METHOD AND INSTALLATION FOR LASER WELDING WITH A N2/HE GAS MIXTURE, THE N2/HE CONTENT BEING CONTROLLED ACCORDING TO THE LASER POWER

摘要

The invention relates to a laser welding method and installation that make use of a protective gas mixture containing nitrogen and helium. According to the invention, the proportion of nitrogen and/or helium in said gas mixture is chosen or adjusted according to the power or the power density of the laser beam. The laser power is included between 0.5 kW and 30 kW and, preferably, between 5kW and 20 kW. The protective gas mixture comprises nitrogen and/or helium and, preferably, the gas mixture contains a volume proportion of helium of between 30 % and 80 %, the remainder being nitrogen and, possibly, inevitable impurities.