Electron beam welding
Electron beam welding (EBW) is a welding process where the energy to melt the material is applied by an electron beam. To avoid dispersion of the electron beam, the workpiece is typically placed in a vacuum chamber, although electron beam welding under atmospheric pressure is also possible.
EBW can produce deep narrow welds in thick material with minimal heat-input and narrow heat affected zones. Welds can be made in steel up to 8 inches thick, aluminum up to 6 inches thick and copper up to 4 inches thick.
Electron beam welding is an established branch of electron beam technology.
References
American Welding Society, Welding Handbook, Volume 2 (8th ed.)