PSI - Issue 68

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

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Procedia Structural Integrity 68 (2025) 1003–1009

European Conference on Fracture 2024 Indentation Behavior of Additively Manufactured 316L Stainless Steel Welded Joints via Gas Tungsten Arc Welding and Laser Welding Mohamed Elsayed a , Mahmoud Khedr a, b, 1* , Antti Järvenpää b , A. M. Gaafer a , Atef Hamada b a Mechanical Engineering Department, Faculty of Engineering at Shoubra, Benha University, Cairo 11629, Egypt. b Future Manufacturing Technologies (FMT), Kerttu Saalasti Institute, University of Oulu, Pajatie 5, Nivala, FI-85500, Finland. Abstract Additively manufactured 316L stainless steel specimens were welded by two different techniques: gas tungsten arc welding (GTAW) and laser welding (LW). The relationship between indentation hardness (H IT ) property and microstructure evolution of the different weldments were studied. Microstructural analysis of the weldments was conducted using laser confocal scanning microscope, while hardness measurements were obtained through micro-indentation Berkovich approach. The microstructure of FZ in GTAW joints displayed austenite matrix with ~2 wt.% delta ferrite, whereas its counterparts welded by LW displayed a fully austenitic structure. This is attributed to the various applied heat inputs, 360 and 50 J/mm for GTAW and LW, respectively. Despite, a filler metal of ER-316L was used in GTAW, LW was autogenous, i.e., without a filler metal. Consequently, the H IT of the FZ processed by GTAW was lower than that processed by LW, recording 1.98±0.18 GPa and 2.1±0.14 GPa, respectively. © 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: LPBF; GTAW; Laser welding; Microstructure; Hardness. a a, b, 1* b a , b a Mechanical Engineering Department, Faculty of Engineering at Shoubra, Benha University, Cairo 11629, Egypt. b Future Manufacturing Technologies (FMT), Kerttu Saalasti Institute, University of Oulu, Pajatie 5, Nivala, FI-85500, Finland. Abstract Additively manufactured 316L stainless steel specimens were welded by two different techniques: gas tungsten arc welding (GTAW) and laser welding (LW). The relationship between indentation hardness (H IT ) property and microstructure evolution of the different weldments were studied. Microstructural analysis of the weldments was conducted using laser confocal scanning microscope, while hardness measurements were obtained through micro-indentation Berkovich approach. The microstructure of FZ in GTAW joints displayed austenite matrix with ~2 wt.% delta ferrite, whereas its counterparts welded by LW displayed a fully austenitic structure. This is attributed to the various applied heat inputs, 360 and 50 J/mm for GTAW and LW, respectively. Despite, a filler metal of ER-316L was used in GTAW, LW was autogenous, i.e., without a filler metal. Consequently, the H IT of the FZ processed by GTAW was lower than that processed by LW, recording 1.98±0.18 GPa and 2.1±0.14 GPa, respectively. © 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: LPBF; GTAW; Laser welding; Microstructure; Hardness.

1. Introduction 316L austenitic stainless-steel (SS) is recognized by its low carbon content, which enhances its weldability. This alloy is ideal for advanced engineering applications where lightweight and high strength are required (Khedr et al., 2024). Additive manufacturing (AM) is a key process for printing 316L SS with superior mechanical properties (Liu 1. Introduction 316L austenitic stainless-steel (SS) is recognized by its low carbon content, which enhances its weldability. This alloy is ideal for advanced engineering applications where lightweight and high strength are required (Khedr et al., 2024). Additive manufacturing (AM) is a key process for printing 316L SS with superior mechanical properties (Liu

1 * Corresponding author. Tel.: +358417913505 E-mail address: mahmoud.khedr@feng.bu.edu.eg, mahmoud.khedr@oulu.fi 1 * Corresponding author. Tel.: +358417913505 E-mail address: mahmoud.khedr@feng.bu.edu.eg, 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

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.2025.06.162