Elimination of hot cracking in the electron beam welding of AA2024-T351 by controlling the welding speed and heat input

Hot cracking sensitivity of AA2024-T351 in the electron beam welding (EBW) was evaluated and the effects of welding speeds and heat input on the hot cracking were investigated. In this research, welding speed was set to 15-40 mm/s and microstructure of the welded zone was studied thoroughly by scanning electron microscopy (SEM). Appearance and geometry of weldments were also observed by stereo microscope. Microstructural observations showed that the hot crack length decreased with the increasing welding speed and decreasing the heat input and, as a result, in welding speed of 30 mm/s and heat input of 150 J/mm the crack-free weldment was achieved. The relationship between the welding speed and microstructure of the welded zone was also discussed. It could be concluded that decreasing the heat input alleviated thermal stresses and strains improved the grain structure, hence prevented nucleation and growth of hot cracks in the weld metal.