Product Code: ICA10_505

Influence on the Efficiency of the Heat Conduction Mode Laser Beam Welding Process Regarding Different Laser Spot Geometries
Authors:
Rüediger Daub, Technische Universität Műnchen. Institute for Machine Tools and Industrial Management; Garching Germany
Robert Wiedenmann, Technische Universität Műnchen. Institute for Machine Tools and Industrial Management; Garching Germany
Achim Mahrle, University of Technology Dresden, Institute for Surface and Production Technology; Dresden Germany
Jeudi Duong, Lappeenranta University of Technology; LUT Metals Finland
Michael F. Zaeh, Technische Universität Műnchen. Institute for Machine Tools and Industrial Management; Garching Germany
Presented at ICALEO 2010

In heat conduction mode processes with a Nd:YAG-laser of steel materials, like welding, brazing, cladding or alloying, about 35% of the beam energy induces heat in the irradiated material. The percentage of the beam energy, which is used for the melting process, is even smaller. A significant amount of this energy is lost by heat-conduction and convection. Applying non-conventional spot geometries, improved process results can be achieved. In this paper it will be shown, that laser spot geometries have an impact on the energy transport mechanisms. Hereby, they can enhance the overall process efficiency and change the temperature field in the material. Gaussian-, rectangular-, and twin-spot geometries were used in experiments on a stainless steel. The results have been compared for their process efficiencies and seam geometries. FE-simulations with experimental conditions have been conducted to explain the influence of the spot geometry on the process efficiency. For energy transport mechanisms heat conduction, radiation, buoyancy- and Marangoni-convection has been taken into account. In addition, non-linear behaviour of the surface tension influencing the Marangoni-convection was respected in the FE-simulation. The melt-pool-geometry, -flow and the temperature distribution were calculated. Results of the FE-simulation have been compared with the experimental data.