Experimental and Numerical Analysis of Gas Dynamics in the Keyhole During Laser Metal Welding

AbstractThe keyhole is the crucial factor for an appropriate weld seam in laser metal welding. The stability of the keyhole is governed by multiple hydrodynamic effects such as melt flow, evaporation on the keyhole front, gas dynamics inside the evolving vapor plume and the resulting pressures from all these phenomena. Due to their elusive nature the measurement of pressures inside the keyhole is still an unresolved task. Here we show a quantification of the density of the metal vapor and the pressure inside the keyhole through measuring the keyhole opening geometry, the evaporation rate and the flow velocity inside the vapor plume. Furthermore, a comparison to a simulation model is shown. Our results are in accordance with theoretical approaches. In the future this results can support an increase of process understanding which eventually leads to a better control of the process in industry