Nitrogen concentrations above Sieverts Law calculations are observed in steel weldments in the presence of a plasma.Understanding of this enhanced dissolution of diatomic gases into the weld metal during high energy density welding operations has been recently improved with the development of the "two temperature" model.This model provides a framework for the calculation of the enhanced solubility of nitrogen based on knowledge of the surface temperature and a hypothetical dissociation temperature for the diatomic nitrogen species.At present,there is no unified methodology to determine this hypothetical dissociation temperature.The goal of this work is to better understand the interaction between the plasma phase and the weld pool surface in order to more accurately determine the enhanced nitrogen solubility from fundamental principles.
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