PSI - Issue 68

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 68 (2025) 1017–1023

European Conference on Fracture 2024 Gas Tungsten Arc Welding of Low Carbon Steel with Ni-Cr and Medium Mn Stainless Steels Mahmoud Khedr a, b,** , Ibrahim R. Awad c , Tamer. S. Mahmoud b , and Atef Hamada a a Kerttu Saalasti Institute, Future Manufacturing Technologies (FMT), University of Oulu, Nivala FI-85500, Finland b Mechanical Engineering Department, Faculty of Engineering at Shoubra, Benha University, Cairo 11629, Egypt c Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75205, USA Abstract This research conducted a comparative analysis of dissimilar butt joints of low carbon steel (LCS) with low-Ni medium-Mn austenitic stainless steel (MMn-SS), and LCS with Ni-Cr austenitic stainless steel (NiCr-SS), utilizing gas tungsten arc welding. The welding process employed ER309MoL filler metal. The microstructural analysis, tensile strength, and hardness properties were conducted using optical microscopy, uniaxial tensile tests, and Vickers hardness testing, respectively. Findings revealed the formation of a duplex microstructure consisting of an austenite matrix and a minor δ-ferrite fraction < 9.5 %, in the fusion zone (FZ) processed at heat inputs of 0.697 kJ/mm for LCS/MMn-SS and 0.741 kJ/mm for LCS/NiCr-SS joints. The FZ of the welded specimens, LCS/MMn-SS and LCS/NiCr-SS exhibited hardness values (166.8 HV and 155.5 HV, respectively) lower than the corresponding stainless-steel sides yet higher than the LCS side. The tensile properties of the joints closely approximate those of the LCS base metal, with deformation and fracture primarily localized at the LCS side. Furthermore, the welded joints exhibited characteristic dimple features indicative of ductile fracture behavior, as revealed by scanning electron microscopy (SEM). © 2025 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 ECF24 organizers a b c © 2025 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 ECF24 organizers

Keywords: Gas tungsten arc welding; Low carbon steel; Stainless steel; Dissimilar welded joints.

* Corresponding author. Tel.: +358-417913505. E-mail address: Mahmoud.khedr@oulu.fi.

2452-3216 © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.164