PSI - Issue 83

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

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periods of one, three, and six months, respectively, while the remaining group served as a reference and was kept under laboratory atmospheric conditions. The exposure tests were conducted in natural seawater at a depth of approximately 10 m in the northern Adriatic Sea near Rijeka, Croatia. After the designated exposure period, the specimens were retrieved from the sea (Figure 1b). Any corrosion deposits were gently removed using a soft brush under running water. The samples were then rinsed with distilled water and allowed to dry at room temperature. The cleaning procedure was consistent with protocols reported in earlier studies. Mass measurements were performed before and after exposure using an Ohaus 3000 digital balance in order to quantify material loss caused by corrosion. Mechanical characterization was conducted through uniaxial tensile testing using a Hegewald & Peschke Inspekt Table universal testing machine with a 20 kN load capacity. The tensile specimens were prepared according to the applicable testing standard (Vukelic et al., 2025). All tests were carried out under standardized conditions to obtain engineering stress–strain curves, which were subsequently used to evaluate the mechanical properties of the material.

(a)

(b)

Fig. 1. (a) Three types of specimens tested; (c) Specimens after 6 months of exposure.

3. Results Using the recorded measurements taken before and after seawater exposure, the average percentage of mass loss was determined for each group of specimens. These values were then related to the respective immersion periods, as illustrated in Figure 2. To further interpret the results, trend curves were fitted to the experimental data in order to visualize the dependence of average mass loss on exposure time. The coefficient of determination ( R ²) is provided to evaluate the goodness of fit of the applied approximation (Vukelic et al., 2022).

Fig. 2. The average percentage of mass loss (ML) for CM-CM, AM-AM, and CM-AM welded AISI 316L steel exposed to the natural marine environment. Specimens kept in room atmosphere (RA) are shown for reference.