Estudo da resistência ao desgaste abrasivo de ferros fundidos brancos alto cromo e molibdênio

• Ano de defesa: 2006
• Autor(a) principal: Regattieri, Cíntia Nunes Braga
• 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: Ferro fundido; Molibdênio; Fundição; Engenharia Mecânica; 621
• Link de acesso: http://repositorio.ufes.br/handle/10/4194

The performance of high chromium white cast iron (HCWCI) reggarding abrasive wear is a function of both the materials microstructure and properties and the tribosystem parameters. Thus, this work intends to evaluate the effects of chemical composition and tribological conditions on the wear resistance of HCWCI with different molybdenum contents (0, 3, 6 and 9 wt%). Twenty different alloys were estudied with a fixed Cr/C ratio of 10. The chromium contents were 16, 20 and 24 wt% for the hypoeutectic, 28 wt% for the eutectic and 32 wt% for the hypereutectic alloys. The abrasive wear resistance were evaluated by pin-on-disk (two-body configuration) and three-body abrasive wear tests. For the two-body configuration, the alloys with ferritic and perlitic matrix showed the highest wear rates. The wear rates of Mo free alloys tested with a in three-body configuration test increased with the chromium content. For the compositions with Mo alloying, the behavior abrasive was almost the same, except for the hypereutectic alloys with higher wear rates. The micro mechanisms involved were analyzed. For the two body tests (pin-on-disc), the worn samples surfaces showed micro cutting as prevailing micro mechanism. Differences between the alloys were detected by differences in both the intensity and depth of grooves and the inter groove region morphology. Multiple ductile indentations covered almost the totality of the worn surfaces in the threebody tests, except for the hypereutectic alloys (6 and 9 % Mo), which presented a brittle micromechanism detected by detachment and cracking of carbides.