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Electrical potential difference during laser welding

Published online by Cambridge University Press:  25 July 2014

H. Zohm ,
G. Ambrosy  and
K. Lackner
H. Zohm*
Affiliation:
Max-Planck-Institut für Plasmaphysik, Boltzmannstr 2, D-85748 Garching, Germany
G. Ambrosy
Affiliation:
Institut für Strahlwerkzeuge, Universität Stuttgart, Pfaffenwaldring 43, D-70569 Stuttgart, Germany
K. Lackner
Affiliation:
Max-Planck-Institut für Plasmaphysik, Boltzmannstr 2, D-85748 Garching, Germany
*
†Email address for correspondence: hartmut.zohm@ipp.mpg.de
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Abstract

We present a new model for the generation of thermoelectric currents during laser welding, taking into account sheath effects at both contact points as well as the potential drop within the quasi-neutral plasma generated by the laser. We show that the model is in good agreement with experimentally measured electric potential difference between the hot and the cold parts of the welded workpiece. In particular, all three elements of the model are needed to correctly reproduce the sign of the measured voltage difference. The mechanism proposed relies on the temperature dependence of the electron flux from the plasma to the workpiece and hence does not need thermoemission from the workpiece surface to explain the experimentally observed sign and magnitude of the potential drop.

Type
Research Article
Information
Journal of Plasma Physics , Volume 81 , Issue 1 , January 2015 , 905810109
Copyright
Copyright © Cambridge University Press 2014 

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References

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