PSI - Issue 83

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

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(a) (b) Figure 6: True stress-true strain curves determined with the Kamaya model (a) and the Lopez and Fatemi method (b).

Table 2. Comparison of yield and ultimate strengths obtained from tensile tests of non welded specimen. Tensile test Predictive model Percentage difference σ y [MPa] σ UTS [MPa] σ y,ave [MPa] σ UTS, ave [MPa] Δσ y [%] Δσ UTS [%] 548 763 567 809 3.3 5.7

When the hardness-based local estimation is compared with the tensile-test results of the welded specimen, the agreement is satisfactory for the yield strength, with a difference of 2.3%, but becomes much poorer for the ultimate tensile strength, for which the discrepancy reaches 35.4%, as reported in Table 3. The model is based on local hardness-derived quantities and therefore describes the behaviour of an isolated material region, whereas the tensile test performed on the welded specimen reflects the global response of a heterogeneous system.

Table 3. Comparison of yield and ultimate strengths obtained from tensile tests of welded specimen. Tensile test Predictive model Percentage difference σ y [MPa] σ UTS [MPa] σ y,ave [MPa] σ UTS, ave [MPa] Δσ y [%] Δσ UTS [%] 377 382 386 592 2.3 35.4

The mechanical-property values reported in Table 2 and Table 3 are further condensed in the following figure into a bar chart representation. The figure highlights the relationship between experimentally measured tensile properties and hardness-based predictions in AM AISI 316L specimens in non-welded and welded configurations.

Figure 7: Comparison between experimentally measured tensile properties and hardness-based predictions for DMLS-manufactured AISI 316L: yield strength and ultimate tensile strength in the non-welded and welded configurations.