PSI - Issue 83

Goran Vukelić et al. / Procedia Structural Integrity 83 (2026) 57– 62

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equipment (Bogdanovic and Ivosevic, 2025; Ermakova et al., 2019; Lampreia et al., 2026; Polemis and Boviatsis, 2023). Although AM offers significant advantages in design flexibility and manufacturing efficiency, its practical use often requires welding operations. Welding may be necessary either to assemble multiple AM components or to connect AM parts with conventionally manufactured (CM) materials (Guzman et al., 2025). However, welding AM metals introduces specific challenges, particularly in hybrid joints between AM and CM materials. Differences in thermal behavior, microstructure, and mechanical properties between these materials can promote the formation of stress concentrations, cracking, and other welding-related imperfections (Braun et al., 2023). The harsh conditions of the marine environment further complicate the application of such materials because seawater is highly corrosive (Dantas et al., 2024). While stainless steels are generally well known for their resistance to uniform corrosion, long-term exposure to seawater can still trigger localized corrosion mechanisms, including pitting corrosion, crevice corrosion, and stress corrosion cracking (Ettefagh et al., 2021). These degradation processes may compromise the reliability and service life of critical structures such as offshore platforms, marine propulsion systems, and related installations (Kopic and Mihaljec, 2025). In the case of AM stainless steels, corrosion behavior may differ from that of conventionally produced materials due to process-related features such as distinct surface characteristics, heterogeneous residual stress fields, and unique microstructural morphologies (Monkova et al., 2024). In addition, welded regions often represent areas of increased susceptibility where corrosion and mechanical deterioration can initiate and progress more rapidly (Senior et al., 2021). Therefore, evaluating the combined influence of welding and seawater exposure on the performance of AM stainless steels is crucial for assessing their suitability for marine and offshore applications (Malíková et al., 2024). In this work, an experimental study was conducted to assess the impact of natural marine exposure on welded additively manufactured AISI 316L stainless steel. Three different joint configurations were prepared: AM–AM welds, hybrid AM–CM welds, and CM–CM welds used as reference specimens, as the mechanical behavior of CM and AM steel can differ (Santonocito et al., 2023). The samples were submerged below the sea surface in the Adriatic Sea for exposure periods of one, three, and six months. After the exposure period, the specimens were examined to determine variations in mass and tensile strength. 2. Materials and methods Butt-welded specimens made of AISI 316L stainless steel were submerged below the sea surface for periods of one, three, and six months in order to investigate the effects of natural marine exposure on their corrosion performance. Exposure in a real marine environment enables a more representative evaluation of corrosion processes compared with controlled laboratory conditions (Hoque and Presuel-Moreno, 2025). After recovery, the specimens were analyzed to determine relative mass variations associated with corrosion-related material loss, and the obtained values were compared with the corresponding immersion durations. Mechanical performance was evaluated through uniaxial tensile testing carried out in accordance with standardized procedures, from which engineering stress–strain curves were obtained. These results were used to identify potential changes in tensile strength resulting from prolonged exposure to seawater. The outcomes of the mechanical tests are discussed with respect to the different exposure periods. The experimental investigation focused on AISI 316L stainless steel, commonly classified as marine-grade stainless steel (Hamada et al., 2025; Zanichelli et al., 2024). For specimen preparation, plates of both conventionally manufactured (CM) and additively manufactured (AM) AISI 316L stainless steel were produced with dimensions of 210 × 90 × 2 mm. The AM plates were fabricated using Laser Powder Bed Fusion (PBF) on an EOS M280 system. The metal powder employed in the process had particle sizes ranging from 10 to 40 μ m. During the additive manufacturing process, the plates were printed in a horizontal (flat) orientation. After fabrication, the surfaces were treated by shot peening to obtain the required surface condition. The prepared rectangular plates were then joined by tungsten inert gas (TIG) welding, with welding parameters selected to achieve full penetration of the butt joints (Cortis et al., 2024; Khedr et al., 2025). Three different welded configurations were produced: (i) joints between two CM plates, (ii) joints between two AM plates, and (iii) hybrid joints combining CM and AM plates. From these welded plates, butt-welded tensile specimens were extracted using laser cutting technology, as illustrated in Figure 1a. A total of twenty specimens were prepared for each configuration and further divided into groups of five. Three groups were exposed to seawater for