CA single track simulation of laser conduction welding with stainless steel 316L (1.4404)

The study presents a coupled cellular automata (CA) approach for a single track microstructure simulation used for laser conduction welding. A high-power CO2 laser beam (1000W) traverses the substrate, with the beam shaped by conventional optics, which produces a Gaussian profile. The process relies on a shallow melt phase to maintain a conduction limited weld. Laser conduction welding does not require a filler material. The stainless steel material 1.4404 was used as substrate material with an initial grain size of 10µm and 20µm. The melt pool geometry, temperature history, cooling rates and diffusivities define the grain morphology. Temperature-dependent diffusivity coefficients and atomic spacing parameters are suggested. The simulation outputs of the grain morphology are qualitatively and quantitatively compared to experimental results. Initial results have shown that due to the individual melt pool conditions complex microstructures are developed. These fine, complicated microstructures cannot be satisfactorily resolved and quantified using standard optical microscopy. Electron backscatter diffraction (EBSD) has to be used for validation.ISSN:2212-827