GB1356483A - Welding using a beam of energy - Google Patents

Abstract

1356483 Welding by fusion D SCIAKY 6 Jan 1972 [29 March 1971] 653/72 Heading B3R In butt or lap seam welding by a beam of energy, e.g. an electron beam, to permit high speed seam welding without producing an upper side bead build-up and a lower side groove due to chilling and solidification, the beam is oscillated backwards and forwards along the beam/workpiece path at an amplitude equal to the cross-sectional area of the beam, and the energy density delivered to the workpiece during each oscillation is varied to simulate a beam which, in cross-section adjacent the workpiece, varies in energy density. In examples given, the energy density variation may simulate a beam having high and low energy density regions respectively at its leading and trailing edges, or a high energy density region between relatively low energy density regions at its leading and trailing edges. The energy density variation may be effected by variation of one or more of beam current (as by acting on the potential of a control electrode of a triode gun), beam accelerating voltage, and beam deflection speed (to vary instantaneous speed of beam). Preferably, the average velocity of each oscillation is made at least 10 times beam/workpiece velocity. As described, the gun is fixed and the workpiece is movable on a carriage.