ELECTRON BEAM WELDING OF AUTOGENOUS BUTT-JOINTS FOR AA5083-O ALUMINUM–MAGNESIUM ALLOY SHEET

Electron beam welding (EBW) is increasingly being used in welding of structural metals. The thermal cycles associated with EBW are generally much faster than those involved in conventional arc welding processes, leading to a rather small fusion zone. Complete information on the tensile properties is essential for understanding the joint performance in service. Therefore, experimental investigation was performed on the mechanical properties of EBW welded AA5083-O sheets, using flat tensile specimens. An autogenous single electron beam pass was used to weld butt joints and butt joints with integral backup. The specimens were examined by visual testing, metallography light microscopy, microindentation hardness measurements and a tensile test. The results of the welded tensile specimens were compared to base metal (BM) specimens machined from the as received materials. The yield stress of the welded samples is higher and the elongation is lower than the BM. An insignificant narrow heat affected zone (HAZ) was observed. The dendritic microstructure of the fusion zone (FZ) was relatively homogenous and the BM microstructure showed preferred orientation. Slightly higher microhardness values were observed in the welding zone (FZ and HAZ) than in the BM.