A 3-25 mm metal plate 22, 27, usually ferrous, is welded by a heavy-duty laser (5-25 kw) which melts through the plate and into a support member 24, 31 below to give a unitary weld. A gas supply to the laser beam focus is provided such that on the one hand the plasma is retained at least partially near...http://www.google.es/patents/US4866242?utm_source=gb-gplus-sharePatente US4866242 - Laser beam welding
