PSI - Issue 77

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Procedia Structural Integrity 77 (2026) 264–271

International Conference on Structural Integrity Fatigue crack growth rate and fracture toughness of

© 2026 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 ICSI organizers Keywords: Fatigue crack growth rate; fracture toughness; hydrogen embrittlement; electrochemical charging; HFW welds; X52 steel Abstract The paper deals with the testing of fatigue crack growth rate (FCGR) and fracture toughness (FT) of electrochemically hydrogen-charged HFW welds of X52 steel. The FCGR tests revealed a significantly accelerated crack growth rate in the presence of hydrogen, particularly at low ΔK values. This effect gradually decreased at higher ΔK levels, likely due to electrolyte de pletion. The fracture surfaces of samples at ΔK = 20 MPa.m 0.5 show ductile striation patterns in samples tested in air; on the other hand, samples tested in hydrogen show mixed fractures with quasi-cleavage facets and indistinct striation patterns. In FT testing, hydrogen caused a notable reduction in the J 0.2 parameter (43 %). The samples tested in air consistently exceeded 200 kJ/m²; hydrogen charged samples mostly fell below this threshold, with one case even dropping under 100 kJ/m². Fractography analysis confirmed a micro-void coalescence mechanism in air and quasi-cleavage facets with localized dimple areas under hydrogen charging. electrochemically hydrogen-charged HFW welds of X52 steel Jan Kec a, * , Lukáš Jeníček a , Jakub Jindra a , Martin Šperl b , Lubomír Gajdoš b , Jan Bejdl b , Klára Kuchťáková c , Tomáš Prošek c a SVÚM a.s., Strength Department, Tovární 2053, 250 88 Čelákovice, Czech Republic b Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, v. v. i. Prosecká 809/76, 190 00 Prague, Czech Republic c University of Chemistry and Technology Prague, Technopark Kralupy, Department of Metallic Materials, Nám. G. Karse 7, 278 01 Kralupy nad Vltavou, Czech Republic

* Corresponding author. Tel.: +420 326 509 044. E- mail address: kec@svum.cz

2452-3216 © 2026 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 ICSI organizers 10.1016/j.prostr.2026.01.035