The transition from stable to metastable system and its relation with the ferrite halo extension in SG cast irons

ABSTRACT

Microsegregations of alloying elements developed during solidification are known to affect solid state transformations in spheroidal graphite cast irons. However, no clear relation between them and the presence and extension of ferrite halos has been established until now. The aim of the present work is to expose how the microsegregations of Si, Mn and Cu influence in the transition from stable to metastable system during solid state transformations and how the extension of the ferrite halo is affected accordingly. The study was carried out on samples cast at a cooling rate of 20 K/min, which allowed the diffusion of carbon under equilibrium conditions.

KEYWORDS:

• Spheroidal graphite cast irons
• ferrite halo
• microsegregations
• eutectoid critical temperatures

Acknowledgements

The authors would like to thank the Sánchez and Piccioni company for allowing the authors using its facilities to carry out the casts. Laura N. García and Fernando D. Carazo are members of CONICET and would like to thank the institution for the provided economic support.