Visualization of Submerged Arc Welding Phenomena by X-ray Observation and Direct Observation

Abstract

Behaviors of flux, slag and molten metal during a submerged arc welding with a large current were observed by the X-ray observation system including a high speed video camera. Moreover, the direct observation using a high speed video camera was also carried out to observe the arc phenomena, which could not be observed by the X-ray observation. From X-ray observation results, the weld part during a submerged arc welding was classified broadly into 4 regions. Then, it was clarified that a slag was pushed backward in a welding direction when it approached to a wire which an arc plasma existed around. As a result of this series of slag behaviors, the preformed cavity was filled by the slag at the backward of the heat source. In addition, from a direct observation, it was made clear that there were bluish white plasma at beneath a molten metal droplet and orange emitting region around the plasma.

Progress of computational plasma fluid mechanics

“…8,9,[111][112][113][114][115][116][117][118] The molten metals produced during arc welding have also been investigated. The melting and deforming behaviors of weld pools and molten fluxes in SA welding were captured by an Xray transmission imaging technnique 119,120) to support the mechanism clarifications. 121,122) The deforming behaviors of molten electrodes were observed directly using high-speed video recording during a SA welding 120) and a GTA welding.…”

“…The melting and deforming behaviors of weld pools and molten fluxes in SA welding were captured by an Xray transmission imaging technnique 119,120) to support the mechanism clarifications. 121,122) The deforming behaviors of molten electrodes were observed directly using high-speed video recording during a SA welding 120) and a GTA welding. 123,124) Especially in a GTA welding, the transport of emitter additives in a tungsten electrode is also important because it affects the stability of arc discharge and the lifetime of the electrode.…”

Visualization of electromagnetic-thermal-fluid phenomena in arc welding

“…Li et al 23) also conducted a similar observation using a tunnel and a laser light source. Komen et al 24) performed high-speed observations with not only a similar tunnel but also an X-ray system. They revealed that a slag was formed and pushed backward when it approached a wire.…”

High speed X-ray observation of digital controlled submerged arc welding phenomena

“…Recently, direct observations have been made in order to elucidate welding phenomena during SAW. In 2015, Mendez et al observed droplet transfer in the cavity [19] formed by evaporated flux using an iron tunnel orthogonal to the welding direction [20], followed by the similar approach of Komen et al [21]. In 2016, Reisgen et al observed droplet transfer during SAW through heat-resistant glass set parallel to the welding direction.…”