Product Code: ICA11_1606

Experimental Investigation of the Laser-Plume Interaction During High Power Fiber Laser Welding
Authors:
Pavel Shcheglov, Federal Institute for Materials Research and Testing Berlin; Berlin Germany
Andrey Gumenyuk, Federal Institute for Materials Research and Testing Berlin; Berlin Germany
Igor Gornushkin, Federal Institute for Materials Research and Testing Berlin; Berlin Germany
Michael Rethmeier, Federal Institute for Materials Research and Testing Berlin; Berlin Germany
Presented at ICALEO 2011

The effect of the well-known plasma absorption and refraction in CO2-laser metal welding plumes is in case of high power solid state laser welding negligibly small. By contrast, the diffraction effects of shorter wavelength laser radiation are considerable. According to the results of preliminary studies, the fine condensed metal particles in the welding plume can lead to essential worsening of the laser beam quality.
This work is devoted to the investigation of the laser-matter interaction during up to 20 kW ytterbium fiber laser welding of thick mild steel plates. The plume attenuation of a probe 1.3 µm wavelength diode laser beam as well as of continuous radiation in 250-600 nm wavelength range was measured during welding with and without Ar shielding gas supply. The measured results allow it to calculate average size and concentration of fine condensed metal particles in different plume areas using the multi-wavelength method and the Mie scattering theory. The plume temperature, which determines the condensation conditions, was measured by means of Fe I atom spectral line emission registration.
The obtained results can be also of interest for remote metal treatment with high-power fiber or disc lasers.