Electron beam welding is a fusion welding process that uses a beam of high-velocity electrons to join materials. The process works by accelerating electrons in an electron gun and focusing them via magnetic lenses to produce heat from kinetic energy. This heat is used to fuse materials in a vacuum chamber. Key advantages are the ability to weld dissimilar metals without filler and produce high quality, low defect welds. However, the process requires expensive equipment and high skill levels.