Papers Published in Conferences

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Abstract
The ongoing growth of the Brazilian oil industry has increased interest in underwater welding processes due to the need for marine structure construction and repair. In particular, underwater wet welding enables the production of joints in direct contact with water, reducing costs and operational time. However, hydrostatic pressure and the environment compromise the mechanical properties of the weld. Furthermore, as a manual process, productivity and diver safety are significantly affected. In this context, Underwater Wet Flux-Cored Arc Welding technology has emerged as an alternative for maintenance work in underwater environments. The continuous consumable feed improves productivity and weld bead deposition quality while also offering automation potential, overcoming the challenges of conventional Shielded Metal Arc Welding. This work presents the development of a self-shielded flux-cored wire with 60% nickel by weight. Nickel is a key element in enhancing the mechanical properties of the weld metal, as it reduces the diffusible hydrogen content, thereby minimizing the risk of cold cracking. Weld beads were produced using a constant voltage welding source. A factorial experimental design was adopted, considering two factors at two levels, depth (0.3 m and 30 m) and polarity (direct and inverse). The key results indicated that arc stability deteriorated with increasing depth, especially in Direct polarity. The predictive model for diffusible hydrogen revealed higher values in direct polarity and with increased welding current. Moreover, cross-sectional porosity and oxygen content in the weld metal were higher at 30 m depth. It was concluded that the developed flux-cored wire demonstrated good operational performance as a consumable for wet welding, exhibiting satisfactory weldability and acceptable surface quality in shallow water. Additionally, the diffusible hydrogen content was comparable to that of austenitic consumables reported in literature and lower than that of rutile and basic consumables. Finally, this study suggests further investigation into welding parameters variation to enhance weldability and weld bead quality at greater depths.
Keywords: Self-shielded flux-cored wire, diffusible hydrogen, nickel-based, weld bead porosity, austenitic consumable.

Referência:
GONZALEZ, O. M. C.; URIBE, A. M. M.; ARIAS, A. R.; SILVA, R. H. G.; QUINTANA, D. S.; LOBO, E. J. S.. Polarity and depth effects in wet welding performance using a Nickel-based tubular wire. 28th ABCM International Congress of Mechanical Engineering (COBEM), November 9-14, 2025. Curitiba, PR, Brazil. doi://10.26678/ABCM.COBEM2025.COB2025-2760