Welding of die-casted magnesium alloys on production machines

摘要

The importance of light weight magnesium alloys especially for the automotive industry is growing significantly, due to rising environmental requirements. Especially going along with ever more demanding safety standards which require the installation of heavy safety appliances, the use of light weight materials becomes more and more important. Magnesium is an extremely suitable material for die-casting. One goal of die-casting to reduce production costs is to avoid following process steps. Nevertheless joining processes have to be developed to fully benefit from the whole designing potential of this material. Laser beam welding turns out to be very suitable to join magnesium parts. Results welding the magnesium alloys AZ91HP and AM50HP with a 3 kW Nd:YAG-laser and a 6 kW CO2-laser with an industrial robot and a gantry robot system are shown from a production point of view. Especially the determination of the process window by analyzing the influence of laser type, power, welding velocity and shielding gas as well as the influence of the base material leads to conclusions about process stability and production tolerances. Further investigations concerning fixturing techniques as well as seam preparation and joint geometry show effects on the process flexibility and the effort to realize high quality seams under production conditions. The investigated process parameters are evaluated mainly in respect to their influence on the static strength of the welding seam.