Influence of Interwire Distance and Arc Length on Welding Process and Defect Formation Mechanism in Double-Wire Pulsed Narrow-Gap Gas Metal Arc Welding

The effects of interwire distance (d) and arc length correction coefficient (C-c) on the arc behaviors, droplet transfer and welding process stability in the double-wire narrow-gap gas metal arc welding (NG-GMAW) were investigated. With d changing from 10mm to 20mm, the arc deflection only occurs at the background stage of pulsed welding current, and the droplet transfer mode keeps unchanged. A large C-c (20%) leads to serious peak arc deflection and unstable droplet transfer, whereas a small C-c (- 10%) eliminates the arc deflection and brings about short-circuiting droplet transfer. The arc interruption frequently occurs when d is 20mm or C-c is 20%. Moreover, when d is 10mm or C-c is 20%, serious sidewall arcs occur in double-wire NG-GMAW. With the increase in d and/or decrease in C-c, the welding process stability can be improved at first and then gets worse. In general, the trailing arc is more stable than the leading arc. Increasing C-c will result in a serious surface depression defect on the left side of the weld bead because of the serious peak arc deflection. A sound weld bead is obtained when the interwire distance is 15mm.

Automated summary

The study investigated the effects of interwire distance and arc length correction coefficient on arc behavior, droplet transfer, and welding process stability in double-wire narrow-gap gas metal arc welding. Adjusting d and C-c can improve or worsen the stability of the welding process and the quality of the weld bead.