Efeito da polaridade sobre a morfologia e estabilidade de soldas subaquáticas molhadas com eletrodos E6013 e WW70

• Ano de defesa: 2018
• Autor(a) principal: Andres Mauricio Moreno Uribe
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia mecânica; Eletrodos; Estabilidade; Soldagem subaquática
• Link de acesso: http://hdl.handle.net/1843/BUBD-AYNKRF

Underwater Wet Welding (UWW) is a repair solution for semi-submersible structures and shipyards. Specifically, the application of this technology with coated electrodes ensures lower costs and reduces maintenance times compared to other welding processes used in the offshore area. Thus, it is of great technological importance the knowledge of the phenomena involved in this process. On the one hand, the welds made in the air show greater penetration in the configuration of reverse polarity For this reason, in this research we looked for indications of the effects of the conditions and parameters of the process under the penetration. In the development of this project, welds were made at the simulated depths of 5 m and 10 m and thus, compared to welds made at atmospheric pressure. In addition, with the use of macrographs and stability indexes, the behavior of the cord under the influence of water and the inherent problems of this environment were reported: typical instability of the process at low depths, dissociation of water molecules and its effect under the final composition of the weld metal, etc. In this last specific point, chemical analyzes were carried out with the aim of better structuring the knowledge that has been under the behavior of the consumables. One of the electrodes, the WW70 is a consumable developed in a partnership between the Brazilian industry and the academy. This electrode provides much superior characteristics compared to other commercial consumables and is still in the study and development stage, because it is an electrode made specifically for underwater wet welding. Also, the electrode E6013 was used as reference point to compare the performance of the experimental consumable. As a main result, with the use of electrode E6013, welds in aquatic environment present higher penetration and lower melting rate in direct polarity; however, welds made with the oxyrutilic electrode (WW70), exhibit the highest penetration values for the electrode configuration at the positive pole. Also, the hydrostatic pressure affects the metal transfer and the stability of the wet underwater welding process