Research on bead width and penetration depth of multicomponent flux-aided arc welding of grade 316 L stainless steel

Abstract

This work investigated the influence of a multicomponent flux on the bead width and penetration depth of grade 316L stainless steels subjected to gas tungsten arc welding (GTAW) and plasma arc welding (PAW). Powdered oxide/fluoride mixture mixed with single or multicomponent solvent was used as the flux. This paper also discusses the potential mechanism leading to the increase in joint-penetrating capability with use of the flux during PAW, and it compares results obtained with flux-aided GTAW (F-GTAW). The results indicate that a 60% methanol/40% water or a 40% acetone/60% water is an appropriate solvent mixture for mixing with the multicomponent powders. Compared with GTAW, which formed a shallow and wide profile, F-GTAW, PAW, or flux-aided PAW (F-PAW) formed a deep and narrow profile. F-GTAW produced a weld cross-sectional profile similar to that produced by PAW. The influence of the flux on the geometry of the PA weld was not as pronounced as that on the geometry of the GTA weld. The results of our study suggest that a 30% SiO2, 25% TiO2, 20% ZnO, 12% NiO, 5% MgO, 3% Cu2O and 5% FeF2 flux not only substantially improves the joint penetration of the GTA weld, but it also produces a PA weld with a more uniform cross-sectional profile.