Analysis of metal transfer and weld forming characteristics in triple-wire gas indirect arc welding

Abstract

Triple-wire gas indirect arc welding (TW-GIA) has the advantages of low heat input and high deposition rate. However, the simultaneous melting of triple wires makes the metal transfer mode complicated. The unknown of the metal transfer mode restricts the development of this technology. In this paper, high-speed camera systems and electrical signal acquisition sensors were used to explore the TW-GIA metal transfer mode. The static force model and the arc conductive channel model were used to discuss the droplet force and energy conversion characteristics respectively. Results showed that the TW-GIA metal transfer modes can be divided into: short-circuit transfer (SCT), main wire projected transfer + side wire globular transfer (PGT), main wire streaming transfer + side wire projected transfer (SPT) and main wire streaming transfer + side wire streaming transfer (SST). Moreover, the process parameter ranges corresponding to the four modes were summarized. Due to the stable arc and the uniform metal transfer process, SPT and SST can form desirable weld seam. The gravity and z-axis components of electromagnetic force are the main forces that promote metal transfer.The x-axis and y-axis components of the electromagnetic force deviate the metal transfer path from the arc coverage. Due to the change of arc conductive channel, the energy transferred from TW-GIA to the base metal is less than that of GMAW, showing the advantages of small welding deformation, narrow heat affected zone and grain refinement. KeywordsTriple-wire gas indirect arc welding•metal transfer•energy conversion•arc conductive channel

Effects of Oscillation Width on Arc Characteristics and Droplet Transfer in Vertical Oscillation Arc Narrow-Gap P-GMAW of X80 Steel

“…Lassaline et al [17] carried out welding experiments with double-wire narrow-gap welding with a bent conductive nozzle. Liu et al [18,19] placed a tungsten electrode arc after the triple-wire indirect arc for narrowgap welding, which led the weld bead surface to transform from a convex to a concave shape. An oscillation laser is also used in narrow-gap welding, and the influence of laser oscillation parameters on weld forming, the relationship between groove width and lack of fusion and the microstructure and mechanical properties of welded parts have also been studied by scholars [20][21][22][23].…”

The Influence of Oscillation Parameters on the Formation of Overhead Welding Seams in the Narrow-Gap GMAW Process

“…Yang and Guo et al [16,17] optimized the narrow-gap welding torch with a rotating arc. Liu et al [18][19][20] designed a narrowgap gas shielded three-wired indirect arc welding torch, greatly improving the welding efficiency. After the narrow-gap three-wired indirect arc, a tungsten electrode arc was used, making the convex shape of the weld surface change into a concave shape.…”

Effect of Increasing Oscillation Width on the Arc Characteristics and Droplet Transfer Behavior of X80 Steel in the Overhead Welding Position of Narrow Gap P-GMAW

“…Li et al [39,40] established a prediction model for sidewall penetration in rotating arc narrow gap MAG welding with support vector machines, which can be used for penetration control. In addition, methods such as laser-arc hybrid welding [41][42][43], dual-wire or triplewire welding [44][45][46], and magnetic field-assisted welding [47,48] have also been used in narrow gap welding processes. A series of research studies focusing on arc characteristics, droplet transfer, process parameter optimization [49], oscillating arc, rotating arc, multiwire welding, hybrid welding, and magnetic field-assisted welding have significantly optimized weld formation and improved welding efficiency.…”