Nitriding effect on fatigue resistance of grey and nodular cast irons

Data de publicação
International Heat Treatment and Surface Engineering
Citações (Scopus)
Neves Penha R.
Morilla J.C.
Vatavuck J.
Canale L.C.F.
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The influence of nitriding on the fatigue resistance of grey and nodular (ductile) cast iron piston rings was studied for six chemical compositions. The selected materials include three grey cast irons: one with a mixed initial microstructure (martensite plus bainite), the second martensitic and another martensitic alloyed with niobium; and three nodular cast irons: one common nodular cast iron, the second alloyed with Nb and another alloyed with Al and V. These materials were gas nitrided for 3 and 6 h. The relationship between the mechanical behaviour and the treatment time (depth of nitrided layer) was established. Samples were tested under a cyclical bending load. The stresses were determined in the cross-section, where the biggest moment was experienced. Results were statistically treated by means of Weibull analysis. Nitriding showed that fatigue resistance of grey cast iron with a martensitic structure is higher than that of a mixed structure. Fatigue resistance of nodular cast irons is reduced due to nitriding. © 2012 IHTSE Partnership Published by Maney on behalf of the Partnership.
Assuntos Scopus
Chemical compositions , Cyclical bending , Fatigue Limit , Grey cast iron , Martensitic structures , Mechanical behaviour , Mixed structure , Nitrided , Nitrided layer , Treatment time , Weibull analysis