抄録
The electric current direct heating technique enables the production of ADI at a reduced processing time. In this study, in order to apply this method for ferrite matrix ductile cast iron in which carbon does not diffuse sufficiently into austenite under short heating, the effect of contained graphite characteristics on quick austempering process was examined. Microstructures of ADI obtained through the above technique strongly depend upon the characteristics of spheroidal graphite in supplied ductile iron. The banite structure domain expands as the size of each graphite decrease and its count increases even when the graphite area fraction is the same. It is clear that quick austempering based on direct electric current supply is applicable for ferrite structure ductile cast iron by controlling the graphite size. Consequently, an ADI with excellent mechanical properties can be produced successfully even from ferrite based ductile cast iron by quick austempering.
