Patent ID: 8968497
Filing Date: 2015-03-03
Classification: C21D,F03D,F05B,F05C,Y02E,Y02P

Abstract:
1. A method of making a ductile iron article, comprising: providing a ductile iron article preform; deforming the ductile iron article preform by hot-working to provide a hot-worked portion of the ductile iron article preform, the hot-working performed at a temperature above a eutectoid temperature of the ductile iron to provide a microstructure of stable austenite; cooling the ductile iron article preform to an austempering temperature; austempering the ductile iron article preform for a predetermined time sufficient to provide an austempered ductile iron article preform comprising an austempered microstructure; and ausforming the ductile iron article preform after cooling and prior to the predetermined time to provide an ausformed portion of the ductile iron article preform, wherein the austempered microstructure of the hot-worked portion and the ausformed portion are different than in other portions of the austempered ductile iron article preform, and wherein the different austempered microstructure of the hot-worked portion and the ausformed portion comprises at least one of a refined acicular ferrite phase having a reduced platelet width, a shape of deformed graphite nodules, or a reduced porosity, as compared to the other portions of the austempered ductile iron article preform.