PSI - Issue 83

Niccolò Vilotta et al. / Procedia Structural Integrity 83 (2026) 246–255

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3.1. Global analysis The global mechanical response was first analysed on the non-welded specimens, since these data were also used as calibration reference for the local constitutive reconstruction. Figure 3(a) shows a representative tensile test on a non welded specimen, whereas Figure 3(b) reports the corresponding true stress-strain curves after application of the toe compensation method. The corrected base-material response was then used to derive the calibration quantities required by the Lopez and Fatemi and Kamaya approaches.

(a) (b) Figure 3: Tensile strength test on an AM AISI 316L non welded specimen (a); true stress-strain curves obtained by applying the toe-compensation method (b). The global behaviour of the welded AM AISI 316L specimens is reported in Figure 4 in terms of average true stress strain response. In comparison with the non-welded condition, the welded configuration exhibits a reduction in mechanical performance, consistently with the presence of heterogeneities and defects introduced by the joint [9–12]. From a macroscopic point of view, the welded specimen does not behave as a homogeneous material; hence, its tensile response reflects the combined mechanical contribution of the BM, HAZ, and WM [9–11].

Figure 4: Tensile strength test - AM AISI 316L welded specimens.

3.2. Micro-hardness measurements and local mechanical properties correlation The local analysis is based on correlating the hardness mapping across the welded section with local mechanical properties. Figure 5(a) shows the hardness distribution, while Figure 5 (b) displays the corresponding regions, namely BM, HAZ and WM on the test specimen. The results highlight a progressive decrease in hardness from the base material to the weld metal, with the heat-affected zone assuming intermediate values [10,11,17].