An Approach to Assessing S960QL Steel Welded Joints Using EBW and GMAW

In recent years, ultra-high-strength structural (UHSS) steel in quenched and tempered (Q+T) conditions, for example, S960QL has been found wider application areas such as structures, cranes, trucks due to its extraordinary material properties acceptable weldability. The motivation of the study is investigate unique capabilities electron beam welding (EBW) compared conventional gas metal arc (GMAW) a deep, narrow weld with small heat-affected zone (HAZ) minimum thermal distortion welded joint without significantly affecting mechanical properties. this study, base (BM) specimens thickness 15 mm were butt-welded filler at speed 10 mm/s using high-vacuum (2 × 10?4 mbar) EBW process. Microstructural characteristics analyzed an optical microscope (OM), scanning (SEM), fractography, backscatter diffraction (EBSD) analysis. macro hardness, tensile strength, instrumented Charpy-V impact test performed evaluate Further, results these tests joints GMAW same grade thickness. Higher hardness observed fusion (FZ) HAZ BM but under limit qualifying value (450 HV10) Q+T steels according ISO 15614-11 specifications. strength EBW-welded (1044 MPa) reached level fractured BM. FZ microstructure consists fine dendritic martensite predominantly martensite. Instrumented testing was on ?40 °C, which showed brittle behavior both lower extent GMAW. measured average toughness 162 J are 45 ± 11 44 20 J, respectively.