Austempered Ductile Iron Castings for Chassis Applications

Austempered ductile iron (ADI) castings provide a unique combination of high strength and toughness coupled with excellent design flexibility for chassis applications.

This paper describes the development of the upper control arm for the 1999 Ford Mustang Cobra as an austempered ductile iron casting. The full service development process used is described from initial design through finite element analysis (FEA), design verification, casting production, heat treatment, nondestructive evaluation and machining. To achieve significant weight savings, an austempered ductile iron casting was chosen for this application instead of an as-cast SAE J434¹, Grade D4512 ductile iron casting or a steel forging.

This is believed to be the first application of an austempered ductile iron casting for a safety critical, automotive chassis application.