Study of assist gas flow behavior during laser welding Available to Purchase

Gas shielding is very crucial for high power laser welding. The oxygen content of the flow emitted by various gas nozzles (inclined, coaxial or annular nozzle) has been initially analyzed using a mass spectrometer, for bead on plate or groove configuration. Then, during CO2 laser welding experiments, the effect of several operating parameters (geometrical parameters and gas flow conditions) has then been observed on the resulting weld seam characteristics (surface roughness and oxidation, penetration depth, plasma size and fluctuation, weld pool geometry, …). Important differences have been observed between "Back Protection" (when the nozzle flow is directed towards the welding direction) and "Front Protection" (opposite direction of flow). Also, the laser interaction using groove geometry shows a very great interest. All these experiments have also been simulated using the 3D hydrodynamic software Fluent. It has been seen that thermo-convective effects from the heated surface or dragged flow induced by the emitted plasma, strongly perturb the shielding flow. This study finally allows us to define optimized shielding conditions ensuring the best possible protection against atmosphere contamination and reproducible conditions for better high power laser - material interaction.