Tensile testing of S690QL1 HSS welded joint heterogeneous zones using small scale specimens and indentation methods

Abstract The welded joints are structures with significant heterogeneity, indicated by their fundamental segmentation into base metal (BM), heat affected zone (HAZ), and weld metal (WM). The heat affected zone, having width in millimeter scale for fusion welding processes, is further segmented into several characteristic regions, having differences in grain structure and size. The microstructural heterogeneity results in significant differences in mechanical properties of individual welded joint zones. Mechanical testing of such small material volumes is inconvenient, or even impossible, using the standard size specimens proposed in testing standards. Requirement to precisely position the specimens, even ones with subsize dimensions, and investigate mechanical properties of specific narrow HAZ regions presents certain challenge. This work investigates the X welded joint of S690QL1 grade high strength steel (HSS), welded with slightly overmatching filler metal. The material tensile properties are tested, using small scale specimens and indentation methods. Small scale specimens are ASTM E8 round tensile subsize and flat sheet mini tensile specimens (MTS). The indentation methods include hardness testing and profilometry-based indentation plastometry (PIP) method, to gain additional insights into material stress–strain behavior. Finally, paper evaluates the testing methods, comparatively processes the collected experimental data, and provides guidelines for heterogeneous structures testing.