Tecnologia em Metalurgia, Materiais e Mineração
https://www.tecnologiammm.com.br/article/doi/10.4322/tmm.2013.043
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

DESENVOLVIMENTO DE NOVOS AÇOS VÁLVULA PARA APLICAÇÃO EM MOTORES DE ALTO DESEMPENHO

DEVELOPMENT OF NEW VALVE STEELS FOR APPLICATION IN HIGH PERFORMANCE ENGINES

Farina, Alexandre Bellegard; Liberto, Rodrigo Cesar N.; Barbosa, Celso Antonio

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Resumo

As ligas UNS N07751 e UNS N07080 são comumente utilizadas na fabricação de válvulas automotivas para motores de combustão interna de alto desempenho. Estas ligas apresentam elevada resistência mecânica a quente, à oxidação, à corrosão, à fluência e estabilidade microestrutural. No entanto, estas ligas apresentam baixa resistência ao desgaste e elevado custo devido aos altos teores de Ni. Neste trabalho é apresentado o desenvolvimento de duas novas ligas de Ni para aplicação em válvulas automotivas de alto desempenho alternativas às ligas UNS N07751 e UNS N07080. As novas ligas desenvolvidas baseiam-se em uma matriz austenítica de alto teor de cromo e níquel com dispersão das fases γ’ e γ’’ e quantidades diferentes de NbC. Devido à redução dos teores de Ni nestas ligas em relação às ligas atualmente utilizadas, as novas ligas apresentam grande vantagem econômica para substituição das ligas UNS N07751 e UNS N07080.

Palavras-chave

Ligas de níquel, Aços válvula, Caracterização, Válvulas automotivas

Abstract

UNS N07751 and UNS N07080 alloys are commonly applied for automotive valves production for high performance internal combustion engines. These alloys present high hot resistance to mechanical strength, oxidation, corrosion, creep and microstructural stability. However, these alloys presents low wear resistance and high cost due to the high nickel contents. In this work it is presented the development of two new Ni-based alloys for application in high performance automotive valve as an alternative to the alloys UNS N07751 and UNS N07080. The new developed alloys are based on a high nickel-chromium austenitic matrix with dispersion of γ’ and γ’’ phases and containing different NbC contents. Due to the nickel content reduction in the developed alloys in comparison with these actually used alloys, the new alloys present an economical advantage for substitution of UNS N07751 and UNS N0780 alloys.

Keywords

Ni-based alloys, Valve steels, Characterization, Automotive valves

Referências



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