Estudo do desgaste por deslizamento de ligas de cobalto

• Autor(a) principal: Falqueto, Leandro Entringer
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/9806
• topic: Sliding wear; Cobalt alloys; Supermartensitic stainless steel; Desgaste por deslizamento; Ligas de cobalto; Aço inoxidável; Supermartensítico; Ligas de cobalto; Aço inoxidável; Engenharia Mecânica; 621

Cobalt alloys are used in many industrial applications due to their good mechanical properties at high temperatures. Duringsupermartensitic stainless steel 13%Crseamless tubes manufacturing by Mannesmann process, the hot rolling guides, made of Co-Cr-Fe alloy, have a severe wear. To increase the life of these components, sliding wear tests were performed at room temperature and 500 °C inpin-on-disc configuration, without lubrication and varying the normal load. The pin was made ofsupermartensiticstainless steel 13%Cr. The discs were fabricated with the Co-Cr-Fe alloy. In addition to this, three coatings, Stellite 1, 6 and 12, applied by laser claddingprocess, were investigated, with a total of four materials. The wear surface was analyzed as to the worn volume through 3D profilometry. The micromechanisms were observed with a stereoscopic and scanning electron microscope. And, to assess the elemental composition of the wear track, analyzes were performed by energy dispersive spectroscopy. The results indicate that the samples coated with Stellite showed a betterperformance than the Co-Cr-Fe alloy. And, among the coatings, the Stellite 1 showed the best wear resistance, both at room temperature as in the tests performed at 500 °C. The Co-Cr-Fe, Stellite 6 and 12alloyspresented constitutively plasticmicromechanisms. WhereasStellite 1presented oxidative wear. In tests performed at room temperature, Co-Cr-Fe, Stellite 6 and 12alloyspresented a friction coefficient close to 0.3 for most normal loads. And, in the tests performed at 500 °C, in general, the coefficient of friction of all alloys showed an increasing trend with the increase of normal load