Energy beam welding method

摘要

Disclosed is a method for producing an elongated weld seam in a workpiece by the use of a beam of charged particles, in particular an electron beam. According to the disclosed method, a beam of charged particles is directed to impinge on a workpiece and has a selected beam current, a selected accelerating voltage and is focused by a focusing field of a selected field strength. In order to produce a weld seam there is provided a relative motion between the charged particle beam and the workpiece, to move the point of impingement along the workpiece. The relative motion has a predetermined selected instantaneous velocity. The depth of penetration of the charged particle beam into the workpiece is varied by changing a parameter selected from the group consisting of the beam current and the velocity of relative motion. According to the improvement of the invention, simultaneous with the changing of the depth of penetration, there is provided an active control to change at least one parameter selected from a second group consisting of the strength of the focusing field, the amplitude of periodic beam deflection in a direction parallel or transverse to the path of the relative motion and the frequency of periodic beam deflection in a direction parallel or transverse to the relative motion.