Book excerpt: Reported progress on the electron-beam welding of commercially pure W indicates that sound crack-free welds can be made if the weld is not restrained during welding. Although the data are not all consistent, welds which are smooth and have minimum fusion and heat-affected zone width should be the strongest and most ductile. Tensile strengths are equivalent to the base metal near the recrystallization temperature but are appreciably lower at room temperature. The ductile-to-brittle transition temperatures for electron-beam-welded tungsten are above that of the base metal. The impact resistance of electron-beam-welded tungsten is very low. Electron-beam welding of tungsten parts should be thoroughly evaluated on production prototypes before specifying its use. (Author).