The effect of low pressure carburizing (LPC) on two low alloyed sintered steels processed according to different routes to obtain different amounts of open porosity was studied. In presence of an open porosity, overcarburizing promotes the precipitation of grain boundary carbides in the Cr steel, and the formation of retained austenite in the Cr free one. In presence of a fully closed porosity LPC results in the formation of a homogeneous case. Even a slight amount of open porosity causes overcarburizing. In absence of overcarburizing, impact toughness is typical of a brittle behavior, as expected. However, an unexpected high toughness is measured in the supercarburized steel containing retained austenite.
Microstructure, microhardness and impact toughness of low pressure carburized PM steels
Menapace, Cinzia;Molinari, Alberto;
2011-01-01
Abstract
The effect of low pressure carburizing (LPC) on two low alloyed sintered steels processed according to different routes to obtain different amounts of open porosity was studied. In presence of an open porosity, overcarburizing promotes the precipitation of grain boundary carbides in the Cr steel, and the formation of retained austenite in the Cr free one. In presence of a fully closed porosity LPC results in the formation of a homogeneous case. Even a slight amount of open porosity causes overcarburizing. In absence of overcarburizing, impact toughness is typical of a brittle behavior, as expected. However, an unexpected high toughness is measured in the supercarburized steel containing retained austenite.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione
