Visualizations and Predictions of Welding Arcs

Abstract

This paper gives the latest trends in research of welding arcs. The recent progress of the visualization and prediction of welding arcs, though the dynamic observations of spectral image by a high speed digital video camera with a monochromator and also the calculations by numerical models, is shown. The dynamic visualizations lead to understanding of metal vapor behavior in arc plasma, for example, the separation of metallic elements in plasma during TIG welding and the temperature minima at arc axis in MIG welding, and also lead to improvement of numerical models. The numerical models of welding arcs, using plasma physics with the basic conservation equations of mass, energy, momentum and current, give predictions of arc plasma temperatures, melting rates of welding wire, droplet temperatures, heat intensity distributions to base metal, temperatures of weld pool surface, evaporation rates of metal vapor, weld pool profiles, heat efficiencies, formations of fume, and so on. All of predictions lead to quantitative understanding of phenomena in welding arcs. The visualizations and predictions of welding arcs will lead to technological innovation for a new system of arc welding process.

Keywords: Arc, Plasma, Metal vapor, Spectroscopic analysis, Numerical calculation, TIG, MIG, Welding