Parametros termicos e estruturais em ferros fundidos cinzento e nodular solidificados em moldes de areia e unidirecionalmente / Thermal and structural parameters in gray and ductile cast irons solidified in sand molds and under unidirectional conditions

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

In the present work unsteady state unidirectional solidification of a hypoeutectic gray cast iron and of a eutectic ductile cast iron is applied to analyze the influence of the process parameters an the flake and nodule count. For comparison purpose some samples were cast in sand molds. The experimental results of temperature variation in the casting were used to estimate the variations of solidification parameters. From the results curves relating flake and nodule count and solidification rate and flake and nodule count and cooling rate were obtained indicating that the number nodule decreases and their dimensions increase as these parameters decreases. From the results obtained relations were established between these parameters. The results showed that nodule count observed for unidirectional solidification far from metal/mold interface approaches to the observed in sand mold, permitting to analyze the influence solidification parameters an the microstructure formation far almost all foundry processes of these alloys. Some measurements of hardness variations from metal/mold interface were carried out indicating that far gray cast iron hardness decreases and for ductile iron increases as solidification rate decreases

ASSUNTO(S)

microestrutura solidification solidificação cast iron ferro fundido microstructure

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