64355 2025 eng 1 17 article Springer Nature 1 -- -- -- High-strength low-alloyed (HSLA) steels with yield strength / proof stress ≥ 600 MPa are the basis of modern light-weight steel constructions. Indeed, the economic and ecological benefits strongly depend on their processability in terms of welding. In this context, the use of highly productive welding processes and suitable welding consumables is of vital interest and requires a fundamental understanding of the microstructural changes in the HSLA steel and especially the heat-affected zone (HAZ) of the welded joint. Microalloying elements, such as Ti or Nb, are essential to achieve the desired mechanical properties. To analyse the weldability, three-layer welds were performed using gas metal arc welding (GMAW) and critical microstructures, such as areas of the HAZ that exhibit significant softening or hardening, were identified. The effect of the softened HAZ region on failure was evaluated using cross-weld tensile specimens. Digital image correlation (DIC) was used for in-situ monitoring of the development and accumulation of the local strains in different HAZ regions during tensile testing. Using a specially designed mirror system, the local strains of the microstructure zones on the top and bottom of the weld were recorded simultaneously. In addition, the analysis of the local deformation helps to understand the effects of the softened HAZ on the global strain, the reduction in area, the fracture position, and the overall fracture behavior. Welding in the World 10.1007/s40194-025-02185-1 urn:nbn:de:kobv:b43-643558 publish 20.10.2025 Creative Commons - CC BY - Namensnennung 4.0 International Nina Schröder Michael Rhode Thomas Kannengießer Arne Kromm Daniel Kadoke Julius Kruse eng uncontrolled High-strength structural steel eng uncontrolled Microalloying influences eng uncontrolled HAZ-softening eng uncontrolled Digital Image Correlation eng uncontrolled Constraint effect eng uncontrolled Thermodynamic simulation Angewandte Physik 8 Zerstörungsfreie Prüfung 8.1 Sensorik, mess- und prüftechnische Verfahren 9 Komponentensicherheit 9.4 Integrität von Schweißverbindungen Energie Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM Windenergie Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/64355/s40194-025-02185-1.pdf