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Modellierung diffusiver und konvektiver Wärme- und Stofftransportprozesse bei der Laser-Schmelzbearbeitung - Kohlenstoffdiffusion beim Laser-Umschmelzen von Gußeisen

 
: Lepski, D.; Luft, A.; Reitzenstein, W.

Geiger, M.; Hollmann, F. ; Deutsche Forschungsgemeinschaft -DFG-, Bonn:
Strahl-Stoff-Wechselwirkung bei der Laserstrahlbearbeitung. Ergebnisse des Schwerpunktprogramms der Deutschen Forschungsgemeinschaft 1991 bis 1992
Bamberg: Meisenbach, 1993
ISBN: 3-87525-059-1
S.135-140 : Abb.,Lit.
Strahl-Stoff-Wechselwirkung bei der Laserstrahlbearbeitung <1993, Erlangen>
Deutsch
Konferenzbeitrag
Fraunhofer IWS ()
Aufschmelzen; cast iron; dendritical; dendritisch; diffusion; diffusion controlled; diffusionsgesteuert; Erstarrung; Graphitauflösung; graphite dissolution; Gußeisen; heat transport; laser remelting; Laser-Umschmelzen; matter transport; melt bath convection; melting; planar; Schmelzbadkonvektion; solidification; Stofftransport; Wärmetransport

Abstract
In the laser melt bath heat and matter are transported by diffusion and convection as well. Hence, particle dissolution and solute distribution proceed very quickly. As a consequence, in cast iron remelting a carbon rich melt contacts a solid phase with a rather low carbon concentration. Carbon diffusion from the liquid into the solid phase decreases the melting temperature and thus supports the melting process. Therefore, the final melt zone geometry depends not only on the temperature field but also on the amount of carbon diffusion and on the laser interaction time. Mathematical modelling leads to a rather complex problem with one or two moving phase boundaries. These considerations are supported by the observed structure in the boundary layer of the melt zone. Therefore, the calculation of the melt zone geometry in the remelting of cast iron requires the calculation of the laser induced temperature field, taking into account the Marangoni convection, as well as modelling of the dif fusion controlled melting process.

: http://publica.fraunhofer.de/dokumente/PX-24595.html