Electron-beam Welding (EBW)

Electron beam welding (EBW) is a welding process which produces coalescence of metals with the heat obtained from a concentrated beam composed primarily of high-velocity electrons impinging upon the surfaces to be joined. The workpieces melt as the kinetic energy of the electrons is transformed into heat upon impact, and the filler metal, if used, also melts to form part of the weld. Pressure is not applied, and a shielding gas is not used, though the welding is often done in conditions of a vacuum to prevent dispersion of the electron beam.

As the electrons strike the workpiece, their energy is converted into heat, instantly vaporizing the metal under temperatures near 25,000 °C. The heat penetrates deeply, making it possible to weld much thicker workpieces than is possible with most other welding processes. However, because the electron beam is tightly focused, the total heat input is actually much lower than that of any arc welding process. As a result, the effect of welding on the surrounding material is minimal, and the heat-affected zone is small. Distortion is slight, and the workpiece cools rapidly, and while normally an advantage, this can lead to cracking in high-carbon steel. Almost all metals can be welded by the process, but the most commonly welded are stainless steels, superalloys, and reactive and refractory metals. The process is also widely used to perform welds of a variety of dissimilar metals combinations. The process was developed in France and released on November 23, 1957 in Paris by J. A. Stohr.