Effects of electron beam oscillation techniques on solidification behaviour and stress rupture properties of Inconel 718 welds

Effects of electron beam oscillation techniques (sinusoidal, square, triangular, ramp, circle and elliptical) in controlling Nb segregation, Laves formation and stress rupture behaviour of Inconel 718 electron beam welds are studied. Effects of various post-weld heat treatments on stress rupture behaviour are compared. Elliptical beam oscillation technique resulted in less Nb segregation and discontinuous and fine Laves in the interdendritic regions compared with other welds and unoscillated beam weld. Response to aging was better for welds made with elliptical oscillated beam compared with welds made with unoscillated beam. Oscillated beam welds exhibited longer rupture life than unoscillated beam welds in both solution treated and aged and directly aged conditions.