Free Ferrite morphology and mechanical properties of ferritic-ausferritic spheroidal graphite cast iron

A. BASSO; R. BOERI; M. CALDERA; J. MASSONE

Jonkoping

Congreso; 11th International Symposium on the Science and Processing of Cast Iron; 2017

The first stage of this study investigates the precipitation of ferrite from the austenite upon furnace cooling of spheroidal graphite cast iron fully austenitized. Several sets of samples of low alloy SGI are austenitized into the austenite + graphite temperature field, to be then cooled down to different temperatures within the intercritical alpha-gamma-graphite field. For each holding temperature, samples are extracted and quenched in water after different times. The kinetics of precipitation of ferrite and its morphology are characterized by optical metallography. The time and temperatures that lead to a fine dispersion of a desired amount of ferrite are identified. Based on these results, heat treatment cycles were performed on tensile, impact and toughness samples. Very good mechanical properties are obtained on the examined chemical composition. The heat treatment appears to be applicable to industrial production requirements.