Abstract: In materials selection, trade-offs occur on a variety of parameters. Although ferrous metals are not typically considered to be amongst the light weight metals, ductile iron is ten percent lighter than steel. In addition, if cost is a significant consideration, austempered ductile iron (ADI) is considered to have the best combination of strength:weight:cost ratio making it appropriate for use in many circumstances, particularly for automotive applications. In the past its use has been limited due to carbides frequently occurring below 6.35 mm thicknesses. Much research including ongoing efforts by the LIFT consortium (Lightweight Innovations For Tomorrow) have been expended into production methods of thin walled ductile iron. Existing methods in lost foam casting currently exist that prevent carbides with standard metallurgy practices. Several production examples are reviewed. In addition, details of trials that have been conducted achieving thicknesses down to 1.9 mm and prototypes for use as a replacement for stampings are covered.
Authors: Sarah Jordan and Mark DeBruin
Keywords: Light, Weight, Thin, Walled, Lost, Foam, Ductile, Iron, Evaporative, Casting, Austempered, ADI, Nodular