Estudo da corrosão de aços-carbono e patinável durante 39 meses de exposição em ambiente marinho-industrial

• Ano de defesa: 2007
• Autor(a) principal: Leite, Leandro Alberto Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Engenharia Mecânica; Centro Tecnológico; UFES; Programa de Pós-Graduação em Engenharia Mecânica
• Palavras-chave em Português: Aço-carbono; Aço - Corrosão; Engenharia Mecânica; 621
• Link de acesso: http://repositorio.ufes.br/handle/10/6232

Following the results presented by OLIVEIRA (2002), in which the corrosive process analysis was carried out after 4 months exposition, the corrosion pattern for longer periods of exposition under similar geo-environmental conditions is investigated by this present work. ASTM A36 and ASTM A242 steel samples were exposed during 39 months in two industrial marine sites located in the southern shore of Espírito Santo State. Meteorological conditions were monitored and SO2 concentration was tested during the exposition period. Mössbauer s spectroscopy was used to characterize the corrosion outcomes. The samples from both sites presented similar composition, with emphasis to α-FeOOH. Smaller fractions of γ- FeOOH, Fe3O4, γ-Fe2O3 and α-Fe2O3 were also observed, being the latter originated from the particulates precipitated from the surrounding environment. Corrosion rates and thickness losses were determined through mass loss essays. The ASTM A36 steel sample showed steeper curves as function of time and always superior to those found for the weathering steel in both sites, especially for the area with higher SO2 concentration. ASTM A242 steel presented specific results for each site. In the less aggressive site, it showed a more stable corrosion process with good formation of protective rust layer and mass loss of around 2% in mass, whilst at the other site it presented similar pattern as the ASTM A36 steel, although less intense. Finally it was determined the industrial applicability of the ASTM A242 steel at regions with lower concentration of sulfates