On the Visualization of Gas Metal Arc Welding Plasma and the Relationship Between Arc Length and Voltage

• Published in: Applied sciences 2017-05, Vol.7 (5), p.503
• Main Authors: Dos Santos, Emanuel, Kuroiwa, Letícia, Ferreira, A., Pistor, Rob, Gerlich, Adrian
• Format: Article
• Language: English
• Subjects: arc length; arc plasma; arc voltage; Bandpass filters; Cameras; Electric potential; Electric wire; Electrical conductivity; Electrical resistivity; Electrodes; Engineering; Evaporation; Filters; GMAW; High current; High speed; high speed imaging; Image acquisition; Imaging; Iron; iron vapor; Light sources; Metals; Plasma; Plasma arc welding; Plasma temperature; Temperature effects; Visualization; Welding
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app7050503

In this article, the camera settings for high-speed imaging of the arc, metal transfer, and weld pool in gas metal arc welding (GMAW) are investigated. The results show that by only changing camera exposure times and the selection of narrow bandpass filters, images that reveal features of the arc such as the iron vapor-dominated region, metal transfer and weld pool behavior can be produced without the need for external light sources. Using the images acquired, the arc length was measured and the relationship between arc length and arc voltage is discussed. The results show that for low values of current, the measured welding voltage increases with increasing arc length; however, for high current values, the arc voltage increases even though the measured arc length becomes shorter. It is suggested that the increase in arc voltage for high values of welding current is due to the increased evaporation of the wire electrode which decreases the plasma temperature and consequently the arc plasma electrical conductivity.