Experimental and numerical modelling of AISI 316L butt-welded joints under tensile stress using local material properties

The mechanical characterization of welded joints is a critical step in assessing the structural reliability of stainless-steel components employed in marine, offshore, and industrial environments. Welding processes introduce significant local variations in microstructure and hardness, leading to heterogeneous mechanical properties that strongly influence fatigue life and structural performance. This study presents an integrated experimental–numerical methodology for the evaluation of local mechanical properties in AISI 316L butt-welded joints through minimally destructive hardness measurements. The approach combines two established hardness–property correlations to derive full true stress–strain curves for each region of the weld. These were subsequently implemented in a finite element model to reproduce the local and global deformation behavior during quasi-static tensile loading. Calibration was achieved using tensile tests on non-welded specimens, and a preliminary validation was conducted through Digital Image Correlation (DIC) strain measurements of both welded and base material specimens. Unlike most existing studies that focus on structural steels, this work investigates AISI 316L welds, austenitic stainless steel widely used in high-integrity applications, through a combined microhardness–FEM–DIC framework. The proposed methodology suggests the possibility to develop robust framework for correlating indentation hardness with mechanical response, offering a rapid, reliable, and potentially non-destructive route for assessing welded structures.