· Metodos de moldeo y materiales ·
Simon N. Lekakh*, David G. C. Robertson* and Carl R. Loper Jr. **
*University of Missouri–Rolla, **University of Wisconsin-Milwaukee, U.S.A.
67th World Foundry Congress
Nodulization for producing spherical graphite in ductile iron (DI) and
inoculation for increasing graphite nodule count are the result of chemical
reactions of the additives with the melt. The multi-component equilibria
and the kinetics of additive dissolution in the melt were computed and
studied experimentally. Measurements of the oxygen activity confirmed
the calculated features of the refining reactions. Possible reaction paths
were identified, as ferrosilicon-based additives dissolved and reacted with
the iron melts. Adding more nuclei to the melt, by C/SiC melt pretreatment
and late additions of small amounts of oxides and sulfides, improved DI
inoculation. Intensification of inoculant dissolution by changing the additive
shape, and by argon stirring, were also investigated for increasing
inoculation efficiency.
