Laser welding consists in fusion of the interface of the joined elements by means of heat resulting from application of a concentrated coherent light beam with very high power density, ca. 102-1011 W/mm2. Welding can be carried out using the welding bath, traditional arc welding or full penetration weld method, in a single- or multi-layer run, with or without filler material, i.e. the keyhole method.
Very high power densities of the laser beam ensure that the welding line energies are at the level of minimum energies required to melt the joint, and the heat effect zone as well as the melt zone are very narrow. At the same time, deformation of joints is so low that the welding can produce the finished product, with no additional machining required.