Abstract: The characteristics of a weld made by electron beam welding are improved by introducing into the region of the pieces to be welded, which is subjected to remelting during welding, a material which is obtained by applying an arc welding process, or a process for remelting under slag, to a mild or slightly alloyed steel. The introduction of the material into the region of the weld increases the production of acicular ferrite which increases the tensile strength of the weld. The material may be introduced by providing a deposit of it over part or the whole of the surface of one or both of the pieces to be welded, by introducing a mass of it between the surfaces to be welded or as a filler wire.

Abstract: In a process for electron beam welding, the electron beam welding gun is controlled to maintain the power absorbed by the pieces being welded substantially constant. In a preferred embodiment the intensity of the electron beam transmitted by the pieces being welded, which corresponds to the power absorbed, is measured, compared with a preset intensity and the difference used to control the focussing current supplied to the gun to maintain the intensity of the transmitted beam constant.