inhibition of grain growth by pearlite improves hydrogen embrittlement susceptibility of the ultra-low carbon ferritic steel: the influence of H-assisted crack initiation and propagation mechanisms, J Mater Sci. 58 (2023) 13460 – 13475. https://doi.org/10.1007/s10853-023-08856-y. References