ELECTRON BEAM WELDING METHOD

PURPOSE:To execute the adequate beam current control meeting a plate thickness so that good welding can be executed by providing an ultrasonic thickness gage in front of the progressing direction of an electron gun for irradiating objects to be welded with an electron beam and automatically controlling a beam current by the measured thickness signal thereof. CONSTITUTION:The ultrasonic thickness gage sensor 6 measures the thickness t1 of the objects 1 to be welded in the position in front (l) of the electron gun 3 in the progressing direction of welding. The measured signal from the ultrasonic thickness gage sensor 6 enters a thickness gage controller 7. This thickness gage controller 7 sends the signal controlling the beam current so as to attain the optimum welding conditions meeting the thickness t1 at the point of the time when the welding point comes to the measurement point on progression of the welding to an electron beam welding machine 5. The beam current of the electron beam 4 at the welding point accordingly attains the optimum conditions meeting the plate thickness.