Electron beam welding is used for joining metallic materials. The very thin weld with its narrow heat affected zones minimises the energy transferred to the work piece and its distortion. Parts and subcomponents that require a high level of mechanical pre-processing can be joined using this method without being damaged due to the low angular distortion and the minimal cross-sectional shrinkage. Added to this is the fact that of all fusion welding methods, EB welding produces the lowest energy per section and attests to the best electrical efficiency.
EB welding is used in a wide range of applications from welding films to large work pieces over 200 mm thickness. Even such deep welding seams are done in a single process without additional filler material. Here the electron beam injects the heat across the whole depth of the weld (deep weld effect). The proportion of energy absorbed during EB welding is in the region of 90 to 95 % and the energy of the electrons impinging to the work piece is converted directly into heat by the interaction with the metal atoms. Thus the welding speed is not limited by the heat conductivity of the materials.
Electromagnetic lenses enable the electron beam to be deflected and focused inertialessly. So it is possible to weld materials that are usually less suited to the process by inertialess oscillating of the electron beam. The variable welding distance allows work pieces of various shapes to be welded.
An extremely fast beam deflection makes other applications possible, which could only be done with difficulty, if at all, using another welding method. It would therefore be possible in a single process to use the electron beam to look for the weld joint ahead, to weld the work piece using the correction values, and to finish by cosmetically treating of the weld. It is also possible to weld a suitable work piece „quasi-simultaneously" at several places. In this case the beam is diverted by the deflection system from one welding position to the next in fractions of a second. The welding will be continued before the vapour capillary collapses at this position. It is also possible to preheat the work piece at the same time as welding it.
EB welding in a vacuum offers a host of advantages, as the high power density of the electron beam enables narrower welds than average, very small heat affected zones without tarnishing effect, good welding depths and high welding speeds. The exact reproducibility of the welds guarantees users consistent quality.
Reactive materials such as titanium are usually welded with (expensive) shielding gas. With electron beam welding, excellent metallurgical results are achieved without harmful emissions in the vacuum of the chamber, which is at a pressure of 5 x 10-4 mbar.
If the design of mechanical components is adapted to the possibilities of the EB process, this method opens up tremendous advantages for fabrication in many sectors of modern industry.
