Inventors:
Jason Robert Parolini - Greer SC, US
Gregory Keith Bouse - Greer SC, US
Subrahmanyam Thangirala - Schenectady NY, US
Scott Denton Thomason - Greer SC, US
Junyoung Park - Greer SC, US
Assignee:
GENERAL ELECTRIC COMPANY - Schenectady NY
International Classification:
C21D 5/00, C22C 37/00, B22D 13/02
Abstract:
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. The method entails casting a ductile iron alloy containing iron, carbon, silicon and alloying constituents. The casting is solidified at a rate that inhibits segregation of the alloying constituents to grain boundaries of the casting, and so that the casting contains graphite nodules having a count of greater than 100 nodules per mm. 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.