Effects of flux bands on arc stability in flux bands constricting arc welding

Abstract

In this study, a new energy efficient welding method called flux bands constricting arc (FBCA) welding was presented. A real-time electrical signal acquisition system and a high-speed camera system were proposed to understand the arc stability in FBCA welding. In ultra-narrow gap groove, the arc voltage and welding current in gas metal arc welding and FBCA welding experiments with various groove gaps (4–10 mm) were acquired. The dynamic characteristics, probability distributions, scatter graphs, and coefficients of variations of voltage and current during welding were adopted to determine the arc stability. Results indicate that flux bands considerably improve the arc stability in the ultra-narrow gap (<10 mm), and the arc stability in FBCA welding deteriorates with the decrease in groove gap. Metal transfer images in FBCA welding show that two metal transfer modes (short-circuiting and flux-wall guided transfers) exist in FBCA welding. The frequent arc extinction caused by the high proportion of flux-wall guided transfer is the main reason of poor arc stability in extreme narrow gap (<4 mm).