Process analysis and optimization for fracture stress of electron beam welded ultra-thin FeCo-V foils

Generally, the quality of a weld joint is directly influenced by the welding parameter settings. In order to obtain a weld metal with desired weld bead quality and profile, it is necessary to adjust suitable process parameters in welding instrument. In this work, numerical and graphical optimization techniques of the electron beam welding of ultra-thin FeCo-V magnetic foils were carried out using response surface methodology (RSM) based on central composite design. The procedure was established to improve the weld strength and increase the productivity by considering the welding parameters range of beam current (0.7-1.7 mA), beam voltage (40-50 kV), welding speed (150-500 mm/min), and focused position (-20 to 0 mm). Tensile test and microhardness measurements were employed in order to study the mechanical behaviors of the welds. Moreover, microstructural observation and phase analysis were carried out in order to elucidate the change mechanism of mechanical properties in the welded area. It was found that RSM can be considered as a powerful tool in experimental welding optimization, even when the experimenter has not a model for the process. Strong, efficient, and acceptable weld joints could be achieved using the optimum welding conditions.