To provide a method by which properties of a component formed of a ductile iron alloy and having thick sections can be promoted with an austempering process.
In the method, when casting the ductile iron alloy 24 containing Fe, C, Si and alloying constituents, the casting is solidified at a rate that inhibits segregation of the alloying 24 constituents to grain boundaries of the casting, and so that the casting contains graphite nodules having a count of greater than 100 nodules per mm2. The casting is then austempered by heating to an austenitization temperature to yield a microstructure having a single-phase matrix of austenite that contains carbon, and then quenching the casting to an austempering temperature. The casting is held at the austempering temperature for a duration sufficient to yield a microstructure whose matrix is mostly ausferrite and essentially free of martensite and pearlite.
BOUSE GREGORY KEITH
THANGIRALA SUBRAHMANYAM
THOMASON SCOTT DENTON
PARK JUNYOUNG
Hirokazu Ogura
Toshihisa Kurokawa
Takuto Tanaka