Gas nitrided stainless steel with reduced hardness gradient to high loaded and corrosive environment
Tipo
Artigo de evento
Data de publicação
2010
Periódico
65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010
Citações (Scopus)
1
Autores
Marques G.A.
Ferrarese A.
Bruno R.A.
Vatavuk J.
Ferrarese A.
Bruno R.A.
Vatavuk J.
Orientador
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Título de Volume
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Programa
Resumo
The nitrided stainless steel is applied on engine components in order to reduce the wear under operation. One application of this is on piston rings. Using the gas nitriding process it is the main application on the top compression rings in Europe and Mercosul. This application is the one with worst tribological conditions once it is near to the combustion chamber exposed to the highest mechanical and thermal loads. When the engine is designed to run with Ethanol in a flex fuel design, the mechanical load increases between 20 to 30% and the sub-products of combustion presents higher corrosion characteristics then when it is run with gasoline. It is also observed a mechanism of detachement called spalling in the mentioned running conditions. Under this agressive environment it was designed a new stainless nitriding treatment in order to improve the toughness through specific hardness gradient. Such development not only reorganized the hardness gradient but also redistributed the carbides in a different arrangement than current process. This arrangement eliminated the occurrances of "angel hair" which also improved the toughness of the nitrided layer. Rig tests and engine tests were conduced in order to evaluate fatigue, scuffing and wear resistance of the developed treatment when applied in a top compression ring of flex fuel engines running with Ethanol.
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Assuntos Scopus
Corrosion characteristics , Corrosive environment , Engine components , Gas nitriding process , Gasnitriding , Nitriding treatment , Running conditions , Tribological conditions